Indentification DDB1as A Novel Substrate Of Hepatitis C Virus(HCV) NS3/4A Protease And Its Role In HCV Replication And Antiviral Response

Approximate3%population around the world are infected by HCV (Hepatitis C Virus),2/3of which would become chronic hepatitis, leading to liver fibrosis, cirrhosis, and hepatocellular carcinoma. HCV NS3/4A protease comprises NS3protease and co-factor NS4A. During HCV polyprotein processing, NS3/4A mediates cleavage at3/4A、4A/4B、4B/5A、5A/5B sites. Besides, NS3/4A can cleave VISA and TRIF, inhibits the production of IFN-I and proinflamatory cytokines, evades the antiviral response.Proteomics has become a indispensable technique in cell molecular biology, which can be used for components indentifying in protein complex and cell organelles, posttranslational modifications and sophisticated functional screening.DDB1is the adaptor protein of Cullin4E3Ub ligase, Viral proteins has been found to hijack Cullin4-DDB1complex to evade the immune response-In the present research,we choose HCV NS3/4A as the bait, using Flag-tag affinity purification and LC-MS to find the NS3/4A interacted proteins.Our result shows that, we indentify a protein DDB1can interact and can be cleaved by NS3/4A in-vitro and in-vivo. The cleavage site is DDB1cystic78. DDB1has an important role in HCV replication. In DDB1RNAi Huh7cells, HCV entry level has no significant change, but HCV RNA replication attenuates sharply, while over-expression of DDB1can enhance the replication of HCV. Furthermore, the DDB1RNAi Huh7has a far more lower supernatant HCV titration compared with the WT Huh7.In summary, DDB1is a novel HCV NS3/4A interacted protein and substrate, which has a vital role for HCV replication in the host cells.