Fig. 7. Small decrease in cell proliferation in the absence of β-catenin without altering cell survival. (A-C) Cell proliferation at E11.5 assayed by BrdU incorporation (brown-stained cells). (A,B) There is a small decrease in cell proliferation in the En1Cre; R26R; β-cat^lof mutants but no significant difference in β-cat^gof mutants (see Table 1). (D-F) Apoptosis at E11.5 as assayed by TUNEL (brown-stained cells); sections are counterstained with methyl green. There is no detectable difference in cell death in the flank and ventral mesenchyme between the mutants and control embryos. (E) TUNEL⁺ cells are detectable in the apical ectodermal ridge of the limb (inset). (A-F) En1 lineage-marked domains are outlined in red. Composites for each panel were created from two or three images taken at the same magnification.