Heterochromatin vs. euchromatin An<unk>  (ACS) is a region of DNA in a eukaryotic chromosome in which histone modifications such as acetylation lead to exposure of the DNA<unk>  thus allowing binding of transcription factors and transcription to take place.<unk><unk>  may also be called euchromatin. ACSs may occur in non-expressed gene regions which are assumed to be "poised" for transcription. The<unk>  once exposed often contains a promoter to begin transcription. At this site acetylation or methylation can take place causing a conformational change to the<unk> . At the<unk>  site deacetylation can caused the gene to be repressed if not being expressed.
Active chromatin sequence
Cis-regulatory element
Low copy repeats
Insertion sequence
Tandemly arrayed genes
Nucleic acid thermodynamics
Origin recognition complex
Tumor suppressor gene