Figure 1.

ptc^+/− mice have ectopic Math1-GFP⁺ cells on the surface of their cerebellum. (A–C) Cerebellar sections from P7 Math1-GFP mice, 5- to 6-wk-old Math1-GFP/ptc^+/− (M-ptc) mice, and tumor-bearing M-ptc mice were stained with antibodies specific for the proliferation marker Ki67 (red) and with DAPI, to label all nuclei. Sections were imaged at 20× magnification using a Leica AxioImager and Metamorph software. Note the colocalization of GFP with Ki67 in the EGL (A), in preneoplastic lesions (asterisk, B), and in tumors (asterisk, C). (D) M-ptc mice were sacrificed at either 6 or 12 wk of age and cerebella were examined for the presence of GFP⁺ lesions. While the majority of M-ptc mice have GFP⁺ lesions at 6 wk, most of these lesions have disappeared by 12 wk of age. (EGL) External germinal layer; (IGL) internal granule layer; (ML) molecular layer.