Fig. 3
From: Drosophila enabled promotes synapse morphogenesis and regulates active zone form and function
Synaptic Abl overgrowth phenotype is epistatic to Dlar and Sdc and requires the catalytic activity of Abl in the pre-synaptic compartment. Third-instar LOF mutants of Dlar (a) and Sdc (b), exhibit decreased bouton number in muscle 6/7 NMJs compared to Canton-S wild-type controls. The phenotypes of Lar and Sdc LOF mutants were suppressed by AblLOF (a-b), indicating that Abl is downstream of the Dlar pathway. Expression of UAS-Abl(+) under the control of the neuronal 1407-GAL4 driver rescued the bouton gain phenotype observed in AblLOF animals to levels observed in Canton-S flies (c). This indicates that pre-synaptic Abl is necessary and sufficient in synapse morphogenesis. Expression of kinase-dead Abl (UAS-Abl(K-N)) pre-synaptically failed to rescue AblLOF phenotypes (c), further supporting the requirement for Abl catalytic activity in synaptogenesis. D, Schematic of the Dlar signaling pathway. Bouton number was determined by quantifying 1b and 1 s boutons. * P < 0.05, n.s. indicates not significant, as determined by Welch’s t-test; error bars indicate ± s.e.m. of genotype; gray shading indicates ± s.e.m. of control; n ≥ 20 NMJs for all genotypes