Biosynthesis and metabolism of sulfated glycosaminoglycans during Drosophila melanogaster development

We developed a simple methodology for labeling sulfated glycosaminoglycans (GAGs) in adult Drosophila melanogaster and studied some aspects of the biosynthesis and metabolism of these polymers during development. Adult D. melanogaster flies were fed with (Na2SO4)-S-35 for 72 h. During this period, S-35-sulfate was incorporated into males and females and used to synthesize S-35-sulfate-heparan sulfate (HS) and S-35-sulfate-chondroitin sulfate (CS). The incorporation of S-35-sulfate into HS was higher when compared to CS. In a pulse-chase experiment, we observed that S-35-sulfate incorporated into adult female was recovered in embryos and used for the synthesis of new S-35-sulfate-GAGs after 2 h of embryonic development. The synthesis of CS was higher than that of HS, indicating a change in the metabolism of these glycans from adult to embryonic and larval stages. Analysis of the CS in embryonic and larval tissues revealed the occurrence of nonsulfated and 4-sulfated disaccharide units in embryos, L1 and L2. In L3, in addition to these disaccharides, we also detected significant amount of 6-sulfated units that are reported here for the first time. Immunohistochemical analysis indicated that HS and CS were present in nonequivalent structures in adult and larval stages of the fly. Overall, these results indicate that S-35-sulfate-precursors are transferred from adult to embryonic and larval tissues and used to assemble different morphological structures during development.