Cloning and expression of a novel, tissue specifically expressed member of the UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase family.
We report the cloning and expression of the fifth member of the mammalian UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase (ppGaNTase) family. Degenerate polymerase chain reaction amplification and hybridization screening of a rat sublingual gland (RSLG) cDNA library were used to identify a novel isoform termed ppGaNTase-T5. Conceptual translation of the cDNA reveals a uniquely long stem region not observed for other members of this enzyme family. Recombinant proteins expressed transiently in COS7 cells displayed transferase activity in vitro. Relative activity and substrate preferences of ppGaNTase-T5 were compared with previously identified isoforms (ppGaNTase-T1, -T3, and -T4); ppGaNTase-T5 and -T4 glycosylated a restricted subset of peptides whereas ppGaNTase-T1 and -T3 glycosylated a broader range of substrates. Northern blot analysis revealed that ppGaNTase-T5 is expressed in a highly tissue-specific manner; abundant expression was seen in the RSLG, with lesser amounts of message in the stomach, small intestine, and colon. Therefore, the pattern of expression of ppGaNTase-T5 is the most restricted of all isoforms examined thus far. The identification of this novel isoform underscores the diversity and complexity of the family of genes controlling O-linked glycosylation.
Ten Hagen
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KG
Center for Oral Biology, Rochester Institute of Biomedical Sciences, University of Rochester Medical Center, Rochester, New York 14642, USA.
Hagen
F K
FK
Balys
M M
MM
Beres
T M
TM
Van Wuyckhuyse
B
B
Tabak
L A
LA
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000235:genetics; D015723:Gene Library; D006031:Glycosylation; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D017350:N-Acetylgalactosaminyltransferases / Q000096:biosynthesis / Q000235:genetics*; D011499:Protein Processing, Post-Translational; D051381:Rats; D011994:Recombinant Proteins / Q000096:biosynthesis; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013361:Sublingual Gland / Q000201:enzymology; D014018:Tissue Distribution; D000097763:Polypeptide N-acetylgalactosaminyltransferase
D018076:DNA, Complementary; D007527:Isoenzymes; D017350:N-Acetylgalactosaminyltransferases; D011994:Recombinant Proteins; D000097763:Polypeptide N-acetylgalactosaminyltransferase