Figure 5: Retinal ganglion cell axons guide astrocyte migration.

Schematic illustrating effects of RGC axon manipulations on astrocyte migration. Top: In retinas lacking both Robo1 and Robo2 genes, axon navigation is disrupted. Instead of projecting directly to the optic nerve head, as in wild-type retina (left), many mutant axons take meandering routes. Migrating astrocytes follow mistargeted axons regardless of their trajectories. Bottom: Atoh7 mutant mice lack RGCs. In these mutants, astrocytes can migrate a short distance from their origin but fail to reach peripheral retina. As a result their density in central retina is abnormally high. For further details see O’Sullivan et al. (2017).