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S. Shatadal, A. Griep, R. Rachel; Comparing the Individual and Combined Roles of Dlg-1 and Scrib in the Mouse Lens Epithelium. Invest. Ophthalmol. Vis. Sci. 2010;51(13):2355.
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© ARVO (1962-2015); The Authors (2016-present)
In Drosophila, studies have shown that PDZ proteins Dlg-1 and Scrib are important regulators of cell proliferation, cell adhesion and polarity. Previous work in our laboratory using transgenic and mutant PDZ models has demonstrated a role for PDZproteins in aspects of cell cycle regulation, polarity and cell adhesion in the lens epithelium. In this report, we extend our knowledge of PDZ function by comparing the lens epithelial phenotypes in mice where Dlg-1, Scrib, or both have been deleted.
Mice carrying Dlg-1 or Scrib conditional allele were crossed with MLR10cre transgenic mice. Double conditional mutants were generated by crossing Dlg-1 and Scrib with MLR10cre (DlgScrib10). Eyes from P2 Dlg10, Scrib10, DlgScrib10 and control mice were embedded in paraffin, sectioned and stained with hematoxylin and eosin (H&E) to assess the histology of the lens. Immunohistochemistry for BrdU (DNA synthesis marker) was used to examine the cell cycle. Cell adhesion was examined by immunofluorescence with antibodies against E-cadherin. Sections were immunostained with antibodies against ZO-1, an apical marker, to assess apical-basal cell polarity.
By H&E staining, the appearance of the epithelium in Dlg10, Scrib10 and DlgScrib10 lenses differed from that in control lenses. The epithelium of the Dlg10 lenses appeared thicker than controls, and contained pockets of multilayering and irregularly shaped cells. The Scrib10 epithelium appeared flattened, vacuolated and cells were irregular in shape. The DlgScrib10 epithelium most closely resembled the Scrib10 epithelium. The %BrdU+ cells in Dlg10 lenses was higher than in controls whereas the %BrdU+ cells in the Scrib10 lenses did not differ from controls. Interestingly, the %BrdU+ cells in the DlgScrib10 lenses was less than controls. In the Dlg10 lenses, E-cadherin staining appeared to be diffuse in apical, basal and lateral membranes of central epithelium. However, E-cadherin staining in the Scrib10 lenses appeared not only diffuse but also reduced. In controls ZO-1 staining was restricted to the apical surface. In Dlg10, ZO-1 was observed along both the apical and basal membranes of the central epithelium. Both Scrib10 and DlgScrib10 lenses showed loss of ZO-1 from the apical epithelial surface.
These data suggest that both Dlg-1 and Scrib are required for maintaining a normal epithelium. However, the effect of each gene individually and together on cell proliferation, cell adhesion and polarity appear to differ. Further studies are in progress to assess the interplay between these genes in the epithelium during lens development.
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