摘要：SummaryThe Arabian killifish,Aphanius dispar, is a small tropical teleost fish living in wide range of habitats in sea water and fresh water in the Middle East. Here, we report extraordinary fluorescent pigment cells in the Arabian killifish embryo. These cells appear brown in transmitted light, yellowish white in reflected light, and as strong fluorescence in GFP and RFP filters. TEM and confocal microscopy analyses show the fluorescence emanates from leucosome-like pigment organelles. The cells express the gene encoding GTP cyclohydrolase (gch), a marker for leucophores and xanthophore. Gene knockdown and knockout ofgchusing morpholino or CRISPR-Cas9 induced loss of fluorescence in these embryos, indicating a crucial role of the enzyme and the associated pterine biosynthesis pathway in the generation of the fluorescence. We concluded that these cells are a highly fluorescent subtype of leucophores and have named them as fluoroleucophores.Graphical AbstractDisplay OmittedHighlights•Arabian killifish embryos possess extremely fluorescent pigment cells•The fluorescent pigment cells show characteristics in common with leucophores•Gene knockout of GTP cyclohydrolase removes fluorescence from the pigment cells•The novel pigment cells are termed fluoroleucophoresSpecialized Functions of Cells; Embryology; Model Organism
