Abstract
Nucleosome assembly during DNA replication is tightly coupled to ongoing DNA synthesis. This process, termed DNA replication-coupled (RC) nucleosome assembly, is essential for chromatin replication and has a great impact on both genome stability maintenance and epigenetic inheritance. This review discusses a set of recent findings regarding the role of replisome components contributing to RC nucleosome assembly. Starting with a brief introduction to the factors involved in nucleosome assembly and some aspects of the architecture of the eukaryotic replisome, we discuss studies from yeast to mammalian cells and the interactions of replisome components with histones and histone chaperones. We describe the proposed functions of replisome components during RC nucleosome assembly and discuss their impacts on histone segregation and implications for epigenetic inheritance.
Highlights
From the disassembly of parental nucleosomes, unwinding of dsDNA, and DNA synthesis to the assembly of daughter nucleosomes, chromatin replication is one of the most complicated molecular events in cells, and it is mediated by an extensive set of protein machinery
During DNA replication, nucleosomes ahead of the replication fork must be disassembled to facilitate the movement of the DNA replication machinery, and behind the fork, new nucleosomes must be reformed on daughter strands with both recycled parental histones and newly synthesized histones to restore the chromatin
In summary, recent advances have illuminated the contribution of the replisome to RC nucleosome assembly (Fig. 1)
Summary
A brief introduction to DNA replication‐coupled (RC) nucleosome assembly Eukaryotic DNA replication occurs in the context of the chromatin environment [1]. Over the last 3 decades, significant progress has been made in identifying and characterizing the functions of histone H3-H4 chaperones involved in newly synthesized histone H3-H4 deposition, such as CAF-1 (chromatin assembly factor-1) [31], Asf (anti-silencing factor 1) [32], Rtt106 (regulator of Ty1 transposon 106) [27, 33], and FACT (facilitates chromatin transaction) [34]. Upon cells entering the G1 phase, licensing factors Cdc (cell division control protein 6) and Cdt (Cdc10dependent transcript 1) load MCM2-7 (minichromosome maintenance complex 2–7) to ORC binding sites to form pre-replication complex (pre-RC) in a process called origin licensing [74, 75]. The replisome assembly is a fundamental process during DNA replication that involves a number of replisome components functioning in a stepwise and highly cooperative fashion
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