Multiplexing bioluminescent and fluorescent reporters to monitor live cells.

Reporter proteins are valuable tools to monitor promoter activities and characterize signal transduction path- ways. Many of the currently available promoter reporters have drawbacks that compromise their performance. Enzyme- based reporter systems using cytosolic luciferases are highly sensitive, but require a cell lysis step that prevents their use in long-term monitoring. By contrast, secreted bioluminescent reporters like Metridia luciferase and Secreted Alkaline Phosphatase can be assayed repeatedly, using supernatant from the same live cell population to produce many sets of data over time. This is crucial for studies with limited amounts of cells, as in the case of stem cells. The use of secreted biolu- minescent reporters also enables broader applications to provide more detailed information using live cells; for example, multiplexing with fluorescent proteins. Here, data is presented describing the characteristics of secreted Metridia lu- ciferase and its use in multiplexing applications with either Secreted Alkaline Phosphatase or a fluorescent protein.