Practice question

Luciferase reporter offers sensitive readout of promoter strength and inducibility in yeast and mammalian cells. Promoter fragment cloned upstream of firefly luciferase in plasmid, introduced by transfection. Upon transcription factor activation and polymerase recruitment, luciferase accumulates catalyzing luciferin oxidation producing light measured by luminometer with wide linear range. Benefits include high sensitivity detecting weak promoters, short protein half-life capturing dynamic pulses, and dual normalization with Renilla control. System extensively used to dissect UASG enhancer, glucose repression elements, hormone responses, and drug-responsive promoters, enabling mapping of minimal promoter requirements and combinatorial regulatory logic efficiently.