Fig. 3. Expression of PKCßI and the effects of V5 domains of PKC{alpha} and PKCß isoforms on cyclin A expression in neuroblastoma cells. A, CHO cells were transfected with CMS-EGFP vectors containing cDNA coding for PKC{alpha}, PKCßI, or PKCßII. The different cell lysates were analyzed with Western blots and detected with isoform-specific antibodies that demonstrate that the PKC isoforms are generated from the expression vectors and that the antibodies are isoform specific. B, lysates of SK-N-BE(2) cells (BE) were analyzed with anti-PKCßI antibody. Lysates of CHO cells transfected with empty CMS-EGFP (-) vector or with vector containing cDNA for PKC{alpha}, PKCßI, or PKCßII were included as positive and negative controls. C, SK-N-BE(2) cells were transfected with expression vectors coding for V5 domains of PKC{alpha}, PKCßI, and PKCßII fused to EGFP. Two days after transfection, transfected cells were analyzed for cyclin A immunoreactivity. Data are expressed as the percentage of transfected cells positive for cyclin A and are the mean ± SE of three separate experiments. Approximately 200 transfected cells identified by the presence of EGFP were scored on each coverslip. Controls (-) are cells expressing EGFP only. Levels of significance: P < 0.01 (**) compared with control cells (Student’s t test).