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Curr Opin Genet Dev,
2015]
The Caenorhabditis elegans hermaphrodite vulva is one of the best studied models for signal transduction and cell fate determination during organogenesis. Systematic forward genetic screens have identified a complex and highly interconnected signaling network formed by the conserved EGFR, NOTCH, and WNT signaling pathways that specifies an invariant pattern of cell fates among the six vulval precursor cells (VPCs). Multiple inhibitory interactions between the EGFR and NOTCH pathways ensure the selection of a single 1 VPC that is always flanked by two 2 VPCs thanks to lateral NOTCH signaling. Building on this 'central dogma' of cell fate specification, scientists have investigated a broad spectrum of novel questions that are summarized in this review. For example, vulval development is a unique model to study the intracellular trafficking of signaling molecules, such as NOTCH or EGFR, to investigate the interactions between the cell cycle and cell fate specification pathways, and to observe epithelial tube morphogenesis and cell invasion at single-cell resolution. Finally, computer scientists have integrated the experimental data into mathematical and state-based 'in silico' models of vulval development, allowing them to test the completeness and limits of our current understanding.
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Biochim Biophys Acta,
2002]
In the nematode Caenorhabditis elegans, the vulva is a simple tubular structure linking the gonads with the external cuticle. In this review we summarize knowledge of inter- and intracellular signaling during vulval development and of the genes required for vulval invagination. Mutants of one set of these genes, the sqv genes, have a normal number of vulval precursor cells (VPCs) with an unperturbed cell lineage but the invagination space, normally a tube, is either collapsed or absent. We review evidence that the sqv genes are involved in glycosaminoglycan synthesis and speculate on ways in which defective glycosaminoglycan formation might lead to
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Curr Top Dev Biol,
2001]
Studies of C. elegans vulval development provide insights into the process of pattern formation during animal development. The invariant pattern of vulval precursor cell fates is specified by the integration of at least two signaling systems. Recent findings suggest that multiple, partially redundant mechanisms are involved in patterning the vulval precursor cells. The inductive signal activates the LET-60/RAS signaling pathway and induces the 1 degree fate, whereas the lateral signal mediated by LIN-12/Notch is required for specification of the 2 degrees fate. Several regulatory pathways antagonize the RAS signaling pathway and specify the non-vulval 3 degrees fate in the absence of induction. The temporal and spatial regulation of VPC competence and production of the inductive and the lateral signal are precisely coordinated to ensure the wild-type vulval pattern.