乙型肝炎病毒亚型A1前核心蛋白的体外表达受HBcAg影响，并可

StephenW

In vitro expression of precore proteins of hepatitis B virus subgenotype A1 is affected by HBcAg, and can affect HBsAg secretion
Aurélie Deroubaix  1   2 , Anna Kramvis  3
Affiliations
Affiliations

    1
    Hepatitis Virus Diversity Research Unit, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. [email protected].
    2
    Life Sciences Imaging Facility, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. [email protected].
    3
    Hepatitis Virus Diversity Research Unit, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa. [email protected].

    PMID: 33854155 DOI: 10.1038/s41598-021-87529-9

Free article
Abstract

HBeAg, a non-particulate protein of hepatitis B virus (HBV), is translated from the precore/core region as a precursor, which is post-translationally modified. Subgenotype A1 of HBV, which is a risk factor for hepatocellular carcinoma (HCC), has unique molecular characteristics in the basic core promoter/precore regions. Carriers of A1 exhibit early HBeAg loss. We sought to further characterize the precore proteins of A1 in vitro. HuH-7 cells were transfected with subgenomic constructs expressing individual precore proteins. Western blot analysis using DAKO anti-core antibody showed the expected sizes and a 1 kDa larger band for P22, P20 and P17. Using confocal microscopy, a cytoplasmic accumulation of HBeAg and precursors was observed with P25-expressing plasmid, whereas P22 localized both in the cytoplasm and nucleus. P20 and P17, which lack the carboxy end of P22 showed strong nuclear accumulation, implicating a nuclear localization signal in the N-terminal 10 amino acids. G1862T, unique to subgenotype A1, is frequently found in HBV from HCC patients. P25 with G1862T showed delayed and reduced HBeAg expression/secretion. Knock-out of core in the replication competent clones led to precore protein accumulation in the cytoplasm/perinuclear region, and decreased HBeAg secretion. Knock-out of precore proteins increased HBsAg secretion but intracellular HBsAg expression was unaffected. Over-expression of precore proteins in trans led to decreased HBsAg expression and secretion. Intracellular trafficking of HBV A1 precore proteins was followed. This was unaffected by the CMV promoter and different cell types. In the viral context, precore protein expression was affected by absence of core, and affected HBsAg expression, suggesting an interrelationship between precore proteins, HBcAg and HBsAg. This modulatory role of HBeAg and its precursors may be important in viral persistence and ultimate development of HCC.

StephenW

乙型肝炎病毒亚型A1前核心蛋白的体外表达受HBcAg影响，并可能影响HBsAg分泌
AurélieDeroubaix 1 2，安娜·克拉姆维斯3
隶属关系
隶属关系

    1个
    南非约翰内斯堡威特沃特斯兰德大学健康科学学院临床医学院内科肝炎病毒多样性研究室。 [email protected]。
    2个
    南非约翰内斯堡威特沃特斯兰德大学健康科学学院生命科学成像设施。 [email protected]。
    3
    南非约翰内斯堡威特沃特斯兰德大学健康科学学院临床医学院内科肝炎病毒多样性研究室。 [email protected]。

    PMID：33854155 DOI：10.1038 / s41598-021-87529-9

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抽象的

HBeAg是乙型肝炎病毒（HBV）的非颗粒蛋白，从前核心/核心区域翻译为前体，并在翻译后进行了修饰。 HBV的亚型A1是肝细胞癌（HCC）的危险因素，在基本核心启动子/前核心区域具有独特的分子特征。 A1的携带者表现出早期HBeAg丢失。我们试图进一步表征A1的体外precore蛋白。用表达单个前核心蛋白的亚基因组构建体转染HuH-7细胞。使用DAKO抗核心抗体的Western印迹分析显示，P22，P20和P17具有预期的大小和1 kDa的较大条带。使用共聚焦显微镜，用表达P25的质粒观察到HBeAg和前体的细胞质积累，而P22定位于细胞质和细胞核中。缺少P22羧基末端的P20和P17表现出强烈的核积累，这暗示了N端10个氨基酸中的核定位信号。 G1862T是亚型A1特有的，通常在HCC患者的HBV中发现。具有G1862T的P25显示出延迟和降低的HBeAg表达/分泌。复制感受态克隆中核心的敲除导致前核心蛋白在细胞质/核周区域中积累，并减少了HBeAg分泌。前核蛋白的敲除增加了HBsAg的分泌，但细胞内HBsAg的表达不受影响。反式前核心蛋白的过表达导致HBsAg表达和分泌减少。跟踪HBV A1前核心蛋白的细胞内运输。这不受CMV启动子和不同细胞类型的影响。在病毒环境中，前核心蛋白表达受到核心缺失的影响，并影响HBsAg表达，这表明前核心蛋白，HBcAg和HBsAg之间存在相互关系。 HBeAg及其前体的这种调节作用可能对病毒的持久性和肝癌的最终发展很重要。

StephenW

https://www.nature.com/articles/s41598-021-87529-9.pdf