Hematopoietic progenitors from ICSBP^−/−mice display reduced adhesion to fibronectin, but not to laminin. c-kit⁺–enriched cell fractions were prepared as described in Materials and Methods. The percentage of c-kit⁺ cells in lineage-depleted fractions was as follows: 92%, 88.5% (ICSBP^+/+), and 89%, 81% (ICSBP^−/−) in 2 independent sorting experiments, respectively. (A) c-kit⁺–enriched bone marrow cells from wild-type (black bars) or ICSBP^−/− mice (gray bars) were plated on 48-well plates precoated with either fibronectin or BSA in the presence or the absence of the cytokines indicated. Subsequently, adherent, as well as nonadherent fractions, were cultured in the presence of IL-3 (10 ng/mL). Percent adherence was calculated as the number of CFC in the adherent fraction divided by the number of CFC in both fractions × 100% (see Materials and Methods). Data shown represent mean ± SEM of 2 independent experiments. (B) Bone marrow cells from wild-type (black bars) or ICSBP^−/− mice (gray bars) were incubated on 48-well plates precoated with laminin (see Materials and Methods). Adherent cells were subjected to CFC assay as described above. Data shown represent mean ± SEM of 2 independent experiments performed in triplicate with 2 mice per group.