Studies on the biosynthetic mechanism and regulation of the expression of sulfated glycosaminoglycans

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Sulfated glycosaminoglycans including heparin/heparan sulfate and chondroitin/dermatan sulfate have been implicated in numerous pathophysiological phenomena of vertebrates and invertebrates. In this study, we found novel functions of sulfated glycosaminoglycans as follows.1)We identified the causal gene for the spondylepiphyseal dysplasia Omani type as CHST3 that encodes chondroitin 6-O-sulfotransferase-1 (C6ST-1). C6ST-1 catalyzes the modifying step of chondroitin sulfate synthesis by transferring sulfate to the C-6 position of the GalNAc of chondroitin. The findings indicate that the mutation in CHST3 causes a specific but generalized defect of chondroitin sulfate chain sulfation resulting in chondrodysplasia with major involvement of the spine.2)We cloned C.elegans chondroitin polymerizing factor (cChPF). The worm phenotypes including the reversion of cytokinesis, observed after the depletion of cChPF by RNAi, were very similar to the C.elegans chondroitin synthase (cChSy)-RNAi phen … More otypes. Thus, cChPF in addition to cChSy is indispensable for the biosynthesis of chondroitin and embryonic cell division in C.elegans.3)We found that chondroitin sulfate characterized by the E-disaccharide unit was a potent inhibitor of herpes simplex virus infectivity and provided the virus binding sites on gro2C cells. Knowledge of the determinants of antiviral properties of chondroitin sulfate-E will help in the development of inhibitors of herpes simplex virus infections in humans.4)The formation of heparan sulfate (HS) chains is catalyzed by glycosyltransferases encoded by EXT (hereditary multiple exostosin gene) family members. In Drosophila, three EXT family genes named tout-velu (ttv), sister of tout-velu (sotv) and brother of tout-velu (botv), which encode homologues of human EXT1, EXT2 and EXTL3, respectively, have been identified. Here, we demonstrated that all three EXT members in Drosophila, TTV, SOTV and BOTV, are required for the biosynthesis of full-length HS in Drosophila.5)All sulfation reactions in all organisms require activated sulfate, PAPS as a universal donor. We cloned a C.elegans PAPS-synthase gene pps-1. Disruption of the pps-1 gene by RNAi caused pleiotropic developmental defects in muscle patterning and epithelial cell shape changes with decrease in glycosaminoglycan sulfation, suggesting that sulfation is essential for integrity of epidermis in C.elegans. Less