IL-7 mRNA expression from BM adherent cells of C/EBPβ+/+ and C/EBPβ−/− mice. Total RNA was extracted from MPA-treated BM adherent cells of C/EBPβ+/+ and C/EBPβ−/− mice. RT-PCR with mouse IL-7–specific primers was performed from the indicated amounts of RNA (0.1 μg, 0.2 μg). IL-7 mRNA expression was visualized by a Southern blot analysis of RT-PCR products in parallel with constitutively expressed GAPDH by using a mouse IL-7 or a human GAPDH cDNA.