SMO and medulloblastoma: We generated medulloblastoma-bearing mice by breeding the transgenic SmoM2 mouse line, which harbors a mutant, constitutively active allele of Smo, preceded by a LoxP-STOP-LoxP sequence27 with Math1-Cre mice, that express Cre recombinase in CGNPs, driven by the Atoh1 (aka Math1) promoter28–30.