Tubular epithelial cells (TECs) isolated from the PKD2 (1–703) rat (Mut) have reduced p57 and augmented Cdk2 mRNA and protein compared with TECs isolated from normal rat (SD). (A). Real-time PCR of p57 and Cdk2 in isolated TECs. Data represent the mean of normalized fold change from three independent samples ± SEM (ANOVA p < 0.01. * = significant difference). Data were normalized using two housekeeping genes, HPRT and GAPDH. (B). Protein levels of p57 and Cdk2 represented as the mean of normalized fold change of two independent Western blot experiments ± SEM (ANOVA p < 0.05. * = significant difference). Data were normalized by β-tubulin expression. (C). p57 protein levels were determined by western blot analysis in HEK293 stable clones and in NRK-52E transfectants. As expected, protein level of p57 is not perceptibly altered.