Question

Which of the following accurately matches a histone tail modification with its effect on transcription?

Group of answer choices

a Methylation of lysine 4 on the H3 tail activates transcription of downstream genes

b Methylation of lysine 4 on the H3 tail activates transcription of upstream genes

c Acetylation of lysine 16 on H4 prevents transcription from taking place by blocking RNA polymerase from binding

d Acetylation of lysine 16 on H4 prevents transcription from taking place by preventing nucleosome formation

Answer 1

Ans. a and d are correct.

In histone methylation, methyl groups are transferred to amino acids of histone proteins that make up nucleosomes, DNA double helix is wrapped around nucleosomes to form chromosomes. Methylation of lysine 4 on the Histone 3 tail activates transcription of downstream genes.

Acetylation of lysine residues is important mechanism of epigenetic. It regulates the binding of histones to DNA in nucleosomes.