ABSTRACT: We have previously reported that fish pathogens causing vibriosis specifically adhere to GM4 on the epithelial cells of fish intestinal tracts (Chisada, S., Horibata, Y., Hama, Y., Inagaki, M., Furuya, N., Okino, N., and Ito, M. (2005) Biochem. Biophys. Res. Commun. 333, 367-373). To identify the gene encoding the enzyme for GM4 synthesis in the fish intestinal tract, a phylogenetic tree of vertebrate ST3GalVs, including Danio rerio and Oryzias latipes, was generated in which two putative subfamilies of fish ST3GalVs were found. Two putative ST3GalVs of zebrafish (zST3GalV-1 and -2), each belonging to different subfamilies, were cloned from the zebrafish cDNA library. Interestingly, zST3GalV-1 synthesized GM3 (NeuAcalpha2-3Galbeta1-4Glcbeta1-1'Cer) but not GM4, whereas zSTGalV-2 synthesize
