Figure 2.

Point mutations in the β-catenin gene in tumors developed in L-PK/c-myc mice. (A) Sequence analysis showing the D32Y and S37Y mutations. (B) Digestion of the RT-PCR products with appropriate restriction enzyme. Undigested wild-type amplified cDNA fragment (lane 1). Wild-type amplified cDNA fragments digested with XmnI (lane 2) and RsaI (lane 4). Digested amplified cDNA fragments from tumor sample showing a β-catenin gene mutation, the S37Y mutation led to the absence of digestion by the XmnI enzyme (lane 3), and the D32Y mutation led to the appearance of a RsaI restriction site (lane 5) on the mutated allele.