Fig. 7. PN-1 deficiency results in localized cerebellar expansion. Wild-type (A,B) and mutant (C,D) adult-cerebellar midsagittal sections were stained for Ptc1 mRNA by in situ hybridization to reveal the IGL. The mutant cerebella show a global enlargement of the IGL in the zones facing the external side of the cerebellum. (B,D) Higher magnifications of lobe VI. (E) The thickness of the IGL was quantified measuring the highest widths in lobes VI and VIII (indicated as L1 and L2 in A-D). At P10, mutant cerebella exhibit a thicker IGL specifically in lobe VI (+67% compared to wild type). In the adults, this phenotype is still apparent (+60%). The thickness of lobe VIII is also increased, but to a lesser extent (+41%). IGL, internal granular layer; ML, molecular layer. (n=4 for P10; n=5 for adult; ^*** P<0.001; two-ways ANOVA test.) Scale bars: 300 µm in A,C; 100 µm in B,D.