FIG. 8.

Knockdown of cell cycle regulatory protein p27 increases production of PKmut virus in 293 cells. (A) 293 cells infected with WT or PKmut were treated twice with control siRNA (Si-C), or siRNA directed against the p27 protein (Si-p27) prior to transfecting the cells with BZLF1/BRLF1/gp110 to induce lytic infection. The virus titer for each condition is shown (normalized to 1 for the amount of each virus induced in the presence of the control siRNA). (B) Western blot of the total p27 level in 293 WT and PKmut cells (note that 5 μg of total cell protein was loaded on the WT cell p27 blot, whereas 20 μg was loaded on the PKmut cell p27 blot). The level of BZLF1 and β-actin was also determined by immunoblotting analysis. (C) 293 cells infected with PKmut EBV were transfected with BZLF1 in the presence or absence of an EBV-PK expression vector. Western blotting was performed to examine the expression of p27 and β-actin.