Fig. 2.

β-gal⁺ foci number, crypt fission and adenoma formation in Pms2 ^cre/cre and Pms2 ^cre/+ intestines. Wholemount images of the proximal small intestine from a Pms2 ^cre/cre (A) and Pms2 ^cre/+ (B) mouse. Arrows show multicryptal β-gal⁺ foci in (A) and a single β-gal⁺ focus in (B). Note the difference in both number and size of β-gal⁺ foci between Pms2 ^cre/cre and Pms2 ^cre/+ intestines. (C) Pms2 ^cre/cre; Apc ^CKO/CKO intestines have a higher percentage of normal-appearing multicryptal β-gal⁺ foci and transformed β-gal⁺ foci compared with Pms2 ^cre/+; Apc ^CKO/CKO intestines. The percentage of transformed β-gal⁺ foci was determined by scoring frozen sections counterstained with nuclear fast red. (D) The number of β-gal⁺ foci containing more than three villi results in a linear regression of y = 0.004x + 0.2, which is a statistically significant increase with age (P < 0.001). The number of β-gal⁺ foci containing more than three villi was determined via wholemount.