RESUMO
The fireworms Odontosyllis spp. are globally distributed and well-known for their characteristic and fascinating mating behavior, with secreted mucus emitting bluish-green light. However, knowledge about the molecules involved in the light emission are still scarce. The fireworms are believed to emit light with a luciferin-luciferase reaction, but biochemical evidence of the luciferase is established for only one species living in Japan and no information is available for its luciferin structure. In this study, we identified a luciferase gene from a related Puerto Rican fireworm. We identified eight luciferase-like genes in this Puerto Rican fireworm, finding amino acid identities between Japanese and Puerto Rican luciferase-like genes to be less than 60%. We confirmed cross reactivity of extracts of the Japanese fireworm luciferin with a recombinant Puerto Rican luciferase (PR1). The emission spectrum of recombinant PR1 was similar to the crude extract of the native luciferase, suggesting that PR1 is a functional luciferase of this Puerto Rican fireworm. Our results indicate that the molecular mechanism of luminescence is widely conserved among fireworms.
Assuntos
Luciferases/metabolismo , Luminescência , Poliquetos/enzimologia , Poliquetos/genética , Proteínas Recombinantes/metabolismo , Sequência de Aminoácidos , Animais , Japão , Luciferases/genética , Poliquetos/metabolismo , Porto Rico , Proteínas Recombinantes/genética , Homologia de SequênciaRESUMO
In the first molecular study of ostracod (Crustacea) vision, we present partial cDNA sequences of ostracod visual pigment genes (opsins). We found strong support for differential expression of opsins in ostracod median and compound eyes and suggest that photoreceptor specific expression may be a general phenomenon in organisms with multiple receptors. We infer that eye-specific expression predates the divergence of the two species examined, Skogsbergia lerneri and Vargula hilgendorfii, because eye-specific opsin orthologs are present in both species. We found multiple opsin loci in ostracods, estimating that at least eight are present in Skogsbergia lerneri. All opsins from both ostracod species examined are more closely related to each other than to any other known opsin sequences. Because we find no evidence for gene conversion or alternative splicing, we suggest the occurrence of many recent gene duplications. Why ostracods may have retained multiple recent opsin gene duplicates is unknown, but we discuss several possible hypotheses.