Establishment of left/right asymmetry in neuroblast migration by UNC-40/DCC, UNC-73/Trio and DPY-19 proteins in C. elegans.
The bilateral C. elegans neuroblasts QL and QR are born in the same anterior/posterior (A/P) position, but polarize and migrate left/right asymmetrically: QL migrates toward the posterior and QR migrates toward the anterior. After their migrations, QL but not QR switches on the Hox gene mab-5. We find that the UNC-40/netrin receptor and a novel transmembrane protein DPY-19 are required to orient these cells correctly. In unc-40 or dpy-19 mutants, the Q cells polarize randomly; in fact, an individual Q cell polarizes in multiple directions over time. In addition, either cell can express MAB-5. Both UNC-40 and DPY-19, as well as the Trio/GTPase exchange factor homolog UNC-73, are required for full polarization and migration. Thus, these proteins appear to participate in a signaling system that orients and polarizes these migrating cells in a left/right asymmetrical fashion during development. The C. elegans netrin UNC-6, which guides many cells and axons along the dorsoventral axis, is not involved in Q cell polarization, suggesting that a different netrin-like ligand serves to polarize these cells along the anteroposterior axis.
Honigberg
L
L
Program in Neuroscience and Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143-0448, USA.
Kenyon
C
C
D000595:Amino Acid Sequence; D000818:Animals; D019521:Body Patterning; D017173:Caenorhabditis elegans / Q000196:embryology*; D029742:Caenorhabditis elegans Proteins; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000502:physiology*; D002465:Cell Movement; D016764:Cell Polarity; D003001:Cloning, Molecular; D000078404:Epidermal Cells; D004817:Epidermis / Q000196:embryology; D015801:Helminth Proteins / Q000235:genetics / Q000502:physiology*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology*; D009420:Nervous System / Q000166:cytology / Q000196:embryology*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D029742:Caenorhabditis elegans Proteins; D015815:Cell Adhesion Molecules; C417031:DPY-19 protein, C elegans; D015801:Helminth Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011993:Recombinant Fusion Proteins; C102174:UNC-40 protein, C elegans; C111263:UNC-73 protein, C elegans