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Glycosaminoglycan biosynthesis in UDP-glucose dehydrogenase overexpressing 293 cells
Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
Manuscript (Other academic)
URN: urn:nbn:se:uu:diva-92361OAI: oai:DiVA.org:uu-92361DiVA: diva2:165405
Available from: 2004-11-17 Created: 2004-11-17 Last updated: 2010-01-13Bibliographically approved
In thesis
1. Studies on the Role of UDP-Glucose Dehydrogenase in Polysaccharide Biosynthesis
Open this publication in new window or tab >>Studies on the Role of UDP-Glucose Dehydrogenase in Polysaccharide Biosynthesis
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Polysaccharides are found in all forms of life and serve diverse purposes. They are enzymatically synthesised from activated monosaccharide precursors, nucleotide sugars. One such nucleotide sugar is UDP-glucuronic acid, which is formed from UDP-glucose by the UDP-glucose dehydrogenase (UGDH) enzyme. UGDH has been proposed to have a regulatory role in the biosynthesis of polysaccharides. The aim of the studies presented in this thesis was to investigate the role of UGDH in the polysaccharide biosynthesis in three different systems: human cell culture, bacterial cultures and growing plants. The effects of UGDH-overexpression on polysaccharide biosyntheses and, when achievable, on UDP-sugar levels, were investigated.

A mammalian UGDH was cloned from a kidney cDNA library. Transient expression of the cloned enzyme in mammalian cells led to an increased UGDH-activity. Northern blotting analyses revealed a single transcript of 2.6 kb in adult mouse tissues whereas human tissues expressed a predominant transcript of 3.2 kb and a minor transcript of 2.6 kb.

Overexpression of the bovine UGDH in mammalian cells induced increased synthesis of the glycosaminoglycans; heparan sulphate, chondroitin sulphate and hyaluronan, without changing their relative proportions. The effects on glycosaminoglycan synthesis caused by an increased demand of UDP-glucuronic acid were studied by overexpression of hyaluronan synthase (Has3), which requires UDP-glucuronic acid as substrate. Overexpression of Has3 and coexpression of Has3 and UGDH resulted in highly augmented production of hyaluronan without noticeably affecting heparan sulfate and chondroitin sulfate synthesis.

Expression of the bacterial UGDH in E. coli resulted in increased formation of UDP-glucuronic acid, but, unexpectedly, also to synthesis of fewer K5 polysaccharide chains.

Overexpression of UGD1, one of four A. thaliana UGDH genes, in A. thaliana, resulted in dwarfism. Analysis of the cell wall polysaccharides showed alteration in saccharide composition. Paradoxically, the UDP-sugars derived from UDP-glucuronic acid decreased in amount.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2004. 58 p.
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 0282-7476 ; 1388
Biochemistry, UDP-glucose dehydrogenase, polysaccharide biosynthesis, glycosaminoglycan, A. thaliana, E. coli K5, Biokemi
National Category
Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)
Research subject
Medical and Physiological Chemistry
urn:nbn:se:uu:diva-4657 (URN)91-554-6088-7 (ISBN)
Public defence
2004-12-10, B22, BMC, Husargatan 3, Uppsala, 13:15
Available from: 2004-11-17 Created: 2004-11-17Bibliographically approved

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