Subcellular Localization and Tumor Distribution of Human β3-galactosyltransferase by β3GalT7 Antiserum

A novel member of the human β3-galactosyltransferase family, the β3GalT7 gene (AY277592, EC2.4.1.-) was first isolated and cloned by our laboratory. To further study its functions, we constructed a prokaryotic expression system of β3GalT7 and obtained anti-β3GalT7 polyclonal antiserum by immunizing rabbit with purified β3GalT7 protein. Using the antiserum, the expression of β3GalT7 in various tissues and cell lines was analyzed by Western blot and immunochemical assays. Immunochemistry analysis showed the enzyme was expressed significantly higher in some tumor tissues than in normal tissues, indicating its biofunction in tumorogenesis. By immunofluorescence, the enzyme was observed highly accumulated in cytoplasm around nuclear membrane, implying that β3GalT7 may play an important role in the assembly of galactose in RER and Golgi.