title: Embryonic fibroblasts with a gene trap mutation in Ext1 produce short heparan sulfate chains.
abstract: Mutational defects in either EXT1 or EXT2 genes cause multiple exostoses, an autosomal hereditary human disorder. The EXT1 and EXT2 genes encode glycosyltransferases that play an essential role in heparan sulfate chain elongation. In this study, we have analyzed heparan sulfate synthesized by primary fibroblast cell cultures established from mice with a gene trap mutation in Ext1. The gene trap mutation results in embryonic lethality, and homozygous mice die around embryonic day 14. Metabolic labeling and immunohistochemistry revealed that Ext1 mutant fibroblasts still produced small amounts of heparan sulfate. The domain structure of the mutant heparan sulfate was conserved, and the disaccharide composition was similar to that of wild type heparan sulfate. However, a dramatic difference was seen in the polysaccharide chain length. The average molecular sizes of the heparan sulfate chains from wild type and Ext1 mutant embryonic fibroblasts were estimated to be around 70 and 20 kDa, respectively. These data suggest that not only the sulfation pattern but also the length of the heparan sulfate chains is a critical determinant of normal mouse development.
authors.affiliation: Department of Medical Biochemistry and Microbiology, Uppsala University, Biomedical Center, P.O. Box 582, SE-751 23 Uppsala, Sweden.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Yamada
authors.forename: Marta
authors.initials: M
authors.lastname: Busse
authors.forename: Momoyo
authors.initials: M
authors.lastname: Ueno
authors.forename: Olivia G
authors.initials: OG
authors.lastname: Kelly
authors.forename: William C
authors.initials: WC
authors.lastname: Skarnes
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Sugahara
authors.forename: Marion
authors.initials: M
authors.lastname: Kusche-Gullberg
mesh_terms: D000818:Animals; D000838:Anions; D015152:Blotting, Northern; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004252:DNA Mutational Analysis; D004187:Disaccharides / Q000737:chemistry; D005347:Fibroblasts / Q000378:metabolism; D005821:Genetic Techniques; D006133:Growth Substances / Q000378:metabolism; D006497:Heparan Sulfate / Q000737:chemistry / Q000378:metabolism*; D006720:Homozygote; D007150:Immunohistochemistry; D051379:Mice; D008954:Models, Biological; D008957:Models, Genetic; D016296:Mutagenesis; D009154:Mutation; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics* / Q000378:metabolism*; D009608:Nitrous Acid / Q000494:pharmacology; D011134:Polysaccharides / Q000737:chemistry; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013997:Time Factors; D000099065:Exostosin 2; D000099058:Exostosin 1
chemical_list: D000838:Anions; D004187:Disaccharides; D006133:Growth Substances; D006497:Heparan Sulfate; D017351:N-Acetylglucosaminyltransferases; D009608:Nitrous Acid; D011134:Polysaccharides; D012333:RNA, Messenger; D000099065:Exostosin 2; D000099058:Exostosin 1