UNC-40/DCC, SAX-3/Robo, and VAB-1/Eph Polarize F-Actin during Embryonic Morphogenesis by Regulating the WAVE/SCAR Actin Nucleation Complex
Figure 6
Post-embryonic genetic interactions of WAVE/SCAR genes and axonal guidance genes during neuronal migrations.
(A) WAVE/SCAR and Arp2/3 are required for ventral axonal guidance of the AVM neuron. The mec-4::gfp (zdIs5) transgene is expressed in 6 mechanosensory neurons [41]. Micrographs show representative ventral migration patterns. The cartoons below each micrograph show the path of the AVM axon (green) with ALM (black) for reference. In wild type animals the AVM axon migrates ventrally, then anteriorly towards the head. Anterior is on the left. Control RNAi: nematodes were fed the RNAi empty vector, L4440 in HT115 bacteria. (B) Loss of WAVE/SCAR or Arp2/3 partially suppresses the AVM ventral migration defect caused by misexpression of Slt/Robo. The nematode strains myo-3::slt-1 (kyIs218), myr::vab-1(quIs5) and myr::unc-40::gfp (lqIs131), carry transgenes that cause gain of function phenotypes in three axonal guidance receptors. gof = gain-of-function. (C) Summary of AVM defects: ventral migration defects, abnormal cell bodies and ectopic projections. Animals were cultured at 20°C. Asterisks indicate significant change in the phenotypes compared to the single mutants. ** = p<.01, *** = p<0.001 as determined by a One-way Anova test followed by the Tukey test.