In vivo and in vitro trans-cleavage activity of hepatitis C virus serine proteinase expressed by recombinant baculoviruses.

By the use of recombinant baculoviruses, the trans-cleavage of hepatitis C virus (HCV) non-structural polyprotein was studied. The viral serine proteinase encoded by the NS3 gene was expressed efficiently in insect cells infected with a baculovirus recombined with HCV cDNA corresponding to amino acids 1046-1243 and the signal sequence of the rabies virus G protein. Coinfection studies showed the in vivo trans-cleavage activity of the expressed protein by the use of a recombinant producing NS5 as a substrate. We also found that the partially purified NS3 serine proteinase prepared from the recombinant-infected cells could cleave NS5A/5B substrate. Characterization of the proteinase obtained wil provide basic knowledge on processing of the HCV polyprotein.