Fig. 7. Dts57 and tsH5–4 are defective in morphogenesis in a rifampicin release temperature shift protocol.

BSC40 cultures were infected with wt (IHDW) and mutant (Dts57, tsH5–4) viruses in the presence of rifampicin at 31°C (permissive temperature). At 12 h p.i., cells were released from the rifampicin block and either left at 31°C (RR/31) or shifted up to 40°C (RR/S). Alternatively, the rifampicin block was maintained and the cells were left at 31°C (R/31) or shifted up to 40°C (R/S) until 36 h p.i. For protein synthesis and processing, tandem infections (as described above) were pulse labeled with ³⁵S-methionine at 12 h p.i., and then chased in cold medium +/− rifampicin at 31°C or shifted to 40°C for an additional 24 h. A) Schematic of the protocol with corresponding virus yield for each condition. B) Autoradiogram of pulse- and pulse-chase samples. Closed circles indicate precursors and open circles indicate cleaved products. C) Immunoblot analyses for proteolytic cleavage of A10 and G7 proteins. The upper section of the blot was probed with anti-A10 antibody and the bottom section of the blot was probed with anti-G7 antibody.