Effects of MadMyc chimera expression on CDK, cyclin and CKI proteins. Polyclonal populations of RD cells stably transfected with MadMyc chimera and CMV were plated and harvested after 4 days. Cell lysates were analysed by immunoblotting with specific antibodies for indicated proteins. α-tubulin expression shows equal loading. The histograms (lower panel) show the values of fold increase over the control, arbitrarly set at 1, obtained by densitometric analysis of the immunoblottings. Similar results were obtained in two experiments.