Fig. 5. TUNEL analysis of ß-cat^Prx1/- and ß-cat^ex3Prx1/+ mutant limb buds. Apoptotic cells are shown in green; red staining indicates autofluorescence. (A,A') E9.5 (25-26 somites) wild-type (A) and ß-cat^Prx1/- (A') forelimbs showing no significant apoptosis in the mesenchyme. (B,B') E10.25 forelimbs. A few apoptotic cells are visible in wild type (B), but there is a significant increase in apoptotic cells in the proximal mesenchyme in ß-cat^Prx1/- (B'). (C,C') E11 forelimb. Apoptosis is detected in the AER and in a central region of the mesenchyme in wild type (C), whereas an increased number of apoptotic cells is observed throughout the proximal mesenchyme in ß-cat^ex3Prx1/+ limbs (C').