IL-3Rα is expressed in primary mouse and human OBL/stromal cells. (A) Murine stromal cells were grown for 10 days in either α-MEM (control) or osteogenic media (OBL induction). RNA was isolated, and expression of murine IL-3Rα was examined by RT-PCR analysis. The identity of the band as IL-3Rα was confirmed by direct sequencing. (B) Human BM adherent cells were cultured for 1, 2, or 3 weeks in osteogenic media as described in “Materials and methods.” Human IL-3Rα and IL-3 mRNA expression was detected by RT-PCR using specific primer pairs.