A transcriptional survey of the cDNA library of Macrolampis sp2 firefly lanterns (Coleoptera: Lampyridae).

The biochemistry of firefly bioluminescence is well understood; however, the molecular physiology of the lanterns is still poorly studied, especially the biosynthesis and origin of beetle luciferin which are almost unknown. Using a cDNA library previously constructed from Macrolampis sp2 lanterns, we randomly selected and sequenced 572 cDNAs in order to have a first transcriptional profile of the most represented messages found in the lanterns and therefore to better understand their molecular physiology. As expected, high percentage of the gene products (~22%) displayed high similarity with Coleoptera genome products. About 7% represented mitochondrial genes, including several copies of cytochrome oxidase, which are also expected for this tissue. Luciferase genes were especially abundant, representing ca 2% of the products. Gene products involved with cysteine and sulfur metabolism such as the cystathionine β-lyase and the S-adenosylmethionine synthetase were abundant. Noteworthy, an abundance of proteins involved with hormone metabolism was found, suggesting a possible link between bioluminescence and hormone metabolism.