(A) Human ES-derived motor neurons (Hb9-GFP) differentiated upon RA and HH treatment acquire LMC (GFP+, Foxp1+ - arrows) and non-LMC identity (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, error bar: STD). Scale bars :10 μm