FIG 2.

Stable Rb knockdown reduces the production of HCMV virions. (A) Equal amounts of protein lysates from subconfluent, serum-starved primary fibroblasts transduced with a retrovirus expressing a scrambled shRNA sequence (Scr) or an shRNA targeting Rb mRNA (Rb2) were analyzed by Western blotting with the indicated antibodies. (B to D) Serum-starved Scr or Rb2 cells were infected with AD169 at an MOI of 0.1 (B) or 1 (C) or with HCMV strain FIX labeled with GFP (FIX-GFP) at an MOI of 1 (D). Combined cell-free and cell-associated virus was collected 4 days postinfection, and the titers of virus were determined by standard plaque assay. The data are mean titers normalized to the Scr titer ± standard deviations from three biological replicates with technical triplicates. Statistical significance was determined by a permutation test prior to normalization (**, P < 0.01; ***, P < 0.001). (E) Serum-starved Scr or Rb2 cells were mock infected (M) or infected with AD169 at an MOI of 0.1 and harvested at the indicated hours postinfection (hpi). Equal amounts of protein lysates were analyzed by Western blotting with the indicated antibodies.