美国威斯达研究所Paul M. Lieberman研究组发现细胞周期依赖性EBNA1-DNA交联促进oriP和病毒附加体维持时复制终止。相关论文于2021年1月21日发表于国际顶尖学术期刊《细胞》。

他们显示EBNA1与质粒复制oriP的EBV起点形成细胞周期依赖性DNA交联。EBNA1酪氨酸518（Y518）对于交联至oriP是必不可少的，并且是附加体维持和EBV转化的淋巴母细胞样细胞系（LCL）生成所需的功能。从机理上讲，Y518是在oriP体内终止复制叉并在体外形成SDS抗性复合物所必需的。EBNA1-DNA交联对应于特定于复制终止位点（例如四向连接）富集的DNA结构的单链核酸内切酶活性。

这些发现表明，EBNA1在复制终止和病毒附加体维持所需的oriP处形成酪氨酸依赖性DNA-蛋白质交联和单链切割。

据悉，爱泼斯坦-巴尔病毒（EBV）是一种致癌性人类疱疹病毒，在增殖宿主细胞中以多拷贝附加体的形式持续存在。附加体的维持严格依赖于EBNA1，EBNA1是一种序列特异性的DNA结合蛋白，没有已知的酶促活性。

附：英文原文

Title: Cell-cycle-dependent EBNA1-DNA crosslinking promotes replication termination at oriP and viral episome maintenance

Author: Jayaraju Dheekollu, Andreas Wiedmer, Kasirajan Ayyanathan, Julianna S. Deakyne, Troy E. Messick, Paul M. Lieberman

Issue&Volume: 2021-01-21

Abstract: Epstein-Barr virus (EBV) is an oncogenic human herpesvirus that persists as a multicopyepisome in proliferating host cells. Episome maintenance is strictly dependent onEBNA1, a sequence-specific DNA-binding protein with no known enzymatic activities.Here, we show that EBNA1 forms a cell cycle-dependent DNA crosslink with the EBV originof plasmid replication oriP. EBNA1 tyrosine 518 (Y518) is essential for crosslinking to oriP and functionally required for episome maintenance and generation of EBV-transformedlymphoblastoid cell lines (LCLs). Mechanistically, Y518 is required for replicationfork termination at oriP in vivo and for formation of SDS-resistant complexes in vitro. EBNA1-DNA crosslinking corresponds to single-strand endonuclease activity specificto DNA structures enriched at replication-termination sites, such as 4-way junctions.These findings reveal that EBNA1 forms tyrosine-dependent DNA-protein crosslinks andsingle-strand cleavage at oriP required for replication termination and viral episome maintenance.

DOI: 10.1016/j.cell.2020.12.022

Source: https://www.cell.com/cell/fulltext/S0092-8674(20)31692-5