(a) Hematoxylin stained sagittal sections of control and mutant cerebella. Expression of SmoM2 in GNPs using hGFAP::Cre induces medulloblastoma by P10. Removal of Kif3a, an essential gene for ciliogenesis, in SmoM2 expressing cells completely blocks tumorigenesis resulting in atrophic cerebella similar to those of hGFAP::Cre;Kif3afl/fl mice. (b) SmoM2-YFP is highly enriched in primary cilia (green, arrow) associated with the basal body (anti-γ-tubulin staining, shown in red, arrowhead). In hGFAP::Cre; SmoM2fl/+; Kif3afl/fl mice only the basal body is present (arrowhead). (c, d) BrdU incorporation (1h survival) at E16. GNPs proliferation in hGFAP::Cre; SmoM2fl/+; Kif3afl/fl is similar to that observed in hGFAP::Cre; Kif3afl/fl or wild type mice8. In contrast, already by E16, hGFAP::Cre; SmoM2fl/+ mice show an expanded EGL containing significantly more proliferating cells. *: P < 0.05. Scale bar = 0.5 mm (a), 5 µm (b) and 100 µm (c).