FIGURE 2.

HCV NS4a/b proteins are associated with the HCV RNP complex. Western blot analysis of the RNP complexes was carried out after two-step purification using antisera against NS4a and NS4b (see Materials and Methods). (A,B, lanes 1) Lysates prepared from Huh 7 cells hybridized with oligonucleotides specific to the neomycin gene that is complementary to the plus replicon RNA strand; (lanes 2) FCA4 lysates directly immunoprecipitated with anti-digoxigenin monoclonal antibody, omitting the first step of hybridization with biotin- and digoxigenin-tagged oligonucleotides; (lanes 3) FCA4 lysates hybridized to oligonucleotides specific to the neomycin gene that is complementary to the plus replicon RNA strand; (lanes 4) FCA4 lysates hybridized to nonspecific (unrelated) oligonucleotides.