Association of EXT1 and EXT2, hereditary multiple exostoses gene products, in Golgi apparatus.

Abstract

We prepared the specific antibodies for EXT1 and EXT2, hereditary multiple exostoses (HME) gene products, and characterized their expression, subcellular localization, and protein association among EXT members. Biochemical analyses indicate that EXT1 and EXT2 can associate and form homo/hetero-oligomers in vivo with or without HME-linked mutations, EXT1 (R340C) and EXT2 (D227N), when exogenously expressed in COS-7 cells. An immunocytochemical analysis showed that both EXT1 and EXT2 localized in Golgi apparatus, irrespective of HME mutations. An immunohistochemical analysis on developing bones further showed that both EXT1 and EXT2 were concomitantly expressed in hypertrophic chondrocytes of forelimb bones from 1-day-old neonatal mouse, but down-regulated in maturing chondrocytes of developing cartilage from 21-day-old mouse. Taken together with the recent finding that EXTs encode for the glycosyltransferase required for the synthesis of heparan sulfate [Lind, T., Tufaro, F., McCormick, C., Lindahl, U., and Lindholt, K. (1998) J. Biol. Chem. 273, 26265-26268], our results implied a molecular basis that a HME-linked mutation found in EXT genes could interfere the physiological function(s) of EXT homo/hetero-oligomers as glycosyltransferases in the developing bones of HME patients.

• Authors: S Kobayashi, K Morimoto, T Shimizu, M Takahashi, H Kurosawa, T Shirasawa
• Journal: Biochemical and biophysical research communications (Biochem Biophys Res Commun) Vol. 268 Issue 3 Pg. 860-7 (Feb 24 2000) ISSN: 0006-291X [Print] United States
• PMID: 10679296 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2000 Academic Press.

Chemical References

• DNA Primers
• Proteins
• Recombinant Fusion Proteins
• N-Acetylglucosaminyltransferases
• exostosin-1
• exostosin-2

Topics

• Animals
• Animals, Newborn
• Base Sequence
• Bone Development (genetics)
• Bone and Bones (metabolism)
• COS Cells
• DNA Primers (genetics)
• Exostoses, Multiple Hereditary (genetics, metabolism, pathology)
• Gene Expression
• Genetic Linkage
• Golgi Apparatus (metabolism)
• Humans
• Immunohistochemistry
• Mice
• N-Acetylglucosaminyltransferases
• Point Mutation
• Proteins (chemistry, genetics, metabolism)
• Recombinant Fusion Proteins (chemistry, genetics, metabolism)