A brief review of nucleosome structure

Abstract

The nucleosomal subunit organization of chromatin provides a multitude of functions. Nucleosomes elicit an initial ~7-fold linear compaction of genomic DNA. They provide a critical mechanism for stable repression of genes and other DNA-dependent activities by restricting binding of trans-acting factors to cognate DNA sequences. Conversely they are engineered to be nearly meta-stable and disassembled (and reassembled) in a facile manner to allow rapid access to the underlying DNA during processes such as transcription, replication and DNA repair. Nucleosomes protect the genome from DNA damaging agents and provide a lattice onto which a myriad of epigenetic signals are deposited. Moreover, vast strings of nucleosomes provide a framework for assembly of the chromatin fiber and higher-order chromatin structures. Thus, in order to provide a foundation for understanding these functions, we present a review of the basic elements of nucleosome structure and stability, including the association of linker histones.

Immunostaining of Increased Expression of Enhancer of Zeste Homolog 2 (EZH2) in Diffuse Midline Glioma H3K27M-Mutant Patients with Poor Survival

“…Histone H3 is 1 of the 5 main histone proteins in the structure of chromatin in eukaryotic cells [1]. Modification of histone influences transcription and other processes in DNA, and one of these modifications is methylation [2].…”

SMARCA4 regulates gene expression and higher-order chromatin structure in proliferating mammary epithelial cells

“…Packaging of the DNA around the nucleosomes acts to tightly condense the genome (Cutter and Hayes 2015). At the same time, the cell has to regulate the accessibility of the chromatin to many enzymes for the regulation of gene expression, DNA replication, and repair.…”

Structure and Epigenetic Regulation of Chromatin Fibers

“…1). Other high-resolution structures of NCPs containing core histones from different species or with a different DNA sequence, different histone variants, or different nucleosome-binding proteins/peptides have been resolved subsequently to investigate the regulation of nucleosome structure as reviewed previously (Cutter and Hayes 2015;McGinty and Tan 2015;Zhu and Li 2016).…”

“…1). Other high-resolution structures of NCPs containing core histones from different species or with a different DNA sequence, different histone variants, or different nucleosome-binding proteins/peptides have been resolved subsequently to investigate the regulation of nucleosome structure as reviewed previously (Cutter and Hayes 2015;McGinty and Tan 2015;Zhu and Li 2016).Afterward, the manner of how a "beads-on-a-string" nucleosomal array folds into a condensed 30-nm chromatin fiber remains to be determined. Two basic classes of structural models had been proposed previously based on the studies of native 30-nm fibers in nuclei or isolated from nuclei (Finch and Klug 1976;Langmore and Paulson 1983;Widom and Klug 1985;Gerchman and Ramakrishnan 1987;Ghirlando and Felsenfeld 2008).…”