M.M.C.Lai, unpublished results) and associate with the viral replicase complex (Gibson Bost et al., 2000) . Cytoplasmic extracts from MHV-A59-infected cells were immunoprecipitated with anti-Flag antibody-conjugated beads, followed by western blotting with a rabbit polyclonal antibody against p22. At 8 h p.i., p22 was co-precipitated with the Flag-tagged hnRNP A1 from DBT-A1 cells, whereas no precipitation of p22 was observed in DBT-VEC cells ( Figure 7C ). For DBT-A1DC cells, co-immunoprecipitation was performed at 24 h p.i., when abundant MHV proteins were synthesized. p22 was shown to co-precipitate with hnRNP A1DC, indicating that hnRNP A1DC still formed a complex with the viral polymerase gene product. These results suggest that the ability of hnRNP A1DC to interact with the N and polymerase proteins was not altered.