Molecular cloning of globotriaosylceramide/CD77 synthase, a glycosyltransferase that initiates the synthesis of globo series glycosphingolipids.
The expression cloning of a cDNA for globotriaosylceramide (Gb3)/CD77 synthase (alpha1,4-galactosyltransferase) was achieved using an anti-Gb3 antibody and mouse L cells as a recipient cell line for the transfection. The isolated cDNA clone designated pVTR1 predicted a type II membrane protein with 19 amino acids of cytoplasmic domain, 26 amino acids of transmembrane region, and a catalytic domain with 308 amino acids. Introduction of the cDNA clone into L cells resulted in the neosynthesis of Gb3/CD77, and the extracts of the transfectant cells showed alpha1, 4-galactosyltransferase activity only on lactosylceramide and galactosylceramide. In Northern blotting, a 2.3-kilobase mRNA was strongly expressed in heart, kidney, spleen, and placenta and weakly in colon, small intestine, and brain. Transfection of the cDNA into L cells resulted in the constitution of sensitivity to the apoptosis with Shiga-like toxins (verotoxins). Since Gb3/CD77 synthase initiates the synthesis of globo series glycolipids, the isolation of this cDNA will make possible further investigations into the function of its important series of glycolipids.
Kojima
Y
Y
Department of Biochemistry II, Nagoya University School of Medicine, Tsurumai, Nagoya 466-0065, Japan.
Fukumoto
S
S
Furukawa
K
K
Okajima
T
T
Wiels
J
J
Yokoyama
K
K
Suzuki
Y
Y
Urano
T
T
Ohta
M
M
Furukawa
K
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020134:Catalytic Domain; D003001:Cloning, Molecular; D015723:Gene Library; D006028:Glycosphingolipids / Q000096:biosynthesis*; D006801:Humans; D007700:Kinetics; D007739:L Cells; D008545:Melanoma; D051379:Mice; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014162:Transfection; D014281:Trihexosylceramides / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D006028:Glycosphingolipids; D011994:Recombinant Proteins; D014281:Trihexosylceramides; C018549:globotriaosylceramide