Hi everybody,
my question is about the histone mark dynamic. The Methyl group on the carbon 5 of a cytosine can be removed spontaneously without the intervention of demethylating actors (like TETs proteins) by spontaneous deamination with, at the end, the conversion of the nucleotide toward a Thymine. I would like to know if this "spontaneous process" can occur in histone mark context or if it must need of a specific eraser protein.
Thank you for your future replies.
The histone modifications described are dynamic and are catalyzed by specific enzymes.Histone acetyl transferases(HATs) catalyze the addition of acetyl groups to histones, whereas histone deacetylases(HDAcs) remove these modifications. Similarly, histone methyl transferases (HMTs) add methyl groups to histones, and histone demethylases(HDMs) remove these modifications.
Unmodified and methylated histone tails are thought to associate more tightly with nucleosomal DNA than acetylated histone tails. Modification of histone tails creates binding sites for chromatin-modifying enzymes.
Thank you Abel for your reply, it makes sense, and actually this possible turnover is the base of all epigenetic mechanisms. But my question was more focus on whether it is possible or not there is, further the classical system with HAT/HDAC or HMT/HDMT, a possible chemical transformation of the adduct (acetyl or methyl in this example) which triggers the disappearance of the histone mark, like you can see by deamination of methyl 5' Cytosine on DNA.
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