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This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Wasley, L. C. Articles by Kaufman, R. J. Search for Related Content PubMed PubMed Citation Articles by Wasley, L. C. Articles by Kaufman, R. J. Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  The importance of N- and O-linked oligosaccharides for the biosynthesis and in vitro and in vivo biologic activities of erythropoietin LC Wasley, G Timony, P Murtha, J Stoudemire, AJ Dorner, J Caro, M Krieger and RJ Kaufman Genetics Institute, Cambridge, MA 02140. Erythropoietin (EPO) plays a critical role in stimulating the proliferation and differentiation of erythroid precursor cells. EPO is heavily glycosylated with three asparagine (N)-linked tetraantennary oligosaccharides that may contain N-acetyl-lactosamine repeats and a single serine (O)-linked oligosaccharide. EPO expressed in Chinese hamster ovary cells exhibits biologic properties and amino acid and carbohydrate composition similar to natural urinary EPO. The importance of the complex N-linked and the O-linked carbohydrate was studied by expressing EPO in cells that are deficient in UDP-galactose/UDP-N- acetylgalactosamine 4-epimerase activity. In these cells, the ability to add galactose and N-acetylgalactosamine to glycoproteins can be controlled by the addition of these sugars to the culture medium. The results demonstrate that a block in O-linked glycosylation and/or the ability to process N-linked carbohydrate to completion does not alter EPO secretion. EPO produced without O-linked carbohydrate exhibits normal in vitro and in vivo biologic activity and in vivo clearance. However, EPO produced with incompletely processed N-linked oligosaccharides exhibits normal in vitro activity but is at least 500- fold less effective in stimulating erythropoiesis in vivo. Studies on the survival of bioactive EPO remaining in the circulation demonstrated that EPO with incomplete N-linked oligosaccharides exhibits a sevenfold increased rate of clearance. However, this increased clearance may not fully account for the 500-fold loss of in vivo activity. These results suggest a potentially important unique requirement for appropriate complex N-linked oligosaccharides for the intrinsic biologic activity of EPO in vivo. Volume 77, Issue 12, pp. 2624-2632, 06/15/1991 Copyright © 1991 by The American Society of Hematology CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: L. O. Narhi, T. Arakawa, K. Aoki, J. Wen, S. Elliott, T. Boone, and J. Cheetham Asn to Lys mutations at three sites which are N-glycosylated in the mammalian protein decrease the aggregation of Escherichia coli-derived erythropoietin Protein Eng. Des. Sel., February 1, 2001; 14(2): 135 - 140. [Abstract] [Full Text] [PDF] Y. Zhao, J. B. McCabe, J. Vance, and L. G. Berthiaume Palmitoylation of Apolipoprotein B Is Required for Proper Intracellular Sorting and Transport of Cholesteroyl Esters and Triglycerides Mol. Biol. Cell, February 1, 2000; 11(2): 721 - 734. [Abstract] [Full Text]

	Copyright © 1991 by American Society of Hematology         Online ISSN: 1528-0020