Fig. 1

Cortical neurons show abnormal morphologies in Kif20b-/- brains. A Example images of individual pyramidal neurons labeled by Golgi-Cox staining in Kif20b control (+/+, a) and mutant (-/-, b and c) E18.5 brains. An example projection of 3D-tracing is shown of a control neuron (a). Arrowhead in (c) points to proximal apical dendrite. B Apical dendrites of mutant pyramidal neurons were shorter. C Mutant neurons’ apical dendrites tapered more quickly and remained thinner distally. D Average cell body area at E18.5 was the same in control and mutant brains. E Schematic summary of morphological differences of E18.5 mutant cortical neurons. F Examples of retrogradely labeled neurons in control (+/+, a and b) or Kif20b mutant (-/-, c and d) E15.5 cortical plate from lateral diI crystal placements. Arrowheads indicate first branch point of apical dendrite. G Fewer mutant neurons were properly oriented with apical dendrites within 10° of perpendicular to the pia. n = 31 cells each from 4 control and 3 mutant brains, p = .04, Chi-squared test with n-1 correction. H Kif20b mutant neurons had shorter apical dendrites and shorter distance to first branch point. Distance to first branch point was still significant after normalization to cortical thickness. I Average cell body area at E15.5 was the same in control and mutant brains. J Schematic summary of findings from diI retrograde tracing in E15.5 cortices. For E18.5, n = 26 control and 25 mutant neurons from 4 control (3 +/+, 1 +/-) and 3 mutant (-/-) brains. For E15.5, n = 30 control and 31 mutant neurons from 4 control (1 +/+, 3 +/-) and 3 mutant (-/-) brains. Error bars are s.e.m. *, p ≤.05, ** p ≤.01, *** p <0.001, **** p <0.0001; student’s t-test for all except panel G. Scale bars, 20 μm