Infection process of the hepatitis B virus depends on the presence of a defined sequence in the pre-S1 domain
Infection process of the hepatitis B virus depends on the presence of a defined sequence in the pre-S1 domain
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DOI：
10.1128/jvi.73.3.2052-2057.1999
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发表时间：
1999-03-01
影响因子：
5.4
通讯作者：
Gripon, P
中科院分区：
文献类型：
--
作者：
Le Seyec, J;Chouteau, P;Gripon, P
在乙肝病毒的生命周期中，大包膜蛋白(L)起着举足轻重的作用。事实上，这种多肽对病毒组装是必不可少的，可能对感染过程也是必不可少的。通过进行诱变实验，我们先前已经排除了L蛋白的前S2结构域与病毒感染性的可能参与。在本研究中，我们评估了前-S1区在乙肝病毒感染中的作用。为此，我们创造了21个L蛋白的突变体。5个氨基酸的连续缺失覆盖了整个Pre-S1结构域。首先，将糖基化和非糖基化的L突变蛋白分别导入肝癌细胞中，证实了该突变体蛋白的高效表达。包膜蛋白的分泌速率被缺失或正或负改变，这表明前S1结构域含有几个能够影响表面蛋白分泌的调控序列。然后研究了突变蛋白支持病毒粒子产生的能力。只有四个C末端的缺失抑制了病毒粒子的释放，这四个缺失覆盖了可能与细胞质核衣壳相互作用的17个氨基酸。最后，证实了所有分泌的病毒粒子的外侧存在修饰的Pre-S1结构域，并在原代培养的正常人肝细胞上检测了它们的感染性。只有包含78到87个氨基酸的短序列才能容忍内部缺失，而不会影响病毒的感染性。这些结果证实了L蛋白参与了感染过程，并证明了氨基酸3到77之间的序列参与了这一过程。
During the life cycle of hepatitis B virus (HBV), the large envelope protein (L) plays a pivotal role. Indeed, this polypeptide is essential for viral assembly and probably for the infection process. By performing mutagenesis experiments, we have previously excluded a putative involvement of the pre-S2 domain of the L protein in viral infectivity. In the present study, we have evaluated the role of the pre-S1 region in HBV infection. For this purpose, 21 mutants of the L protein were created. The entire pre-S1 domain was covered by contiguous deletions of 5 amino acids. First, after transfection into HepG2 cells, the efficient expression of both glycosylated and unglycosylated L mutant proteins was verified. The secretion rate of envelope proteins was modified positively or negatively by deletions, indicating that the pre-S1 domain contains several regulating sequences able to influence the surface protein secretion. The ability of mutant proteins to support the production of virions was then studied. Only the four C-terminal deletions, covering the 17 amino acids suspected to interact with the cytoplasmic nucleocapsids, inhibited virion release. Finally, the presence of the modified pre-S1 domain at the external side of all secreted virions was confirmed, and their infectivity was assayed on normal human hepatocytes in primary culture. Only a short sequence including amino acids 78 to 87 tolerates internal deletions without affecting viral infectivity. These results confirm the involvement of the L protein in the infection step and demonstrate that the sequence between amino acids 3 and 77 is involved in this process.