G-CSF-dependent proliferation of individual src family-deficient progenitors. (A-B) c-Kit⁺ Lin^- cells were isolated from the bone marrow of mice and cultured for 7 days in the presence of G-CSF and kit ligand (n = 3-5, each genotype). (A) Representative experiment. Data represent the mean ± SEM of triplicate measurements. (B) The fold expansion of cells in culture on day 7 is shown. In each experiment, the fold expansion of wild-type cells was defined as 1. (C) c-Kit⁺ Lin^- cells were placed into methylcellulose containing 100 ng/mL G-CSF and cultured for 7 days (n = 3). Shown is the average number of cells per colony on day 7 of culture. A total of 150 to 282 colonies were analyzed for each genotype. Data represent the average ± SEM. ^*P < .05.