Has a broad role in development, specifically in the genetic pathway SynMuvB that negatively regulates specification of the vulval cell fate. Required for fem-3 3'-UTR-mediated repression in the regulation of the sperm/oocyte switch. Acts by regulating the translation of fem-3 mRNA, by binding to its 3'-UTR. Interacts with hda-1, let-418, lin-1, mog-1, mog-4, mog-5, mog-6, pie-1 and unc-98. Found in all nuclei in the germline, including oocytes, but not those of mature sperm and spermatocytes. Expressed in somatic cells of embryos, the head, hypodermis and tail of larvae and the germline of adults, including oocytes but not mature sperm and spermatocytes. Expressed both maternally and zygotically. Expressed in all developmental stages; highest in embryos, decreasing during early larval development (L1-L3) until the fourth larval stage (L4) where it increases. Expression in hermaphrodite adults is mostly contained to the germline. Worms exhibit temperature-dependent arrested elongation of gonadal arms. Mutants raised at 25 degrees C show reduced numbers of descendants of the gonadal precursors Z1 and Z4, while mutants raised at 15 degrees C show wild type gonadal development. Vulval defects are also temperature sensitive. Mutants grown at 20 degrees C showed protruding vulva (80%) and some had pseudovulvae (15%). At 15 degrees C, fewer mutants exhibited everted (36%) or additional small vulvae (7%).