1. Academic Validation
  2. Developmental and comparative transcriptomic identification of iridophore contribution to white barring in clownfish

Developmental and comparative transcriptomic identification of iridophore contribution to white barring in clownfish

  • Pigment Cell Melanoma Res. 2019 May;32(3):391-402. doi: 10.1111/pcmr.12766.
Pauline Salis 1 Thibault Lorin 2 Victor Lewis 3 4 Carine Rey 5 6 Anna Marcionetti 7 8 Marie-Line Escande 1 Natacha Roux 1 Laurence Besseau 1 Nicolas Salamin 7 8 Marie Sémon 5 David Parichy 4 Jean-Nicolas Volff 2 Vincent Laudet 1
Affiliations

Affiliations

  • 1 Observatoire Océanologique de Banyuls-sur-Mer, UMR CNRS 7232 BIOM, Sorbonne Université, Banyuls-sur-Mer, France.
  • 2 IGFL, ENS de Lyon, UMR 5242 CNRS, Université Claude Bernard Lyon I, Lyon Cedex 07, France.
  • 3 Department of Biology, University of Washington, Seattle, Washington.
  • 4 Department of Biology, Department of Cell Biology, University of Virginia, Charlottesville, Virginia.
  • 5 ENS de Lyon, CNRS UMR 5239, INSERM U1210, LBMC, Université Claude Bernard, Lyon, France.
  • 6 LBBE, CNRS, Université Lyon 1, Villeurbanne, France.
  • 7 Department of Computational Biology, Biophore, University of Lausanne, Lausanne, Switzerland.
  • 8 Swiss Institute of Bioinformatics, Lausanne, Switzerland.
Abstract

Actinopterygian fishes harbor at least eight distinct pigment cell types, leading to a fascinating diversity of colors. Among this diversity, the cellular origin of the white color appears to be linked to several pigment cell types such as iridophores or leucophores. We used the clownfish Amphiprion ocellaris, which has a color pattern consisting of white bars over a darker body, to characterize the pigment cells that underlie the white hue. We observe by electron microscopy that cells in white bars are similar to iridophores. In addition, the transcriptomic signature of clownfish white bars exhibits similarities with that of zebrafish iridophores. We further show by pharmacological treatments that these cells are necessary for the white color. Among the top differentially expressed genes in white skin, we identified several genes (fhl2a, fhl2b, saiyan, gpnmb, and apoD1a) and show that three of them are expressed in iridophores. Finally, we show by CRISPR/Cas9 mutagenesis that these genes are critical for iridophore development in zebrafish. Our analyses provide clues to the genomic underpinning of color diversity and allow identification of new iridophore genes in fish.

Keywords

Amphiprion; clownfish; coral reef fish; iridophore; leucophore; transcriptomic.

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