Fig. 4. Co-expression of Math1 and ß-galactosidase in pre-neoplastic cells and tumor cells. Cerebella were isolated from 6-week-old (A-C) and 12-week-old (D-F) tumor bearing Math1-GFP/patched^+/– mice. Intact cerebella (A,D) were photographed using a Leica MZFLIII microscope and then fixed, frozen and cryosectioned. One set of sections was mounted and photographed using a fluorescent microscope to detect GFP (B,E); adjacent sections were stained with X-gal, mounted and photographed under bright field (C,F). Note the correlation between GFP (green, indicative of Math1 expression) and X-gal staining (blue, indicative of mutant patched expression) in pre-neoplastic (B,C) and tumor-containing (E,F) regions.