title: pigk Mutation underlies macho behavior and affects Rohon-Beard cell excitability.
abstract: The study of touch-evoked behavior allows investigation of both the cells and circuits that generate a response to tactile stimulation. We investigate a touch-insensitive zebrafish mutant, macho (maco), previously shown to have reduced sodium current amplitude and lack of action potential firing in sensory neurons. In the genomes of mutant but not wild-type embryos, we identify a mutation in the pigk gene. The encoded protein, PigK, functions in attachment of glycophosphatidylinositol anchors to precursor proteins. In wild-type embryos, pigk mRNA is present at times when mutant embryos display behavioral phenotypes. Consistent with the predicted loss of function induced by the mutation, knock-down of PigK phenocopies maco touch insensitivity and leads to reduced sodium current (INa) amplitudes in sensory neurons. We further test whether the genetic defect in pigk underlies the maco phenotype by overexpressing wild-type pigk in mutant embryos. We find that ubiquitous expression of wild-type pigk rescues the touch response in maco mutants. In addition, for maco mutants, expression of wild-type pigk restricted to sensory neurons rescues sodium current amplitudes and action potential firing in sensory neurons. However, expression of wild-type pigk limited to sensory cells of mutant embryos does not allow rescue of the behavioral touch response. Our results demonstrate an essential role for pigk in generation of the touch response beyond that required for maintenance of proper INa density and action potential firing in sensory neurons.
authors.affiliation: Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado;
authors.forename: V
authors.initials: V
authors.lastname: Carmean
authors.affiliation: Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado;
authors.forename: M A
authors.initials: MA
authors.lastname: Yonkers
authors.affiliation: Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado;
authors.forename: M B
authors.initials: MB
authors.lastname: Tellez
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky; Zebrafish Mutant Mapping Facility, University of Louisville, Louisville, Kentucky; and.
authors.forename: J R
authors.initials: JR
authors.lastname: Willer
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky; Zebrafish Mutant Mapping Facility, University of Louisville, Louisville, Kentucky; and.
authors.forename: G B
authors.initials: GB
authors.lastname: Willer
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Louisville, Louisville, Kentucky; Zebrafish Mutant Mapping Facility, University of Louisville, Louisville, Kentucky; and.
authors.forename: R G
authors.initials: RG
authors.lastname: Gregg
authors.affiliation: Max-Planck-Institut für Entwicklungsbiologie, Tübingen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Geisler
authors.affiliation: Max-Planck-Institut für Entwicklungsbiologie, Tübingen, Germany.
authors.forename: S C
authors.initials: SC
authors.lastname: Neuhauss
authors.affiliation: Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, Colorado; angie.ribera@ucdenver.edu.
authors.forename: A B
authors.initials: AB
authors.lastname: Ribera
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D030801:Animals, Genetically Modified; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D060005:Genotyping Techniques; D009154:Mutation; D018408:Patch-Clamp Techniques; D010641:Phenotype; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D011984:Sensory Receptor Cells / Q000502:physiology*; D012964:Sodium / Q000378:metabolism; D055698:Touch Perception / Q000235:genetics / Q000502:physiology*; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D015815:Cell Adhesion Molecules; C000607121:PigK protein, zebrafish; D012333:RNA, Messenger; D029961:Zebrafish Proteins; D012964:Sodium
keywords: Nav; Pigk; Rohon-Beard cells; glycophosphatidylinositol-anchored protein; touch response