Analysis of core protein precursor processing at the permissive (31C) and non-permissive (41C) temperatures. (A) Infected BSC40 cells were incubated at the indicated temperature and harvested 24 hours after infection. Lysates were analyzed by Western blot using antisera against the indicated protein. (B) Infected BSC40 cells were labeled with [35S]-methionine and [35S]-cysteine for 45 minutes at 8 hours after infection. Cells were harvested after the pulse (P) and or after being chased (C) with unlabeled methionine and cysteine until 24 hours after infection. Immunoprecipitated samples were separated on a 4–12% SDS PAGE gradient gel. Rifampicin (rif) and hydroxyurea (HU) were used at final concentrations of 100 μg/ml and 8 mM respectively.