FIG. 6.

Effect of roscovitine on the steady-state levels of cdk9 and cdk7 protein. G₀-synchronized cells were released into G₁ and infected with HCMV Towne at an MOI of 5 or with mock supernatant. Cells were treated with 16 μM roscovitine or DMSO at the time of infection or at 8 h p.i. and were harvested at 8 h p.i. (A) or 24 h p.i. (B). For mock- and virus-infected cells that were harvested at 24 h p.i. and treated with roscovitine or DMSO at the beginning of the infection, the medium was removed at 8 h p.i., and fresh medium containing roscovitine or DMSO, respectively, was added. Cell lysates from equal numbers of cells were run on an 8% SDS-polyacrylamide gel and subjected to Western blotting using antibodies for cdk9, cdk7, cdk2, and β-actin (loading control). G₀, cells released from G₀; M, mock treated; V, HCMV infected; −, DMSO treated; +, roscovitine treated at the time of infection; 8, roscovitine treated at 8 h p.i.