what is the difference between proto-oncogenes and oncogenes
Oncogene A proto-oncogene is a normal gene that could become an oncogene due to mutations or increased expression. Proto-oncogenes code for proteins that help to regulate the cell growth and differentiation. Proto-oncogenes are often involved in signal transduction and execution of mitogenic signals, usually through their protein products. Upon acquiring an activating mutation, a proto-oncogene becomes a tumor-inducing agent, an oncogene.[13] Examples of proto-oncogenes include RAS, WNT, MYC, ERK, and TRK. The MYC gene is implicated in Burkitt's lymphoma, which starts when a chromosomal translocation moves an enhancer sequence within the vicinity of the MYC gene. The MYC gene codes for widely used transcription factors. When the enhancer sequence is wrongly placed, these transcription factors are produced at much higher rates. Another example of an oncogene is the Bcr-Abl gene found on the Philadelphia chromosome, a piece of genetic material seen in Chronic Myelogenous Leukemia caused by the translocation of pieces from chromosomes 9 and 22. Bcr-Abl codes for a tyrosine kinase, which is constitutively active, leading to uncontrolled cell proliferation. (More information about the Philadelphia Chromosome below)
Gluconeogenesis In mammals, gluconeogenesis has been believed to be restricted to the liver,[19] the kidney,[19] the intestine,[20] and muscle,[citation needed] but recent evidence indicates gluconeogenesis occurring in astrocytes of the brain.[21] These organs use somewhat different gluconeogenic precursors. The liver preferentially uses lactate, alanine and glycerol (especially alanine) while the kidney preferentially uses lactate, glutamine and glycerol (especially glutamine).[22][7] Lactate from the Cori cycle is quantitatively the largest source of substrate for gluconeogenesis, especially for the kidney.[7] The liver uses both glycogenolysis and gluconeogenesis to produce glucose, whereas the kidney only uses gluconeogenesis.[7] After a meal, the liver shifts to glycogen synthesis, whereas the kidney increases gluconeogenesis.[10] The intestine uses mostly glutamine and glycerol.[20]