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Fig. 4. Antibody localization for Transcription factor 7 like 2 (Tcf7l2). Representative images from confocal and fluorescence light microscopy for larval and post-metamorphic frog corneas, as labeled. (A) Whole mount of larval Xenopus cornea showing presence of Tcf7l2 (green) labeled cells in the skin epithelium, surrounding the cornea. Tcf7l2-positive cells are rarely seen in the peripheral cornea. Regions labeled are those shown in B-G and B′-G’. (B–G) Higher magnification confocal images showing the distribution of Tcf7l2 (green) labeled cells in skin and cornea of larval animals, as labeled. (B′-G′) Merged images for B-G with Hoechst labeled nuclei (magenta). (B-B′) Apical cells of the skin epithelium exhibit Tcf7l2 antibody labeling. Tcf7l2 has cytoplasmic expression in a majority of these apical epithelial cells. (C-C′) Skin basal cells do not express Tcf7l2. (D-D′) No expression is observed in the apical cells of the central cornea. (E-E′) Basal cells in the central corneal epithelium also do not show presence of Tcf7l2. (F-F′) The apical epithelium of the peripheral cornea is predominantly devoid of Tcf7l2-positive cells. Tcf7l2 expressing cells (shown by white arrowhead) are rarely detected in the apical layer of the peripheral cornea. (G-G′) Basal epithelial cells of the peripheral cornea are devoid of antibody labeling. (H–K) Immunofluorescent staining for Tcf7l2 (green) on frozen sections of adult frog epithelia, as labeled. The apical surface is located towards the top of each image, and the basal surface towards the bottom. (H′-K′) Merged images for H-K with Hoechst labeled nuclei (magenta). (H-H′) Tcf7l2 staining is not present in the epithelial cell layers of the central cornea. (I-I′) No Tcf7l2 expression is detected in cells of the limbal epithelium. (J-J′) Cells in the basal and intermediate layers of the outer surface of the ventral eyelid show Tcf7l2 staining, with no expression noted in apical cells. The inner surface epithelium of the eyelid is negative for this protein. (K-K′) Tcf7l2 expression is observed in the basal and intermediate cells of the surrounding skin epithelium. Superficial cells of skin epithelium do not label with this antibody. cc, central cornea; ive, inner ventral eyelid; ove, outer ventral eyelid; pc, peripheral cornea; sk, skin. Scale bar in K′ equals 200 μm for A, 25 μm for B-G, B′-G′, and 50 μm for H-K, H′-K’. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.) |
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Fig. 11. Larval and adult frog epithelia immunostained with Pax6 and Tcf7l2 antibodies. (A–C) Lower magnification confocal images of larval whole-mount cornea showing Pax6 (red), and Tcf7l2 (green) co-staining. The white dotted line represents the boundary demarcating the cornea and skin. (A) A gradient of Pax6 expression is higher in the central cornea (cc), and is lost progressively towards the peripheral cornea (pc), and skin (sk). (B) Tcf7l2-positive cells are abundant in the skin region. (C) Merged image showing Pax6 and Tcf7l2 expression. (D-G, D′-G′ and D”-G′) Cross-sections of adult frog cornea, eyelid and skin immunolabeled with Pax6 (red) and Tcf7l2 (green). The apical surface is located towards the top of each image, and the basal surface towards the bottom. D′, E′, F′ and G′ are merged images for D, D’; E, E’; F, F′ and G, G′, respectively, with Hoechst labeled nuclei (blue). (D, D′ and D′) No Pax6 or Tcf7l2 expression is detected in the central cornea. (E, E′, and E′) The limbal region has undetectable Pax6 or Tcf7l2. (F, F′ and F′) Ventral eyelid region showing Pax6 and Tcf7l2 expression. The inner surface of the eyelid does not stain for either antibody. Outer surface of the eyelid has Pax6 in the apical cells, and Tcf7l2 mainly in the basal layer of cells. (G, G′ and G′) Skin of the adult frog has Pax6 in apical cells of the epithelium, and Tcf7l2 in the basal and intermediate layers of cells. cc, central cornea; ive, inner ventral eyelid; ove, outer ventral eyelid; pc, peripheral cornea; sk, skin. Scale bar in G′ equals 60 μm for A-C, 50 μm for D-G, D′-G′, D′-G”. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.) |
