sqv mutants of Caenorhabditis elegans are defective in vulval epithelial invagination

By screening for mutations that perturb the invagination of the vulva of th e Caenorhabditis elegans hermaphrodite, we have isolated 25 mutations that define eight genes. We have named these genes sqv-1 to sqv-8 (squashed vulv a). All 25 mutations cause the same vulval defect, an apparent partial coll apse of the vulval invagination and an elongation of the central vulval cel ls. Most sqv mutations also cause an oocyte or somatic gonad defect that re sults in hermaphrodite sterility, and some sqv mutations cause maternal-eff ect lethality. We propose that the sqv genes affect a pathway common to vul val invagination, oocyte development, and embryogenesis.