FIG. 4.

(A) The IN mutation C130-G reduces the amount of IN oligomers in viral particles. Western blot analysis of viral particle content was performed as described in the legend to Fig. 2, with antibodies specific for the Gag products MA and CA (left panel) or with anti-HA antibody (middle and right panels) under reducing and nonreducing conditions. IN monomers and oligomers are indicated. Numbers at left show molecular masses in kilodaltons. (B) Pulse-chase labeling of IN expressed in the absence of other viral proteins. Wild-type (IN-WT) and C130-G mutant (IN-Cys−) Flag-tagged IN proteins were transiently expressed in HeLa cells. Transfected cells were metabolically labeled for 1 h and chased by an excess of unlabeled amino acids for the indicated time intervals. Cell lysates were immunoprecipitated with anti-Flag antibody and run on an SDS-polyacrylamide gel electrophoresis gel. CTRL, mock-transfected cells.