Cloning and characterization of a new human UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase, designated pp-GalNAc-T13, that is specifically expressed in neurons and synthesizes GalNAc alpha-serine/threonine antigen.
To date, 10 members of the UDP-N-acetyl-alpha-d-galactosamine:polypeptide N-acetylgalactosaminyltransferase (pp-GalNAc-T) family have been cloned and analyzed in human. In this study, we cloned and analyzed a novel human pp-GalNAc-T from an NT2 cell cDNA library, and we named it pp-GalNAc-T13. In amino acid sequences, pp-GalNAc-T13 was highly homologous, showing 84.3% identity, to pp-GalNAc-T1. Real time PCR analysis revealed pp-GalNAc-T13 to be highly and restrictively expressed in the brain and present at very low or undetectable levels in other tissues, in contrast to the ubiquitous expression of pp-GalNAc-T1. pp-GalNAc-T13 was abundantly expressed in all neuroblastoma cells examined and primary cultured neurons but not in glioblastoma cells and primary cultured astrocytes. pp-GalNAc-T13 exhibited much stronger activity to transfer GalNAc to mucin peptides, such as Muc5Ac and MUC7, than did pp-GalNAc-T1. In addition, pp-GalNAc-T13 differed in substrate specificity to pp-GalNAc-T1. pp-GalNAc-T13 was able to form a triplet Tn epitope, three consecutive GalNAc-Ser/Thr structures, on peptides encoded in syndecan-3, a proteoglycan expressed in neurons. pp-GalNAc-T13-deficient mice have been established in a previous work. Immunohistochemical study showed a remarkable decrease in Tn antigen expression in the cerebellum of the pp-GalNAc-T13 knockout mouse. pp-GalNAc-T13 would be a major enzyme responsible for the synthesis of O-glycan and specifically the Tn antigen epitope in neurons.
Zhang
Yan
Y
Glycogene Function Team, Research Center for Glycoscience, National Institute of Advanced Industrial Science and Technology, Central-2, Open Space Laboratory, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan.
Iwasaki
Hiroko
H
Wang
Han
H
Kudo
Takashi
T
Kalka
Timothy B
TB
Hennet
Thierry
T
Kubota
Tomomi
T
Cheng
Lamei
L
Inaba
Niro
N
Gotoh
Masanori
M
Togayachi
Akira
A
Guo
Jianming
J
Hisatomi
Hisashi
H
Nakajima
Kazuyuki
K
Nishihara
Shoko
S
Nakamura
Mitsuru
M
Marth
Jamey D
JD
Narimatsu
Hisashi
H
D000595:Amino Acid Sequence; D000818:Animals; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000276:immunology / Q000378:metabolism*; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism; D001483:Base Sequence; D002478:Cells, Cultured; D002525:Cerebellar Cortex / Q000166:cytology / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003001:Cloning, Molecular; D006020:Glycopeptides / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D055271:Mucin 5AC; D009077:Mucins / Q000378:metabolism; D017350:N-Acetylgalactosaminyltransferases / Q000235:genetics / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D011509:Proteoglycans / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013379:Substrate Specificity; D053670:Syndecan-3; D014018:Tissue Distribution; D000097763:Polypeptide N-acetylgalactosaminyltransferase
D015295:Antigens, Tumor-Associated, Carbohydrate; D006020:Glycopeptides; D008562:Membrane Glycoproteins; D055271:Mucin 5AC; D009077:Mucins; D017350:N-Acetylgalactosaminyltransferases; D011509:Proteoglycans; D011994:Recombinant Proteins; D053670:Syndecan-3; D000097763:Polypeptide N-acetylgalactosaminyltransferase; C524678:MUC5AC protein, human; C524679:Muc5ac protein, mouse; C508301:SDC3 protein, human; C508302:Sdc3 protein, mouse; C040286:Tn antigen; C470847:UDP-N-acetyl-alpha-D-galactosamine polypeptide N-acetylgalactosaminyltransferase 13, human; C470848:UDP-N-acetyl-alpha-D-galactosamine polypeptide N-acetylgalactosaminyltransferase 13, mouse