firefly luciferase is widely used as a reporter for studying gene regulation and function and for pharmaceutical screening. It is a very sensitive genetic reporter due to the absence of endogenous luciferase activity in mammalian cells or tissues. Renilla luciferase has been used as a reporter gene for studying gene regulation and function in vitro and in vivo. It commonly is used in multiplex transcriptional reporter assays or as a normalizing transfection control for firefly luciferase assays.The firefly/Renilla Dual Luciferase Assay allows measurement of both firefly and Renilla luciferase activity in the same sample with high sensitivity and linearity. firefly luciferase activity is measured first then Renilla Luciferase Assay Buffer 2.0 is added to simultaneously quench firefly luciferase activity and measure Renilla luciferase activity. Renilla Luciferase Assay Buffer 2.0 quenches the firefly luciferase activity to the level of untransfected cells allowing sequential measureme