FIGURE 2.

β1-Integrin-null MECs contain functional β3-containing integrins. a, β1^fx/fx;CreER^TM MECs treated with 4OHT or without (C) were cultured on collagen-I coated coverslips, and the cell morphology was observed by phase microscopy after 3 days. Bar: 50 μm. b, similar cultures were stained for β1-integrin (green), and actin or tubulin (red). Bar: 20 μm. c, untreated control (C) and 4OHT-treated β1^fx/fx;CreER^TM MECs were used for an adhesion assay in serum-free medium on collagen I or FN, in the presence of β1-integrin and β3-integrin function blocking antibodies (10 μg/ml). The error bars represent S.D. of triplicate samples within a representative experiment (n = 3). No a/b, no antibodies, d, single cell suspensions of untreated control (C) and β1-integrin-deleted (4OHT) MECs were labeled with control or Alexa Fluor 488-conjugated anti-β3-integrin antibodies and analyzed by FACS. β3-Integrin was expressed on the surface of MECs, and its levels were similar following β1-integrin gene deletion. control ab, control antibody. e, β1-integrin and β3-integrin RNA levels were compared in control and 4OHT-treated β1^fx/fx;CreER^TM MECs 3 days after isolation from mice, by quantitative PCR. **, p < 0.01.