FIG. 7.

Cyclin D2/Cdk4 complexes accumulate in senescent wild-type but not E6 cells. (A) Western blot analysis of cell lysates prepared from indicated cell extracts which are described in the legend for Fig. 3. Note that anti-cyclin D2 antibody (47) cross-reacts with cyclin D1. (B) Western blot analysis of cyclin D1 and cyclin D2 immunoprecipitates isolated from early-passage (EP), senescent (S), and late senescent (LS) wild-type HDFs. Cyclin D1 and cyclin D2 were sequentially immunoprecipitated from the same extracts. Cyclin D1-specific band visible in cyclin D2 IP is either a “leftover” from cyclin D1 immunoprecipitation or it results from a cross-reaction.