Fig. 7. Depletion of endogenous GM1 or β1 integrin inhibits neurite outgrowth induced by laminin-1. (A,B) PC12 cells were transfected with the vector expressing EGFP and with (A) siRNA targeting GM1 synthase (β1,3-galactosyltransferase) or (B) β1 integrin. Expression levels of GM1 and β1 integrin were analyzed by western blotting 24 hours and 48 hours after the transfection. At 24 hours after each siRNA transfection, neurite outgrowth was analyzed and the percentage of EGFP-expressing cells with neurite outgrowth was determined as described in Materials and Methods. (C) Neurite outgrowth of PC12 cells was analyzed 24 hours after treatment with anti-β1-integrin antibody or normal mouse IgG. Data are given as the means + s.d. of triplicate results; ^*P<0.05 (A), P<0.01 (B,C); two-sided t-test. Bars, 50 µm.