Laboratory of Genetics and Genomics, National Institute on Aging, Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224, USA.
Comparative Medicine Section, National Institute on Aging, Intramural Research Program, National Institutes of Health, Baltimore, MD, 21224, USA.
Antiviral Res. 2022 Dec;208:105451. doi: 10.1016/j.antiviral.2022.105451. Epub 2022 Oct 31.
A recent study demonstrated that a DNA-RNA dual-activity topoisomerase complex, TOP3B-TDRD3, is required for normal replication of positive-sense RNA viruses, including several human flaviviruses and coronaviruses; and the authors proposed that TOP3B is a target of antiviral drugs. Here we examined this hypothesis by investigating whether inactivation of Top3b can inhibit the replication of a mouse coronavirus, MHV, using cell lines and mice that are inactivated of Top3b or Tdrd3. We found that Top3b-KO or Tdrd3-KO cell lines generated by different CRISPR-CAS9 guide RNAs have variable effects on MHV replication. In addition, we did not find significant changes of MHV replication in brains or lungs in Top3B-KO mice. Moreover, immunostaining showed that Top3b proteins are not co-localized with MHV replication complexes but rather, localized in stress granules in the MHV-infected cells. Our results suggest that Top3b does not have a universal role in promoting replication of positive-sense RNA virus, and cautions should be taken when targeting it to develop anti-viral drugs.
最近的一项研究表明，DNA-RNA 双重活性拓扑异构酶复合物 TOP3B-TDRD3 是正链 RNA 病毒（包括几种人类黄病毒和冠状病毒）正常复制所必需的；作者提出 TOP3B 是抗病毒药物的靶点。在这里，我们通过研究缺失 Top3b 是否可以抑制鼠冠状病毒 MHV 的复制来检验这一假设，方法是使用缺失 Top3b 或 Tdrd3 的细胞系和小鼠。我们发现，由不同的 CRISPR-CAS9 向导 RNA 生成的 Top3b-KO 或 Tdrd3-KO 细胞系对 MHV 复制的影响不同。此外，我们没有发现 Top3B-KO 小鼠脑中或肺中 MHV 复制的显著变化。此外，免疫染色显示 Top3b 蛋白与 MHV 复制复合物没有共定位，而是定位于 MHV 感染细胞中的应激颗粒中。我们的结果表明，Top3b 在促进正链 RNA 病毒复制中没有普遍作用，在靶向它开发抗病毒药物时应谨慎。
