P27Kip1is downregulated at the protein level, but not at the mRNA level, in pretumor B cells from LMP2A/λ-MYC mice compared with those in λ-MYC mice. (A) Representative western blots of cell cycle regulators in purified B cells from 3-week-old mice of indicated genotypes (C57BL/6 background). Each lane represents a protein sample from one mouse. (B) P27kip1 protein expression in B cells from 3-week-old mice shown as a ratio to WT expression from 5 independent experiments. (C) qRT-PCR analyses of Cdkn1b expression from 2 independent experiments using a WT mouse as a control for each experiment. All differences in mRNA and protein expression were analyzed by 1-way ANOVA. **P < .01, ***P < .001; ns, not significant. Data represent the mean ± SD.
