Figure 1.

N-RGMa is a repulsive guidance molecule. (a and b) Temporal retinal explants were cultured on substrates patterned with alternating stripes of laminin and laminin plus RGMa peptides. Axons were stained by using the F-actin stain Alexa Fluor-Phalloidin (Green) and the RGMa stripes were labeled with a red fluorophore. (a) When grown on stripes of alternating laminin and laminin plus C-RGMa (10 μg/ml), temporal axons did not show any clear preference. (b) On alternating stripes of laminin and laminin plus N-RGMa (10 μg/ml) temporal axons avoided the N-RGMa containing stripes. (c) Quantification of the avoidance index showed that N-RGMa (average decision index, 2.8±0.1), but not C-RGMa (average decision index, 0.2±0.1), had a clear repulsive guidance effect on growing axons. *P<0.05