Fig. 5.

Internalization assay. (A) CV-1 cells were transfected with Rab7-mRFP 20 h before the addition of fluorescently labeled SV40. Cells were incubated in the cold for 1 h, unbound virus was washed away, and cells were immediately transferred to the microscope. Five z sections of each cell were imaged with a spinning-disc confocal microscope before (10 min after washing) and after (15 min after washing) the addition of trypan blue to quench extracellular fluorescence. (B) Same as A, but cells were incubated at 37°C for 240 min before quenching (at 244 min). (C) Same as A, but cells were preincubated with Baf 1 h before and during incubation with the virus for 240 min at 37°C.