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The β1,3-Galactosyltransferase β3GalT-V Is a Stage-specific Embryonic Antigen-3 (SSEA-3) Synthase

2000; Elsevier BV; Volume: 275; Issue: 30 Linguagem: Inglês

10.1074/jbc.c000263200

1083-351X

Dapeng Zhou, Timothy R. Henion, Firoze B. Jungalwala, Eric G. Berger, Thierry Hennet,

Galectins and Cancer Biology

We have previously reported the molecular cloning of β1,3-galactosyltransferase-V (β3GalT-V), which catalyzes the transfer of Gal to GlcNAc-based acceptors with a preference for the core3 O -linked glycan GlcNAc(β1,3)GalNAc structure. Further characterization indicated that the recombinant β3GalT-V enzyme expressed in Sf9 insect cells also utilized the glycolipid Lc3Cer as an efficient acceptor. Surprisingly, we also found that β3GalT-V catalyzes the transfer of Gal to the terminal GalNAc unit of the globoside Gb4, thereby synthesizing the glycolipid Gb5, also known as the stage-specific embryonic antigen-3 (SSEA-3). The SSEA-3 synthase activity of β3GalT-V was confirmed in vivo by stable expression of the human β3GalT-V gene in F9 mouse teratocarcinoma cells, as detected with the monoclonal antibody MC-631 by flow cytometry analysis and immunostaining of extracted glycolipids. The biological relation between SSEA-3 formation and β3GalT-V was further documented by showing that F9 cells treated with the differentiation-inducing agent retinoic acid induced the expression of both the SSEA-3 epitope and the endogenous mouse β3GalT-V gene. This study represents the first example of a glycosyltransferase, which utilizes two kinds of sugar acceptor substrates without requiring any additional modifier molecule.