This nuclear receptor assay system utilizes proprietary non-human mammalian cells engineered to provide high-level expression of a hybrid form of the Human Estrogen-Related Receptor γ (NR3B3). The N-terminal DNA binding domains (DBD) of the native ERRγ has been substituted with that of the yeast GAL4-DBD. The reporter gene is beetle luciferase functionally linked to the GAL4 upstream activation sequence (UAS). As is true in vivo, these reporter cells express ERRγ that is constitutively active in the (putative) absence of a ligand binding event. Interestingly, the ligand binding domain of ERRγ may be occupied by a ligand that further elevates the constitutive activity of the receptor (an agonist response), or one that results in a dose-dependent loss of constitutive active (an inverse-agonist response). Figure 2 demonstrates the high constitutive activity of ERRγ in the absence of added ligand, as well as agonist and inverse-agonist responses of the receptor upon ligand binding. Therefore, the principle application of this assay system is in the screening of test samples to quantify either agonist or inverse-agonist activities that they may exert against human ERRγ. ERRγ Reporter Cells are prepared using INDIGO's proprietary CryoMiteTM process. This cryo-preservation method yields exceptional cell viability post-thaw, and provides the convenience of immediately dispensing healthy, division-competent reporter cells into assay plates. There is no need for cumbersome intermediate treatment steps such as spin-and-rinse of cells, viability determinations, cell titer adjustments, or the preincubation of reporter cells prior to assay setup. INDIGO Bioscience's Nuclear Receptor Reporter Assays are all-inclusive cell-based assay systems. In addition to ERRγ Reporter Cells, this kit provides two optimized media for use during cell culture and in diluting the user's test samples, a reference agonist, Luciferase Detection Reagent, and a cell culture-ready assay plate.