Figure 2. DSCAM-mediated self-avoidance requires C-terminal interactions in only some amacrine cell types.
(A–C) Dopaminergic amacrine cells (stained for tyrosine hydroxylase, TH) are non-randomly spaced in wild type retinas (A), but lose mosaic spacing and form neurite fascicles in two-week old Dscam∆C/∆C (B) and Dscam-/- (C) retinas. (D) In both mutants, there was a significant increase in cell density. Spacing was quantified by DRP analysis; relative cell densities normalized to the overall density at increasing distances from reference cells are plotted in (E). By Voronoi (F) and nearest neighbor (G) analyses spacing in Dscam∆C/∆C retinas was not significantly different than in Dscam-/- animals. (H–J) Conversely, bNOS-positive amacrine cells were not visibly different between controls (H) and Dscam∆C/∆C retinas (I) despite clear fasciculation and loss of mosaic spacing in Dscam-/- mice (J). Dscam∆C/∆C values were intermediate between control and Dscam∆C/∆C in cell density (K), DRP (L), Voronoi (M), and nearest neighbor (N) analyses, but differences from control were not statistically significant. Means ± s.e.m. are represented in D–E, K–L. Box plots represent the median, first and third quartile, range, and outliers. N = 4–8 retinas per genotype. *p<0.05; **p<0.01; ***p<0.001; n.s. is not significant by Tukey post-hoc test between indicated genotypes or compared to controls. Scale bar is 100 µm. Representative Voronoi domains are in Figure 2—figure supplement 1.
Figure 2—figure supplement 1. Examples of Voronoi tessellation domains in Dscam mutants.
