Distinct and collaborative roles ofDrosophilaEXT family proteins in morphogen signalling and gradient formation

• DOI: 10.1242/dev.01051
• Publication Date: 2004-03-09T01:23:43Z
• Authors: Chun Han; Tatyana Y. Belenkaya; Marat Khodoun; Miyuki Tauchi; Xinda Lin; Xinhua Lin
• Keywords: Decapentaplegic; Morphogen

Heparan sulfate proteoglycans (HSPG) have been implicated in regulating the signalling activities of secreted morphogen molecules including Wingless (Wg), Hedgehog (Hh) and Decapentaplegic (Dpp). HSPG consists a protein core to which heparan (HS) glycosaminoglycan (GAG) chains are attached. The formation HS GAG is catalyzed by glycosyltransferases encoded members EXT family putative tumor suppressors linked hereditary multiple exostoses. Previous studies Drosophila demonstrated that tout-velu (ttv), EXT1, required for Hh movement. However, functions other unknown. We identified isolated two genes, named sister (sotv) brother (botv), encode homologues vertebrate EXT2 EXT-like 3 (EXTL3), respectively. show both Dpp activities, as well their distributions, defective cells mutant ttv, sotv or botv wing disc. Surprisingly, although Wg distribution abnormal botv, only mutants ttv-sotv double mutants, not ttv nor alone, suggesting Ttv Sotv redundant signalling. demonstrate further form complex co-localized vivo. Our results, along with previous on Ttv, provide evidence all three proteins biosynthesis HSPGs, gradient Wg, morphogens. results also suggest HSPGs distinct roles