View the slide viewer

Human RORg Reporter Assay Kit

1 x 96-well format assays IB04001
3 x 32 assays in 96-well format IB04001-32
1 x 384-well format assays IB04002

Product Description and Product Data

This is an all-inclusive cell-based luciferase reporter assay kit targeting the Human RAR-related Orphan Receptor Gamma (RORg). INDIGO’s ROR Gamma reporter assay utilizes proprietary mammalian cells that have been engineered to provide constitutive expression of the ROR Gamma. In addition to ROR Gamma 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. The principal application of this assay is in the screening of test samples to quantify any functional activity, either agonist or antagonist, that they may exert against human ROR Gamma. This kit provides researchers with clear, reproducible results, exceptional cell viability post-thaw, and consistent results lot to lot. Kits must be stored at -80C. Do not store in liquid nitrogen. Note: reporter cells cannot be refrozen or maintained in extended culture.


  • Clear, Reproducible Results

  • All-Inclusive Assay Systems
  • Exceptional Cell Viability Post-Thaw
  • Consistent Results Lot to Lot

Product Specifications

Target TypeNuclear Hormone Receptor
Receptor FormHybrid
Assay ModeInverse Agonist
Kit Components
  • RORg Reporter Cells
  • Cell Recovery Medium (CRM)
  • Compound Screening Medium (CSM)
  • Ursolic acid, (ref. inverse-agonist; in DMSO)
  • Detection Substrate
  • Detection Buffer
  • White, sterile, cell-culture ready assay plate
Shelf Life6 months
Orthologs AvailableYes
Shipping RequirementsDry Ice
Storage temperature-80C


The Human RORγ Assay. Dose-response analyses of the RORγ Assay were performed using the inverse-agonists ML-209 (provided as reference), Ursolic Acid, AZ 5104, TO901317, and SR 1001 (all from Cayman Chemical, USA). RORγ Assay setup was performed as described in the assay Technical Manual. Relative Light Units were quantified and average values of RLU and their respective values of relative standard deviation were determined for each treatment concentration. Non-linear regression analyses were performed and IC50 values determined using GraphPad Prism software. The high Z' value confirms the robust performance of this assay, and its suitability for HTS applications.

Target Background

RAR-related orphan receptor gamma (ROR-gamma), also known as NR1F3 is a nuclear receptor encoded by the RORG gene.The RAR-related orphan receptors (RORs) are members of the nuclear receptor family of intracellular transcription factors. There are three forms of ROR, ROR-α, -β, and -γ and each is encoded by a separate gene (RORA, RORB, and RORC respectively). The RORs are somewhat unusual in that they appear to bind as monomers to hormone response elements as opposed to the majority of other nuclear receptors which bind as dimers. Melatonin has been reported to be the endogenous ligand for ROR-α while CGP 52608 has been identified as a ROR-α selective synthetic ligand. However X-ray crystallographic (PDB 1n83 and 1s0x) and functional data both suggest that cholesterol or a cholesterol derivative may be the endogenous ligand. In contrast, all-trans retinoic acid binds with high affinity to ROR-β and -γ but not ROR-α.

INDIGO’s Human RAR-related Orphan Receptor Gamma (NR1F3; RORγ) Assay utilizes proprietary human cells engineered to provide high-level expression of a hybrid form of RORγ. The N-terminal DNA binding domains (DBD) of the native RORγ and RORγt receptors (isoforms 1 and 2, respectively) have been substituted with that of the yeast GAL4-DBD. Hence, the GAL4-RORγ hybrid expressed in these reporter cells will not discern functional differences that may exist between the native isoform 1 and isoform 2 receptors. Endogenous molecular activators maintain RORγ in a state of constitutive high-level activity. Therefore, the principle application of this reporter assay system is in the screening of test samples to quantify inverse-agonist or agonist activities that they may exert against human RORγ.


Molecular docking is a key method used in virtual screening (VS) campaigns to identify small-molecule ligands for drug discovery targets. While docking provides a tangible way to understand and predict the protein-ligand complex formation, the docking algorithms are often unable to separate active ligands from inactive molecules in practical VS usage. Here, a novel docking and shape-focused pharmacophore VS protocol is demonstrated for facilitating effective hit discovery using retinoic acid receptor-related orphan receptor gamma t (RORγt) as a case study. RORγt is a prospective target for treating inflammatory diseases such as psoriasis and multiple sclerosis. First, a commercial molecular database was flexibly docked. Second, the alternative docking poses were rescored against the shape/electrostatic potential of negative image-based (NIB) models that mirror the target’s binding cavity. The compositions of the NIB models were optimized via iterative trimming and benchmarking using a greedy search-driven algorithm or brute force NIB optimization. Third, a pharmacophore point-based filtering was performed to focus the hit identification on the known RORγt activity hotspots. Fourth, free energy binding affinity evaluation was performed on the remaining molecules. Finally, twenty-eight compounds were selected for in vitro testing and eight compounds were determined to be low μM range RORγt inhibitors, thereby showing that the introduced VS protocol generated an effective hit rate of ~29%.
Bacterial activation of T helper 17 (Th17) cells exacerbates mouse models of autoimmunity, but how human-associated bacteria impact Th17-driven disease remains elusive. We show that human gut Actinobacterium Eggerthella lenta induces intestinal Th17 activation by lifting inhibition of the Th17 transcription factor Rorγt through cell- and antigen-independent mechanisms. E. lenta is enriched in inflammatory bowel disease (IBD) patients and worsens colitis in a Rorc-dependent manner in mice. Th17 activation varies across E. lenta strains, which is attributable to the Cardiac glycoside reductase 2 (Cgr2) enzyme. Cgr2 is sufficient to induce interleukin(IL)-17a, a major Th17 cytokine. cgr2+ E. lenta deplete putative steroidal glycosides in pure culture; related compounds are negatively associated with human IBD severity. Finally, leveraging the sensitivity of Cgr2 to dietary arginine, we prevented E. lenta-induced intestinal inflammation in mice. Together, these results support a role for human gut bacterial metabolism in driving Th17-dependent autoimmunity.

Also available as a service

RAR-related Orphan Receptor Gamma (RORg, NR1F3)