ABSTRACT
A marine dinoflagellate, Gonyaulax polyedra emitts light during the night by oxidizing its luciferin with luciferase. The estimated molecular weight of the Gonyaulax luciferase is 130 kDa. A cDNA expression library in the lZAPII vector was constructed from the polyadenylated RNA prepared from the Gonyaulax cells during the night phase. Approximately 1.2 x 105 phages from the library was screened with the antibody against the Gonyaulax luciferase which catalyzes the light-emitting reaction. Thirtheen positive plaques were obtained and the DNA sequence of two of these were determined. One had a 2.4-kb insert and the other had a 1.6-kb insert. A Northern hybridization using the cDNA as a probe showed that the length of the luciferase mRNA is approximately 4.1-kb which has enough capacity of encoding the 130-kDa luciferase. Polymerase chain reactions using the cloned cDNA or the Gonyaulax chromosomal DNA as the template showed that the cloned region of the luciferase gene does not carry an intron. When expressed in Escherichia coli, the cloned cDNA produced active luciferase.