Figure 1.
Ab-MuLV–induced colony formation in Jak1(+/–) and Jak1(–/–) cells. (A) Fetal livers were infected with Ab-MuLV and subsequently cloned into cytokine-free methylcellulose at a density of 1 × 105 cells per milliliter. One typical colony-formation assay of each genotype is depicted. (B) Quantification of colony formation expressed as function of available B-cell precursors. B-cell precursors represent the target cell population for Ab-MuLV transformation under our conditions; numbers were determined by FACS analysis. Data represent the mean values ± standard deviation of 3 individually plated colony assays for each fetal liver.
