GN11 cells express Robo receptors and respond to class 3 semaphorins and Slit1. A, Reverse transcription-PCR analysis showed expression of Robo1–3 in GN11 cells. B, Immunohistochemistry confirmed the expression of Robo receptors in GN11 cells. C, D, Quantification of GN11 cell migration in a Boyden's chamber, containing Sema3A, Sema3F, Slit1, or control (CM-myc) conditioned media (C). D, Robo1-DN-transfected GN11 cells are less responsive to Sema3A than control (GFP)-transfected cells. Scale bar, 100 μm. ***p < 0.001. Error bars indicate SEM.