Evidence for a calcium requirement in the Cypridina bioluminescence reaction

Imaging of luciferase secretion from transformed Chinese hamster ovary cells

The blue luminescence characteristic of the marine ostracod crustacean Vargula hilgendorfii is from a simple, but highly specific, enzyme-substrate reaction. Light is emitted by the oxidation of Vargula luciferin (substrate) by molecular oxygen, a reaction catalyzed by luciferase. Stable transformants of Chinese hamster ovary cells carrying the Vargula luciferase gene secreted luciferase from discrete sites on the cell surface, and this secretion could be monitored in real time by the bioluminescence produced by the secreted luciferase in the presence of Vargula luciferin by using an image-intensifying technique. Addition of anti-Vargula luciferase IgG to the luminescing cells almost completely extinguished the luminescence, confirming that Vargula luciferase caused the luminescence.

Cloning and expression of cDNA for the luciferase from the marine ostracod Vargula hilgendorfii

The marine ostracod Vargula hilgendorfii ejects luciferin and luciferase into seawater to produce a bright luminous cloud. The light is due to the oxidation of luciferin, an imidazopyrazine compound, by molecular oxygen, catalyzed by luciferase. The mechanism of the reaction has been studied extensively and the 60 kcal/mol required for the blue emission have been shown to be derived from the oxidation of luciferin via a dioxetanone intermediate, in which the excited state oxyluciferin bound to luciferase is the emitter. However, only limited information is available regarding the properties of the enzyme. This paper reports the cloning and sequence analysis of the cDNA for Vargula luciferase and the expression of the cDNA in a mammalian cell system. The primary structure, deduced from the nucleotide sequence, consists of 555 amino acid residues in a single polypeptide chain with a molecular weight of 62,171. Two regions of the enzyme show significant amino acid sequence homology with an N-terminal segment of the photoprotein aequorin. The Vargula luciferase gene, which contains a signal sequence for secretion, should be well suited as a reporter in studies of gene expression.