What are the pathways that underlie the coordinated responses of an organism to well-fed and food-deprived states? A report in this issue of Cell Metabolism suggests that starvation functions via a muscarinic acetylcholine receptor to activate MAP kinase signaling in the pharyngeal muscle of C. elegans ().
Dorsal intercalation is a coordinated cell migration event that rearranges hypodermal cells during C. elegans embryogenesis, and that resembles cell intercalation in many systems from flies to mice. Despite its conservation, the molecular mechanisms that govern dorsal intercalation in worms have remained elusive. Here, we comment on our recent publication, Walck-Shannon etal.,(1) which begins to spatially map the molecular requirements for intercalation. First, we provide a historical perspective on the factors that have previously hampered the study of dorsal intercalation. Next, we provide a summary of the molecular pathways identified in Walck-Shannon etal.,(1) pointing out surprises along the way. Finally, we consider the potential conservation of the molecular pathway we described and discuss future questions surrounding dorsal intercalation. Despite the challenges, dorsal intercalation is a process poised to advance our understanding of cell intercalation during morphogenesis throughout the animal kingdom.
Systematic mapping of genetic interactions for Caenorhabditis elegans genes involved in signaling pathways implicated in human disease reveals a network of 350 interactions. The topology of this network resembles that mapped previously in yeast, reinforcing the idea that similar networks may underlie the genetic basis of complex human disease.
Molecular insights into the genetic control of development have been mainly derived from single gene mutant studies. Francesconi and Lehner (2013) report now in Nature a genome-wide map of natural sequence variants that affect the temporal expression dynamics of thousands of genes during development of the roundworm Caenorhabditis elegans.
A powerful, top-down, holistic approach in biological research is to identify all of the components of a particular cellular process, so that one can define the global picture first and then use it as a framework to understand how the individual components of the process fit together. On page 116 of this issue, Wahout et al. report that they have started to compile a global map of interactions between all of the proteins in the worm Caenorhabditis elegans (1). These investigators commandeered a small number of well-studied proteins to establish the technical and conceptual framework for this mammoth protein-binding project. Their ultimate goal is to illuminate all of the protein-protein interactions in this animal, and to combine this information with that from other functional genomics approaches to work out what each worm gene does.