Genomic cloning and expression of three murine UDP-galactose: beta-N-acetylglucosamine beta1,3-galactosyltransferase genes.
Based on the detection of expressed sequence tags that are similar to known galactosyltransferase sequences, we have isolated three novel UDP-galactose:beta-N-acetylglucosamine beta1, 3-galactosyltransferase (beta3GalT) genes from a mouse genomic library. The three genes, named beta3GalT-I, -II, and -III, encode type II transmembrane proteins of 326, 422, and 331 amino acids, respectively. The three proteins constitute a distinct subfamily as they do not share any sequence identity with other eucaryotic galactosyltransferases. Also, the entire protein-coding region of the three beta3GalT genes was contained in a single exon, which contrasts with the genomic organization of the beta1,4- and alpha1, 3-galactosyltransferase genes. The three beta3GalT genes were mainly expressed in brain tissue. The expression of the full-length murine genes as recombinant baculoviruses in insect cells revealed that the beta3GalT enzymes share the same acceptor specificity for beta-linked GlcNAc, although they differ in their Km for this acceptor and the donor UDP-Gal. The identification of beta3GalT genes emphasizes the structural diversity present in the galactosyltransferase gene family.
Hennet
T
T
Institute of Physiology, University of Zurich, 8057 Zurich, Switzerland.
Dinter
A
A
Kuhnert
P
P
Mattu
T S
TS
Rudd
P M
PM
Berger
E G
EG
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular; D004274:DNA, Recombinant; D051379:Mice; D008969:Molecular Sequence Data; D009237:N-Acetyllactosamine Synthase / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D018411:Spodoptera
D004274:DNA, Recombinant; D009237:N-Acetyllactosamine Synthase