FIG. 4.

Diminished IGF-I mRNA expression in transformed macrophages and bone marrow from C/EBPβ^−/− mice. (A) RT-PCR analysis was performed on total RNA from J2-WT1 and J2-KO1 cells, their clonal derivatives (J2-WT1.CL14 and J2-KO1.CL10), and primary macrophages (BMDM). Total RNA was reverse transcribed with an oligo(dt) primer, and the cDNA was amplified with IGF-I- and GAPDH-specific primers, generating 384-bp (doublet) and 190-bp products, respectively. The IGF-I product was verified by sequencing. (B) RPAs were used to analyze the RNA samples shown in panel A and total bone marrow RNA isolated from wt and C/EBPβ^−/− female mice. RNAs were hybridized to IGF-I and GAPDH probes and digested with RNase. Protected fragments corresponding to IGF-I transcripts were quantitated by phosphorimaging and normalized to GAPDH (au, arbitrary units). The experiment was performed twice with similar results.