title: The Genetics of Axon Guidance and Axon Regeneration in Caenorhabditis elegans.
abstract: The correct wiring of neuronal circuits depends on outgrowth and guidance of neuronal processes during development. In the past two decades, great progress has been made in understanding the molecular basis of axon outgrowth and guidance. Genetic analysis in Caenorhabditis elegans has played a key role in elucidating conserved pathways regulating axon guidance, including Netrin signaling, the slit Slit/Robo pathway, Wnt signaling, and others. Axon guidance factors were first identified by screens for mutations affecting animal behavior, and by direct visual screens for axon guidance defects. Genetic analysis of these pathways has revealed the complex and combinatorial nature of guidance cues, and has delineated how cues guide growth cones via receptor activity and cytoskeletal rearrangement. Several axon guidance pathways also affect directed migrations of non-neuronal cells in C. elegans, with implications for normal and pathological cell migrations in situations such as tumor metastasis. The small number of neurons and highly stereotyped axonal architecture of the C. elegans nervous system allow analysis of axon guidance at the level of single identified axons, and permit in vivo tests of prevailing models of axon guidance. C. elegans axons also have a robust capacity to undergo regenerative regrowth after precise laser injury (axotomy). Although such axon regrowth shares some similarities with developmental axon outgrowth, screens for regrowth mutants have revealed regeneration-specific pathways and factors that were not identified in developmental screens. Several areas remain poorly understood, including how major axon tracts are formed in the embryo, and the function of axon regeneration in the natural environment.
authors.affiliation: Section of Neurobiology, Division of Biological Sciences, and chisholm@ucsd.edu hutter@sfu.ca william.wadsworth@rwjms.rutgers.edu yijin@ucsd.edu.
authors.forename: Andrew D
authors.identifier: http://orcid.org/0000-0001-5091-0537
authors.initials: AD
authors.lastname: Chisholm
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada chisholm@ucsd.edu hutter@sfu.ca william.wadsworth@rwjms.rutgers.edu yijin@ucsd.edu.
authors.forename: Harald
authors.initials: H
authors.lastname: Hutter
authors.affiliation: Section of Neurobiology, Division of Biological Sciences, and chisholm@ucsd.edu hutter@sfu.ca william.wadsworth@rwjms.rutgers.edu yijin@ucsd.edu.|Department of Cellular and Molecular Medicine, School of Medicine, University of California, San Diego, La Jolla, California 92093.|Department of Pathology and Laboratory Medicine, Howard Hughes Medical Institute, Chevy Chase, Maryland, and.
authors.forename: Yishi
authors.identifier: http://orcid.org/0000-0002-9371-9860
authors.initials: Y
authors.lastname: Jin
authors.affiliation: Department of Pathology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854 chisholm@ucsd.edu hutter@sfu.ca william.wadsworth@rwjms.rutgers.edu yijin@ucsd.edu.
authors.forename: William G
authors.identifier: http://orcid.org/0000-0003-3824-2948
authors.initials: WG
authors.lastname: Wadsworth
mesh_terms: D008841:Actin Cytoskeleton / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000071437:Axon Guidance / Q000235:genetics*; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D009416:Nerve Regeneration / Q000235:genetics*
keywords: DLK; Robo; Slit; Wnt; WormBook; actin; ephrin; fasciculation; growth cone; microtubule; netrin; semaphorin