Fels Institute for Cancer Research, Department of Medical Genetics and Molecular Biochemistry, Temple University Lewis Katz School of Medicine, Philadelphia, Pennsylvania, USA.
Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY, USA.
Sci Rep. 2018 Nov 26;8(1):17384. doi: 10.1038/s41598-018-35511-3.
The spread of Zika virus (ZIKV) has caused an international health emergency due to its ability to cause microcephaly in infants. Yet, our knowledge of how ZIKV replicates at the molecular level is limited. For example, how the non-structural protein 5 (NS5) performs replication, and in particular whether the N-terminal methytransferase (MTase) domain is essential for the function of the C-terminal RNA-dependent RNA polymerase (RdRp) remains unclear. In contrast to previous reports, we find that MTase is absolutely essential for all activities of RdRp in vitro. For instance, the MTase domain confers stability onto the RdRp elongation complex (EC) and and is required for de novo RNA synthesis and nucleotide incorporation by RdRp. Finally, structure function analyses identify key conserved residues at the MTase-RdRp interface that specifically activate RdRp elongation and are essential for ZIKV replication in Huh-7.5 cells. These data demonstrate the requirement for the MTase-RdRp interface in ZIKV replication and identify a specific site within this region as a potential site for therapeutic development.
寨卡病毒（ZIKV）的传播因其导致婴儿小头畸形的能力而引发国际卫生紧急事件。然而，我们对 ZIKV 在分子水平上复制的了解是有限的。例如，非结构蛋白 5（NS5）如何进行复制，特别是 N 端甲基转移酶（MTase）结构域是否对 C 端 RNA 依赖性 RNA 聚合酶（RdRp）的功能至关重要，目前仍不清楚。与之前的报告相反，我们发现 MTase 对于 RdRp 的所有体外活性都是绝对必需的。例如，MTase 结构域赋予 RdRp 延伸复合物（EC）稳定性，并需要 RdRp 进行从头 RNA 合成和核苷酸掺入。最后，结构功能分析确定了 MTase-RdRp 界面上的关键保守残基，这些残基特异性地激活 RdRp 延伸，并对 Huh-7.5 细胞中的 ZIKV 复制至关重要。这些数据表明 MTase-RdRp 界面在 ZIKV 复制中的必要性，并确定了该区域内的一个特定位点作为治疗开发的潜在位点。
