Ventral cord and vulva development are analyzed in a large sample of nematode species of the suborder Cephalobina. We find a specific range of evolutionary variations at distinct developmental steps. (1) Unlike Caenorhabditis elegans and relatives, the vulva is formed from the four precursor cells P(5-8).p or, exceptionally, from P(6, 7).p only. (2) The vulval competence group is restricted to ...

The C. elegans hermaphrodite vulva is an established model system to study mechanisms of cell fate specification and tissue morphogenesis. The adult vulva is a tubular shaped organ composed of seven concentric toroids that arise from selective fusion between differentiated vulval progeny. The dorsal end of the vulval tubule is connected to the uterus via a multinucleate syncytium utse (uterine-...

MOTIVATION Caenorhabditis elegans vulval development is a paradigmatic example of animal organogenesis with extensive experimental data. During vulval induction, each of the six multipotent vulval precursor cells (VPCs) commits to one of three fates (primary, secondary, tertiary). The precise primary-secondary-tertiary formation of VPC fates is controlled by a network of intercellular signaling...

The let-60 ras gene of Caenorhabditis elegans is one of the key players in a signal transduction pathway that controls the choice between vulval and epidermal differentiation in response to extracellular signals. To identify components acting downstream of let-60 ras in the vulval signaling pathway, we have identified a reduction-of-function mutation in the sur-1 gene that completely suppresses...

Cell invasion through basement membranes is crucial during morphogenesis and cancer metastasis. Here, we genetically dissect this process during anchor-cell invasion into the vulval epithelium in C. elegans. We have identified the fos transcription factor ortholog fos-1 as a critical regulator of basement-membrane removal. In fos-1 mutants, the gonadal anchor cell extends cellular processes nor...

The synthetic multivulva (synMuv) genes define two functionally redundant pathways that antagonize RTK/Ras signaling during Caenorhabditis elegans vulval induction. The synMuv gene lin-35 encodes a protein similar to the mammalian tumor suppressor pRB and has been proposed to act as a transcriptional repressor. Studies using mammalian cells have shown that pRB can prevent cell cycle progression...

Models of cell function that assign a variable to each gene frequently lead to systems of equations with many parameters whose behavior is obscure. Geometric models reduce dynamics to intuitive pictorial elements that provide compact representations for sparse in vivo data and transparent descriptions of developmental transitions. To illustrate, a geometric model fit to vulval development in Ca...