Luciferase Gene - lux - In the presence of a suitable substrate, the enzyme luciferase confers on the organism carrying it, the ability to glow in the dark. In other words the organism carrying this enzyme exhibits luminiscence on an assay for the enzyme luciferase.

The enzyme luciferase differs in bacteria and firefly. While in bacteria, it consists of two peptide subunits coded by genes lux A and lux E, in firefly it consists of a single polypeptide coded by a gene lux.

The enzyme luciferase in these two systems uses different substrates for luminiscence. Therefore, depending upon the source of luciferase gene used as a scoreable marker gene, the assay for detection of its presence also differs