Expression of Rac3 mRNA in E13 mice. Parasagittal sections of E12.5 to E13 wild-type (wt) and knockout (ko) mouse embryos were hybridized with antisense (AS) or sense (S) digoxigenin-labeled cRNAs for Rac3 and examined for signal detection. (A) Rac3 is specifically and widely expressed in the developing nervous system. (B) Cerebellum; (C) mesencephalon; (D and E) medulla oblongata; (F) trigeminal ganglion; (G) eye; (H and I) dorsal root ganglia; (J and K) spinal cord. Abbreviations: ctz, cortical transitory zone; dcn, deep cerebellar nuclei; di, diencephalon; drg, dorsal root ganglia; hb, hindbrain; he, heart; li, liver; lu, lung; mc, mouth cavity; me, mesencephalon; mg, midgut; nc, nasal cavity; ob, olfactory bulb; re, rectum; sc, spinal cord; se, septum; te, telencephalic vesicle. Bars: 500 μm (A); 200 μm (B to K).