The pha-4 gene is required to generate the pharyngeal primordium of Caenorhabditis elegans.
In the 4-cell Caenorhabditis elegans embryo, two blastomeres are destined to generate pharyngeal cells, each by a distinct developmental strategy: one pathway is inductive, while the other is autonomous. Here, we identify the pha-4 locus. In animals lacking pha-4 activity, an early step in pharyngeal organogenesis is blocked: no pharyngeal primordium is formed and differentiated pharyngeal cells are absent. Most other tissues are generated normally in pha-4 mutants, including cells related to pharyngeal cells by cell lineage and position. Thus, pha-4 activity is required to form the pharyngeal primordium. We propose that pha-4 marks a convergence of the inductive and autonomous pathways of pharyngeal development and suggest that establishment of pharyngeal organ identity is a crucial step for pharyngeal organogenesis.
Mango
S E
SE
Laboratory of Molecular Biology, University of Wisconsin-Madison 53706, USA.
Lambie
E J
EJ
Kimble
J
J
D000818:Animals; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics; D017238:Genes, Helminth; D008854:Microscopy, Electron; D008954:Models, Biological; D009024:Morphogenesis / Q000235:genetics; D009154:Mutation; D010614:Pharynx / Q000196:embryology*; D010641:Phenotype; D012007:Rectum / Q000196:embryology