A genomic approach of the hepatitis C virus generates a protein interaction map

The hepatitis C virus (HCV) causes severe liver disease, including liver ca ncer. A vaccine preventing HCV infection has not yet been developed, and, g iven the increasing number of infected people, this virus is now considered a major public-health problem. The HCV genome is a plus-stranded RNA that encodes a single polyprotein processed into at least 10 mature polypeptides . So far, only the interaction between the protease NS3 and its cofactor, N S4A, which is involved in the processing of the non-structural region, has been extensively studied. Our work was aimed at constructing a protein inte raction map of HCV. A classical two-hybrid system failed to detect any inte ractions between mature HCV polypeptides, suggesting incorrect folding, exp ression or targetting of these proteins. We therefore developed a two-hybri d strategy, based on exhaustive screens of a random genomic HCV library. Us ing this method, we found known interactions, such as the capsid homodimer and the protease dimer, NS3-NS4A, as well as several novel interactions suc h as NS4A-NS2. Thus, our results are consistent with the idea that the use of a random genomic HCV library allows the selection of correctly folded vi ral protein fragments. Interacting domains of the viral polyprotein an iden tified, opening the possibility of developing specific anti-viral agents, b ased on their ability to modulate these interactions. (C) 2000 Elsevier Sci ence B.V. All rights reserved.