Dual-Luciferase Reporter Assay System

a. Promoter structure analysis: The promoter region sequence (typically ~2kb) is serially truncated or specific sites are mutated, then cloned into the luciferase reporter vector to detect promoter activity.
b. Promoter SNP analysis: Analyze the relative activity of single nucleotide polymorphisms (SNPs) present in the promoter region of some genes using the luciferase reporter system.
c. Verifying the interaction between a specific transcription factor and its regulatory sequence: Insert the sequence (usually the promoter region) into the reporter gene vector, and co-transfect an overexpression plasmid of the transcription factor into the experimental cells. Analyze whether transcription factor overexpression increases luciferase activity.
d. Analyzing signaling pathway activation: Clone the sequence of a downstream response element of the signaling pathway into the reporter gene vector. Under different upstream signal conditions, the luciferase activity represents the downstream response of the pathway. For example, in GPCR research, loading the cAMP response element (CRE) into a reporter gene vector and constructing a stable cell line can be used to analyze GPCR activation and inhibitor screening. Similarly, inserting the HIF1α response element, hypoxia-responsive element (HRE), into a luciferase reporter vector to create a stable cell line can be used for hypoxia-related pathway studies.
e. Verifying microRNA target sequences: Insert the candidate 3'UTR sequence into the reporter gene vector, then co-transfect the microRNA. A decrease in luciferase activity suggests it is a target sequence.

Firefly luciferase acts on luciferin in the presence of oxygen, magnesium, and ATP, while luciferase from the sea pansy (Renilla reniformis) acts on coelenterazine in the presence of oxygen. Dual-reporter assays combine Firefly luciferase and Renilla luciferase tests.