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XB-ART-57362
Sci Adv September 1, 2020; 6 (38):

Single-molecule imaging reveals control of parental histone recycling by free histones during DNA replication.

Gruszka DT , Xie S , Kimura H , Yardimci H .


Abstract
During replication, nucleosomes are disrupted ahead of the replication fork, followed by their reassembly on daughter strands from the pool of recycled parental and new histones. However, because no previous studies have managed to capture the moment that replication forks encounter nucleosomes, the mechanism of recycling has remained unclear. Here, through real-time single-molecule visualization of replication fork progression in Xenopus egg extracts, we determine explicitly the outcome of fork collisions with nucleosomes. Most of the parental histones are evicted from the DNA, with histone recycling, nucleosome sliding, and replication fork stalling also occurring but at lower frequencies. Critically, we find that local histone recycling becomes dominant upon depletion of endogenous histones from extracts, revealing that free histone concentration is a key modulator of parental histone dynamics at the replication fork. The mechanistic details revealed by these studies have major implications for our understanding of epigenetic inheritance.

PubMed ID: 32948589
PMC ID: PMC7500940
Article link: Sci Adv


Genes referenced: fen1 h2ac21 h2bc21
GO keywords: nucleosome [+]


Article Images: [+] show captions
References [+] :
Alabert, Chromatin Replication and Histone Dynamics. 2018, Pubmed