FIG. 4.

Core protein processing and viral morphogenesis. (A) Cleavage of P4b. BS-C-1 cells were infected with 5 PFU per cell of vG9i in the absence or presence of 50 μM IPTG (I). After 12 and 24 h, whole-cell extracts were prepared and analyzed by SDS-PAGE and Western blotting with antibody to P4b/4b. (B, C, and D) Electron microscopy. BS-C-1 cells were infected with 10 PFU per cell of vG9i for 21 h in the absence of IPTG. Ultrathin sections were prepared and examined by transmission electron microscopy Abbreviations: C, crescent; IV, immature virion; N, immature virions with nucleoid. Magnification is indicated by bars.