GR is encoded by the gene NR3C1, which is located on chromosome 5q31-32 in humans, and acts as a ligand-inducible transcription factor belonging to the nuclear receptor superfamily. The molecular structure of GR includes four components: (1) an N-terminal transactivation domain (NTD), (2) a central DNA binding domain (DBD), (3) a C-terminal ligand-binding domain (LBD), and (4) a hinge region separating the DBD and the LBD. the LBD is a highly structured domain, consisting of 12 α-helices and four small β-strands, which forms a hydrophobic cavity for glucocorticoid binding and also contains an activation function (AF2). GR has also been shown to be intimately involved in the pathogenesis of many common cardiovascular diseases, including heart failure, atherosclerosis, sepsis, and myocardial ischemia. Dexamethasone is an agonist of GR, RU486 and cyproterone acetate are antagonists of GR, and progesterone and DHEA have antagonistic effects on GR.
Gal4 is a ubiquitous transcriptional activator in eukaryotic cells.
The sea pansy (Renilla reniformis) is another luciferase (RLuc) that has been extensively investigated; RLuc uses coelenterazine as a substrate and does not require ATP to produce light. With the use of commercially available molecular kits, the humanized forms of FLuc and RLuc (designated as hFLuc and hRLuc, respectively) were combined as dual reporters to image cultured cells in vivo because both enzymes used different substrates.