Question

b. (4 pt) Describe how active 6mA DNA demethylation occurs.

Answer 1

Answer: - DNA methylation is a type of epigenetic process. DNA methylation is a process in which there is an addition of a methyl group (CH₃) to all four types of DNA nucleotides. DNA N⁶-adenine methylation (6mA) is prevalent in prokaryotes and functions in the host defense system. DNA N⁶-adenine methylation, the methylation occurs on the sixth position of the purine ring in DNA adenine also called N6-methadenine (6mA) and thus the name. DNA 6mA methylation specifically occurs by the addition of a methyl group from S-adenosyl-L-methionine to the exocyclic NH₂ at the sixth position of the purine ring in adenine by some specific methyltransferase enzymes. In prokaryotes such as bacteria, it is Dam and m.MunI that executes the process of DNA adenine methyltransferase. However, in eukaryotes, only the DNA N6 adenine methyltransferase 1 (DAMT-1) in C. elegans is known to possess this activity in DNA adenine methylation.