Luciferase Reporter Assays to Assess Liver X Receptor Transcriptional Activity

Luciferase reporter assays are sensitive and accurate tests that enable the analysis of regulatory sequences, the magnitude of transcriptional activity by transcription factors, and the discovery of gene regulatory elements and small-molecule modulators with high levels of precision. This is made possible through detection of bioluminescence produced by luciferase-coding reporters in a wide range of cellular environments. These assays are routinely used to analyze the activity of transcription factors, including the lipid-activated liver X receptor (LXR), in response to different stimuli as well as for the identification of their ligands. In this chapter we describe in detail the assays performed to investigate LXR activity in a macrophage-like cell line (RAW 267.4). These can be easily adapted to other nuclear receptors and transcription factors.