Abstract
Purpose: :
In Drosophila, Dlg-1 and Scrib are known to regulate of cell proliferation, cell adhesion and polarity. We reported previously that Dlg-1 and Scrib are required for mouse lens development. Interestingly, the Dlg-1 mutant lens phenotype resembles that described for the Vangl2Lp/Lp mouse, which has a mutation in Vangl2, a core member of the Wnt/PCP pathway. Thus, we asked if Dlg-1 and Scrib interact with Vangl2 to regulate lens epithelial cell adhesion, polarity and proliferation.
Methods: :
Dlg-1 or Scrib conditional null mice were crossed with MLR10cre mice and the progeny were crossed with Vangl2Lp/+ mice. Eyes from P2 Dlgf/+, Dlgf/+cre, Vangl2Lp/+;Dlgf/+, Vangl2Lp/+;Dlgf/+cre, Scribf/+, Scribf/+cre, Vangl2Lp/+;Scribf/+and Vangl2Lp/+;Scribf/+cre mice were embedded in paraffin, sectioned and stained with H&E to assess the histology of the lens. BrdU immunohistochemistry was used to assess cell cycle regulation. Immunofluorescence was used to assess the patterns of the cell adhesion molecule, E-cadherin, and the apical protein, ZO-1.
Results: :
Dlgf/+, Scribf/+, Dlg f/+cre and Scribf/+cre epithelium were normal. However, the Vangl2Lp/+;Dlgf/+ and Vangl2Lp/+;Scribf/+ epithelium contained irregularly shaped, randomly organized cells and multilayered areas. The Vangl2Lp/+;Dlgf/+cre epithelium appeared more disorganized than the Vangl2Lp/+;Dlgf/+ lenses. The Vangl2Lp/+;Scribf/+cre epithelium appeared more similar to controls. The %BrdU+ cells in Vangl2Lp/+;Dlgf/+ and Vangl2Lp/+;Dlgf/+cre epithelium were higher than controls, Dlg-1 or Scrib heterozygous lenses whereas the %BrdU+ cells in Vangl2Lp/+;Scribf/+cre epithelium did not differ from controls. E-cadherin staining in control, Dlg-1 and Scrib heterozygous lenses showed punctate staining on the apical membranes whereas Vangl2Lp/+;Dlgf/+ and Vangl2Lp/+;Scribf/+ lenses showed diffuse staining on all membranes. Staining in the Vangl2Lp/+;Dlgf/+cre lenses was the most disorganized while staining in the Vangl2Lp/+;Scribf/+cre epithelium was similar to controls. Lenses from Vangl2Lp/+;Dlgf/+, Vangl2Lp/+;Dlgf/+cre and Vangl2Lp/+;Scribf/+ mice showed loss of ZO-1 from the apical epithelial surface but ZO-1 staining was preserved in the epithelial apical surface of Vangl2Lp/+;Scribf/+cre lenses.
Conclusions: :
These data indicate that Vangl2 is required to maintain epithelial cell adhesion, polarity and proliferation. As deficiency in Dlg-1 enhances while deficiency in Scrib suppresses the Vangl2 phenotype, Dlg-1 and Scrib have opposing effects on Vangl2. Future studies will ask if Dlg-1 and Scrib modulate Wnt signaling through their interaction with Vangl2.
Keywords: development • anatomy • proliferation