Molecular analysis on the tumorigenicity of hepatitis C virus nonstructural protein NS3

为了检测丙型肝炎病毒（HCV）NS 3对细胞的影响，我们采用脂质体转染法。含HCV NS 3基因组5 ′端半序列的转染子（HCV-NS 3-N）在裸鼠体内迅速增殖并形成肿瘤。而p53基因共转染后，HCV-NS 3-N+p53转染细胞无致瘤性。提示HCV-NS 3对p53的功能有一定影响。为了研究HCV-NS 3与p53的相互作用，我们制备了在细菌中表达的融合蛋白GST-HCV-NS 3。在使用细胞提取物的体外结合实验中，我们没有检测到NS 3与p53的结合。这并不排除HCV-NS 3与p53之间存在弱或间接相互作用的可能性。实际上，我们发现90 kDa的蛋白可以结合HCV-NS 3。另一方面，我们试图利用HCV相关病毒，即日本脑炎病毒（JEV）的复制系统来寻找有效的抗病毒药物。测试试剂之一呋喃萘醌（FNQ）显示抗病毒活性（Takegami等人，1998年）。抑制HCV的复制和抑制病毒与宿主细胞的某些反应是延缓HCV致瘤的关键。进一步分析HCV-NS 3与p53等宿主蛋白的相互作用及FNQ的抗病毒作用机制是十分必要的。

In order to examine the influence of hepatitis C virus (HCV) NS3 to the cells, we used transfection method using lipofectin. Transfectant containing 5'half sequence of the HCV genome segment encoding NS3 (HCV-NS3-N) rapidly proliferated and formed tumors in nude mice. However, after the cotransfection with tumor suppressor gene p53 transfectants (HCV-NS3-N+p53) did not show any tumorigenicity. The result suggest that HCV-NS3 has some influence to the function of p53. To investigate the interaction between HCV-NS3 and p53, we prepared the fusion-protein GST-HCV-NS3 expressed in the bacteria. In the binding experiment in vitro using cell extracts, we did not detect the binding of NS3 to p53. This does not exclude the possibility of the weak or indirect interaction between HCV-NS3 and p53. Actually we found 90 kDa protein which could bind to HCV-NS3. On the other hand, we tried to find the effective antiviral drug using the replication system of HCV-related virus, i.e. Japanese encephalitis virus (JEV). One of tested reagents, furanonaphtoquinone (FNQ) showed antiviral activity (Takegami et al., 1998). To retard the tumorigenesis by HCV,it is important to inhibit viral replication and some reactions between virus and host cells. Further analyzes on the interaction of HCV-NS3 and host proteins including p53, and mechanism of antiviral effect of FNQ are essential.