Identification of critical residues in the regulatory protein HBx for Smc5/6 interaction and hepatitis B virus production
Identification of critical residues in the regulatory protein HBx for Smc5/6 interaction and hepatitis B virus production
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鉴定调节蛋白 HBx 中 Smc5/6 相互作用和乙型肝炎病毒产生的关键残基
DOI：
10.1016/j.antiviral.2022.105519
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发表时间：
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影响因子：
7.6
通讯作者：
Zhuqing Ouyang
中科院分区：
文献类型：
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作者：
Lili He;Huanyu Shen;Hui Deng;Xiaoyan Zhang;Yang Xu;Chunwei Shi;Zhuqing Ouyang
宿主5/6号染色体结构维持复合体（Smc 5/6）是B型肝炎病毒（HBV）的一种限制性因子，可抑制病毒ccDNA的转录。HBV通过表达调节性X蛋白（HBx）来拮抗这种限制，该调节性X蛋白（HBx）靶向Smc 5/6，通过DNA损伤结合蛋白1（DDB 1）E3泛素连接酶降解。然而，Smc 5/6如何与HBx相互作用的分子见解仍然难以捉摸。本研究系统地研究了Smc 5/6与HBx的相互作用。在pull-down试验中，在不存在DDB 1的情况下，Smc 5/6通过多个位点与HBx相互作用。HBx C-末端足以相互作用。最重要的是，在所有HBV亚型中严格保守的残基Phe 132是与Smc 5/6在体外和体内相互作用的关键。该位点（F132 A）的突变导致Smc 5/6相互作用、染色体外报告基因转录和细胞和小鼠模型中HBV产生的缺陷。总的来说，我们的数据确定了HBx上Smc 5/6相互作用和病毒产生的关键残基。这些结果为基础研究和靶向HBx的治疗药物提供了有价值的信息。
The host structural maintenance of chromosomes 5/6 complex (Smc5/6) is a restriction factor of hepatitis B virus (HBV) that inhibits the transcription of viral ccDNA. HBV antagonizes this restriction by expressing the regulatory X protein (HBx) which targets Smc5/6 for degradation via DNA damage-binding protein 1 (DDB1) E3 ubiquitin ligase. However, the molecular insights into how Smc5/6 interacts with HBx remain elusive. In this study, we systematically investigated the interaction between Smc5/6 and HBx. Smc5/6 interacts with HBx through multiple sites in the absence of DDB1 in the pull-down assay. HBx C-terminal is sufficient for the interaction. Most importantly, residue Phe132, which is strictly conserved in all HBV subtypes, is critical for interaction with Smc5/6 bothin vitroandin vivo. Mutation of this site (F132A) results in defect in Smc5/6 interaction, extrachromosomal reporter transcription, and HBV production both in cells and in mouse model. Collectively, our data identifies a key residue on HBx for Smc5/6 interaction and viral production. These results provide valuable information for both basic research and therapeutic drugs targeting HBx.