乙型肝炎病毒X蛋白促进SMC5 / 6的降解增强HBV的复制

StephenW

Cell Rep. 2016 Sep 13;16(11):2846-2854. doi: 10.1016/j.celrep.2016.08.026.
Hepatitis B Virus X Protein Promotes Degradation of SMC5/6 to Enhance HBV Replication.Murphy CM1, Xu Y2, Li F1, Nio K1, Reszka-Blanco N1, Li X1, Wu Y1, Yu Y3, Xiong Y4, Su L5.
Author information

• 1Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
• 2Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
• 3J. Craig Venter Institute, 9714 Medical Center Drive, Rockville, MD 20850, USA.
• 4Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. Electronic address: [email protected].
• 5Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. Electronic address: [email protected].
  

AbstractThe hepatitis B virus (HBV) regulatory protein X (HBx) activates gene expression from the HBV covalently closed circular DNA (cccDNA) genome. Interaction of HBx with the DDB1-CUL4-ROC1 (CRL4) E3 ligase is critical for this function. Using substrate-trapping proteomics, we identified the structural maintenance of chromosomes (SMC) complex proteins SMC5 and SMC6 as CRL4HBx substrates. HBx expression and HBV infection degraded the SMC5/6 complex in human hepatocytes in vitro and in humanized mice in vivo. HBx targets SMC5/6 for ubiquitylation by the CRL4HBx E3 ligase and subsequent degradation by the proteasome. Using a minicircle HBV (mcHBV) reporter system with HBx-dependent activity, we demonstrate that SMC5/6 knockdown, or inhibition with a dominant-negative SMC6, enhance HBx null mcHBV-Gluc gene expression. Furthermore, SMC5/6 knockdown rescued HBx-deficient HBV replication in human hepatocytes. These results indicate that a primary function of HBx is to degrade SMC5/6, which restricts HBV replication by inhibiting HBV gene expression.
Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.


PMID:27626656DOI:10.1016/j.celrep.2016.08.026

StephenW

细胞报道2016年9月13日; 16（11）：2846年至2854年。 DOI：10.1016 / j.celrep.2016.08.026。
乙型肝炎病毒X蛋白促进SMC5 / 6的降解增强HBV的复制。
墨菲CM1，徐Y2，李F1，仁王K1，Reszka布兰科N1，李X1，Y1吴，俞Y3，Y4雄，苏L5。
作者信息

    1Lineberger综合癌症中心，北卡罗来纳大学教堂山分校，教堂山，NC 27599，USA;微生物学和免疫学，北卡罗来纳大学教堂山分校，教堂山，NC 27599，USA系。
    2Lineberger综合癌症中心，北卡罗来纳大学教堂山分校，教堂山，NC 27599，USA;生物化学与生物物理，北卡罗来纳大学教堂山分校，教堂山，NC 27599，USA系。
    3J。克雷格·文特尔研究所，9714医疗中心道，Rockville，MD 20850，USA。
    4Lineberger综合癌症中心，北卡罗来纳大学教堂山分校，教堂山，NC 27599，USA;生物化学与生物物理，北卡罗来纳大学教堂山分校，教堂山，NC 27599，USA系。电子地址：[email protected]。
    5Lineberger综合癌症中心，北卡罗来纳大学教堂山分校，教堂山，NC 27599，USA;微生物学和免疫学，北卡罗来纳大学教堂山分校，教堂山，NC 27599，USA系。电子地址：[email protected]。

抽象

乙肝病毒（HBV）调节蛋白X（HBx蛋白）激活从HBV的共价闭合环状DNA（cccDNA的）基因组中的基因表达。 HBx蛋白与DDB1-CUL4-ROC1（CRL4）E3连接互动是这一功能的关键。使用衬底俘获蛋白质组学，我们确定了染色体（SMC）复杂蛋白质SMC5和SMC6作为CRL4HBx衬底的结构维持。 HBx蛋白表达与HBV感染体外培养的人肝细胞和体内人性化小鼠降解SMC5 / 6复杂。 HBx蛋白由CRL4HBx E3连接和随后降解的泛素蛋白酶体针对SMC5 / 6。使用小环的HBV（mcHBV）报道系统与HBx的依赖性活性，我们表明，SMC5 / 6击倒，或具有显性负SMC6抑制，增强HBx的空mcHBV-GLUC基因的表达。此外，SMC5 / 6击倒救出人肝细胞的HBx缺陷病毒复制。这些结果表明了HBx的一个主要功能是降低SMC5 / 6，其通过抑制HBV的基因表达限制HBV复制。

版权所有©2016年的作者。发布时间由Elsevier公司保留所有权利。

结论：
    27626656
DOI：
    10.1016 / j.celrep.2016.08.026