Y. Takenaka, A. Noda-Ogura, T. Imanishi, A. Yamaguchi, T. Gojobori, Y. Shigeri
Gene, 528(2):201-5, (2013)
We recently reported the cDNA sequences of 11 copepod luciferases from
the superfamily Augaptiloidea in the order Calanoida. They were
classified into two groups, Metridinidae and
Heterorhabdidae/Lucicutiidae families, by phylogenetic analyses. To
elucidate the evolutionary processes, we have now further isolated 12
copepod luciferases from Augaptiloidea species (Metridia asymmetrica, Metridia curticauda, Pleuromamma scutullata, Pleuromamma xiphias, Lucicutia ovaliformis and Heterorhabdus tanneri).
Codon-based synonymous/nonsynonymous tests of positive selection for 25
identified copepod luciferases suggested that positive Darwinian
selection operated in the evolution of Heterorhabdidae luciferases,
whereas two types of Metridinidae luciferases had diversified via neutral mechanism. By in silico
analysis of the decoded amino acid sequences of 25 copepod luciferases,
we inferred two protein sequences as ancestral copepod luciferases.
They were expressed in HEK293 cells where they exhibited notable
luciferase activity both in intracellular lysates and cultured media,
indicating that the luciferase activity was established before
evolutionary diversification of these copepod species.