Histone deacetylase inhibitors are a class of drugs used as mood stabilizers and anti-epileptics that are also being researched for their efficacy as anti-cancer agents. Histone deacetylase inhibitors block the action of histone deacetylases, which remove acetyl groups from lysine residues in histone tails. How will blocking histone deacetylases affect gene expression in the cell?

Answer: Chromatin will become more open, and gene expression will be increased

Explanation:

The histone deactylase inhibitors are the chemical compounds that inhibits the histone deacetylases. These compounds are used as a class of drugs that is used for psychiatry and mood stabilizer. Most recently it is being used for the inflammatory disease and treatment of cancer.

In this class of drug there is an assistance of histone acetyl transferase which acetylate the lysine residues in core histones which leads to transcriptionally active and less compact chromatin.

Hence, the chromatin will be more open and gene expression is increased.