title: Pax7 is required for establishment of the xanthophore lineage in zebrafish embryos.
abstract: The pigment pattern of many animal species is a result of the arrangement of different types of pigment-producing chromatophores. The zebrafish has three different types of chromatophores: black melanophores, yellow xanthophores, and shimmering iridophores arranged in a characteristic pattern of golden and blue horizontal stripes. In the zebrafish embryo, chromatophores derive from the neural crest cells. Using pax7a and pax7b zebrafish mutants, we identified a previously unknown requirement for Pax7 in xanthophore lineage formation. The absence of Pax7 results in a severe reduction of xanthophore precursor cells and a complete depletion of differentiated xanthophores in embryos as well as in adult zebrafish. In contrast, the melanophore lineage is increased in pax7a/pax7b double-mutant embryos and larvae, whereas juvenile and adult pax7a/pax7b double-mutant zebrafish display a severe decrease in melanophores and a pigment pattern disorganization indicative of a xanthophore- deficient phenotype. In summary, we propose a novel role for Pax7 in the early specification of chromatophore precursor cells.
authors.affiliation: Umeå Centre for Molecular Medicine, Umeå University, 90187 Umeå, Sweden.
authors.forename: Hanna
authors.initials: H
authors.lastname: Nord
authors.affiliation: Umeå Centre for Molecular Medicine, Umeå University, 90187 Umeå, Sweden.
authors.forename: Nils
authors.initials: N
authors.lastname: Dennhag
authors.affiliation: Umeå Centre for Molecular Medicine, Umeå University, 90187 Umeå, Sweden Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany.
authors.forename: Joscha
authors.initials: J
authors.lastname: Muck
authors.affiliation: Umeå Centre for Molecular Medicine, Umeå University, 90187 Umeå, Sweden Department for Integrative Medical Biology, Umeå University, 90187 Umeå, Sweden jonas.von.hofsten@umu.se.
authors.forename: Jonas
authors.initials: J
authors.lastname: von Hofsten
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D002454:Cell Differentiation / Q000235:genetics; D002856:Chromatophores; D004625:Embryo, Nonmammalian / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D008547:Melanophores / Q000378:metabolism; D009432:Neural Crest / Q000378:metabolism; D051762:PAX2 Transcription Factor / Q000235:genetics* / Q000378:metabolism*; D010858:Pigmentation / Q000235:genetics* / Q000502:physiology; D015027:Zebrafish / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism*
chemical_list: D051762:PAX2 Transcription Factor; D029961:Zebrafish Proteins; C000619973:pax7a protein, zebrafish