Fig. 4. O-fut1 was required for the endocytic transportation of Notch in a manner independent of its enzymatic activity. (A) Genomic organization of the Gmd locus. Exons are shown as boxes, and the predicted coding region is in black. The regions 3' to the Pelement insertion site of GS13045 are deleted in Gmd^H43 (0.4 kb) and Gmd^H78 (0.8 kb). (B) Concentration of GDP-fucose in Gmd mutants. GDP-fucose in wild-type and heterozygous and homozygous Gmd mutant larvae was measured in duplicate. ND, not detected. (C-F) Wild-type (C,E) and Gmd^H78 homozygous (D,F) wing discs stained with anti-Wg (C,D) and anti-En antibodies (E,F). (G) Uptake of fluorescent dextran by live Gmd^H78 homozygous mutant wing discs after a 10 minute incubation and a 20 minute chase at 25°C. Dextran and Notch are shown in green and magenta, respectively. Some dextran-positive vesicles are indicated by arrowheads. (H,I) Notch staining in wild-type (H) and Gmd^H78 (I) wing discs. (J) O-fut1^- clones generated in Gmd^H78 wing discs, then stained with anti-Notch (magenta) and anti-myc (clone marker, green) antibodies. The clone boundary is indicated by a white dashed line. All wing discs were isolated from late third-instar larvae.