The C. elegans pharynx: a model for organogenesis.
The C. elegans foregut (pharynx) has emerged as a powerful system to study organ formation during embryogenesis. Here I review recent advances regarding cell-fate specification and epithelial morphogenesis during pharynx development. Maternally-supplied gene products function prior to gastrulation to establish pluripotent blastomeres. As gastrulation gets under way, pharyngeal precursors become committed to pharyngeal fate in a process that requires PHA-4/FoxA and the Tbox transcription factors TBX-2, TBX-35, TBX-37 and TBX-38. Subsequent waves of gene expression depend on the affinity of PHA-4 for its target promoters, coupled with combinatorial strategies such as feed-forward and positive-feedback loops. During later embryogenesis, pharyngeal precursors undergo reorganization and a mesenchymal-to-epithelial transition to form the linear gut tube. Surprisingly, epithelium formation does not depend on cadherins, catenins or integrins. Rather, the kinesin ZEN-4/MKLP1 and CYK-4/RhoGAP are critical to establish the apical domain during epithelial polarization. Finally, I discuss similarities and differences between the nematode pharynx and the vertebrate heart.
Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112, USA. susan.mango@hci.utah.edu
Susan E
SE
Mango
D000818:Animals; D017173:Caenorhabditis elegans / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology; D019070:Cell Lineage; D004848:Epithelium / Q000502:physiology; D006801:Humans; D023421:Models, Animal; D038081:Organogenesis / Q000235:genetics / Q000502:physiology*; D010614:Pharynx / Q000033:anatomy & histology / Q000502:physiology; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology; D014158:Transcription, Genetic
D029742:Caenorhabditis elegans Proteins; C113277:Pha-4 protein, C elegans; D015534:Trans-Activators