Fig. 1. Wg is required for the maintenance of Vg expression in the DV boundary. (A) Wild-type expression pattern of Vg in wing discs. Vg is expressed in both DV and non-DV cells. (B,C) Vg expression in DV and non-DV cells is regulated by vg-BE (B) and vg-QE (C), respectively. (D-F) vg-GAL4/UAS-DN-TCF/pan wing discs stained with anti-Vg antibodies (D), vg-BE (E) and vg-QE (F). Misexpression of DN-TCF/pan in wing discs downregulates Vg expression in both DV and non-DV cells. (G) Wing disc with arm^H8.6/arm^H8.6 mitotic clones. (G1) lacZ marker (arm-lacZ P[FRT]18A); loss of lacZ expression marks arm^H8.6/arm^H8.6 cells. (G2) Vg expression pattern in the same disc. (G3) DAPI staining in the same disc. (G4) Merge image of G1-G3. Note that in a representative arm^H8.6/arm^H8.6 clone at the DV boundary (arrow), Vg expression is downregulated. Downregulation of Vg in non-DV cells (arrowhead) in arm^– clones is also shown.