A Transfected Sialyltransferase That Is Elevated in Breast Cancer and Localizes to the medial/trans-Golgi Apparatus Inhibits the Development of core-2–based O-Glycans

Whitehouse, Caroline; Burchell, Joy; Gschmeissner, Stephen; Brockhausen, Inka; Lloyd, Kenneth O.; Taylor-Papadimitriou, Joyce

Immunoelectron Microscopy. Thin-sections of pellets of the transfected MTSV1-7 and T47D cells were labeled with the myc antibody followed by goat anti-mouse coupled to gold particles. From visual observations of the immunoelectron micrographs of both cell types, the gold labeling appeared to be localized over the Golgi stack and was polarized to one side (Fig. 9, a and b) . Since the structure of the Golgi apparatus was more clearly defined in MTSV1-7 cells and the expression of the transfected gene Figure 5 . HPAEC analysis of radiolabeled reduced oligosaccharides from MUC1. (a) T47D, (b) T47Dneo, (c) T47D 3STMYC 2, and (d) T47D 3STMYC 3. MUC1 was immunoprecipitated from [ 3 H]glucosamine-hydrochloride-labeled cell lysates with the polyclonal antibody CT1 (ᮀ), or with preimmune serum (᭜). Peak 1 consists of neutral oligosaccharides, peak 2 corresponds to monosialylated species, and peak 3 elutes with disialo oligosaccharides (Lloyd et al., 1996) . The extra peak at 9 min in b is free NeuAc released during the work up of the sample. was used in double-labeling experiments (Fig. 9, c and d) .