Involvment of PlexinA in vulval morphogenesis Shin Takagi, Takashi Fujii, Akira Nukazuka, Yukimasa Shibata, Go Shioi, Hajime Fujisawa Laboratory of Developmental Neurobiology, Division of Biological Science, Graduate School of Science, Nagoya University, Japan, CREST, JST The plexin family transmembrane proteins are putative receptors for semaphorins, which are implicated in the morphogenesis of animal embryos including axonal guidance. We have generated and characterized putative null mutants of the
plx-1 ( pka.
cep-2 ) gene encoding C. elegans plexinA.
plx-1 mutants exhibited morphological defects in several organs of epidermal origin, such as Ray1 in the male tail (see Fujii et al . in this Meeting) and alae. Here we report on the defects in vulvae of
plx-1 mutants.
plx-1 adult hermaphrodites sometimes had a deformed vulva or extra vulva-like structures.
plx-1::gfp transgene was expressed in the vulval primordial cells. Since the epidermal cells composing the vulval primordium are known to undergo dynamic changes in shape and position during the vulval morphogenesis, we analyzed the vulval primordium with MH27::gfp . The epidermal cells of the vulval primordium were aberrantly arranged in
plx-1 mutants: the rotation-symmetric configuration of the primordum was often disrupted, and some cells were not in contact with each other. Some cells failed to participate in the formation of the main vulva and formed an extra vulva-like depression. The results indicate that
plx-1 regulates the arrangement and/or migration of epidermal cells in this system.