FIG. 7.

Ultrastructural analysis of BPV1 pseudovirion infection. Cells were preincubated at 4°C for 2 h with virions before being warmed to 37°C. Samples were obtained 5 min (A), 2 h (B), and 7 h (C and D) after the warming step. (A) A virion is bound at the plasma membrane (PM; star), and internalization into a vesicle is occurring (arrow). (B) A virion-filled vesicle has pinched off from the plasma membrane into the cytoplasm (arrow). (C) The ER and a virus-filled vesicle membrane are fusing (arrow). (D) Viruses are found free floating in the ER or perinuclear (N, nucleus) region and in a formed vesicle.