Question

Nucleosomes are made up of DNA and histones. Histones undergo various kinds of modifications by different groups of proteins. They are known as histone writers, readers, and erasers. Which of the following is/are histone writer(s)?

• A. {Histone acetyl transferases}
• B. {Histone methyl transferases}
• C. {Histone deacetylases}
• D. {DNA methyl transferases}

Hint:

Histone writers include proteins that add acetyl or methyl groups to histones, influencing chromatin structure and gene expression.

Answer 1

The Correct Option is A, B

Histone writers are proteins that add chemical groups to histones, thereby modifying chromatin structure and influencing gene expression.
- Histone acetyl transferases (HATs) add acetyl groups to histones, which leads to the loosening of the chromatin structure and promotes gene transcription. Therefore, HATs are considered histone writers.
- Histone methyl transferases (HMTs) add methyl groups to histones, which can either activate or repress gene expression, depending on the specific methylation pattern. HMTs are also histone writers.
- Histone deacetylases (HDACs) remove acetyl groups from histones, leading to chromatin condensation and gene repression, making them histone erasers, not writers.
- DNA methyl transferases (DNMTs) add methyl groups to DNA rather than histones, affecting gene expression, but they are not histone writers.
Thus, the correct answer is (A) and (B).