Figure 3. Ruffled IGL and ectopic CGN patches in cerebellum-specific Plxnb2 mutant.

(A– D) Whole-mount TO-PRO-3 staining of P14 and P30 cerebella from Plxnb2^fl/fl and En1^Cre;Plxnb2^fl/fl littermates cleared with iDISCO+. In 3D, TO-PRO-3 staining mainly reveals the structure of the cell-dense IGL. Plxnb2^fl/fl control cerebella (A) display a very smooth IGL. A thin layer of EGL remains at P14 but not at P30 (C). In P14 En1^Cre;Plxnb2^fl/fl mice, the regressing EGL contains ectopic clusters of CGNs (B) that remain at P30 (D). In addition, Plxnb2 mutant IGL (B, D) shows many invaginations in different directions, independent of normal fissure orientation. Although some fissures are clearly formed and visible (prf, ppf), many others are absent. The paraflocculus (pf), present in P30 control, was lost during dissection in the Plxnb2 mutant. Greek numbers indicate cerebellar lobes. Scale bars: 700 μm for the 3D images, 500 μm for the coronal and horizontal sections. Pfr: primary fissure, psf: posterior superior fissure, ppf: prepyramidal fissure, sf: secondary fissure. Figure 3—figure supplement 1A shows quantification of 3D cerebellar volume (Figure 3—figure supplement 1—source data 1).

Figure 3—figure supplement 1. Difference in cerebellar volume but not motor function.

(A) Quantification of cerebellar volume was done by 3D segmentation of the cerebellum in Imaris. Data is normalized to control cerebellum (dotted line at 100%) P4: 85.64 ± 4.425%. Mann Whitney U (MWU) test. MWU(0) p=0.0079, N = 5 ctl and 5 mut. P30: 84.03 ± 1.808%. MWU(0) p=0.0022, N = 6 ctl and 6 mut. (Figure 3—figure supplement 1—source data 1) (B) Quantification of the time to fall in rotarod assay on three consecutive trial. Day1 ctl 151.3 ± 16.6 s vs. mut 132.6 ± 9.7 s (Not significant); Day 2 ctl 155.6 ± 16.1 s vs. mut 169.8 ± 10.0 s (Not significant); Day 3 ctl 168.8 ± 20.8 s vs. mut 189.9 ± 12.5 s (Not significant). Six controls and 10 mutant mice, 19 weeks old, were tested. (Figure 3—figure supplement 1—source data 1).