FIG. 7.

Double labeling of p16 and gp27 at 4 h 30 min postinfection. Cryosections were labeled with anti-p16 (10-nm-diameter gold) (arrowheads) and anti-gp27 (5-nm-diameter gold) (arrows). (A, C, and D) MVA in HeLa cells; (B) MVA in BHK cells. Panel A shows scattered labeling for both antigens in the vicinity of the Golgi stack (G). Note the concentration of p16 in structures that are in continuity with the smooth ER membranes. These domains are mostly devoid of gp27. In panel B, in addition to scattered ER labeling of p16, some is found on a multivesicular body-like structure (asterisk). The large arrow in panel B indicates the first hint, at 4 h 30 min, of a small crescent domain labeled for p16. In panels C and D examples of the membrane-rich vesicles described in the text are shown. Bars, 200 nm.