NS3 protein of Hepatitis C virus associates with the tumour suppressor p53 and inhibits its function in an NS3 sequence-dependent manner
NS3 protein of Hepatitis C virus associates with the tumour suppressor p53 and inhibits its function in an NS3 sequence-dependent manner
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DOI：
10.1099/vir.0.81735-0
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发表时间：
2006-06-01
影响因子：
3.8
通讯作者：
Hotta, Hak
中科院分区：
文献类型：
--
作者：
Deng, Lin;Nagano-Fujii, Motoko;Hotta, Hak
从29例患者中获得的丙型肝炎病毒（HCV）1b亚型的NS 3（NS 3-N）的N-末端198个残基，以及全长NS 3（NS 3-Full），分析了它们的亚细胞定位，与肿瘤抑制因子p53的相互作用以及在存在和不存在病毒辅因子NS 4A的情况下的丝氨酸蛋白酶活性。根据NS 4A缺失时的亚细胞定位模式，将NS 3-N序列分为三组，每组均表现出点状、弥漫性或混合型定位。嵌合NS 3-全序列，每个由单独的NS 3-N和共享的C-末端序列组成，显示出与相应的NS 3-N相同的定位模式。定点突变实验表明，在NS 3-N的特定位置处的单个或几个氨基酸取代改变了定位模式。有趣的是，在存在和不存在NS 4A的情况下，点样类型的NS 3，无论是NS 3-N还是NS 3-Full，与p53的相互作用都比弥漫型的强。此外，点样型的NS 3-N抑制p53的反式激活活性比弥散型的更强。丝氨酸蛋白酶活性在两种NS 3之间没有显著差异。在携带HCV RNA复制子的细胞中，观察到NS 3和p53之间的物理相互作用，并且与HCV RNA阴性对照细胞相比，p53介导的转录激活被显著抑制。我们的研究结果共同表明，NS 3在HCV的肝癌发生中起着重要作用的可能性，通过与p53在NS 3序列依赖的方式差异相互作用。
The N-terminal 198 residues of NS3 (NS3-N) of Hepatitis C virus (HCV) subtype 1b obtained from 29 patients, as well as full-length NS3 (NS3-Full), were analysed for their subcellular localization, interaction with the tumour suppressor p53 and serine protease activity in the presence and absence of the viral cofactor NS4A. Based on the subcellular-localization patterns in the absence of NS4A, NS3-N sequences were classified into three groups, with each group exhibiting either dot-like, diffuse or a mixed type of localization. Chimeric NS3-Full sequences, each consisting of an individual NS3-N and a shared C-terminal sequence, showed the same localization patterns as those of the respective NS3-N. Site-directed mutagenesis experiments revealed that a single or a few amino acid substitutions at a particular position(s) of NS3-N altered the localization pattern. Interestingly, NS3 of the dot-like type, either NS3-N or NS3-Full, interacted with p53 more strongly than that of the diffuse type, in both the presence and the absence of NS4A. Moreover, NS3-N of the dot-like type suppressed trans-activating activity of p53 more strongly than that of the diffuse type. Serine protease activity did not differ significantly between the two types of NS3. In HCV RNA replicon-harbouring cells, physical interaction between NS3 and p53 was observed consistently and p53-mediated transcriptional activation was suppressed significantly compared with HCV RNA-negative control cells. Our results collectively suggest the possibility that NS3 plays an important role in the hepatocarcinogenesis of HCV by interacting differentially with p53 in an NS3 sequence-dependent manner.