title: Acropora digitifera Encodes the Largest Known Family of Fluorescent Proteins that Has Persisted during the Evolution of Acropora Species.
abstract: Fluorescent proteins (FPs) are well known and broadly used as bio-imaging markers in molecular biology research. Many FP genes were cloned from anthozoan species and it was suggested that multi-copies of these genes are present in their genomes. However, the full complement of FP genes in any single coral species remained unidentified. In this study, we analyzed the FP genes in two stony coral species. FP cDNA sequences from Acropora digitifera and Acropora tenuis revealed the presence of a multi-gene family with an unexpectedly large number of genes, separated into short-/middle-wavelength emission (S/MWE), middle-/long-wavelength emission (M/LWE), and chromoprotein (CP) clades. FP gene copy numbers in the genomes of four A. digitifera colonies were estimated as 16-22 in the S/MWE, 3-6 in the M/LWE, and 8-12 in the CP clades, and, in total, 35, 31, 33, and 33 FP gene copies per individual shown by quantitative PCR. To the best of our knowledge, these are the largest sets of FP genes per genome. The fluorescent light produced by recombinant protein products encoded by the newly isolated genes explained the fluorescent range of live A. digitifera, suggesting that the high copy multi-FP gene family generates coral fluorescence. The functionally diverse multi-FP gene family must have existed in the ancestor of Acropora species, as suggested by molecular phylogenetic and evolutionary analyses. The persistence of a diverse function and high copy number multi-FP gene family may indicate the biological importance of diverse fluorescence emission and light absorption in Acropora species.
authors.affiliation: Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Japan.
authors.forename: Shiho
authors.initials: S
authors.lastname: Takahashi-Kariyazono
authors.affiliation: Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Gojobori
authors.affiliation: Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Satta
authors.affiliation: Department of Coral Reef and Biological Science, Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, 3422 Sesoko, Motobu, Okinawa 905-0227, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Sakai
authors.affiliation: Department of Evolutionary Studies of Biosystems, SOKENDAI (The Graduate University for Advanced Studies), Shonan Village, Hayama, Japan terai_yohei@soken.ac.jp.
authors.forename: Yohey
authors.initials: Y
authors.lastname: Terai
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D008164:Luminescent Proteins / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D011110:Polymorphism, Genetic
chemical_list: D008164:Luminescent Proteins
keywords: copy number variation; fluorescence diversity; reef-building corals