Figure 4.

Wnt/β-catenin signalling regulates epithelial cell phenotype, proliferation and differentiation in embryonic lenses. Tissues were stained with either haematoxylin and eosin (a,d,g), E-cadherin antibody (b,e,h) or for BrdU-incorporation (c,f,i). (a–c) At E13.5, cell proliferation in wild-type lens (Wt) is restricted to the E-cadherin-positive epithelial cells (c, arrowheads). (d–f) Loss of β-catenin (Catnb^Ex3-6/Ex3-6/Cre) abrogates Wnt signalling and results in the loss of lens epithelial cells (e, arrowheads) and reduction in lens cell proliferation (f, arrowheads). (g–i) Constitutive activation of Wnt/β-catenin signalling by a truncating mutation of Apc (Apc^580S/580S/Cre) results in the failure of lens equatorial cells to differentiate into fibres, with aberrant labelling for E-cadherin (h) and cell proliferation (i) extending into the fibre cell mass. Adapted from Cain et al. [43] and Martinez et al. [44].