What happens when you methylate cytosine?
Methylation of cytosine to form 5-methylcytosine occurs at the same 5 position on the pyrimidine ring where the DNA base thymine’s methyl group is located; the same position distinguishes thymine from the analogous RNA base uracil, which has no methyl group.
What is cytosine methylation used for?
Cytosine methylation affects the accessibility of the genomic regions to regulatory proteins/protein complexes, which influences chromatin structure and/or affects the rate of transcription of the gene. Cytosine methylation is the only well-studied DNA modification with established maintenance mechanisms.
Does cytosine have a methyl group?
In the mammalian genome, DNA methylation is an epigenetic mechanism involving the transfer of a methyl group onto the C5 position of the cytosine to form 5-methylcytosine.
What causes hypomethylation?
Gene hypomethylation contributing to tumor formation & tumor progression. Hypomethylation of gene regions, which has been implicated in various diseases [147], may foster the formation and progression of tumors in diverse ways.
What is hypermethylation associated with?
We demonstrate that DNA hypermethylation can be associated not only with downregulation of gene expression, but also that a considerable fraction of hypermethylated genes is associated with upregulation of gene expression.
How does DNA methylation repress gene expression?
DNA methylation regulates gene expression by recruiting proteins involved in gene repression or by inhibiting the binding of transcription factor(s) to DNA. As a consequence, differentiated cells develop a stable and unique DNA methylation pattern that regulates tissue-specific gene transcription.
What does histone methylation do?
Methylation of histones can either increase or decrease transcription of genes, depending on which amino acids in the histones are methylated, and how many methyl groups are attached. This process is critical for the regulation of gene expression that allows different cells to express different genes.
Why is cytosine so important?
Cytosine is an important part of DNA and RNA, where it is one of the nitrogenous bases coding the genetic information these molecules carry. Cytosine can even be modified into different bases to carry epigenetic information. Cytosine has other roles in the cell, too, as the energy carrier and cofactor CTP.