Dataset Information

Histone octamer structure is altered early in ISW2 ATP-dependent remodeling of nucleosomes

ABSTRACT: Histone octamers are thought to be a rigid part of nucleosomes that shape chromatin and block cellular machinery from accessing DNA. ATP-dependent chromatin remodelers like ISW2 mobilize nucleosomes to provide DNA access. We find evidence for histone octamer distortion preceding DNA being moved into nucleosomes and processive movement of the ATPase motor of ISW2 on nucleosomal DNA. DNA entering nucleosome is uncoupled from the ATPase activity of ISW2 and alterations of the histone octamer structure mediated by ISW2 by deletion of the SANT domain from the C-terminus of the Isw2 catalytic subunit. We also find that restricting histone movement by chemical crosslinking traps remodeling intermediates resembling those seen by loss of the SANT domain, further supporting the importance of changes in histone octamer structure early in ISW2 remodeling. Transient octamer distortions are stabilized by H3-H4 tetramer disulfide crosslinking, thereby linking intrinsic histone octamer flexibility to chromatin remodeling.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Xenopus Laevis (african Clawed Frog)

SUBMITTER: Jie Luo

LAB HEAD: Jeff Ranish

PROVIDER: PXD013967 | Pride | 2020-05-27

REPOSITORIES: Pride

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Publications

Histone Octamer Structure Is Altered Early in ISW2 ATP-Dependent Nucleosome Remodeling.

Hada Arjan A Hota Swetansu K SK Luo Jie J Lin Yuan-Chi YC Kale Seyit S Shaytan Alexey K AK Bhardwaj Saurabh K SK Persinger Jim J Ranish Jeff J Panchenko Anna R AR Bartholomew Blaine B

Cell reports 20190701 1

Nucleosomes are the fundamental building blocks of chromatin that regulate DNA access and are composed of histone octamers. ATP-dependent chromatin remodelers like ISW2 regulate chromatin access by translationally moving nucleosomes to different DNA regions. We find that histone octamers are more pliable than previously assumed and distorted by ISW2 early in remodeling before DNA enters nucleosomes and the ATPase motor moves processively on nucleosomal DNA. Uncoupling the ATPase activity of ISW2 ...[more]

PMID: 31269447

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Project description:Methylation of DNA at CpG dinucleotides represents one of the most important epigenetic mechanisms involved in the control of gene expression in vertebrate cells. In this report, we conducted high-throughput nucleosome reconstitution experiments on 572 KB of human DNA and 668 KB of mouse DNA that was unmethylated or methylated in order to investigate the effects of this epigenetic modification on the positioning and stability of nucleosomes. The DNA loci from both species contained the genes that encode the serum albumin family, the MYC protein, and the tumor suppressor p53. The results demonstrated that a small subset of nucleosomes positioned by nucleotide sequence was sensitive to methylation where the modification increased the affinity of these sequences for the histone octamer. The features that distinguished these nucleosomes from the bulk of the methylation-insensitive nucleosomes were an increase in the frequency of CpG dinucleotides and a unique rotational orientation of CpGs such that their minor grooves tended to face toward the histones in the nucleosome rather than away. We propose that these features serve to enhance the affinity of methylated DNA for the histone octamer and that this effect could be involved in gene regulatory mechanisms such as silencing. These methylation-sensitive nucleosomes were preferentially associated with exons as compared to introns while unmethylated CpG islands near transcription start sites became enriched in nucleosomes upon methylation. The results of this study suggest that the effects of DNA methylation on nucleosome stability in vitro can recapitulate what has been observed in the cell and provide a direct link between DNA methylation and the structure and function of chromatin. For the human data, there were 3 unmethylated nucleosome replicates, 2 methylated nucleosome replicates, an unmethylated MNase control, and an unmethylated sonicated control. For the mouse data, there were 2 unmethylated nucleosome replicates, 2 methylated nucleosome replicates, an unmethylated MNase control, a methylated MNase control, and an unmethylated sonicated control.

Dataset Information

Histone octamer structure is altered early in ISW2 ATP-dependent remodeling of nucleosomes

Publications

Histone Octamer Structure Is Altered Early in ISW2 ATP-Dependent Nucleosome Remodeling.

Similar Datasets

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