Detailed O-glycomics of the Muc2 mucin from colon of wild-type, core 1- and core 3-transferase-deficient mice highlights differences compared with human MUC2

Glycobiology. 2012 Aug;22(8):1128-39. doi: 10.1093/glycob/cws083. Epub 2012 May 11.

Abstract

The heavily O-glycosylated mucin MUC2 constitutes the major protein in the mucosal layer that acts as a physical barrier protecting the epithelial layer in the colon. In this study, Muc2 was purified from mucosal scrapings from the colon of wild-type (WT) mice, core 3 transferase knockout (C3Gnt(-/-)) mice and intestinal epithelial cell-specific core 1 knockout (IEC C1Galt1(-/-)) mice. The Muc2 O-glycans were released by reductive β-elimination and analyzed with liquid chromatography-mass spectrometry in the negative-ion mode. Muc2 from the distal colon of WT and C3Gnt(-/-) knockout mice carried a mixture of core 1- or core 2-type glycans, whereas Muc2 from IEC C1Galt1(-/-) mice carried highly sialylated core 3- and core 4-type glycans. A large portion of NeuAc in all mouse models was positioned on disialylated N-acetyllactosamine units, an epitope not reported on human colonic MUC2. Mass spectra and proton NMR spectroscopy revealed an abundant NeuAc linked to internally positioned N-acetylglucosamine on colonic murine Muc2, which also differs markedly from human MUC2. Our results highlight that murine colonic Muc2 O-glycosylation is substantially different from human MUC2, which could be one explanation for the different commensal microbiota of these two species.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Sugars / metabolism*
  • Animals
  • Carbohydrate Sequence
  • Chromatography, Liquid
  • Colon / metabolism*
  • Epitopes
  • Galactosyltransferases / physiology*
  • Glycomics*
  • Glycosylation
  • Humans
  • Intestinal Mucosa / cytology
  • Intestinal Mucosa / metabolism
  • Intestinal Mucosa / microbiology
  • Magnetic Resonance Spectroscopy
  • Metagenome
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Molecular Sequence Data
  • Mucin-2 / metabolism*
  • N-Acetylglucosaminyltransferases / physiology*
  • Polysaccharides / metabolism
  • Spectrometry, Mass, Electrospray Ionization

Substances

  • Amino Sugars
  • Epitopes
  • MUC2 protein, human
  • Muc2 protein, mouse
  • Mucin-2
  • Polysaccharides
  • N-acetyllactosamine
  • C1galt1 protein, mouse
  • Galactosyltransferases
  • N-Acetylglucosaminyltransferases
  • beta-1,3-galactosyl-O-glycosyl-glycoprotein beta-1,6-N-acetylglucosaminyltransferase 3