mDia localization in DCs and characterization of cell morphology and adhesion in mDia1^−/− BMDCs. (A) mDia1 expression in DCs. B6 and mDia1^−/− BMDCs were incubated on FN-coated coverslips for 16 hours and stained with phalloidin and mDia1 Ab to reveal F-actin (green) and mDia1 (red). The cell nucleus was detected using 4,6-diamidino-2-phenylindole staining (blue). Bar represents 10 μm. (B) B6 and mDia1^−/− BMDCs incubated on FN-coated coverslips for 30 minutes, 4 hours, and 18 hours were stained with phalloidin; immunofluorescent images are shown. Open and closed arrowheads indicate membrane protrusion/lamellipodia and filopodia, respectively. (C) Morphology of BMDCs. B6 and mDia1^−/−BMDCs were incubated on coverslips coated with or without FN for 18 hours, and the major/minor axis ratio of BMDCs was measured. (D) Cell adhesion. B6 and mDia1^−/− BMDCs were labeled with CFSE and incubated in a 96-well-plate coated with or without FN for 45 minutes. The percentage of adherent BMDCs was measured using a fluorometer. Data are mean ± SD of 3 independent experiments. *P < .05 vs corresponding B6 mice.