Fig 6.
pUL78 is required for viral entry into ARPE19 cells. ARPE19 cells were infected (0.1 TCID50/cell) at 4°C with TB40/Ewt-mCherry (TB40/Ewt) or TB40/E-mCherry-dlUL78-1 (dlUL78-1) for 1 h and then washed twice with PBS at 4°C. (A) Cell-associated viral DNA was assessed by qPCR as a measure of the relative number of particles bound to the cells. As a control, TB40/Ewt-infected cells were treated with trypsin to remove surface-exposed virus. (B) To monitor viral entry, infected cultures were shifted to 37°C for various time intervals following the 4°C washes. Virions that did not enter the cell were removed by trypsin treatment. As a control, cells were treated immediately following the 4°C incubation and returned to 37°C for 5 h to ensure that the trypsin treatment efficiently removed bound virus. Samples were assayed by qPCR in triplicate and normalized to the level of the cellular MDM2 gene.