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Inhibition of apoptosis by the NS3 protein of hepatitis C virus and its interaction with the p53 tumor suppressor protein.

丙型肝炎病毒 NS3 蛋白对细胞凋亡的抑制及其与 p53 肿瘤抑制蛋白的相互作用。

基本信息

批准号：
09670317
负责人：
HOTTA Hak
金额：
$ 1.98万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09670317/
关键词：
hepatitis C virus NS3 protein p53 tumor suppressor protein complex formation inhibition of apoptosis

项目摘要

Cells expressing the NS3 protein of hepatitis C virus, which were more resistant against actinomycin D-induced apoptosis, expressed a decreased level of p53 tumor suppressor protein than that of the control cells. Therefore, possible interaction between NS3 and p53 was studied. The full-size NS3 (NS3F) and a C-terminally truncated form of NS3 (NS3DELTAC), both of which were localized in the cytoplasm and the nucleus when expressed alone, were shown to be colocalized with p53 almost exclusively in the nucleus. On the other hand, NS3DELTANDELTAC, which lacks N-terminal 174 amino acid (aa) residues of NS3DELTAC, was not colocalized with p53. Immunoprecipitation analysis revealed that NS3F and NS3DELTAC, but not NS3DELTANDELTAC, coprecipitated with p53, suggesting that NS3 and p53 can form a complex through an N-terminal portion of NS3. A mutant form of NS3DELTAC that lacks N-terminal 28 aa residues still formed a complex with p53, although it did not form a complex with NS4A.This result indicates that p53-binding domain of NS3 is different from the NS4A-binding domain, supporting our observation that complex formation between NS3 and p53 takes place even in the presence of NS4A.Whereas an N-terminally truncated form of p53 bbund to NS3, C-terminal 93 aa-deleted p53 did not bind to NS3. Taken together, these results suggest that a portion near the N-terminus of NS3 (aa 1055 - 1200) and a C-terminal portion of p53 (aa 301 - 393), the latter of which contains p53 polymerization domain, are important for the complex formation between the two molecules. By using a CAT reporter plasmid that carries a p53-responsive promoter, NS3F and NS3DELTAC, but not NS3DELTANDELTAC, were shown to suppress transactivating function of p53, further implying the possible involvement of NS3 in hepatocarcinogenesis by hepatitis C virus.

表达丙型肝炎病毒NS3蛋白的细胞对放线菌素D诱导的细胞凋亡具有更强的抵抗力，P53抑癌蛋白的表达水平低于对照细胞。因此，我们研究了NS3与P53之间可能的相互作用。全长NS3(NS3F)和C端截短型NS3(NS3DELTAC)单独表达时均定位于胞浆和胞核，与P53共同定位于胞核。另一方面，NS3DELTANDELTAC缺少NS3DELTAC的174个氨基酸残基，不与P53共定位。免疫共沉淀分析表明，NS3F和NS3DELTAC与P53共沉淀，而不是NS3DELTAC，表明NS3和P53可以通过NS3的N端部分形成复合体。一个缺失N端28个氨基酸残基的突变体NS3DELTAC虽然没有与NS4A形成复合体，但它仍然与P53形成复合体。这一结果表明NS3的P53结合域不同于NS4A结合域，支持我们的观察，即即使在NS4A存在的情况下，NS3和P53之间也会形成复合体。由于N端截短的P53结合到NS3，C端93 AA缺失的P53不与NS3结合。综上所述，这些结果表明，NS3 N端附近的部分(AA 1055-1200)和P53的C端部分(AA301-393)对于这两个分子之间的复合体的形成是重要的，后者含有P53聚合域。通过使用携带P53应答启动子的CAT报告质粒，NS3F和NS3DELTAC，而不是NS3DELTANDELTAC，被证明抑制了P53的反式激活功能，进一步暗示NS3可能参与了丙型肝炎病毒引起的肝癌的发生。