Glycobiology Advance Access published online on February 3, 2009
Glycobiology, doi:10.1093/glycob/cwp005
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Structural and Functional Changes of Sulfated Glycosaminoglycans in Xenopus laevis during Embryogenesis
2 Laboratory of Proteoglycan Signaling and Therapeutics, Hokkaido University Graduate School of Life Science, Sapporo 001-0021
3 Department of Biochemistry, Kobe Pharmaceutical University, Higashinada-ku, Kobe 658-8558
4 ICORP Organ Regeneration Project, Japan Science and Technology Agency (JST), Tokyo 153-8902
5 Department of Life Sciences (Biology), Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
1 To whom corresponding may be addressed: Laboratory of Proteoglycan Signaling and Therapeutics, Graduate School of Life Science, Hokkaido University, Frontier Research Center for Post-Genomic Science and Technology, Nishi 11-choume, Kita 21-jo, Kita-ku, Sapporo, Hokkaido 001-0021, Japan. Tel.: 81-(11)-706-9055; Fax: 81-(11)-706-9055; E-mail: tjohej{at}sci.hokudai.ac.jp or k-sugar{at}sci.hokudai.ac.jp
Received on July 9, 2008; accepted on January 16, 2009
Xenopus laevis is an excellent animal for analyzing early vertebrate development. Various effects of glycosaminoglycans (GAGs) on growth factor-related cellular events during embryogenesis have been demonstrated in Xenopus. To elucidate the relationship between alterations in fine structure and changes in the specificity of growth factor-binding during Xenopus development, heparan sulfate (HS) and chondroitin/dermatan sulfate (CS/DS) chains were isolated at four different embryonic stages and their structure and growth factor-binding capacities were compared. The total amounts of both HS and CS/DS chains decreased from the pre-midblastula transition to the gastrula stage, but increased exponentially during the following developmental stages. The length of HS chains was not significantly affected by development, whereas that of CS/DS chains increased with development. The disaccharide composition of GAGs in embryos also changed during development. The degree of sulfation of the HS chains gradually decreased with development. The predominant sulfation position in the CS/DS chains shifted from C4 to C6 of GalNAc during embryogenesis. Growth factor-binding experiments using a BIAcore system demonstrated that GAGs bound growth factors including fibroblast growth factors-1, and -2, midkine, and pleiotrophin, with comparable affinities. These affinities significantly varied during development, although the correlation between the structural alterations of GAGs and the change in the ability to bind growth factors remains to be clarified. Expression of saccharide sequences, which specifically interact with a growth factor, might be regulated during development.
Key words: Xenopus laevis / chondroitin sulfate / heparan sulfate / glycosaminoglycan / embryogenesis
6 Present address: RIKEN Advanced Science Institute Chemical Biology Department System Glycobiology Research Group Disease Glycomics Team, Wako, Saitama 351-0198, Japan
7 Present address: Division of Stem Cell Medicine, Center for Cancer and Stem Cell Research, Cancer Research Institute, Kanazawa University, Kanazawa, Ishikawa 920-0934, Japan