Question

Question 9: How does the addition of an acetyl group to a histone protein affect nucleosome structure, and why? How would the actions of a histone acetyltransferase or a histone deacetylase affect the rates of transcription, respectively? (Keep in mind that DNA that is easier to access is more robustly transcribed.)

Answer 1

Acetylation is the process of addition of acetyl group to the specific amino acid Residue of histone proteins. It is generally associated with an increase in the level of transcription of the genes to which the modified histone proteins are associated.

Acetylation leads to loosening of chromatin associated with the histone which is acetylated and this loosening leads to an easy accessibility of RNA polymerase and transcription factors to the gene. This leads to an increase in the rate of transcription of the gene.

Histone acetyltransferase is the enzyme which leads to the addition of acetyl group and thereby increasing gene expression where as histone deacetylase lead to the removal of acetyl group and decreases gene expression.

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