FIG. 4.

Electron microscopy of BSA-gold-labeled Vero cells at 48 (A, B, and C) or 72 (D) h after RUB infection. A mock-infected Vero cell at 72 h is shown in panel E. Panels A to C show long, virus-induced, tubular membrane structures connecting several endocytosed gold-containing CPVIs (asterisks). These large, proliferated membrane structures often consisted of several stacked lamina-like membranes close to CPVIs (B, C, and the enlarged inserts). In panel D, a large, convoluted membrane structure surrounds part of the cell cytoplasm. M stands for mitochondria, and L stands for membrane-bound lipid vesicles. Bars, 200 nm.