Fig. 2

Defects in peripheral nerves in Olig2-Cre;Rac1 ^CKO/− embryos. (a–d’) Neurofilament (NF) immunostaining of whole-mount E11.5 embryos reveals severely thinned XIIth and C1 nerves (green arrows in (b) vs. red arrowheads in (b’)) and phrenic nerve (green arrow in (c) vs. red arrowhead in (c’)) and a complete absence of the VIth nerve (arrows in (d) vs. arrowheads in (d’)) in the Olig2-Cre;Rac1 ^CKO/− embryo. The VIIth nerve is unaffected (lower arrows in (d) and (d’)). b–c’ are maximum intensity projections of subsets of complete Z stacks. In (d) and (d’) axons are color coded to represent depth within the Z stack, with red, green, and blue representing axons on the near, center, and far sides of the stack, respectively. N = 3 WT and N = 8 mutants. Scale bars: a, 1 mm; b, 200 μm; c and d, 100 μm. e–h’ Neurofilament (NF) immunostaining of whole-mount E13.5 limbs shows thinned dorsal and ventral nerves in Olig2-Cre;Rac1 ^CKO/− embryos compared to control forelimbs and hindlimbs. e’–h’ show magnified views of the boxed regions in (e–h). The red to blue color code represents depth within the Z stack, oriented along the dorsal to ventral axis. Arrows (control) and arrowheads (mutant) indicate corresponding nerves that are thinner in the mutant. D distal; P proximal. N = 14 for each genotype (summing E12.5 and E13.5). Scale bars: e, 500 μm; e’, 100 μm