gp130^flox/flox/TCre bone marrow does not produce hematopoietic cells in long-term cultures. (A) Photomicrographs of long-term bone marrow cultures. The stromal-cell monolayer appears normal in the gp130^flox/flox/Cre culture, but there are markedly reduced numbers of nonadherent hematopoietic cells. Magnification, × 100. (B) Quantification of myeloid cells produced in long-term bone marrow cultures. Data represent the mean ± SD of triplicate determinations and are representative of at least 3 independent experiments. ^*P < .05 and ^**P < .01 compared with gp130^+/+/TCre. (C) Quantification of CAFC frequency in long-term bone marrow cultures plated on irradiated stromal cells of the indicated genotype. ^*P < .05 compared with bone marrow cells plated on gp130^+/+/TCre stromal cells. (D) Immunocytochemistry of stromal cells in gp130^flox/flox/TCre cultures probed with control or anti-gp130 antibodies. Scale bar represents 10 μm. (E) Immunoblots of lysates of stromal cells from long-term bone marrow cultures probed with antibodies to gp130 or Tie2. Data are representative of 3 independent experiments.