人源 Rev1 聚合酶可破坏 G-四链体 DNA。

Human Rev1 polymerase disrupts G-quadruplex DNA.

机构信息

Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205-7199, USA and Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, Gyeonggi-do 440-746, Republic of Korea.

出版信息

Nucleic Acids Res. 2014 Mar;42(5):3272-85. doi: 10.1093/nar/gkt1314. Epub 2013 Dec 23.

DOI:10.1093/nar/gkt1314

PMID:24366879

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC3950705/

Abstract

The Y-family DNA polymerase Rev1 is required for successful replication of G-quadruplex DNA (G4 DNA) in higher eukaryotes. Here we show that human Rev1 (hRev1) disrupts G4 DNA structures and prevents refolding in vitro. Nucleotidyl transfer by hRev1 is not necessary for mechanical unfolding to occur. hRev1 binds G4 DNA substrates with Kd,DNA values that are 4-15-fold lower than those of non-G4 DNA substrates. The pre-steady-state rate constant of deoxycytidine monophosphate (dCMP) insertion opposite the first tetrad-guanine by hRev1 is ∼56% as fast as that observed for non-G4 DNA substrates. Thus, hRev1 can promote fork progression by either dislodging tetrad guanines to unfold the G4 DNA, which could assist in extension by other DNA polymerases, or hRev1 can prevent refolding of G4 DNA structures. The hRev1 mechanism of action against G-quadruplexes helps explain why replication progress is impeded at G4 DNA sites in Rev1-deficient cells and illustrates another unique feature of this enzyme with important implications for genome maintenance.

摘要

Y 家族 DNA 聚合酶 Rev1 是真核生物中成功复制 G-四链体 DNA（G4 DNA）所必需的。在这里，我们表明人类 Rev1（hRev1）破坏 G4 DNA 结构并防止体外重折叠。hRev1 的核苷酸转移对于发生机械展开不是必需的。hRev1 与 G4 DNA 底物的结合 Kd，DNA 值比非 G4 DNA 底物低 4-15 倍。hRev1 在第一个四联体-鸟嘌呤的对面插入脱氧胞苷单磷酸（dCMP）的预稳态速率常数比观察到的非 G4 DNA 底物快约 56%。因此，hRev1 可以通过两种方式促进叉的进展：一是将四联体鸟嘌呤排挤出来展开 G4 DNA，这有助于其他 DNA 聚合酶的延伸；或者 hRev1 可以防止 G4 DNA 结构的重折叠。hRev1 对 G-四链体的作用机制有助于解释为什么在 Rev1 缺陷细胞中 G4 DNA 位点的复制进展受阻，并说明了该酶的另一个独特特征，这对基因组维护具有重要意义。