Cellular symmetry breaking during Caenorhabditis elegans development.
The nematode worm Caenorhabditis elegans has produced a wellspring of insights into mechanisms that govern cellular symmetry breaking during animal development. Here we focus on two highly conserved systems that underlie many of the key symmetry-breaking events that occur during embryonic and larval development in the worm. One involves the interplay between Par proteins, Rho GTPases, and the actomyosin cytoskeleton and mediates asymmetric cell divisions that establish the germline. The other uses elements of the Wnt signaling pathway and a highly reiterative mechanism that distinguishes anterior from posterior daughter cell fates. Much of what we know about these systems comes from intensive study of a few key events-Par/Rho/actomyosin-mediated polarization of the zygote in response to a sperm-derived cue and the Wnt-mediated induction of endoderm at the four-cell stage. However, a growing body of work is revealing how C. elegans exploits elements/variants of these systems to accomplish a diversity of symmetry-breaking tasks throughout embryonic and larval development.
Munro
Edwin
E
Center for Cell Dynamics, Friday Harbor Labs, 620 University Rd, Friday Harbor WA 98250, USA. munroem@u.washington.edu
Bowerman
Bruce
B
D000818:Animals; D019521:Body Patterning; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D016764:Cell Polarity; D018507:Gene Expression Regulation, Developmental; D008954:Models, Biological; D051176:beta Catenin / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism*
D029742:Caenorhabditis elegans Proteins; D051176:beta Catenin; D020741:rho GTP-Binding Proteins