Identification and Characterization of a Luciferase Isotype in the Japanese Firefly, Luciola cruciata, Involving in the Dim Glow of Firefly Eggs

摘要

We isolated the cDNA of a luciferase isotype (LcLuc2) from the Japanese firefly, Luciola cruciatan(Lampyridae, Coleoptera). The gene product of LcLuc2 (LcLuc2) showed 59%amino acid identity with fireflynluciferase LcLuc1, which was previously identified in L. cruciata. The recombinant LcLuc2 showed bothnluminescence activity and fatty acyl-CoA synthetic activity comparable to those of LcLuc1. The spectral maximanof the luminescence by LcLuc1 and LcLuc2 were 554 and 543 nm, respectively. Reverse transcription-PCRnanalysis showed that the transcripts of LcLuc1were abundant in the lanterns of larva, adultmale, and adult female,nwhereas both LcLuc1 and LcLuc2 were expressed in eggs. The luminescence spectra of the lantern extracts fromnlarva, adult male, and adult female were in good agreement with that of recombinant LcLuc1. On the other hand,nthe emission maximum of the extract from eggs was between those of LcLuc1 and LcLuc2. These results suggestnthat L. cruciata possesses two luciferases: LcLuc1 is responsible for the major luminescence in larva and adult,nwhereas LcLuc1 and LcLuc2 are responsible for the dim glow in firefly eggs.