Role of N-linked glycans in the functions of hepatitis C virus envelope glycoproteins
Role of N-linked glycans in the functions of hepatitis C virus envelope glycoproteins
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DOI：
10.1128/jvi.79.13.8400-8409.2005
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发表时间：
2005-07-01
影响因子：
5.4
通讯作者：
Dubuisson, J
中科院分区：
文献类型：
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作者：
Goffard, A;Callens, N;Dubuisson, J
丙型肝炎病毒（HCV）编码两种病毒包膜糖蛋白。 E1含有4或5个N联糖基化位点，E2含有多达11个，其中大多数位点都非常保守，表明它们在这些蛋白质的某些功能中发挥重要作用。在这项研究中，我们使用含有突变的 HCV 包膜糖蛋白的逆转录病毒假型颗粒来研究这些聚糖。突变体以 N 后跟与每个糖蛋白中潜在糖基化位点的相对位置相关的数字命名（E1 突变体为 E1N1 至 E1N4，E2 突变体为 E2N1 至 E2N11）。这些突变体的表征使我们能够定义三种表型。对于第一组（E1N3、E2N3、E2N5、E2N6、E2N7 和 E2N9），突变体的感染性接近野生型。第二组（E1N1、E1N2、E1N4、E2N1 和 E2N11）包含仍然具有传染性的突变体，但其传染性已降至野生型的 < 50%。第三组（E2N2、E2N4、E2N8 和 E2N10）包含几乎完全失去感染性的突变体。 E2N8 和 E2N10 突变体缺乏感染性是由于 E1E2 异二聚体未掺入 HCVpp，这是由于异二聚体错误折叠所致，如构象敏感抗体免疫沉淀和 CD81 Pull-down 测定所示。 E2N2 和 E2N4 突变体缺乏感染性表明这两种聚糖参与控制 HCV 进入。总之，数据表明HCV包膜糖蛋白的一些聚糖在蛋白质折叠中起主要作用，而其他聚糖在HCV进入中发挥作用。
Hepatitis C virus (HCV) encodes two viral envelope glycoproteins. El contains 4 or 5 N-linked glycosylation sites and E2 contains up to 11, with most of the sites being well conserved, suggesting that they play an essential role in some functions of these proteins. For this study, we used retroviral pseudotyped particles harboring mutated HCV envelope glycoproteins to study these glycans. The mutants were named with an N followed by a number related to the relative position of the potential glycosylation site in each glycoprotein (E1N1 to E1N4 for E1 mutants and E2N1 to E2N11 for E2 mutants). The characterization of these mutants allowed us to define three phenotypes. For the first group (E1N3, E2N3, E2N5, E2N6, E2N7, and E2N9), the infectivities of the mutants were close to that of the wild type. The second group (E1N1, E1N2, E1N4, E2N1, and E2N11) contained mutants that were still infectious but whose infectivities were reduced to < 50% that of the wild type. The third group (E2N2, E2N4, E2N8, and E2N10) contained mutants that had almost totally lost infectivity. The absence of infectivity of the E2N8 and E2N10 mutants was due to the lack of incorporation of the E1E2 heterodimer into HCVpp, which was due to misfolding of the heterodimer, as shown by immunoprecipitation with conformation-sensitive antibodies and by a CD81 pull-down assay. The absence of infectivity of the E2N2 and E2N4 mutants indicated that these two glycans are involved in controlling HCV entry. Altogether, the data indicate that some glycans of HCV envelope glycoproteins play a major role in protein folding and others play a role in HCV entry.