FIGURE 1.

MUC1 isoforms and MUC1 expression in transfected cells. A, schematic of MUC1 isoforms used for transfection: MUC1/22TR, containing 22 tandem repeats in the VNTR region; MUC1/2TR, containing two tandem repeats; MUC1/Y and MUC1/Z, which lack the VNTR region. MUC1/22TR, MUC1/2TR, and MUC1/Z are composed of two noncovalently linked subunits, α and β. MUC1/Y is expressed as a single protein. All forms have the same C-terminal region (black boxes) composed of the transmembrane domain and the cytoplasmic tail recognized by anti-MUC1 antibody Ab5, but they differ in the N-terminal region (white boxes). The VNTR region is recognized by antibodies 3C6 and VU4H5 (hypoglycosylated VNTR). B, flow cytometry analysis showing MUC1 expression in transfected cells as detected by antibody Ab5.