FIG. 5.

Interactions between P and P mutant with NP or L and oligomer formation of P. (A and B) Coimmunoprecipitation of P and P mutants with either L (with two Flag tags) or NP, respectively. BSR T7 cells were transfected with empty plasmid or plasmids encoding P, Pcpi−, Pcpi+, S157F, and/or L (A) or and/or NP (B). At 24 h posttransfection, the cells were metabolically labeled with ³⁵S-ProMix, lysed, and then subjected to immunoprecipitation with anti-P and anti-NP antibody (A) or anti-Flag antibody for L (B). The precipitates were then resolved in 10% SDS-PAGE and visualized by using a Storm PhosphorImager. (C) P protein oligomer formation. P and P mutants were expressed in BSR T7 cells, metabolically labeled, and then cross-linked using disuccinimidyl tartrate or dimethylsulfoxide as a control. The cells were lysed then subjected to immunoprecipitation with anti-P antibody. The precipitates were mixed with protein lysis buffer in the presence or absence of DTT, resolved in 10% SDS-PAGE, and visualized as described in Materials and Methods.