Question

what is the relationship between DNA methyl and histone methylation

Answer 1

Ans.

Both DNA methylation and Histone methylation are involved in changing the expression profile of the DNA molecule, both of them are generally associated with the transcriptional repression.

DNA methylation is the addition of methyl group to the bases (adenine and cytosine) of the DNA. DNA methyltransferase catalyse the addition of methyl group to the DNA. Cytosine is most commonly methylated. DNA methylation repress the transcription of gene.

Histone methylation is the addition of methyl group to the lysine (K) and arginine (R) residues of the histone tail. Histone methylation is carried out by the enzyme histone methyltransferase that catalyse the addition of methyl group to lysine and arginine residues of the histone tail. Lysine is most commonly methylated. Histone methylation leads to transcriptional repression or activation according to the amino acid that is being methylated.