Bimodal response of human ES-MNs to Sema3a. A, Human ESC-derived motor neurons (Hb9-GFP) differentiated upon RA and Hh treatment acquire LMC (GFP+, Foxp1+, arrows) and non-LMC identities (GFP+). B, Human ES-MNs grown on laminin demonstrate elaborated growth cones with F-actin-rich filopodia (phalloidin staining in red). C, Human ES-MNs are responsive to Sema3a. Growth cone collapse in response to 300 ng/ml Sema3a is protein synthesis dependent (significantly attenuated by cycloheximide; n = 2), while response to 900 ng/ml is protein synthesis independent (two-way ANOVA with post hoc analysis, *p < 0.05, **p < 0.01, ***p < 0.001). n.s., No significance; CHX, cycloheximide. Error bar indicates SD. Scale bars, 10 μm.