Fig. 8
From: Mutation of Kinesin-6 Kif20b causes defects in cortical neuron polarization and morphogenesis
Kif20b mutant neurons’ growth cones have longer filopodia. A Representative images of control and Kif20b mutant growth cones of dissociated E14.5 cortical neurons cultured 2 DIV and immunostained to label neuronal tubulin (TuJ1, red), actin (phalloidin, green), and nuclei (DAPI, blue). Scale bars 10 μm. B The growth cones of axons are significantly larger in area than those of minor neurites, but similar in control (+/-, gray bars) and mutant (-/-, white bars) cells. C The average number of filopodia per growth cone did not differ significantly in Kif20b mutant neurons on either axons or minor neurites. For B-C, n = 38 control (+/-) axonal and 54 minor neurite growth cones; mutant (-/-) n = 37 axonal and 49 nascent dendritic growth cones. D Kif20b mutant neurons have longer filopodia on both axonal and nascent dendritic growth cones. Axonal filopodia are slightly but significantly longer than dendritic filopodia regardless of genotype. n = 217 control and 308 mutant filopodia from 39 and 37 axonal growth cones, and n = 155 +/- and 134 -/- filopodia from 25 and 22 minor neurite growth cones respectively. For (A-D), error bars are ± s.e.m. *, p < 0.01; **, p <10-3; ***p <10-5; ****p <10-6; *****, p <10-8; n.s., not significant, t-test. E In Kif20b mutant neurons, a higher percentage of growth cone filopodia contain detectable microtubules than in controls, in both axons and minor neurites. n = 217 for +/- and 308 -/- filopodia on axonal growth cones and n =155 +/- and 134 -/- filopodia on minor neurite growth cones. *, p <0.05 Fisher’s exact test. F Axonal growth cone labeled for actin (green) and tubulin (red). Arrowheads mark filopodia containing microtubules