Bioluminescence of a firefly pupa: involvement of a luciferase isotype in the dim glow of pupae and eggs in the Japanese firefly, Luciola lateralis

摘要

We isolated cDNA for a luciferase isotype, LILuc2, from the ovary of the Japanese firefly, Luciola lateralis. The gene product LILuc2 showed 59% amino acid identity with LILucI, which had been isolated from the adult L. lateralis lantern. Molecular phylogenetic analysis indicated that LILuc2 is an orthologue of LcLuc2 from Luciola cruciata. The spectral maxima of the luminescence by recombinant LILucI and LILuc2 were 550 and 539 nm, respectively. Quantitative PCR analysis revealed that LILud was expressed predominantly in larvae and adults, and LILuc2 was expressed in eggs and pupae, which glow dimly, and we found that the in vivo luminescence spectra of the egg and pupa in L lateralis were in good agreement with the in vitro luminescence spectrum by LILuc2. These results suggest that, in L. lateralis, LILud is responsible for the yellowish luminescence of larval and adult lanterns, and LILuc2 is responsible for the dim, greenish glow of eggs and whole pupae. Similar results were obtained in L cruciata.