Worm Breeder's Gazette 13(5): e1 (February 1, 1995)
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
* Glaxo-IMCB Group, Institute of Molecular and Cell Biology, National University of Singapore, 10 Kent Ridge Crescent, Singapore 0511 and + Institute of Neurology, 1 Wakefield Street, London WC1N 1PJ, UK p21 Ras has been implicated in vulval differentiation in Caenorhabditis elegans. We now describe the characteristics during nematode development of the related p21 RhoA which has been ascribed a morphological role in mammals. The cDNA encoding C. elegans RhoA, CeRhoA, was isolated from a mixed stage cDNA library. The encoded sequence of 192 amino acids residues displays a high level of identity with its homologues in other organisms (e.g. 87.6% identity to human RhoA). Genomic Southern analysis indicates the presence of a single Rho gene in C. elegans. Its 2 kb mRNA is expressed at the highest levels during embryogenesis and decreases gradually thereafter. However, the level of the 24 kD protein during development as detected by the anti-CeRhoA antibody is high at the larval stages but low in embryos. The GST/CeRhoA fusion protein expressed in E. coli displays conserved biochemical activities, such as GTP-binding and stimulation of its intrinsic GTPase activity by GAPs. Unlike its counterpart in mammalian cells which is predominantly cytosolic, most of CeRhoA is associated with the membrane and the cytoskeleton throughout development. Indirect immunofluorescence analysis indicates an ubiquitous expression of CeRhoA throughout development with a particular enrichment at larval stages in the pharyngeal nerve ring as well as at the tip of the head containing chemosensory and mechanosensory neurons. This suggests an involvement of p21 RhoA in events underlying the postembryonic development of the sensory circuitry in C. elegans.