Fig. 6. Disruption of neuronal differentiation in kreisler^r3/r5 embryos. (A-D) The differentiation of neurones revealed by immunodetection of ß-tubulin is shown in dorsal views (A-C) and a lateral view (D) of E12.5 wild type (A) and kreisler^r3/r5 (B-D) embryos. (C) A higher magnification view of the ectopic nucleus seen in B; axons are seen extending dorsolaterally along the cleft at the r4/r5 boundary. (E-H) ß-galactosidase staining of r3/r5 lacZ reporter line shown in dorsal view at E11.5 (E,F) and parasagittal longitudinal section at E12.5 (G,H). v, ventricle; m, mantle region of neural tube. Arrows in B,D indicate the clefts that form at r3 and r5 in kreisler^r3/r5 embryos.