Year: 2016
Type: article
Abstract: All the DNA in a cell's nucleus is packaged into a material called chromatin consisting of DNA and DNA-associated proteins.The basic unit of chromatin is the nucleosome which consists of ~147 bases of DNA wrapped around a protein core composed of two copies each of histones H2A, H2B, H3, and H4.DNA wrapped into a nucleosome is inaccessible to most DNA processing machinery.This machinery needs access to the DNA to perform processes such as transcription, replication, and repair.The cell uses many mechanisms to modulate this protection including nucleosome unwrapping, sliding, remodeling, disassembly, and chemical modification.This work used transcription factors along with fluorescent methods to probe the accessibility of DNA near the ends of the nucleosome.The DNA in this entry-exit region can spontaneously unwrap to provide transient access to DNA binding factors such as transcription factors.We studied the effect of histone post-translational modifications on the accessibility of DNA in the entry-exit region.We found that the phosphorylation at H3Y41ph increased DNA accessibility in vitro by 3-fold, which is similar in size to the effect of a previously studied modification H3K56ac.Since both of these modifications are associated with active genes and could occur together, we studied nucleosomes with both modifications and they showed a 17±5-fold increase in accessibility.This indicates that the
Author: Matthew Brehove
Institution: The Ohio State University
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2699596768