Reelin-Dab1 signaling is required for normal neurite organization and branching but does not control total neurite length. (A) L6 neurons in r/r Ct-CM and s/s Ct-CM explants had the same total neurite arbor length as wt neurons, despite longer primary neurites observed in mutant neurons. (B) Mutant neurons also displayed higher numbers of primary neurites (emitted from cell soma), but a decrease in higher order branch number as compared to wt controls. Rln-CM injection into r/r mutant explants rescued primary neurite length and branching patterns. (C) Categorization of neurons by primary neurite number and treatment condition. (D) 3-D Sholl analysis of traced GFP + neurons revealed consistent profiles of neurite crosses vs. radius for r/r Rln-CM neurons and wt neurons at all radial domains (a-d). Error bars denote standard error of the mean. Kruskal-Wallis one-way ANOVA on ranks with post-hoc Dunn tests were performed between treatment conditions. * p < 0.05, as compared to wt controls. wt analysis: 209 neurons reconstructed from 22 explants across 9 litters. r/r Ct-CM analysis: 105 neurons reconstructed from 7 explants across 5 separate. s/s Ct-CM analysis: 49 neurons reconstructed from 3 explants across 3 litters. r/r Rln-CM analysis: 86 neurons reconstructed from 8 explants across 4 separate litters.