title: Leucophores are similar to xanthophores in their specification and differentiation processes in medaka.
abstract: Animal body color is generated primarily by neural crest-derived pigment cells in the skin. Mammals and birds have only melanocytes on the surface of their bodies; however, fish have a variety of pigment cell types or chromatophores, including melanophores, xanthophores, and iridophores. The medaka has a unique chromatophore type called the leucophore. The genetic basis of chromatophore diversity remains poorly understood. Here, we report that three loci in medaka, namely, leucophore free (lf), lf-2, and white leucophore (wl), which affect leucophore and xanthophore differentiation, encode solute carrier family 2, member 15b (slc2a15b), paired box gene 7a (pax7a), and solute carrier family 2 facilitated glucose transporter, member 11b (slc2a11b), respectively. Because lf-2, a loss-of-function mutant for pax7a, causes defects in the formation of xanthophore and leucophore precursor cells, pax7a is critical for the development of the chromatophores. This genetic evidence implies that leucophores are similar to xanthophores, although it was previously thought that leucophores were related to iridophores, as these chromatophores have purine-dependent light reflection. Our identification of slc2a15b and slc2a11b as genes critical for the differentiation of leucophores and xanthophores in medaka led to a further finding that the existence of these two genes in the genome coincides with the presence of xanthophores in nonmammalian vertebrates: birds have yellow-pigmented irises with xanthophore-like intracellular organelles. Our findings provide clues for revealing diverse evolutionary mechanisms of pigment cell formation in animals.
authors.affiliation: Interuniversity Bio-Backup Project Center, National Institute for Basic Biology, Okazaki 444-8787, Aichi, Japan;Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8787, Japan; tekimura@nibb.ac.jp.
authors.forename: Tetsuaki
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Bioscience and Biotechnology Center and Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan;
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Nagao
authors.affiliation: Bioscience and Biotechnology Center and Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan;
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hashimoto
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan;
authors.forename: Yo-ichi
authors.initials: Y
authors.lastname: Yamamoto-Shiraishi
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan;
authors.forename: Shiori
authors.initials: S
authors.lastname: Yamamoto
authors.affiliation: Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8787, Japan;Okazaki Institute for Integrative Bioscience and National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan;
authors.forename: Taijiro
authors.initials: T
authors.lastname: Yabe
authors.affiliation: Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8787, Japan;Okazaki Institute for Integrative Bioscience and National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan;
authors.forename: Shinji
authors.initials: S
authors.lastname: Takada
authors.affiliation: Division of Applied Bioscience, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan; and.
authors.forename: Masato
authors.initials: M
authors.lastname: Kinoshita
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan;
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kuroiwa
authors.affiliation: Interuniversity Bio-Backup Project Center, National Institute for Basic Biology, Okazaki 444-8787, Aichi, Japan;Department of Basic Biology, School of Life Science, Graduate University for Advanced Studies (SOKENDAI), Okazaki, Aichi 444-8787, Japan;Laboratory of Bioresources, National Institute for Basic Biology, Okazaki 444-8585, Aichi, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Naruse
mesh_terms: D000818:Animals; D019521:Body Patterning; D002454:Cell Differentiation; D002642:Chick Embryo; D002856:Chromatophores / Q000378:metabolism / Q000502:physiology*; D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D016678:Genome; D051246:Glucose Transport Proteins, Facilitative / Q000378:metabolism; D008547:Melanophores / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009432:Neural Crest / Q000166:cytology / Q000473:pathology; D009990:Oryzias / Q000196:embryology* / Q000502:physiology; D051763:PAX7 Transcription Factor / Q000378:metabolism; D010641:Phenotype; D010802:Phylogeny; D010858:Pigmentation; D014714:Vertebrates
chemical_list: D051246:Glucose Transport Proteins, Facilitative; D051763:PAX7 Transcription Factor
keywords: genome evolution; neural crest differentiation; pigment cell variation; vertebrate body color