title: Marriage in Korea

text: "Love" marriage, as it is often called in South Korea, has become common in the past few decades. The expression refers to the marriage of two people who meet and fall in love without going through matchmakers or family-arranged meetings. Most often, the bride and groom first met on a blind date arranged by friends, on a group date, at their workplace, or while in college or university. South Korean families accept this type of marriage more readily than they used to.


title: Marriage in Korea

text: Historically, the divorce rate in South Korea was comparatively low before it began rapidly increasing in the mid-1990’s. The divorce rate peaked at 3.5 divorces per 1,000 people within the population, which is noted to be a higher rate than several European countries. The divorce rate in South Korea began to decline in the 2010’s, with a rate of 2.1-2.3 per 1,000. The South Korean population has generally shown conservative attitudes towards divorce but has increasingly shown open attitudes alongside the rising divorce rate. There is limited data available to determine the likelihood of remarriage after divorce in Korea.


title: Marriage in Korea

text: Studies have shown that marriages between a Korean national and foreign spouse are much more likely to divorce. Approximately 19% of marriages between a Korean husband and a foreign wife were dissolved within 48 months, while approximately 13% of marriages between a Korean wife and foreign spouse dissolved within 48 months. In comparison, only 6% of marriages between Korean nationals ended within 48 months. Studies also suggest that marriages between a Korean Husband and a foreign wife may have the highest rate of divorce due to their lower quality of married life. While less educated wives and husbands have an overall higher risk of divorce, foreign wives with a lower level of education face an extremely high risk of divorce in Korea.


title: Marriage in Korea

text: It has been noted that an increasing percentage of the Korean population end marriages at a later age. The average age of males and females who have filed for divorce rose to 50.1 and 46.8 in 2021. Within the last decade, the average age for males divorcing rose 4.7 years and the average age for females rose 5.2 years. The rate of divorce for other age groups declined in 2021, while those over sixty saw an increase, which is known as a “gray divorce”. Couples that have separated after living 30 or more years together increased 7.5 percent in 2021, which is more than double compared to the previous decade”.


title: Marriage in Korea

text: Korean law may dictate which spouse may file for divorce. The Supreme Court of Korea may not grant a divorce if the petitioner is found responsible for the breakdown of a marriage. If one spouse has committed an act of unchastity the other spouse may file for divorce. There are exceptions that include any serious cause that may make it difficult to continue a marriage. The Supreme Court of Korea does not completely rule out divorce that is petitioned by the spouse that was found to be at fault. Several other factors may be taken into consideration, such as the amount of time that has passed since separation and the feelings of the other spouse. A couple that mutually consents may be granted a divorce without court proceedings. Korean attorneys expect that Korea will move to a no-fault divorce system in the future. In 2015, the Constitutional Court decided that a law that made adultery a crime was unconstitutional.


title: Land Transportation Office (Philippines)

text: The Land Transportation Office (; LTO) is an agency of the Philippine government under the Department of Transportation responsible for all land transportation in the Philippines. Functions of the LTO include the inspection and registration of motor vehicles, issuance of licenses and permits, enforcement of land transportation rules and regulations, and adjudication of traffic cases.


text: Its primary mission is to rationalize land transportation services and facilities, and effectively implement various transportation laws, rules, and regulations. It believes that it is the responsibility of those involved in the public service to be more vigilant in their part in the over-all development scheme of national leadership. Hence, the promotion of safety and comfort in land travel is one of LTO's continuing commitments. It aims to be a frontline government agency that showcases fast and efficient public service for a progressive land transport sector.


text: In order to regulate and license of operators for motor vehicles in the Philippines, Act No. 2159 was enacted in 1912 under the American colonial Insular Government. This was the first formal law on land transportation in the country. It created the Automobile Section under the Administrative Division of the Bureau of Public Works.


text: In 1926, Act No. 3045 compiled and incorporated all laws governing motor vehicles. The Automobile Section was upgraded to the Automobile Division but still under the supervision of the Bureau of Public Works. Act No. 3992 (Revised Motor Vehicle Law) was enacted in 1933, amending Act No. 3045. The Automobile Division was renamed Division of Motor Vehicles.


text: In 1945, the Department of Public Works and Highways issued Department Order No. 4 for the reorganization of the Division. It took effect after the Philippines were liberated from the Japanese during World War II. Executive Order No. 94 was promulgated in 1947 reorganizing the different executive departments, bureaus, and offices. Under Section 82 of E.O. 94, the Division of Motor Vehicles was upgraded into the Motor Vehicles Office (MVO) with the category of the Bureau. However, the Motor Vehicle Office was abolished in 1964 by Republic Act No. 4136 or the Land Transportation and Traffic Code. The Land Transportation and Traffic Code was an act that compiled all the laws relative to transportation and traffic rules, to create a land transportation commission and for other purposes. This act was eventually replaced by the Land Transportation Commission. The Land Transportation Commission was tasked with the registration and operation of motor vehicles and the licensing of conductors and drivers. In order for the commission to effectively carry out its duty, regional offices were established in various parts of the country. Additionally, the powers, functions, and duties previously conferred on the Chief of the Motor Vehicles are now performed by the Land Transportation Commissioner.


text: During the Marcos dictatorship, Executive Order No. 546 was promulgated in 1979, creating the Ministry of Transportation and Communications (MOTC). The Land Transportation Commission was renamed into Bureau of Land Transportation and was absorbed into that ministry. The creation of the Board of Transportation and the Bureau of Land Transportation was nullified in 1985 by Executive Order 1011. The E.O. established the Land Transportation Commission, which was tasked to perform functions such as registering motor vehicles, licensing of drivers and conductors, franchising of public utility vehicles and enforcing land transportation rules and regulations.


text: The Land Transportation Commission was abolished in 1987, and two offices were created, namely the Land Transportation Office (LTO) and the Land Transportation Franchising and Regulatory Board (LTFRB). The LTO took over the functions of the former BLT while the LTFRB took over the functions of the BOT. The MOTC was likewise renamed as the Department of Transportation and Communications (DOTC).


text: The LTO is in charge of the issuance, renewal, and regulation of driver's licenses. It can issue licenses to both citizens and foreigners provided that they meet the requirements for those licenses. The LTO provides the non-professional driver's license, which allows holders to operate vehicles under the restriction codes 1,2, and 4. It also provides the professional driver's license, which allows the bearer to operate vehicles under all 8 restriction codes. The LTO also issues student permits (SP), which are a primary requirement for both the non-professional and professional driver's licenses. All applicants are also required to pass both a written and practical examination to be granted their license. The application process for any license or permit may be done at any LTO Licensing Center and District/Extension Office.


text: The LTO is responsible for the registration of motor vehicles and renewals. It can register brand new vehicles, including locally manufactured vehicles, imported vehicles, light electric vehicles, low speed vehicles, three wheeled vehicles, and tax exempt vehicles. Each category has an obligatory set of requirements and procedures to follow to be fully registered. Renewals are also obligated to submit the necessary requirements and to follow procedures to be fully renewed. The LTO also oversees miscellaneous transactions, specifically transactions requiring change of certificate of registration, and transactions that do not require the change of certificate of registration.


text: One of the main functions of the LTO is to strictly implement and enforce the laws regarding land transportation. Necessary requirements and procedures are to be followed in settlements of admitted cases and contested cases of motor vehicles, plates, and driver's licenses. The LTO also follows a strict procedure in settlements of impounded violations. It also allows private and for hire motor vehicles to apply for duplicate plates.


text: Furthermore, the LTO is in charge of ensuring that public land transportation services abide by the fares set by the LTFRB. It has sanctions for the overcharging and undercharging of fares, and for non-issuance of fare tickets.


text: The LTO grants accreditation to certain manufacturers, assemblers, importers, and dealers who wish to transact business with the LTO. A firm, person, or corporation must file an application for accreditation with Assistant Secretary of the Land Transportation Office containing certain requirements and qualifications in order to transact business with the LTO relative to Motor Vehicles or its components. It also issues the Certificate of Stock Reported (CSR) which certifies that a motor vehicle or its component has already been reported by its manufacturer, assembler, or importer to MAIDRS. The LTO also requires sales reports that inform the LTO that the reported stock is already sold to the end-user. Sales reports include regular sales transactions and stock transfers. It also reports the issuance of a single CSR, of Motor Vehicles (MVs) formed out of combining components (new, used, or previously registered) MV/MC that are undocumented in a procedure called special reporting. The LTO also maintains the processes that facilitate requests for the approval of the MAID office with LTO related transactions. Such transactions include the issuance of a conduction sticker, a public bidding of a motor vehicle, and the stamping of chassis identification number.


text: In 1987, under section 11 of Executive Order No. 125, the Regional Offices of the Land Transportation Commission were abolished and their functions were transferred to the Regional Offices for Land Transportation. The newly renamed Department of Transportation and Communication was placed under the authority of the Secretary of Transportation and Communication. As with the Land Transportation Commission before it, the Land Transportation Office is an office under the Department of Transportation and is headed by the Assistant Secretary for Land Transportation, who is appointed by the President upon the recommendation of the Secretary.


text: To service the entirety of the country, the LTO has established many branches in the different regions of the Philippines:


text: The Land Transportation Office is in charge of various projects which aims to improve its functions and mandates.


text: In 2012, the Department of Transportation and Communication and the Land Transportation Office introduced a project entitled the Land Transportation Office Infrastructure and Information System (LTO-IIS) which aims to utilize information and communication technology to enhance the functional efficiency of the LTO in the delivery of its front line services to the public and the performance of its mandate. LTO-IIS involves building an IT network for the LTO which can host and support its Front and Back Office Applications in order to computerize and automate its processes and services, develop its database information system, and provide interconnection between and among LTO offices nationwide. In short, the LTO-IIS serves as an efficient means to process motor vehicle registrations, renewal and application of drivers’ licenses and permits, back-end transactions, apprehensions, and such ancillary transactions or processes. This new LTO-IT system aimed to make accessing relevant vehicle information easier for authorities especially for tracing stolen vehicles while addressing issues including the involvement of third-party providers with key data such as vehicle registration. The IT system overhaul was estimated to cost P8.2-billion.


text: August 29, 2017 marked the beginning of the five-year validity of drivers' licenses cards issued by the LTO. Applications were accepted beginning October 2016 for driver's licenses as well as renewals with five-year validity, however, issues with the printers' contracts stalled the card printing for almost one year resulting in a backlog of 3.6 million driver's licenses which only began to be processed September 2017.


text: Republic Act (RA) No. 10930 effectively amended Section 23 of Republic Act No. 4136, otherwise known as the "Land Transportation (LTO) and Traffic Code" which was signed on August 2, 2017 by President Rodrigo Duterte to extend the validity of the driver's license from three years to five years. According to the law, "Except for student permits, all drivers' licenses shall be valid for five years reckoned from the birthdate of the licensee, unless sooner revoked or suspended."


text: This amendment also added that holders of nonprofessional and professional driver's licenses who do not commit violations in RA 4136 or any other traffic laws during the five-year period "shall be entitled to a renewal of such license of 10 years, subject to the restrictions as may be imposed by the LTO."


text: Besides the amendments to the law, new improvements to the quality and security of the license cards were introduced. The old cards with three-year validity were made from PVC, thermally printed, and had limited security features. The new plastic license cards are laser engraved and made of polycarbonate material which are more durable. The new cards also includes several new security features.


text: The Transportation Secretary, Arthur Tugade, and LTO chief Assistant Secretary, Edgar Galvante, led the official rollout.


text: The Land Transportation Office and their various constituent branches and offices are notorious for their corrupt employees who engage in the malpractice of hiring and colluding with ‘fixers’ to illicitly garner more income. Fixers litter the various branches of the LTO, offering faster and/or easier transactions and procurement of official LTO paraphernalia at a more expensive price than the standard fee. These fixers and their employers pocket the extra payment in exchange for placing a client higher up in the queuing system, falsifying official government documents, fabricating driving test and written test results, and many other illegal practices.


text: Section 11 of the Republic Act No. 9485 or the “Anti-Red Tape Act of 2007” lists fixing and/or collusion with fixers as a grave offense, with the penalty being dismissal and perpetual disqualification from public service. The fixers themselves can receive a penalty of imprisonment not exceeding six years or a fine not less than Twenty Thousand Pesos (P20,000.00) but not more than Two Hundred Thousand Pesos (P200,000.00) or both fine and imprisonment at the discretion of the court.


text: The Private Motor Vehicle Inspection controversy involved allegations of corruption that the 800-million Php fund fraud drying of the LTO-PMVIC wherein the charge of 1500-1800 Php for each private vehicle inspection another 900 Php in case it fails the first inspection and to give benefited high ranking officials and car inspection centers.


text: Senator Grace Poe vowed to recommend to the Senate blue ribbon an investigation into the alleged scandals and anomalies in the Private Motor Vehicle Inspection Centers (PMVICs), specifically on the deals of Department of Transportation (DOTr) with the private inspection centers.


text: Poe warned that passing the mandate of vehicle inspection from DOTr to the private sector may have legal infirmities.


text: The senator lamented that even without an exhaustive public consultation and public information campaign, DOTr and LTO still issued a memorandum order on December 29, 2020, directing the immediate implementation of PMVIC in the middle of the COVID-19 pandemic.


title: Juliette Gréco

text: Juliette Gréco (; 7 February 1927 – 23 September 2020) was a French singer and actress. Her best known songs are "Paris Canaille" (1962, originally sung by Léo Ferré), "La Javanaise" (1963, written by Serge Gainsbourg for Gréco) and "Déshabillez-moi" (1967). She often sang tracks with lyrics written by French poets such as Jacques Prévert and Boris Vian, as well as singers like Jacques Brel and Charles Aznavour. Her 60-year career came to an end in 2015 when she began her last worldwide tour titled "Merci".


title: Juliette Gréco

text: As an actress, Gréco played roles in films by French directors such as Jean Cocteau and Jean-Pierre Melville.


title: Juliette Gréco

text: Juliette Gréco was born in Montpellier, France, to an absent Corsican father, Gérard Gréco; her mother Juliette Lafeychine (1899–1978) was from Bordeaux. Her lineage hails in part from Greece. She did not receive love from her mother in her childhood and suffered from her harsh comments due to being an unwanted child, such as "You ain't my daughter. You're the child of rape". She was raised by her maternal grandparents in Bordeaux with her older sister Charlotte. After the death of her grandparents, her mother took them to Paris. In 1938, she became a ballerina at the Opéra Garnier.


title: Juliette Gréco

text: When World War II began, the family returned to the southwest of France. Gréco was a student at the Institut Royal d'éducation Sainte Jeanne d'Arc in Montauban. The Gréco family became active in the Resistance and her mother was arrested in 1943. The two sisters decided to move back to Paris but were captured and tortured by the Gestapo, then imprisoned in Fresnes Prison in September 1943. Her mother and sister were deported to Ravensbrück while Juliette, being only 16, remained in prison for several months before being released. After her release, she walked the eight miles back to Paris to retrieve her belongings from the Gestapo headquarters. Her former French teacher and her mother's friend, Hélène Duc, decided to take care of her.


title: Juliette Gréco

text: In 1945, Gréco's mother and sister returned from deportation after the liberation of Ravensbrück by the Red Army. Gréco moved to Saint-Germain-des-Prés in 1945 after her mother moved to Indochina, leaving Gréco and her sister behind.


title: Juliette Gréco

text: Gréco became a devotee of the bohemian fashion of some intellectuals of post-war France. Duc sent her to attend acting classes given by Solange Sicard. She made her debut in the play "Victor ou les Enfants au pouvoir" in November 1946 and began to host a radio show dedicated to poetry.


title: Juliette Gréco

text: Her friend Jean-Paul Sartre installed her at the Hotel La Louisiane and commented that Greco had "millions of poems in her voice". She was known to many of the writers and artists working in Saint-Germain-des-Prés, such as Albert Camus, Jacques Prévert and Boris Vian, thus gaining the nickname "la Muse de l'existentialisme".


title: Juliette Gréco

text: Gréco spent the post-Liberation years frequenting the Saint-Germain-des-Prés cafes, immersing herself in political and philosophical bohemian culture. As a regular at music and poetry venues like Le Tabou on Rue Dauphine, she was acquainted with Jean Cocteau, and was given a role in Cocteau's film "Orphée" (1950).


title: Juliette Gréco

text: In 1949, she began an affair with the American jazz musician Miles Davis. In 1957, they decided to always be just lovers because their careers were in different countries and his fear of damaging her career by being in an interracial relationship. They remained lovers and friends until his death in 1991.


title: Juliette Gréco

text: She made her debut as a cabaret singer in the Parisian cabaret "Le Bœuf sur le toit" in 1949, performing the lyrics of a number of well-known French writers; Raymond Queneau's "Si tu t'imagines" was one of her earliest songs to become popular.


title: Juliette Gréco

text: She made her film debut in "Les frères Bouquinquant" (1947) and appeared in several French films. When Darryl F. Zanuck saw her photo in Time Magazine she was offered a role in "The Sun Also Rises" (1957) that led to other Hollywood financed international films.


title: Juliette Gréco

text: With Lemaire, she had a daughter, Laurence-Marie, born in 1954. Laurence-Marie Lemaire died from cancer in 2016 aged 62.


title: Juliette Gréco

text: In the year leading up to his death in January 1949, Gréco was the lover of married racing driver Jean-Pierre Wimille and suffered a miscarriage after his death.


title: Juliette Gréco

text: According to Spanish writer Manuel Vicent, Juliette Gréco was Albert Camus's lover. She also was in relationships with French singer Sacha Distel and Hollywood producer Darryl F. Zanuck.


title: Juliette Gréco

text: During her affair with Miles Davis, she was also dating U.S. record producer Quincy Jones. According to Jones' autobiography, Davis was irritated with him for years when he found out.


title: Juliette Gréco

text: In September 1965, Gréco attempted suicide by an overdose of sleeping pills. She was found unconscious in her bathroom and taken to the hospital by Françoise Sagan.


title: Juliette Gréco

text: A leftist, she supported François Mitterrand in the 1974 presidential election, and was an initial investor in "Minute", when it was mainly non-political and focused on the entertainment world.


title: Juliette Gréco

text: Jean-Paul Sartre based the singer in his trilogy "The Roads to Freedom" ("Les chemins de la liberté") on Gréco.


title: Juliette Gréco

text: An allusion to Gréco is made by English singer Ray Davies in the song "Art School Babe" from his album "Storyteller."


title: Juliette Gréco

text: "Michelle" by the Beatles was inspired by Gréco and the Parisian Left Bank culture. Paul McCartney said of the song: "We'd tag along to these parties, and it was at the time of people like Juliette Greco, the French bohemian thing. They'd all wear black turtleneck sweaters, it's kind of where we got all that from, and we fancied Juliette like mad. Have you ever seen her? Dark hair, real chanteuse, really happening. So I used to pretend to be French, and I had this song that turned out later to be 'Michelle'."


title: Juliette Gréco

text: John Lennon wrote in "Skywriting by Word of Mouth": "I'd always had a fantasy about a woman who would be a beautiful, intelligent, dark-haired, high-cheek-boned, free-spirited artist à la Juliette Gréco."


title: Juliette Gréco

text: Marianne Faithfull said of Gréco: "When I was a young girl, Juliette Gréco was my absolute idol...She’s my role model for life. If I want to be anybody, I want to be Juliette Gréco."


title: Juliette Gréco

text: On 23 September 2021, "Place Juliette Gréco" was inaugurated in Paris. It can be found beside the Church of Saint-Germain-des-Pres, in the 6th arrondissement of Paris.


title: Church bell

text: A church bell in Christian architecture is a bell which is rung in a church for a variety of religious purposes, and can be heard outside the building. Traditionally they are used to call worshippers to the church for a communal service, and to announce the fixed times of daily Christian prayer, called the canonical hours, which number seven and are contained in breviaries. They are also rung on special occasions such as a wedding, or a funeral service. In some religious traditions they are used within the liturgy of the church service to signify to people that a particular part of the service has been reached. The ringing of church bells, in the Christian tradition, is also believed to drive out demons.


title: Church bell

text: The traditional European church bell "(see cutaway drawing)" used in Christian churches worldwide consists of a cup-shaped metal resonator with a pivoted clapper hanging inside which strikes the sides when the bell is swung. It is hung within a steeple or belltower of a church or religious building, so the sound can reach a wide area. Such bells are either fixed in position ("hung dead") or hung from a pivoted beam (the "headstock") so they can swing to and fro. A rope hangs from a lever or wheel attached to the headstock, and when the bell ringer pulls on the rope the bell swings back and forth and the clapper hits the inside, sounding the bell. Bells that are hung dead are normally sounded by hitting the sound bow with a hammer or occasionally by a rope which pulls the internal clapper against the bell.


title: Church bell

text: A church may have a single bell, or a collection of bells which are tuned to a common scale. They may be stationary and chimed, rung randomly by swinging through a small arc, or swung through a full circle to enable the high degree of control of English change ringing.


title: Church bell

text: Before modern communications, church bells were a common way to call the community together for all purposes, both sacred and secular.


title: Church bell

text: Oriental Orthodox Christians, such as Copts and Indians, use a breviary such as the Agpeya and Shehimo to pray the canonical hours seven times a day while facing in the eastward direction; church bells are tolled, especially in monasteries, to mark these seven fixed prayer times.


title: Church bell

text: In Christianity, some churches ring their church bells from belltowers three times a day, at 9 am, 12 pm and 3 pm to summon the Christian faithful to recite the Lord's Prayer; the injunction to pray the Lord's prayer thrice daily was given in "Didache" 8, 2 f., which, in turn, was influenced by the Jewish practice of praying thrice daily found in the Old Testament, specifically in , which suggests "evening and morning and at noon", and , in which the prophet Daniel prays thrice a day. The early Christians thus came to pray the Lord's Prayer at 9 am, 12 pm and 3 pm.


title: Church bell

text: Many Catholic Christian churches ring their bells thrice a day, at 6 am, 12 pm, and 6 pm to call the faithful to recite the Angelus, a prayer recited in honour of the Incarnation of God.


title: Church bell

text: Some Protestant Christian Churches ring church bells during the congregational recitation of the Lord's Prayer, after the sermon, in order to alert those who are unable to be present to "unite themselves in spirit with the congregation".


title: Church bell

text: In many historic Christian Churches, church bells are also rung on All Hallows' Eve, as well as during the processions of Candlemas and Palm Sunday; the only time of the Christian Year when church bells are not rung include Maundy Thursday through the Easter Vigil. The Christian tradition of the ringing of church bells from a belltower is analogous to the Islamic tradition of the adhan from a minaret.


title: Church bell

text: Most Christian denominations ring church bells to call the faithful to worship, signalling the start of a mass or service of worship.


title: Church bell

text: In the United Kingdom predominantly in the Anglican church, there is a strong tradition of change ringing on full-circle tower bells for about half an hour before a service. This originated from the early 17th century when bell ringers found that swinging a bell through a large arc gave more control over the time between successive strikes of the clapper. This culminated in ringing bells through a full circle, which let ringers easily produce different striking sequences; known as "changes".


title: Church bell

text: In Christianity, the ringing of church bells is traditionally believed to drive out demons and other unclean spirits. Inscriptions on church bells relating to this purpose of church bells, as well as the purpose of serving as a call to prayer and worship, were customary, for example "the sound of this bell vanquishes tempests, repels demons, and summons men". Some churches have several bells with the justification that "the more bells a church had, the more loudly they rang, and the greater the distance over which they could be heard, the less likely it was that evil forces would trouble the parish."


title: Church bell

text: The ringing of a church bell in the English tradition to announce a death is called a death knell. The pattern of striking depended on the person who had died; for example in the counties of Kent and Surrey in England it was customary to ring three times three strokes for a man and three times two for a woman, with a varying usage for children. The age of the deceased was then rung out. In small settlements this could effectively identify who had just died.


title: Church bell

text: There were three occasions surrounding a death when bells could be rung. There was the "Passing Bell" to warn of impending death, the second the Death Knell to announce the death, and the last was the "Lych Bell", or "Corpse Bell" which was rung at the funeral as the procession approached the church. This latter is known today as the Funeral toll.


title: Church bell

text: A more modern tradition where there are full-circle bells is to use "half-muffles" when sounding one bell as a tolled bell, or all the bells in change-ringing. This means a leather muffle is placed on the clapper of each bell so that there is a loud "open" strike followed by a muffled strike, which has a very sonorous and mournful effect. The tradition in the United Kingdom is that bells are only fully muffled for the death of a sovereign. A slight variant on this rule occurred in 2015 when the bones of Richard III of England were interred in Leicester Cathedral 532 years after his death.


title: Church bell

text: The term "Sanctus bell" traditionally referred to a bell suspended in a bell-cot at the apex of the nave roof, over the chancel arch, or hung in the church tower, in medieval churches. This bell was rung at the singing of the Sanctus and again at the elevation of the consecrated elements, to indicate to those not present in the building that the moment of consecration had been reached. The practice and the term remain in common use in many Anglican churches.


title: Church bell

text: Within the body of a church the function of a sanctus bell can also be performed by a small hand bell or set of such bells (called altar bells) rung shortly before the consecration of the bread and wine into the Body and Blood of Christ and again when the consecrated elements are shown to the people. Sacring rings or "Gloria wheels" are commonly used in Catholic churches in Spain and its former colonies for this purpose.


title: Church bell

text: In the Eastern Orthodox Church there is a long and complex history of bell ringing, with particular bells being rung in particular ways to signify different parts of the divine services, Funeral tolls, etc. This custom is particularly sophisticated in the Russian Orthodox Church. Russian bells are usually stationary, and are sounded by pulling on a rope that is attached to the clapper so that it will strike the inside of the bell.


title: Church bell

text: The noon church bell tolling in Europe has a specific historical significance that has its roots in the Siege of Belgrade by the Ottomans in 1456. Initially, the bell ringing was intended as a call to prayer for the victory of the defenders of Belgrade. However, because in many European countries the news of victory arrived before the order for prayer, the ringing of the church bells was believed to be in celebration of the victory. As a result, the significance of noon bell ringing is now a commemoration of John Hunyadi's victory against the Turks.


title: Church bell

text: Some churches have a clock chime which uses a turret clock to broadcast the time by striking the hours and sometimes the quarters. A well-known musical striking pattern is the Westminster Quarters. This is only done when the bells are stationary, and the clock mechanism actuates hammers striking on the outside of the sound-bows of the bells. In the cases of bells which are normally swung for other ringing, there is a manual lock-out mechanism which prevents the hammers from operating whilst the bells are being rung.


title: Church bell

text: In World War II in Great Britain, all church bells were silenced, to ring only to inform of an invasion by enemy troops. However this ban was lifted temporarily in 1942 by order of Winston Churchill. Starting with Easter Sunday, April 25, 1943, the Control of Noise (Defence) (No. 2) Order, 1943, allowed that church bells could be rung to summon worshippers to church on Sundays, Good Friday and Christmas Day. On May 27, 1943, all restrictions were removed.


title: Church bell

text: In the 2021 German floods it was reported that church bells were rung to warn inhabitants of coming floods. In Beyenburg in Wuppertal the last friar of rang the storm bells after other systems failed. Some church bells are being used in England for similar purposes.


title: Church bell

text: Christian church bells have the form of a cup-shaped cast metal resonator with a flared thickened rim, and a pivoted "clapper" hanging from its centre inside. It is usually mounted high in a bell tower on top of the church, so it can be heard by the surrounding community. The bell is suspended from a headstock which can swing on bearings. A rope is tied to a wheel or lever on the headstock, and hangs down to the bell ringer. To ring the bell, the ringer pulls on the rope, swinging the bell. The motion causes the clapper to strike the inside of the bell rim as it swings, thereby sounding the bell. Some bells have full-circle wheels, which is used to swing the bell through a larger arc, such as in the United Kingdom where full- circle ringing is practised.


title: Church bell

text: Bells which are not swung are "chimed", which means they are struck by an external hammer, or by a rope attached to the internal clapper, which is the tradition in Russia.


title: Church bell

text: In the Roman Catholic Church the name "Baptism of Bells" has been given to the ceremonial blessing of church bells, at least in France, since the eleventh century. It is derived from the washing of the bell with holy water by the bishop, before he anoints it with the "oil of the infirm" without and with chrism within; a fuming censer is placed under it and the bishop prays that these sacramentals of the Church may, at the sound of the bell, put the demons to flight, protect from storms, and call the faithful to prayer.


title: Church bell

text: Before the introduction of church bells into the Christian Church, different methods were used to call the worshippers: playing trumpets, hitting wooden planks, shouting, or using a courier. In AD 604, Pope Sabinian officially sanctioned the usage of bells. These "tintinnabula" were made from forged metal and did not have large dimensions. Larger bells were made at the end of the 7th and during the 8th century by casting metal originating from Campania. The bells consequently took the name of "campana" and "nola" from the eponymous city in the region. This would explain the apparently erroneous attribution of the origin of church bells to Paulinus of Nola in AD 400. By the early Middle Ages, church bells became common in Europe. They were first common in northern Europe, reflecting Celtic influence, especially that of Irish missionaries. Before the use of church bells, Greek monasteries would ring a flat metal plate (see "semantron") to announce services. The "signa" and "campanae" used to announce services before Irish influence may have been flat plates like the "semantron" rather than bells. The oldest surviving circle of bells in Great Britain is housed in St Lawrence Church, Ipswich.


title: Church bell

text: The evocative sound of church bells has inspired many writers, both in poetry and prose. One example is an early poem by the English poet Letitia Elizabeth Landon entitled simply,


title: Church bell

text: The sound of church bells is capable of causing noise that interrupts or prevents people from sleeping. A 2013 study from the Swiss Federal Institute of Technology in Zurich found that 'An estimated 2.5-3.5 percent of the population in the Canton of Zurich experiences at least one additional awakening per night due to church bell noise.' It concluded that 'The number of awakenings could be reduced by more than 99 percent by, for example, suspending church bell ringing between midnight and 06 h in the morning', or by 'about 75 percent (...) by reducing the sound-pressure levels of bells by 5 dB.'


title: Church bell

text: In the Netherlands, there have been lawsuits about church bell noise pollution experienced by nearby residents. The complaints are usually, but not always, raised by new local residents (or tourists who spend the night in the neighbourhood who are not used to the noise at night or during the day. Local residents who had been used to it for longer usually retort that the newcomers 'should have known this before they moved here' and that the ringing bells 'belong to the local tradition', which sometimes goes back more than a hundred years.


title: Brooke Bundy

text: As a teenager, Bundy was a model in New York before she went to Hollywood on vacation and remained there to become an actress. While in New York, she attended the Professional Children's School.


title: Brooke Bundy

text: She is perhaps best known for her role as Elaine Parker in the 1987 hit horror film "" and its sequel, "" (1988). Bundy appeared in Daniel Farrands' documentary film, "".


title: Brooke Bundy

text: Bundy had an early role in the second season of Barnaby Jones; episode titled, "Death Leap" (09/23/1973). She had two long-running roles on the soap opera "Days of Our Lives" as Rebecca North (1975–77) and "General Hospital" as Diana Maynard Taylor R.N. (1977–81). She has made guest appearances on a variety of television shows including "The Big Valley", "Mr. Novak", "Daniel Boone", "Lassie" (playing "Terri Young" in Season 12, Episode 10 "In the Midst of Splendor"), "Lancer", "Charlie's Angels", "The Brady Bunch", "The Partridge Family", "Medical Center", "Gunsmoke", "Bonanza", "Cannon (Season 4, Episode 17 "The Killer on the Hill")," "Rawhide", "The Virginian", " (Season 4, Episodes 3, 4 "The Controllers" Part One, Part Two)", "Mannix", "The Mod Squad", "McMillan and Wife", "Voyage to the Bottom of the Sea", "Moonlighting", "Gidget", "Land of the Lost", "" (Season 1 episode "The Naked Now"), Starman TV Series (Season 1 Episode 20 -Starscape part 1), "My Three Sons" and "The Donna Reed Show". As a stock actress for Jack Webb's production company Mark VII Limited, she appeared as several different characters in a few shows like "Emergency!" and "Sierra".


title: Eukaryotic DNA replication

text: Eukaryotic DNA replication is a conserved mechanism that restricts DNA replication to once per cell cycle. Eukaryotic DNA replication of chromosomal DNA is central for the duplication of a cell and is necessary for the maintenance of the eukaryotic genome.


title: Eukaryotic DNA replication

text: DNA replication is the action of DNA polymerases synthesizing a DNA strand complementary to the original template strand. To synthesize DNA, the double-stranded DNA is unwound by DNA helicases ahead of polymerases, forming a replication fork containing two single-stranded templates. Replication processes permit the copying of a single DNA double helix into two DNA helices, which are divided into the daughter cells at mitosis. The major enzymatic functions carried out at the replication fork are well conserved from prokaryotes to eukaryotes, but the replication machinery in eukaryotic DNA replication is a much larger complex, coordinating many proteins at the site of replication, forming the replisome.


title: Eukaryotic DNA replication

text: The replisome is responsible for copying the entirety of genomic DNA in each proliferative cell. This process allows for the high-fidelity passage of hereditary/genetic information from parental cell to daughter cell and is thus essential to all organisms. Much of the cell cycle is built around ensuring that DNA replication occurs without errors.


title: Eukaryotic DNA replication

text: In G phase of the cell cycle, many of the DNA replication regulatory processes are initiated. In eukaryotes, the vast majority of DNA synthesis occurs during S phase of the cell cycle, and the entire genome must be unwound and duplicated to form two daughter copies. During G, any damaged DNA or replication errors are corrected. Finally, one copy of the genomes is segregated to each daughter cell at mitosis or M phase. These daughter copies each contain one strand from the parental duplex DNA and one nascent antiparallel strand.


title: Eukaryotic DNA replication

text: This mechanism is conserved from prokaryotes to eukaryotes and is known as semiconservative DNA replication. The process of semiconservative replication for the site of DNA replication is a fork-like DNA structure, the replication fork, where the DNA helix is open, or unwound, exposing unpaired DNA nucleotides for recognition and base pairing for the incorporation


title: Eukaryotic DNA replication

text: Initiation of eukaryotic DNA replication is the first stage of DNA synthesis where the DNA double helix is unwound and an initial priming event by DNA polymerase α occurs on the leading strand. The priming event on the lagging strand establishes a replication fork. Priming of the DNA helix consists of synthesis of an RNA primer to allow DNA synthesis by DNA polymerase α. Priming occurs once at the origin on the leading strand and at the start of each Okazaki fragment on the lagging strand.


title: Eukaryotic DNA replication

text: DNA replication is initiated from specific sequences called origins of replication, and eukaryotic cells have multiple replication origins. To initiate DNA replication, multiple replicative proteins assemble on and dissociate from these replicative origins. The individual factors described below work together to direct the formation of the pre-replication complex (pre-RC), a key intermediate in the replication initiation process.


title: Eukaryotic DNA replication

text: Association of the origin recognition complex (ORC) with a replication origin recruits the cell division cycle 6 protein (Cdc6) to form a platform for the loading of the minichromosome maintenance (Mcm 2-7) complex proteins, facilitated by the chromatin licensing and DNA replication factor 1 protein (Cdt1). The ORC, Cdc6, and Cdt1 together are required for the stable association of the Mcm2-7 complex with replicative origins during G phase of the cell cycle.


title: Eukaryotic DNA replication

text: Eukaryotic origins of replication control the formation of a number of protein complexes that lead to the assembly of two bidirectional DNA replication forks. These events are initiated by the formation of the pre-replication complex (pre-RC) at the origins of replication. This process takes place in the G stage of the cell cycle. The pre-RC formation involves the ordered assembly of many replication factors including the origin recognition complex (ORC), Cdc6 protein, Cdt1 protein, and minichromosome maintenance proteins (Mcm2-7). Once the pre-RC is formed, activation of the complex is triggered by two kinases, cyclin-dependent kinase 2 (CDK) and Dbf4-dependent kinase (DDK) that help transition the pre-RC to the initiation complex prior to the initiation of DNA replication. This transition involves the ordered assembly of additional replication factors to unwind the DNA and accumulate the multiple eukaryotic DNA polymerases around the unwound DNA. Central to the question of how bidirectional replication forks are established at replication origins is the mechanism by which ORC recruits two head-to-head Mcm2-7 complexes to every replication origin to form the pre-replication complex.


title: Eukaryotic DNA replication

text: The first step in the assembly of the pre-replication complex (pre-RC) is the binding of the origin recognition complex (ORC) to the replication origin. In late mitosis, Cdc6 protein joins the bound ORC followed by the binding of the Cdt1-Mcm2-7 complex. ORC, Cdc6, and Cdt1 are all required to load the six protein minichromosome maintenance (Mcm 2-7) complex onto the DNA. The ORC is a six-subunit, Orc1p-6, protein complex that selects the replicative origin sites on DNA for initiation of replication and ORC binding to chromatin is regulated through the cell cycle. Generally, the function and size of the ORC subunits are conserved throughout many eukaryotic genomes with the difference being their diverged DNA binding sites.


title: Eukaryotic DNA replication

text: The most widely studied origin recognition complex is that of "Saccharomyces cerevisiae" or yeast which is known to bind to the autonomously replicating sequence (ARS). The "S. cerevisiae" ORC interacts specifically with both the A and B1 elements of yeast origins of replication, spanning a region of 30 base pairs. The binding to these sequences requires ATP.


title: Eukaryotic DNA replication

text: The atomic structure of the "S. cerevisiae" ORC bound to ARS DNA has been determined. Orc1, Orc2, Orc3, Orc4, and Orc5 encircle the A element by means of two types of interactions, base non-specific and base-specific, that bend the DNA at the A element. All five subunits contact the sugar phosphate backbone at multiple points of the A element to form a tight grip without base specificity. Orc1 and Orc2 contact the minor groove of the A element while a winged helix domain of Orc4 contacts the methyl groups of the invariant Ts in the major groove of the A element via an insertion helix (IH). The absence of this IH in metazoans explains the lack of sequence specificity in human ORC. Removing the IH from the "Sc"ORC causes it to lose its specificity for the A element, and to bind promiscuously and preferentially (83%) to promoter regions. The ARS DNA is also bent at the B1 element through interactions with Orc2, Orc5 and Orc6. The bending of origin DNA by ORC appears to be evolutionarily conserved suggesting that it may be required for the Mcm2-7 complex loading mechanism.


title: Eukaryotic DNA replication

text: When the ORC binds to DNA at replication origins, it serves as a scaffold for the assembly of other key initiation factors of the pre-replicative complex. This pre-replicative complex assembly during the G stage of the cell cycle is required prior to the activation of DNA replication during the S phase. The removal of at least part of the complex (Orc1) from the chromosome at metaphase is part of the regulation of mammalian ORC to ensure that the pre-replicative complex formation prior to the completion of metaphase is eliminated.


title: Eukaryotic DNA replication

text: Binding of the cell division cycle 6 (Cdc6) protein to the origin recognition complex (ORC) is an essential step in the assembly of the pre-replication complex (pre-RC) at the origins of replication. Cdc6 binds to the ORC on DNA in an ATP-dependent manner, which induces a change in the pattern of origin binding that requires Orc1 ATPase. Cdc6 requires ORC in order to associate with chromatin and is in turn required for the Cdt1-Mcm2-7 heptamer to bind to the chromatin. The ORC-Cdc6 complex forms a ring-shaped structure and is analogous to other ATP-dependent protein machines. The levels and activity of Cdc6 regulate the frequency with which the origins of replication are utilized during the cell cycle.


title: Eukaryotic DNA replication

text: The chromatin licensing and DNA replication factor 1 (Cdt1) protein is required for the licensing of chromatin for DNA replication. In "S. cerevisiae", Cdt1 facilitates the loading of the Mcm2-7 complex one at a time onto the chromosome by stabilising the left-handed open-ring structure of the Mcm2-7 single hexamer. Cdt1 has been shown to associate with the C terminus of Cdc6 to cooperatively promote the association of Mcm proteins to the chromatin. The cryo-EM structure of the OCCM (ORC-Cdc6-Cdt1-MCM) complex shows that the Cdt1-CTD interacts with the Mcm6-WHD. In metazoans, Cdt1 activity during the cell cycle is tightly regulated by its association with the protein geminin, which both inhibits Cdt1 activity during S phase in order to prevent re-replication of DNA and prevents it from ubiquitination and subsequent proteolysis.


title: Eukaryotic DNA replication

text: The minichromosome maintenance (Mcm) proteins were named after a genetic screen for DNA replication initiation mutants in "S. cerevisiae" that affect plasmid stability in an ARS-specific manner"." Mcm2, Mcm3, Mcm4, Mcm5, Mcm6 and Mcm7 form a hexameric complex that has an open-ring structure with a gap between Mcm2 and Mcm5. The assembly of the Mcm proteins onto chromatin requires the coordinated function of the origin recognition complex (ORC), Cdc6, and Cdt1. Once the Mcm proteins have been loaded onto the chromatin, ORC and Cdc6 can be removed from the chromatin without preventing subsequent DNA replication. This observation suggests that the primary role of the pre-replication complex is to correctly load the Mcm proteins.


title: Eukaryotic DNA replication

text: The Mcm proteins on chromatin form a head-to-head double hexamer with the two rings slightly tilted, twisted and off-centred to create a kink in the central channel where the bound DNA is captured at the interface of the two rings. Each hexameric Mcm2-7 ring first serves as the scaffold for the assembly of the replisome and then as the core of the catalytic CMG (Cdc45-MCM-GINS) helicase, which is a main component of the replisome. Each Mcm protein is highly related to all others, but unique sequences distinguishing each of the subunit types are conserved across eukaryotes. All eukaryotes have exactly six Mcm protein analogs that each fall into one of the existing classes (Mcm2-7), indicating that each Mcm protein has a unique and important function.


title: Eukaryotic DNA replication

text: Minichromosome maintenance proteins are required for DNA helicase activity. Inactivation of any of the six Mcm proteins during S phase irreversibly prevents further progression of the replication fork suggesting that the helicase cannot be recycled and must be assembled at replication origins. Along with the minichromosome maintenance protein complex helicase activity, the complex also has associated ATPase activity. Studies have shown that within the Mcm protein complex are specific catalytic pairs of Mcm proteins that function together to coordinate ATP hydrolysis. These studies, confirmed by cryo-EM structures of the Mcm2-7 complexes, showed that the Mcm complex is a hexamer with subunits arranged in a ring in the order of Mcm2-Mcm6-Mcm4-Mcm7-Mcm3-Mcm5-. Both members of each catalytic pair contribute to the conformation that allows ATP binding and hydrolysis and the mixture of active and inactive subunits presumably allows the Mcm hexameric complex to complete ATP binding and hydrolysis as a whole to create a coordinated ATPase activity.


title: Eukaryotic DNA replication

text: The nuclear localization of the minichromosome maintenance proteins is regulated in budding yeast cells. The Mcm proteins are present in the nucleus in G stage and S phase of the cell cycle, but are exported to the cytoplasm during the G stage and M phase. A complete and intact six subunit Mcm complex is required to enter into the cell nucleus. In "S. cerevisiae", nuclear export is promoted by cyclin-dependent kinase (CDK) activity. Mcm proteins that are associated with chromatin are protected from CDK export machinery due to the lack of accessibility to CDK.


title: Eukaryotic DNA replication

text: During the G stage of the cell cycle, the replication initiation factors, origin recognition complex (ORC), Cdc6, Cdt1, and minichromosome maintenance (Mcm) protein complex, bind sequentially to DNA to form the pre-replication complex (pre-RC). At the transition of the G stage to the S phase of the cell cycle, S phase–specific cyclin-dependent protein kinase (CDK) and Cdc7/Dbf4 kinase (DDK) transform the pre-RC into an active replication fork. During this transformation, the pre-RC is disassembled with the loss of Cdc6, creating the initiation complex. In addition to the binding of the Mcm proteins, cell division cycle 45 (Cdc45) protein is also essential for initiating DNA replication. Studies have shown that Mcm is critical for the loading of Cdc45 onto chromatin and this complex containing both Mcm and Cdc45 is formed at the onset of the S phase of the cell cycle. Cdc45 targets the Mcm protein complex, which has been loaded onto the chromatin, as a component of the pre-RC at the origin of replication during the G stage of the cell cycle.


title: Eukaryotic DNA replication

text: Cell division cycle 45 (Cdc45) protein is a critical component for the conversion of the pre-replicative complex to the initiation complex. The Cdc45 protein assembles at replication origins before initiation and is required for replication to begin in "Saccharomyces cerevisiae", and has an essential role during elongation. Thus, Cdc45 has central roles in both initiation and elongation phases of chromosomal DNA replication.


title: Eukaryotic DNA replication

text: Cdc45 associates with chromatin after the beginning of initiation in late G stage and during the S phase of the cell cycle. Cdc45 physically associates with Mcm5 and displays genetic interactions with five of the six members of the Mcm gene family and the ORC2 gene. The loading of Cdc45 onto chromatin is critical for loading other various replication proteins, including DNA polymerase α, DNA polymerase ε, replication protein A (RPA) and proliferating cell nuclear antigen (PCNA) onto chromatin.


title: Eukaryotic DNA replication

text: Within a "Xenopus" nucleus-free system, it has been demonstrated that Cdc45 is required for the unwinding of plasmid DNA. The "Xenopus" nucleus-free system also demonstrates that DNA unwinding and tight RPA binding to chromatin occurs only in the presence of Cdc45.


title: Eukaryotic DNA replication

text: Binding of Cdc45 to chromatin depends on Clb-Cdc28 kinase activity as well as functional Cdc6 and Mcm2, which suggests that Cdc45 associates with the pre-RC after activation of S-phase cyclin-dependent kinases (CDKs). As indicated by the timing and the CDK dependence, binding of Cdc45 to chromatin is crucial for commitment to initiation of DNA replication. During S phase, Cdc45 physically interacts with Mcm proteins on chromatin; however, dissociation of Cdc45 from chromatin is slower than that of the Mcm, which indicates that the proteins are released by different mechanisms.


title: Eukaryotic DNA replication

text: The six minichromosome maintenance proteins and Cdc45 are essential during initiation and elongation for the movement of replication forks and for unwinding of the DNA. GINS are essential for the interaction of Mcm and Cdc45 at the origins of replication during initiation and then at DNA replication forks as the replisome progresses. The GINS complex is composed of four small proteins Sld5 (Cdc105), Psf1 (Cdc101), Psf2 (Cdc102) and Psf3 (Cdc103), GINS represents 'go, ichi, ni, san' which means '5, 1, 2, 3' in Japanese. Cdc45, Mcm2-7 and GINS together form the CMG helicase, the replicative helicase of the replisome. Although the Mcm2-7 complex alone has weak helicase activity Cdc45 and GINS are required for robust helicase activity


title: Eukaryotic DNA replication

text: Mcm10 is essential for chromosome replication and interacts with the minichromosome maintenance 2-7 helicase that is loaded in an inactive form at origins of DNA replication. Mcm10 also chaperones the catalytic DNA polymerase α and helps stabilize the polymerase at replication forks.


title: Eukaryotic DNA replication

text: At the onset of S phase, the pre-replicative complex must be activated by two S phase-specific kinases in order to form an initiation complex at an origin of replication. One kinase is the Cdc7-Dbf4 kinase called Dbf4-dependent kinase (DDK) and the other is cyclin-dependent kinase (CDK). Chromatin-binding assays of Cdc45 in yeast and "Xenopus" have shown that a downstream event of CDK action is loading of Cdc45 onto chromatin. Cdc6 has been speculated to be a target of CDK action, because of the association between Cdc6 and CDK, and the CDK-dependent phosphorylation of Cdc6. The CDK-dependent phosphorylation of Cdc6 has been considered to be required for entry into the S phase.


title: Eukaryotic DNA replication

text: Both the catalytic subunits of DDK, Cdc7, and the activator protein, Dbf4, are conserved in eukaryotes and are required for the onset of S phase of the cell cycle. Both Dbf4 and Cdc7 are required for the loading of Cdc45 onto chromatin origins of replication. The target for binding of the DDK kinase is the chromatin-bound form of the Mcm complex. High resolution cryoEM structures showed that the Dbf4 subunit of DDK straddles across the hexamer interface of the DNA-bound MCM-DH, contacting Mcm2 of one hexamer and Mcm4/6 of the opposite hexamer. Mcm2, Mcm4 and Mcm6 are all substrates of phosphorylation by DDK but only the N-terminal serine/threonine-rich domain (NSD) of Mcm4 is an essential DDK target. Phosphorylation of the NSD leads to the activation of Mcm helicase activity.


title: Eukaryotic DNA replication

text: Sld3, Sld2, and Dpb11 interact with many replication proteins. Sld3 and Cdc45 form a complex that associated with the pre-RC at the early origins of replication even in the G1 phase and with the later origins of replication in the S phase in a mutually Mcm-dependent manner. Dpb11 and Sld2 interact with Polymerase ɛ and cross-linking experiments have indicated that Dpb11 and Polymerase ɛ coprecipitate in the S phase and associate with replication origins.


title: Eukaryotic DNA replication

text: Sld3 and Sld2 are phosphorylated by CDK, which enables the two replicative proteins to bind to Dpb11. Dpb11 had two pairs of BRCA1 C Terminus (BRCT) domains which are known as a phosphopeptide-binding domains. The N-terminal pair of the BRCT domains binds to phosphorylated Sld3, and the C-terminal pair binds to phosphorylated Sld2. Both of these interactions are essential for CDK-dependent activation of DNA budding in yeast.


title: Eukaryotic DNA replication

text: Dpb11 also interacts with GINS and participates in the initiation and elongation steps of chromosomal DNA replication. GINS are one of the replication proteins found at the replication forks and forms a complex with Cdc45 and Mcm.


title: Eukaryotic DNA replication

text: These phosphorylation-dependent interactions between Dpb11, Sld2, and Sld3 are essential for CDK-dependent activation of DNA replication, and by using cross-linking reagents within some experiments, a fragile complex was identified called the pre-loading complex (pre-LC). This complex contains Pol ɛ, GINS, Sld2, and Dpb11. The pre-LC is found to form before any association with the origins in a CDK-dependent and DDK-dependent manner and CDK activity regulates the initiation of DNA replication through the formation of the pre-LC.


title: Eukaryotic DNA replication

text: The formation of the pre-replicative complex (pre-RC) marks the potential sites for the initiation of DNA replication. Consistent with the minichromosome maintenance complex encircling double stranded DNA, formation of the pre-RC does not lead to the immediate unwinding of origin DNA or the recruitment of DNA polymerases. Instead, the pre-RC that is formed during the G of the cell cycle is only activated to unwind the DNA and initiate replication after the cells pass from the G to the S phase of the cell cycle.


title: Eukaryotic DNA replication

text: Once the initiation complex is formed and the cells pass into the S phase, the complex then becomes a replisome. The eukaryotic replisome complex is responsible for coordinating DNA replication. Replication on the leading and lagging strands is performed by DNA polymerase ε and DNA polymerase δ. Many replisome factors including Claspin, And1, replication factor C clamp loader and the fork protection complex are responsible for regulating polymerase functions and coordinating DNA synthesis with the unwinding of the template strand by Cdc45-Mcm-GINS complex. As the DNA is unwound the twist number decreases. To compensate for this the writhe number increases, introducing positive supercoils in the DNA. These supercoils would cause DNA replication to halt if they were not removed. Topoisomerases are responsible for removing these supercoils ahead of the replication fork.


title: Eukaryotic DNA replication

text: The replisome is responsible for copying the entire genomic DNA in each proliferative cell. The base pairing and chain formation reactions, which form the daughter helix, are catalyzed by DNA polymerases. These enzymes move along single-stranded DNA and allow for the extension of the nascent DNA strand by "reading" the template strand and allowing for incorporation of the proper purine nucleobases, adenine and guanine, and pyrimidine nucleobases, thymine and cytosine. Activated free deoxyribonucleotides exist in the cell as deoxyribonucleotide triphosphates (dNTPs). These free nucleotides are added to an exposed 3'-hydroxyl group on the last incorporated nucleotide. In this reaction, a pyrophosphate is released from the free dNTP, generating energy for the polymerization reaction and exposing the 5' monophosphate, which is then covalently bonded to the 3' oxygen. Additionally, incorrectly inserted nucleotides can be removed and replaced by the correct nucleotides in an energetically favorable reaction. This property is vital to proper proofreading and repair of errors that occur during DNA replication.


title: Eukaryotic DNA replication

text: The replication fork is the junction between the newly separated template strands, known as the leading and lagging strands, and the double stranded DNA. Since duplex DNA is antiparallel, DNA replication occurs in opposite directions


title: Eukaryotic DNA replication

text: between the two new strands at the replication fork, but all DNA polymerases synthesize DNA in the 5' to 3' direction with respect to the newly synthesized strand. Further coordination is required during DNA replication. Two replicative polymerases synthesize DNA in opposite orientations. Polymerase ε synthesizes DNA on the "leading" DNA strand continuously as it is pointing in the same direction as DNA unwinding by the replisome. In contrast, polymerase δ synthesizes DNA on the "lagging" strand, which is the opposite DNA template strand, in a fragmented or discontinuous manner.


title: Eukaryotic DNA replication

text: The discontinuous stretches of DNA replication products on the lagging strand are known as Okazaki fragments and are about 100 to 200 bases in length at eukaryotic replication forks. The lagging strand usually contains longer stretches of single-stranded DNA that is coated with single-stranded binding proteins, which help stabilize the single-stranded templates by preventing a secondary structure formation. In eukaryotes, these single-stranded binding proteins are a heterotrimeric complex known as replication protein A (RPA).


title: Eukaryotic DNA replication

text: Each Okazaki fragment is preceded by an RNA primer, which is displaced by the procession of the next Okazaki fragment during synthesis. RNase H recognizes the DNA:RNA hybrids that are created by the use of RNA primers and is responsible for removing these from the replicated strand, leaving behind a primer:template junction. DNA polymerase α, recognizes these sites and elongates the breaks left by primer removal. In eukaryotic cells, a small amount of the DNA segment immediately upstream of the RNA primer is also displaced, creating a flap structure. This flap is then cleaved by endonucleases. At the replication fork, the gap in DNA after removal of the flap is sealed by DNA ligase I, which repairs the nicks that are left between the 3'-OH and 5'phosphate of the newly synthesized strand. Owing to the relatively short nature of the eukaryotic Okazaki fragment, DNA replication synthesis occurring discontinuously on the lagging strand is less efficient and more time-consuming than leading-strand synthesis. DNA synthesis is complete once all RNA primers are removed and nicks are repaired.


title: Eukaryotic DNA replication

text: During DNA replication, the replisome will unwind the parental duplex DNA into a two single-stranded DNA template replication fork in a 5' to 3' direction. The leading strand is the template strand that is being replicated in the same direction as the movement of the replication fork. This allows the newly synthesized strand complementary to the original strand to be synthesized 5' to 3' in the same direction as the movement of the replication fork.


title: Eukaryotic DNA replication

text: Once an RNA primer has been added by a primase to the 3' end of the leading strand, DNA synthesis will continue in a 3' to 5' direction with respect to the leading strand uninterrupted. DNA Polymerase ε will continuously add nucleotides to the template strand therefore making leading strand synthesis require only one primer and has uninterrupted DNA polymerase activity.


title: Eukaryotic DNA replication

text: DNA replication on the lagging strand is discontinuous. In lagging strand synthesis, the movement of DNA polymerase in the opposite direction of the replication fork requires the use of multiple RNA primers. DNA polymerase will synthesize short fragments of DNA called Okazaki fragments which are added to the 3' end of the primer. These fragments can be anywhere between 100–400 nucleotides long in eukaryotes.


title: Eukaryotic DNA replication

text: At the end of Okazaki fragment synthesis, DNA polymerase δ runs into the previous Okazaki fragment and displaces its 5' end containing the RNA primer and a small segment of DNA. This generates an RNA-DNA single strand flap, which must be cleaved, and the nick between the two Okazaki fragments must be sealed by DNA ligase I. This process is known as Okazaki fragment maturation and can be handled in two ways: one mechanism processes short flaps, while the other deals with long flaps. DNA polymerase δ is able to displace up to 2 to 3 nucleotides of DNA or RNA ahead of its polymerization, generating a short "flap" substrate for Fen1, which can remove nucleotides from the flap, one nucleotide at a time.


title: Eukaryotic DNA replication

text: By repeating cycles of this process, DNA polymerase δ and Fen1 can coordinate the removal of RNA primers and leave a DNA nick at the lagging strand. It has been proposed that this iterative process is preferable to the cell because it is tightly


title: Eukaryotic DNA replication

text: regulated and does not generate large flaps that need to be excised. In the event of deregulated Fen1/DNA polymerase δ activity, the cell uses an alternative mechanism to generate and process long flaps by using Dna2, which has both helicase and nuclease activities. The nuclease activity of Dna2 is required for removing these long flaps, leaving a shorter flap to be processed by Fen1. Electron microscopy studies indicate that nucleosome loading on the lagging strand occurs very close to the site of synthesis. Thus, Okazaki fragment maturation is an efficient process that occurs immediately after the nascent DNA is synthesized.


title: Eukaryotic DNA replication

text: After the replicative helicase has unwound the parental DNA duplex, exposing two single-stranded DNA templates, replicative polymerases are needed to generate two copies of the parental genome. DNA polymerase function is highly specialized and accomplish replication on specific templates and in narrow localizations. At the eukaryotic replication fork, there are three distinct replicative polymerase complexes that contribute to DNA replication: Polymerase α, Polymerase δ, and Polymerase ε. These three polymerases are essential for viability of the cell.


title: Eukaryotic DNA replication

text: Because DNA polymerases require a primer on which to begin DNA synthesis, polymerase α (Pol α) acts as a replicative primase. Pol α is associated with an RNA primase and this complex accomplishes the priming task by synthesizing a primer that contains a short 10 nucleotide stretch of RNA followed by 10 to 20 DNA bases. Importantly, this priming action occurs at replication initiation at origins to begin leading-strand synthesis and also at the 5' end of each Okazaki fragment on the lagging strand.


title: Eukaryotic DNA replication

text: However, Pol α is not able to continue DNA replication and must be replaced with another polymerase to continue DNA synthesis. Polymerase switching requires clamp loaders and it has been proven that normal DNA replication requires the coordinated actions of all three DNA polymerases: Pol α for priming synthesis, Pol ε for leading-strand replication, and the Pol δ, which is constantly loaded, for generating Okazaki fragments during lagging-strand synthesis.


title: Eukaryotic DNA replication

text: The DNA helicases and polymerases must remain in close contact at the replication fork. If unwinding occurs too far in advance of synthesis, large tracts of single-stranded DNA are exposed. This can activate DNA damage signaling or induce DNA repair processes. To thwart these problems, the eukaryotic replisome contains specialized proteins that are designed to regulate the helicase activity ahead of the replication fork. These proteins also provide docking sites for physical interaction between helicases and polymerases, thereby ensuring that duplex unwinding is coupled with DNA synthesis.


title: Eukaryotic DNA replication

text: For DNA polymerases to function, the double-stranded DNA helix has to be unwound to expose two single-stranded DNA templates for replication. DNA helicases are responsible for unwinding the double-stranded DNA during chromosome replication. Helicases in eukaryotic cells are remarkably complex. The catalytic core of the helicase is composed of six minichromosome maintenance (Mcm2-7) proteins, forming a hexameric ring. Away from DNA, the Mcm2-7 proteins form a single heterohexamer and are loaded in an inactive form at origins of DNA replication as a head-to-head double hexamers around double-stranded DNA. The Mcm proteins are recruited to replication origins then redistributed throughout the genomic DNA during S phase, indicative of their localization to the replication fork.


title: Eukaryotic DNA replication

text: Loading of Mcm proteins can only occur during the G of the cell cycle, and the loaded complex is then activated during S phase by recruitment of the Cdc45 protein and the GINS complex to form the active Cdc45–Mcm–GINS (CMG) helicase at DNA replication forks. Mcm activity is required throughout the S phase for DNA replication. A variety of regulatory factors assemble around the CMG helicase to produce the ‘Replisome Progression Complex’ which associates with DNA polymerases to form the eukaryotic replisome, the structure of which is still quite poorly defined in comparison with its bacterial counterpart.


title: Eukaryotic DNA replication

text: The isolated CMG helicase and Replisome Progression Complex contain a single Mcm protein ring complex suggesting that the loaded double hexamer of the Mcm proteins at origins might be broken into two single hexameric rings as part of the initiation process, with each Mcm protein complex ring forming the core of a CMG helicase at the two replication forks established from each origin. The full CMG complex is required for DNA unwinding, and the complex of CDC45-Mcm-GINS is the functional DNA helicase in eukaryotic cells.


title: Eukaryotic DNA replication

text: The CMG complex interacts with the replisome through the interaction with Ctf4 and And1 proteins. Ctf4/And1 proteins interact with both the CMG complex and DNA polymerase α. Ctf4 is a polymerase α accessory factor, which is required for the recruitment of polymerase α to replication origins.


title: Eukaryotic DNA replication

text: Mrc1/Claspin proteins couple leading-strand synthesis with the CMG complex helicase activity. Mrc1 interacts with polymerase ε as well as Mcm proteins. The importance of this direct link between the helicase and the leading-strand polymerase is underscored by results in cultured human cells, where Mrc1/Claspin is required for efficient replication fork progression. These results suggest that efficient DNA replication also requires the coupling of helicases and leading-strand synthesis...


title: Eukaryotic DNA replication

text: DNA polymerases require additional factors to support DNA replication. DNA polymerases have a semiclosed 'hand' structure, which allows the polymerase to load onto the DNA and begin translocating. This structure permits DNA polymerase to hold the single-stranded DNA template, incorporate dNTPs at the active site, and release the newly formed double-stranded DNA. However, the structure of DNA polymerases does not allow a continuous stable interaction with the template DNA.


title: Eukaryotic DNA replication

text: To strengthen the interaction between the polymerase and the template DNA, DNA sliding clamps associate with the polymerase to promote the processivity of the replicative polymerase. In eukaryotes, the sliding clamp is a homotrimer ring structure known as the proliferating cell nuclear antigen (PCNA). The PCNA ring has polarity with surfaces that interact with DNA polymerases and tethers them securely to the DNA template. PCNA-dependent stabilization of DNA polymerases has a significant effect on DNA replication because PCNAs are able to enhance the polymerase processivity up to 1,000-fold. PCNA is an essential cofactor and has the distinction of being one of the most common interaction platforms in the replisome to accommodate multiple processes at the replication fork, and so PCNA is also viewed as a regulatory cofactor for DNA polymerases.


title: Eukaryotic DNA replication

text: PCNA fully encircles the DNA template strand and must be loaded onto DNA at the replication fork. At the leading strand, loading of the PCNA is an infrequent process, because DNA replication on the leading strand is continuous until replication is terminated. However, at the lagging strand, DNA polymerase δ needs to be continually loaded at the start of each Okazaki fragment. This constant initiation of Okazaki fragment synthesis requires repeated PCNA loading for efficient DNA replication.


title: Eukaryotic DNA replication

text: PCNA loading is accomplished by the replication factor C (RFC) complex. The RFC complex is composed of five ATPases: Rfc1, Rfc2, Rfc3, Rfc4 and Rfc5. RFC recognizes primer-template junctions and loads PCNA at these sites. The PCNA homotrimer is opened by RFC by ATP hydrolysis and is then loaded onto DNA in the proper orientation to facilitate its association with the polymerase. Clamp loaders can also unload PCNA from DNA; a mechanism needed when replication must be terminated.


title: Eukaryotic DNA replication

text: DNA replication at the replication fork can be halted by a shortage of deoxynucleotide triphosphates (dNTPs) or by DNA damage, resulting in replication stress. This halting of replication is described as a stalled replication fork. A fork protection complex of proteins stabilizes the replication fork until DNA damage or other replication problems can be fixed. Prolonged replication fork stalling can lead to further DNA damage. Stalling signals are deactivated if the problems causing the replication fork are resolved.


title: Eukaryotic DNA replication

text: Termination of eukaryotic DNA replication requires different processes depending on whether the chromosomes are circular or linear. Unlike linear molecules, circular chromosomes are able to replicate the entire molecule. However, the two DNA molecules will remain linked together. This issue is handled by decatenation of the two DNA molecules by a type II topoisomerase. Type II topoisomerases are also used to separate linear strands as they are intricately folded into a nucleosome within the cell.


title: Eukaryotic DNA replication

text: As previously mentioned, linear chromosomes face another issue that is not seen in circular DNA replication. Due to the fact that an RNA primer is required for initiation of DNA synthesis, the lagging strand is at a disadvantage in replicating the entire chromosome. While the leading strand can use a single RNA primer to extend the 5' terminus of the replicating DNA strand, multiple RNA primers are responsible for lagging strand synthesis, creating Okazaki fragments. This leads to an issue due to the fact that DNA polymerase is only able to add to the 3' end of the DNA strand. The 3'-5' action of DNA polymerase along the parent strand leaves a short single-stranded DNA (ssDNA) region at the 3' end of the parent strand when the Okazaki fragments have been repaired. Since replication occurs in opposite directions at opposite ends of parent chromosomes, each strand is a lagging strand at one end. Over time this would result in progressive shortening of both daughter chromosomes. This is known as the end replication problem.


title: Eukaryotic DNA replication

text: The end replication problem is handled in eukaryotic cells by telomere regions and telomerase. Telomeres extend the 3' end of the parental chromosome beyond the 5' end of the daughter strand. This single-stranded DNA structure can act as an origin of replication that recruits telomerase. Telomerase is a specialized DNA polymerase that consists of multiple protein subunits and an RNA component. The RNA component of telomerase anneals to the single stranded 3' end of the template DNA and contains 1.5 copies of the telomeric sequence. Telomerase contains a protein subunit that is a reverse transcriptase called telomerase reverse transcriptase or TERT. TERT synthesizes DNA until the end of the template telomerase RNA and then disengages. This process can be repeated as many times as needed with the extension of the 3' end of the parental DNA molecule. This 3' addition provides a template for extension of the 5' end of the daughter strand by lagging strand DNA synthesis. Regulation of telomerase activity is handled by telomere-binding proteins.


title: Eukaryotic DNA replication

text: Prokaryotic DNA replication is bidirectional; within a replicative origin, replisome complexes are created at each end of the replication origin and replisomes move away from each other from the initial starting point. In prokaryotes, bidirectional replication initiates at one replicative origin on the circular chromosome and terminates at a site opposed from the initial start of the origin. These termination regions have DNA sequences known as "Ter" sites. These "Ter" sites are bound by the Tus protein. The "Ter"-Tus complex is able to stop helicase activity, terminating replication.


title: Eukaryotic DNA replication

text: In eukaryotic cells, termination of replication usually occurs through the collision of the two replicative forks between two active replication origins. The location of the collision varies on the timing of origin firing. In this way, if a replication fork becomes stalled or collapses at a certain site, replication of the site can be rescued when a replisome traveling in the opposite direction completes copying the region. There are programmed replication fork barriers (RFBs) bound by RFB proteins in various locations, throughout the genome, which are able to terminate or pause replication forks, stopping progression of the replisome.


title: Eukaryotic DNA replication

text: It has been found that replication happens in a localised way in the cell nucleus. Contrary to the traditional view of moving replication forks along stagnant DNA, a concept of "replication factories" emerged, which means replication forks are concentrated towards some immobilised 'factory' regions through which the template DNA strands pass like conveyor belts.


title: Eukaryotic DNA replication

text: DNA replication is a tightly orchestrated process that is controlled within the context of the cell cycle. Progress through the cell cycle and in turn DNA replication is tightly regulated by the formation and activation of pre-replicative complexes (pre-RCs) which is achieved through the activation and inactivation of cyclin-dependent kinases (Cdks, CDKs). Specifically it is the interactions of cyclins and cyclin dependent kinases that are responsible for the transition from G into S-phase.


title: Eukaryotic DNA replication

text: During the G phase of the cell cycle there are low levels of CDK activity. This low level of CDK activity allows for the formation of new pre-RC complexes but is not sufficient for DNA replication to be initiated by the newly formed pre-RCs. During the remaining phases of the cell cycle there are elevated levels of CDK activity. This high level of CDK activity is responsible for initiating DNA replication as well as inhibiting new pre-RC complex formation. Once DNA replication has been initiated the pre-RC complex is broken down. Due to the fact that CDK levels remain high during the S phase, G, and M phases of the cell cycle no new pre-RC complexes can be formed. This all helps to ensure that no initiation can occur until the cell division is complete.


title: Eukaryotic DNA replication

text: In addition to cyclin dependent kinases a new round of replication is thought to be prevented through the downregulation of Cdt1. This is achieved via degradation of Cdt1 as well as through the inhibitory actions of a protein known as geminin. Geminin binds tightly to Cdt1 and is thought to be the major inhibitor of re-replication. Geminin first appears in S-phase and is degraded at the metaphase-anaphase transition, possibly through ubiquination by anaphase promoting complex (APC).


title: Eukaryotic DNA replication

text: Various cell cycle checkpoints are present throughout the course of the cell cycle that determine whether a cell will progress through division entirely. Importantly in replication the G, or restriction, checkpoint makes the determination of whether or not initiation of replication will begin or whether the cell will be placed in a resting stage known as G. Cells in the G stage of the cell cycle are prevented from initiating a round of replication because the minichromosome maintenance proteins are not expressed. Transition into the S-phase indicates replication has begun.


title: Eukaryotic DNA replication

text: In order to preserve genetic information during cell division, DNA replication must be completed with high fidelity. In order to achieve this task, eukaryotic cells have proteins in place during certain points in the replication process that are able to detect any errors during DNA replication and are able to preserve genomic integrity. These checkpoint proteins are able to stop the cell cycle from entering mitosis in order to allow time for DNA repair. Checkpoint proteins are also involved in some DNA repair pathways, while they stabilize the structure of the replication fork to prevent further damage. These checkpoint proteins are essential to avoid passing down mutations or other chromosomal aberrations to offspring.


title: Eukaryotic DNA replication

text: Eukaryotic checkpoint proteins are well conserved and involve two phosphatidylinositol 3-kinase-related kinases (PIKKs), ATR and ATM. Both ATR and ATM share a target phosphorylation sequence, the SQ/TQ motif, but their individual roles in cells differ.


title: Eukaryotic DNA replication

text: ATR is involved in arresting the cell cycle in response to DNA double-stranded breaks. ATR has an obligate checkpoint partner, ATR-interacting-protein (ATRIP), and together these two proteins are responsive to stretches of single-stranded DNA that are coated by replication protein A (RPA). The formation of single-stranded DNA occurs frequently, more often during replication stress. ATR-ATRIP is able to arrest the cell cycle to preserve genome integrity. ATR is found on chromatin during S phase, similar to RPA and claspin.


title: Eukaryotic DNA replication

text: The generation of single-stranded DNA tracts is important in initiating the checkpoint pathways downstream of replication damage. Once single-stranded DNA becomes sufficiently long, single-stranded DNA coated with RPA are able to recruit ATR-ATRIP. In order to become fully active, the ATR kinase rely on sensor proteins that sense whether the checkpoint proteins are localized to a valid site of DNA replication stress. The RAD9-HUS1-Rad1 (9-1-1) heterotrimeric clamp and its clamp loader RFC are able to recognize gapped or nicked DNA. The RFC clamp loader loads 9-1-1 onto the damaged DNA. The presence of 9-1-1 on DNA is enough to facilitate the interaction between ATR-ATRIP and a group of proteins termed checkpoint mediators, such as TOPBP1 and Mrc1/claspin. TOPBP1 interacts with and recruits the phosphorylated Rad9 component of 9-1-1 and binds ATR-ATRIP, which phosphorylates Chk1. Mrc1/Claspin is also required for


title: Eukaryotic DNA replication

text: the complete activation of ATR-ATRIP that phosphorylates Chk1, the major downstream checkpoint effector kinase. Claspin is a component of the replisome and contains a domain for docking with Chk1, revealing a specific function of Claspin during DNA replication: the promotion of


title: Eukaryotic DNA replication

text: Chk1 signaling is vital for arresting the cell cycle and preventing cells from entering mitosis with incomplete DNA replication or DNA damage. The Chk1-dependent Cdk inhibition is important for the function of the ATR-Chk1 checkpoint and to arrest the cell cycle and allow sufficient time for completion of DNA repair mechanisms, which in turn prevents the inheritance of damaged DNA. In addition, Chk1-dependent Cdk inhibition plays a critical role in inhibiting origin firing during S phase. This mechanism prevents continued DNA synthesis and is required for the protection of the genome in the


title: Eukaryotic DNA replication

text: presence of replication stress and potential genotoxic conditions. Thus, ATR-Chk1 activity further prevents potential replication problems at the level of single replication origins by inhibiting initiation of replication throughout the genome, until the signaling cascade maintaining cell-cycle arrest is turned off.


title: Eukaryotic DNA replication

text: Eukaryotic DNA must be tightly compacted in order to fit within the confined space of the nucleus. Chromosomes are packaged by wrapping 147 nucleotides around an octamer of histone proteins, forming a nucleosome. The nucleosome octamer includes two copies of each histone H2A, H2B, H3, and H4. Due to the tight association of histone proteins to DNA, eukaryotic cells have proteins that are designed to remodel histones ahead of the replication fork, in order to allow smooth progression of the replisome. There are also proteins involved in reassembling histones behind the replication fork to reestablish the nucleosome conformation.


title: Eukaryotic DNA replication

text: There are several histone chaperones that are known to be involved in nucleosome assembly after replication. The FACT complex has been found to interact with DNA polymerase α-primase complex, and the subunits of the FACT complex interacted genetically with replication factors. The FACT complex is a heterodimer that does not hydrolyze ATP, but is able to facilitate "loosening" of histones in nucleosomes, but how the FACT complex is able to relieve the tight association of histones for DNA removal remains unanswered.


title: Eukaryotic DNA replication

text: Another histone chaperone that associates with the replisome is Asf1, which interacts with the Mcm complex dependent on histone dimers H3-H4. Asf1 is able to pass newly synthesized H3-H4 dimer to deposition factors behind the replication fork and this activity makes the H3-H4 histone dimers available at the site of histone deposition just after replication. Asf1 (and its partner Rtt109) has also been implicated in inhibiting gene expression from replicated genes during S-phase.


title: Eukaryotic DNA replication

text: The heterotrimeric chaperone chromatin assembly factor 1 (CAF-1) is a chromatin formation protein that is involved in depositing histones onto both newly replicated DNA strands to form chromatin. CAF-1 contains a PCNA-binding motif, called a PIP-box, that allows CAF-1 to associate with the replisome through PCNA and is able to deposit histone H3-H4 dimers onto newly synthesized DNA. The Rtt106 chaperone is also involved in this process, and associated with CAF-1 and H3-H4 dimers during chromatin formation. These processes load newly synthesized histones onto DNA.


title: Eukaryotic DNA replication

text: After the deposition of histones H3-H4, nucleosomes form by the association of histone H2A-H2B. This process is thought to occur through the FACT complex, since it already associated with the replisome and is able to bind free H2A-H2B, or there is the possibility of another H2A-H2B chaperone, Nap1. Electron microscopy studies show that this occurs very quickly, as nucleosomes can be observed forming just a few hundred base pairs after the replication fork. Therefore, the entire process of forming new


title: Eukaryotic DNA replication

text: nucleosomes takes place just after replication due to the coupling of histone chaperones to the replisome.


title: Eukaryotic DNA replication

text: When compared to prokaryotic DNA replication, the completion of eukaryotic DNA replication is more complex and involves multiple origins of replication and replicative proteins to accomplish. Prokaryotic DNA is arranged in a circular shape, and has only one replication origin when replication starts. By contrast, eukaryotic DNA is linear. When replicated, there are as many as one thousand origins of replication.


title: Eukaryotic DNA replication

text: Eukaryotic DNA is bidirectional. Here the meaning of the word bidirectional is different. Eukaryotic linear DNA has many origins (called O) and termini (called T). "T" is present to the right of "O". One "O" and one "T" together form one replicon. After the formation of pre-initiation complex, when one replicon starts elongation, initiation starts in second replicon. Now, if the first replicon moves in clockwise direction, the second replicon moves in anticlockwise direction, until "T" of first replicon is reached. At "T", both the replicons merge to complete the process of replication. Meanwhile, the second replicon is moving in forward direction also, to meet with the third replicon. This clockwise and counter-clockwise movement of two replicons is termed as bidirectional replication.


title: Eukaryotic DNA replication

text: Eukaryotic DNA replication requires precise coordination of all DNA polymerases and associated proteins to replicate the entire genome each time a cell divides. This process is achieved through a series of steps of protein assemblies at origins of replication, mainly focusing the regulation of DNA replication on the association of the MCM helicase with the DNA. These origins of replication direct the number of protein complexes that will form to initiate replication. In prokaryotic DNA replication regulation focuses on the binding of the DnaA initiator protein to the DNA, with initiation of replication occurring multiple times during one cell cycle. Both prokaryotic and eukaryotic DNA use ATP binding and hydrolysis to direct helicase loading and in both cases the helicase is loaded in the inactive form. However, eukaryotic helicases are double hexamers that are loaded onto double stranded DNA whereas prokaryotic helicases are single hexamers loaded onto single stranded DNA.


title: Eukaryotic DNA replication

text: Segregation of chromosomes is another difference between prokaryotic and eukaryotic cells. Rapidly dividing cells, such as bacteria, will often begin to segregate chromosomes that are still in the process of replication. In eukaryotic cells chromosome segregation into the daughter cells is not initiated until replication is complete in all chromosomes. Despite these differences, however, the underlying process of replication is similar for both prokaryotic and eukaryotic DNA.


title: Meshes of the Afternoon

text: Meshes of the Afternoon is a 1943 American short experimental film directed by and starring wife-and-husband team Maya Deren and Alexandr Hackenschmied. The film's narrative is circular and repeats several motifs, including a flower on a long driveway, a key falling, a door unlocked, a knife in a loaf of bread, a mysterious Grim Reaper–like cloaked figure with a mirror for a face, a phone off the hook and an ocean. Through creative editing, distinct camera angles, and slow motion, the surrealist film depicts a world in which it is more and more difficult to grasp reality.


title: Meshes of the Afternoon

text: In 1990, "Meshes of the Afternoon" was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant", going into the registry in the second year of voting. In 2015 the BBC named the film the 40th greatest American movie ever made. In 2022, it was voted the 16th greatest film of all time in the "Sight & Sound" poll.


title: Meshes of the Afternoon

text: A woman (Maya Deren) sees someone on the street as she is walking back to her home. She goes to her room and falls asleep in a chair. As soon as she is asleep, she experiences a dream in which she repeatedly tries to chase a mysterious hooded figure with a mirror for a face but is unable to catch it. With each failure, she re-enters her house and sees numerous household objects, including a key, a bread knife, a flower, a telephone, and a phonograph. The woman follows the hooded figure to her bedroom, where she sees the figure hide the knife under a pillow. Throughout the story, she sees multiple instances of herself, all bits of her dream that she has already experienced. The woman tries to kill her sleeping body with a knife but is awakened by a man (Alexander Hammid). The man leads her to the bedroom, and she realizes that everything she saw in the dream was actually happening. She notices that the man's posture is similar to that of the hooded figure when it hid the knife under the pillow. She attempts to injure him and fails. Towards the end of the film the man walks into the house and sees a broken mirror being dropped onto wet ground. He then sees the woman in the chair, who was previously sleeping but is now dead.


title: Meshes of the Afternoon

text: The film was the product of Deren's and Hammid's desire to create an avant-garde personal film that dealt with complex psychology, like the surrealist films "Un Chien Andalou" (1929) and "L'Age d'Or" (1930) by Salvador Dalí and Luis Buñuel.


title: Meshes of the Afternoon

text: Deren and Hammid wrote, directed, and performed in the film. Although Deren is usually credited as its principal artistic creator, filmmaker Stan Brakhage, who knew the couple, has claimed in his book "Film at Wit's End" that "Meshes" was in fact largely Hammid's creation and that their marriage began to suffer when Deren received more credit. Other sources claim that Hammid's role in the creation of "Meshes of the Afternoon" is mainly as cameraperson. Deren made extensive storyboards for all of her films, including camera movements and camera effects. She wrote about these techniques in professional filmmaking magazines. The ideas and execution of the film are mostly attributable to Deren. Hammid also acknowledged Deren as the sole creator of "Meshes of the Afternoon".


title: Meshes of the Afternoon

text: The original print had no score. However, a musical score influenced by classical Japanese music was added in 1959 by Deren's third husband, Teiji Ito.


title: Meshes of the Afternoon

text: In the early 1970s, J. Hoberman claimed that "Meshes of the Afternoon" was "less related to European surrealism" and more related to "Hollywood wartime "film noir"".


title: Meshes of the Afternoon

text: Deren explained that "Meshes" "...is concerned with the interior experiences of an individual. It does not record an event which could be witnessed by other persons. Rather, it reproduces the way in which the subconscious of an individual will develop, interpret and elaborate an apparently simple and casual incident into a critical emotional experience."


title: Meshes of the Afternoon

text: Writing about "Meshes of the Afternoon", Lewis Jacobs credits Maya Deren with being the first film maker since the end of World War II to "inject a fresh note into experimental film production".


title: Meshes of the Afternoon

text: Further in his discussion of experimental cinema in postwar America, Jacobs says the film "attempted to show the way in which an apparently simple and casual occurrence develops subconsciously into a critical and emotional experience. A girl comes home one afternoon and falls asleep. In a dream she sees herself returning home, tortured by loneliness and frustration and impulsively committing suicide. The story has a double climax, in which it appears that the imagined, the dream, has become real.”


title: Meshes of the Afternoon

text: Deren uses specific cinematic devices in this film to convey deeper meaning. In a particular scene, Deren is walking up a normal set of stairs, and each time she pushes against the wall, it triggers the camera to move in that direction, almost as if the camera is part of her body. As she pulls herself up the last stair, the top of the stairs leads her to a window in her bedroom, which breaks the expectations of the viewer. In doing so, Deren destroys the normal sense of time and space. There is no longer a sense of what space she is in, nor for how long is was there. Deren constantly asks the viewer to pay attention and remember certain things by repeating the same actions over and over with only very subtle changes.