Fig. 9. Profound alterations in cerebellar topography in the Ebf2 null cerebellum. (A) posterior, dorsal and anterior views of a wholemount X-gal stained adult cerebellum. The lobules in the vermis are labeled (I-X). Expression of the transgene is similar to that in the heterozygote (see Fig. 8) except for a dramatic narrowing on the anterior lobes due to PC death (I-V). (B,B'-H,H') Matched pairs of immunoperoxidase-stained transverse sections from the +/- (B-G) and -/- (B'-G') vermis; ZII expression from lobule IX to lobule I; SPHK1a expression in lobule VIII (H,H'). Posterior lobules: alternating ZII^+/- stripes in the heterozygote (IX, VIII, VII) have been replaced by uniform ZII+ expression domains (IX, VII) or by intermingled positive and negative PCs as in lobule VIII, where superimposable changes are observed with SPHK1a immunostaining (H,H'). In the AZ, alternating ZII+ stripes are preserved in the null (E-G: P1+ and P2+ are labeled in F) but stripe spacing is reduced due to loss of the ZII-immunonegative P1-stripe. The alterations in stripe patterning are evident in cerebella wholemount- immunostained for ZII. (I,J) Posterior hemispheres. (K,L) Posterior vermis: ZII-immunonegative stripes are absent in L. (M,N) anterior hemispheres. (O,P) anterior vermis: ZII-stripes in P are present but shrunk, due to perinatal PC apoptosis. Scale bars: in A, 2 mm for A; in H', 500 µm for B,B'-H,H'; in I, 1 mm for I,J,M,N; in L, 1 mm for K,L,O,P.