Figure 8
Enhanced cyclin–cdk activity in Jdp2KO MEFs. Cell growth was synchronized and cells were stimulated as described in the text. (a) Western blots (Wes) of cyclin-A2, cyclin-E2, cdk1 and β-actin in whole-cell lysates (left panel) and NEs (right panel). (b) Levels of the cdk-associated cyclin family. Whole-cell extracts from WT and Jdp2KO MEFs were immunoprecipitated (IP) with antibodies specific for cdk2 and then immunoprecipitates were subjected to sodium dodecyl sulfate-PAGE (10% acrylamide) and blotted with antibodies against cyclin-A2, cyclin-E2 and cdk2. Control of western blot using β-actin is indicated (lower panel). (c) Induction of cyclin–cdk phosphorylation of histone-H1. Immunoprecipitates containing the complexes with cyclin-A2 and cyclin-E2 were isolated from whole-cell extracts (400 μg total protein) using cyclin-A2- and cyclin-E2-specific antibodies and histone-H1-phosphorylating activity was determined in vitro as described in the text. cdk, cyclin-dependent kinase; KO, Jdp2-knockout; MEF, murine embryonic fibroblast; NE, nuclear extract; WT, wild type.
