Analysis of genes differentially expressed in c-Myb^Plt4/Plt4 pro-B cells. (A) Semiquantitative RT-PCR of gene expression in pro-B cells (B220⁺CD19⁺c-kit⁺) isolated from the bone marrow of 3- to 4-week-old c-Myb^+/+ and c-Myb^Plt4/Plt4 mice. Wedges indicate serial dilution of cDNA. Data are representative of 2 experiments. (B) Flow cytometry of Sca-1 (Ly6a) surface expression on pro-B cells from 3-week-old mice of the indicated genotypes. Plots are representative of 3 mice per genotype. (C) Quantitative real-time PCR of gene expression in pro-B cells (B220⁺CD19⁺c-kit⁺) isolated from the bone marrow of 3- to 4-week-old c-Myb^+/+ and c-Myb^Plt4/Plt4 mice. Expression is normalized to Hprt1 and is presented as relative to that in one of the wild-type samples, set as 1. *P < .05 in test group vs c-Myb^+/+ cells. Data represent the mean ± SEM of 3 to 6 samples of each genotype.