Figure 8. Dendrite Morphogenesis and Axonal Projections of Ndel1^−/− Neurons.

(A–F) Morphology and dendrite pattern of pyramidal cells in the cortex (A and B), in the CA3 layer of the hippocampus (C and D), and in Purkinje cells of the cerebellum (E and F) in control- (A, C, and E) and Ndel1-MADM (B, D, and F). Genotypes of green and red cells are shown below each panel. All images are from P21 animals with the following genotypes: MADM-11^GT/TG;Emx1^Cre/+ (A and C); MADM-11^GT/TG,Ndel1;Emx1^Cre/+ (B and D); MADM-11^GT/TG;Nestin-spCre^+/− (E); MADM-11^GT/TG,Ndel1;Nestin-spCre^+/− (F). Arrows in (A and B) point to basal segments of pyramidal cells in the cortex; white stars (A, B, and D) mark apical dendrites in pyramidal cells in the cortex (A and B) and CA3 hippocampus (D). ML, molecular layer; PC, Purkinje cell layer; IGL, internal granule layer.

(G–R) Axonal projections in control- and Ndel1-MADM using Emx1^Cre/+. (G–J) Corticothalamic projections in thalamus at P21 (G and H) and P1 (I and J). Inset in (G and H) are higher magnification images highlighting axonal varicosities in Ndel1^−/− corticothalamic projections. Inset in (J) highlights red Ndel1^+/+, yellow Ndel1^+/−, and green Ndel1^−/− nascent growing axons in P1 thalamus.

(K–P) Time course of axonal projections in the internal capsule in control- (K, M and O) and Ndel1-MADM (L, N and P) at P1 (K and L), P7 (M and N) and P21 (O and P). Note the progressive increase in number and size of axonal varicosities as marked by white arrows (N and P) in green Ndel1^−/− mutant subcortical projections. (Q and R) Hippocampal efferents in the fornix in control- (Q) and Ndel1-MADM (R) at P21. White arrow in (R) marks accumulation of varicosities from green Ndel1^−/− axons.

Scale bar, 30 μm (A–D); 50 μm (E and F); 230 μm (G, H, and M–P); 200 μm (K and L); 110 μm (I, J, Q, and R). See also Figures S8 and S9.