Question

Describe the role of histones and epigenetics in the organization and gene regulation in chromosomal structures.

Please be descriptive, but make it easy to understand! Thank you!

Answer 1

The chromatin is found in the form of beaded like structure. These beads are nucleosomes. Nucleosomes consists of histone protein and DNA.

Epigenetic is defined as the regulation of gene without changing its gene sequence. This is done by means of histone protein modification. There are two modes of epigenetic modification:

* Acetylation: when there is found acetylation of histone tail by acetyl transferase, then loosely bounded nucleosome are found. This leads to enhance the expression of gene because transcription factor can bind to the loosley bound DNA easily.

But when the acetyl group is removed from the histone tail by deacetylase enzyme, then there will be not found loosely bound nucelosome and leads to the repression of gene expression.

* Methylation: When the methyl group is added to the histone 3 at 3rd lysine position, then gene repression is found.

When methyl group is added at 4th lysine position in H3, then gene expression is found.