title: Gap junctions composed of connexins 41.8 and 39.4 are essential for colour pattern formation in zebrafish.
abstract: Interactions between all three pigment cell types are required to form the stripe pattern of adult zebrafish (Danio rerio), but their molecular nature is poorly understood. Mutations in leopard (leo), encoding Connexin 41.8 (Cx41.8), a gap junction subunit, cause a phenotypic series of spotted patterns. A new dominant allele, leo(tK3), leads to a complete loss of the pattern, suggesting a dominant negative impact on another component of gap junctions. In a genetic screen, we identified this component as Cx39.4 (luchs). Loss-of-function alleles demonstrate that luchs is required for stripe formation in zebrafish; however, the fins are almost not affected. Double mutants and chimeras, which show that leo and luchs are only required in xanthophores and melanophores, but not in iridophores, suggest that both connexins form heteromeric gap junctions. The phenotypes indicate that these promote homotypic interactions between melanophores and xanthophores, respectively, and those cells instruct the patterning of the iridophores.
authors.affiliation: Max Planck Institute for Developmental Biology, Tübingen, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Irion
authors.affiliation: Max Planck Institute for Developmental Biology, Tübingen, Germany.
authors.forename: Hans Georg
authors.initials: HG
authors.lastname: Frohnhöfer
authors.affiliation: Max Planck Institute for Developmental Biology, Tübingen, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Krauss
authors.affiliation: Max Planck Institute for Developmental Biology, Tübingen, Germany.
authors.forename: Tuǧba
authors.initials: T
authors.lastname: Çolak Champollion
authors.affiliation: Max Planck Institute for Developmental Biology, Tübingen, Germany.
authors.forename: Hans-Martin
authors.initials: HM
authors.lastname: Maischein
authors.affiliation: Max Planck Institute for Developmental Biology, Tübingen, Germany.
authors.forename: Silke
authors.initials: S
authors.lastname: Geiger-Rudolph
authors.affiliation: Max Planck Institute for Developmental Biology, Tübingen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Weiler
authors.affiliation: Max Planck Institute for Developmental Biology, Tübingen, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Nüsslein-Volhard
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D002678:Chimera / Q000235:genetics* / Q000378:metabolism; D003116:Color; D017630:Connexins / Q000235:genetics* / Q000378:metabolism; D004625:Embryo, Nonmammalian; D005260:Female; D017629:Gap Junctions / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005838:Genotype; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010858:Pigmentation / Q000235:genetics*; D010860:Pigments, Biological / Q000096:biosynthesis; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015027:Zebrafish / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D017630:Connexins; C000601037:Cx39.4 protein, zebrafish; D010860:Pigments, Biological; D020033:Protein Isoforms; D029961:Zebrafish Proteins; C574532:gja5b protein, zebrafish
keywords: chromosomes; connexins; developmental biology; gap junctions; genes; leopard; pigmentation; stem cells; zebrafish