title: The C. elegans F-spondin family protein SPON-1 maintains cell adhesion in neural and non-neural tissues.
abstract: The F-spondin family of extracellular matrix proteins has been implicated in axon outgrowth, fasciculation and neuronal cell migration, as well as in the differentiation and proliferation of non-neuronal cells. In screens for mutants defective in C. elegans embryonic morphogenesis, we identified SPON-1, the only C. elegans member of the spondin family. SPON-1 is synthesized in body muscles and localizes to integrin-containing structures on body muscles and to other basement membranes. SPON-1 maintains strong attachments of muscles to epidermis; in the absence of SPON-1, muscles progressively detach from the epidermis, causing defective epidermal elongation. In animals with reduced integrin function, SPON-1 becomes dose dependent, suggesting that SPON-1 and integrins function in concert to promote the attachment of muscles to the basement membrane. Although spon-1 mutants display largely normal neurite outgrowth, spon-1 synergizes with outgrowth defective mutants, revealing a cryptic role for SPON-1 in axon extension. In motoneurons, SPON-1 acts in axon guidance and fasciculation, whereas in interneurons SPON-1 maintains process position. Our results show that a spondin maintains cell-matrix adhesion in multiple tissues.
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, Sinsheimer Laboratories, University of California, Santa Cruz, CA 95064.
authors.forename: Wei-Meng
authors.initials: WM
authors.lastname: Woo
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, Sinsheimer Laboratories, University of California, Santa Cruz, CA 95064.|Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093.
authors.forename: Emily
authors.initials: E
authors.lastname: Berry
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, Sinsheimer Laboratories, University of California, Santa Cruz, CA 95064.
authors.forename: Martin L
authors.initials: ML
authors.lastname: Hudson
authors.affiliation: Department of Molecular, Cell, and Developmental Biology, Sinsheimer Laboratories, University of California, Santa Cruz, CA 95064.
authors.forename: Ryann E
authors.initials: RE
authors.lastname: Swale
authors.affiliation: Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093.|Howard Hughes Medical Institute.
authors.forename: Alexandr
authors.initials: A
authors.lastname: Goncharov
authors.affiliation: Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Chisholm
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000502:physiology; D001485:Basement Membrane / Q000502:physiology; D017173:Caenorhabditis elegans / Q000196:embryology / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology*; D002448:Cell Adhesion; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000502:physiology*; D016023:Integrins / Q000502:physiology; D008969:Molecular Sequence Data; D009024:Morphogenesis / Q000502:physiology; D009046:Motor Neurons / Q000502:physiology; D009132:Muscles / Q000502:physiology; D009154:Mutation; D009420:Nervous System / Q000196:embryology* / Q000378:metabolism; D016501:Neurites / Q000502:physiology
chemical_list: D029742:Caenorhabditis elegans Proteins; D016326:Extracellular Matrix Proteins; D016023:Integrins; C533066:spon-1 protein, C elegans