Postigo Antonio, Ramsden Amy E, Howell Michael, Way Michael
Cellular Signalling and Cytoskeletal Function Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT London, UK.
High Throughput Screening Facility, The Francis Crick Institute, 1 Midland Road, NW1 1AT London, UK.
Cell Rep. 2017 May 2;19(5):1022-1032. doi: 10.1016/j.celrep.2017.04.025.
In contrast to most DNA viruses, poxviruses replicate their genomes in the cytoplasm without host involvement. We find that vaccinia virus induces cytoplasmic activation of ATR early during infection, before genome uncoating, which is unexpected because ATR plays a fundamental nuclear role in maintaining host genome integrity. ATR, RPA, INTS7, and Chk1 are recruited to cytoplasmic DNA viral factories, suggesting canonical ATR pathway activation. Consistent with this, pharmacological and RNAi-mediated inhibition of canonical ATR signaling suppresses genome replication. RPA and the sliding clamp PCNA interact with the viral polymerase E9 and are required for DNA replication. Moreover, the ATR activator TOPBP1 promotes genome replication and associates with the viral replisome component H5. Our study suggests that, in contrast to long-held beliefs, vaccinia recruits conserved components of the eukaryote DNA replication and repair machinery to amplify its genome in the host cytoplasm.
与大多数DNA病毒不同，痘病毒在没有宿主参与的情况下在细胞质中复制其基因组。我们发现，痘苗病毒在感染早期、基因组去衣壳之前就诱导了ATR在细胞质中的激活，这是出乎意料的，因为ATR在维持宿主基因组完整性方面起着重要的核作用。ATR、RPA、INTS7和Chk1被招募到细胞质DNA病毒工厂，表明经典的ATR途径被激活。与此一致的是，药理学和RNAi介导的对经典ATR信号的抑制会抑制基因组复制。RPA和滑动夹PCNA与病毒聚合酶E9相互作用，是DNA复制所必需的。此外，ATR激活剂TOPBP1促进基因组复制并与病毒复制体成分H5相关联。我们的研究表明，与长期以来的观点相反，痘苗病毒招募真核生物DNA复制和修复机制的保守成分，以在宿主细胞质中扩增其基因组。
