Notch does not reach the cell surface in Ofut1 mutant cells. (A)-(D) Wing disks with Ofut1 mutant clones (green), stained with antibodies against the Notch extracellular domain (magenta). (A) Horizontal and (B) vertical sections of a disk stained after detergent treatment. Apical is up. Increased and mis-localized Notch protein is observed within Ofut1 mutant cells (green), as reported previously using antibodies against the intracellular domain . (C) Horizontal and (D) vertical sections of a disk stained without detergent treatment. An Ofut1 mutant clone is devoid of cell surface Notch (arrow), but Notch is readily detected along the surface of wild-type cells. (E),(F) Correlations in localization among ER markers. Vertical sections of a wing disk doubly stained with KDEL (magenta) and with either (E) Boca or (F) Calnexin (green). Additional examples are shown in additional file 1.