Molecular cloning and expression of a cDNA encoding the luciferase from the firefly, Hotaria unmunsana

We have cloned and characterized a cDNA encoding the luciferase from the firefly, Hotaria unmunsana. The cDNA encoding the luciferase of H. unmunsana was isolated by RT-PCR with a gene-specific primer set. The cDNA encoding the luciferase of H. unmunsana is 1644 base pairs long with an open reading frame of 548 amino acid residues. The deduced amino acid sequence of the luciferase gene of H. unmunsana showed 98.0 and 96.8% identity to H. parvula and Luciola mingrelica, respectively. Phylogenetic analysis further confirmed that the deduced amino acid sequences of the H. unmunsana luciferase gene belonged to the same subfamily, Luciolinae. Southern blot analysis of genomic DNA suggested the presence of the H. unmunsana luciferase gene as a single copy and Northern blot analysis confirmed light organ-specific expression at the transcriptional level. The cDNA encoding the luciferase of H. unmunsana was expressed as a 61-kDa band in the baculovirus-infected insect cells and the extracts of the recombinant baculovirus-infected cells emitted luminescence in the luciferase activity assay.