sqv-3 -7, and -8, a set of genes affecting morphogenesis in Caenorhabditiselegans, encode enzymes required for glycosaminoglycan biosynthesis

sqv (squashed vulva) genes comprise a set of eight independent loci in Caen orhabditis elegans required zygotically for the invagination of vulval epit helial cells and maternally for normal oocyte formation and embryogenesis. Sequencing of sqv-3, sqv-7, and sqv-8 suggested a role for the encoded prot eins in glycolipid or glycoprotein biosynthesis. Using a combination of in vitro analysis of SQV enzymatic activities, sqv(+)-mediated rescue of verte brate cell lines, and biochemical characterization of sqv mutants, we show that sqv-3, -7, and -8 all affect the biosynthesis of glycosaminoglycans an d therefore compromise the function of one specific class of glycoconjugate s, proteoglycans. These findings establish the importance of proteoglycans and their associated glycosaminoglycans in epithelial morphogenesis and pat terning during C. elegans development.