Stat5 contributes to IL-7–dependent B-cell precursor expansion, but

abl-induced transformation is independent of Stat5. (A) Ability to form IL-7–dependent colonies. Bone marrow was cloned in methylcellulose containing IL-7. (B) Ability to form Ab-MuLV–induced colonies. Bone marrow was infected with Ab-MuLV and cloned in methylcellulose under growth factor–free conditions. (C, D) Bone marrow from Stat5-deficient as well as control animals was cocultivated for 48 hours with GP+E86 producer cell lines for MSCV-bcr-abl p210/IRES-GFP and MSCV-bcr-ablp185/IRES-GFP. Three days after transduction, the cells were plated in methylcellulose.