Data from: An extracellular biochemical screen reveals that FLRTs and Unc5s mediate neuronal subtype recognition in the retina

In the inner plexiform layer of the mouse retina, ~70 neuronal subtypes form a stereotyped circuit that underlies visual processing. During development, subtypes organize into an intricate laminar structure. This organization is choreographed by extracellular interactions that mediate cell recognition events. To identify recognition proteins involved in lamination, we utilized microarray data from 13 subtypes to identify differentially-expressed cell surface and secreted proteins. Using these candidates, we performed a biochemical screen and identified ~50 previously-unknown receptor-ligand pairs. We tested the response of retinal neurons to several candidates and found that both members of one interaction pair, FLRT2-Unc5C, induce repulsion; each in a different neuronal subtype(s). Consistent with a repulsive role in mediating lamination, we observed a complementary expression pattern of FLRT2 and Unc5C in vivo. We identified that Starburst amacrine cells express FLRT2 and are repelled by Unc5C. These data support a repulsive mechanism for laminar restriction of Starburst amacrines.