Imbalanced expression of the individual members of miR-17-92 is associated with the loss of p53. (A) Quantitative RT-PCR analysis of individual precursor miR-17-92 expression in the KH9 and KH16 erythroleukemic cell lines derived from p53^−/− mice, relative to normal spleens. Each experiment was performed in quadruplicate, where error bars represent SD. (B) p53 and p21 protein expression in SB1 cells transduced to express the p53^Val−135 allele or empty vector cultured at 37°C and 32°C, where β-actin was used as a loading control. TK6 human B-lymphoblastoid and NIH-3T3 cells were used as positive controls (+control) for p53 and p21 expression, respectively. (C) Proliferation rates of empty vector control and p53^Val−135 transduced SB1 cells, as determined on the indicated days using the Trypan blue exclusion assay. Quantitative RT-PCR analysis of individual precursor miR-17-92 expression in (D) empty vector control and p53^Val−135 transduced SB1 cells cultured at 32°C, and (E-F left panel) indicated B-CLL patients displaying a p53⁻ and p53⁺ signature, respectively. Each experiment was performed in quadruplicate, where error bars represent SD; *P < .05, **P < .005. (E-F right panel) p53 and p21 protein expression in the indicated B-CLL patient samples, where β-actin was used as a loading control. B cells isolated from 5 normal healthy volunteers and the p53⁺ TK6 cells were used as controls.