Dual Reporter Assay
Luciferase is widely used as a reporter due to its sensitivity and linear range, and a wide variety of luciferase-based systems are available for monitoring promoter activity in prokaryotic and eukaryotic cells. While these systems offer high sensitivity in diverse combinations of luciferases, many are unsuitable for use in living cells because cell lysis is required prior to measurement of bioluminescence produced by the action of the luciferase on its substrate. Wu et al. have devised a reporter system that incorporates two secreted luciferases, one produced by the marine ostracod crustacean Cypridina (CLuc) and the second by the marine copepod Gaussia (GLuc). Luciferase activity can be assayed in the medium of cultured cells, circumventing the need for cell lysis and permitting monitoring of promoter activity in a single population of cells over hours or days. Because GLuc activity is inhibited by SDS, the assay can be performed in a single tube, assaying GLuc activity, followed by addition of SDS, and measurement of CLuc activity. -Page 290