Expression Level of Small Envelope Protein in Addition to Sequence Divergence inside Its Major Hydrophilic Region Contributes to More Efficient Surface Antigen Secretion by Hepatitis B Virus Subgenotype D2 than Subgenotype A2.
Expression Level of Small Envelope Protein in Addition to Sequence Divergence inside Its Major Hydrophilic Region Contributes to More Efficient Surface Antigen Secretion by Hepatitis B Virus Subgenotype D2 than Subgenotype A2.
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DOI：
10.3390/v12090967
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发表时间：
2020-09-01
期刊：
影响因子：
--
通讯作者：
Tong S
中科院分区：
文献类型：
--
作者：
Wang Q;Fu S;Zhang J;Yuan Q;Li J;Xia N;Wen YM;Wang Y;Tong S
乙型肝炎表面抗原（HBsAg）促进持久性乙型肝炎病毒（HBV）感染。它主要与亚病毒颗粒分泌的小(S)包膜蛋白相对应。我们之前发现基因型D克隆比基因型A克隆表达更少的S蛋白，但显示更高的细胞外/细胞内HBsAg比例，表明更有效的分泌。本研究旨在通过比较A2亚基因型克隆（geno5.4）和D2亚基因型克隆（geno1.2）来表征其潜在机制。将5种全长或亚基因组构建物以不同剂量转染Huh7细胞。采用酶联免疫吸附法定量HBsAg， Western blot检测包膜蛋白。我们发现，随着DNA转染量的增加，细胞外/细胞内HBsAg的比例降低。来自两种亚基因组结构的相互矛盾的发现证实了基因型d衍生的大包膜蛋白的分泌抑制作用更强。嵌合构建后的定点突变显示，S蛋白中基因1.2特异性V118/T127和F161/A168分别促进和抑制HBsAg的分泌。综上所述，D2亚基因型比A2亚基因型更有效地分泌HBsAg，这是因为除了S蛋白中的V118和T127外，D2亚基因型的S蛋白表达水平较低，而其F161和A168序列反而减少了HBsAg的分泌。
Hepatitis B surface antigen (HBsAg) promotes persistent hepatitis B virus (HBV) infection. It primarily corresponds to small (S) envelope protein secreted as subviral particles. We previously found that genotype D clones expressed less S protein than genotype A clones but showed higher extracellular/intracellular ratio of HBsAg suggesting more efficient secretion. The current study aimed to characterize the underlying mechanism(s) by comparing a subgenotype A2 clone (geno5.4) with a subgenotype D2 clone (geno1.2). Five types of full-length or subgenomic constructs were transfected to Huh7 cells at different dosage. HBsAg was quantified by enzyme linked immunosorbent assay while envelope proteins were detected by Western blot. We found that ratio of extracellular/intracellular HBsAg decreased at increasing amounts of DNA transfected. Conflicting findings from two types of subgenomic construct confirmed stronger secretion inhibitory effect of the genotype D-derived large envelope protein. Chimeric constructs followed by site-directed mutagenesis revealed geno1.2 specific V118/T127 and F161/A168 in the S protein as promoting and inhibitory of HBsAg secretion, respectively. In conclusion, more efficient HBsAg secretion by subgenotype D2 than subgenotype A2 is attributed to lower level of S protein expression in addition to V118 and T127 in S protein, although its F161 and A168 sequences rather reduce HBsAg secretion.
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影响因子：
25.7
作者：
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