Table 1.
Nuclear receptor (NR) complements characterized in metazoan genomes.
| Subfamily | Group | Name | NRNC Symbol | Abbreviation | Physiological Ligand |
|---|---|---|---|---|---|
| # * | A | NRs with two DBDs | NR#A1 | 2DBD-NRα | |
| B | NR#B1 | 2DBD-NRβ | |||
| C | NR#C1 | 2DBD-NRγ | |||
| D | NR#D1 | 2DBD-NRδ | |||
| 0 | A * | Zygotic gap protein | NR0A1 | KNI | x |
| Zygotic gap protein- related | NR0A2 | KNRL | x | ||
| Egon | NR0A3 | EG | x | ||
| ODR-7 | NR0A4 | ODR-7 | x | ||
| Trithorax | NR0A5 | TRX | x | ||
| B | Dosage-sensitive sex reversal-adrenal hypoplasia congenital critical region on the X chromosome, gene 1 | NR0B1 | DAX1 | x | |
| Small heterodimer partner | NR0B2 | SHP | x | ||
| 1 | A | Thyroid hormone receptor | NR1A1,2 | THRα,β | T3 |
| B | Retinoic acid receptor | NR1B1-3 | RARα-γ | All-trans-RA | |
| C | Peroxisome proliferator-activated receptor | NR1C1-3 | PPARα-γ | Fatty acids, Prostaglandins | |
| D | Rev-ErbA | NR1D1,2 | Rev-ErbAα,β | x | |
| E * | Ecdysone-regulated E78 gene | NR1E | E78 | ||
| F | RAR-related orphan receptor | NR1F1-3 | RORα-γ | x | |
| HR3 * | NR1F4 | HR3 | |||
| G * | CNR14-like | NR1G1 | Sex-1 | x | |
| H | Liver X receptor-like | NR1H1 * | EcR | Ecdysteroids | |
| NR1H2,3 | LXRα,β | Oxysterols | |||
| NR1H4,5 | FXRα,β | x | |||
| I | Vitamin D receptor-like | NR1I1 | VDR | Vitamin D | |
| NR1I2 | PXR | Xenobiotics | |||
| NR1I3 | CAR | Androstane | |||
| J * | NHR96 | NR1J1 | DHR96 | ||
| K * | VDR/PXRα,β | NR1K1,2 | VDRα,β-like | ||
| L * | HNR-like 97 | NR1L | HR97 | ||
| M * | HNR-like 19 | NR1M1 | HR10 | ||
| N * | HNR-like 11 | NR1N1 | HR11 | ||
| O * | NR1O | ||||
| P * | NR1P1-11 | ||||
| 2 | A | Hepatocyte nuclear factor 4 | NR2A1-3 | HNF4α,γ | Fatty acids |
| NR2A4 * | HNF4 | ||||
| B | Retinoid X receptor | NR2B1-3 | RXRα-γ | x | |
| NR2B4 | USP | x | |||
| C | Testicular receptor | NR2C1 | TR2 | x | |
| NR2C2 | TR4 | x | |||
| D * | DHR78 | NR2D1 | HR78 | ||
| E | Tailless / Photoreceptor cell-specific nuclear receptor | NR2E1 | TLX | x | |
| NR2E2 * | TLL | x | |||
| NR2E3 | PNR/HR51 * | x | |||
| Dissatisfaction nuclear receptor * | NR2E4 | DSF | |||
| Nuclear hormone receptor FAX-1 * | NR2E5 | FAX1 | |||
| F | Chicken ovalbumin upstream promoter transcription factor | NR2F1,2 | COUP-TFI,II | x | |
| Seven-up * | NR2F3 | SVP | |||
| Chicken ovalbumin upstream promoter transcription factor III * | NR2F4 | COUP-TFIII | |||
| Seven-up related protein 46 * | NR2F5 | SVP-46 | |||
| V-erbA-related protein 2 | NR2F6 | EAR-2 | x | ||
| 3 | A | Estrogen receptor | NR3A1,2 | ERα,β | Estradiol |
| B | Estrogen-related receptor | NR3B1-3 | ERRα-γ | x | |
| NR3B4 * | ERR | x | |||
| C | Steroid receptor / Ketosteroid receptors | NR3C1 | Glucocorticoid receptor, GR | Cortisol | |
| NR3C2 | Mineralocorticoid receptor, MR | Aldosterone | |||
| NR3C3 | Progesterone receptor, PR | Progesterone | |||
| NR3C4 | Androgen receptor, AR | Testosterone | |||
| D * | Estrogen receptor-like in Protostomia | NR3D | ER-like | ||
| E * | Estrogen receptor-like in Cnidaria | NR3E | ER-like | ||
| F * | Estrogen receptor-like in Placozoa | NR3F | ER-like | ||
| 4 | A | Nerve growth factor IB | NR4A1 | NGFIB | x |
| Nuclear receptor related 1 | NR4A2 | NURR1 | x | ||
| Neuron-derived orphan receptor 1 | NR4A3 | NOR1 | x | ||
| DHR38 * | NR4A4 | HR38 | |||
| 5 | A | Steroidogenic factor 1 | NR5A1 | SF1 | Phosphatidylinositols |
| Liver receptor homolog-1 | NR5A2 | LRH1 | Phosphatidylinositols | ||
| NHR FTZ1-α * | NR5A3 | FTZ1-α | |||
| B * | NHR39/FTZ1-β | NR5B1 | HR39 | ||
| 6 | A | Germ cell nuclear factor | NR6A1 | GCNF | x |
| HR4 * | NR6A2 | HR4 | |||
| 7/8 * | A | NR7/8A1 |
Non-vertebrate NR subfamilies and receptors are indicated by (*). Physiological ligands refer to in vivo conditions in vertebrates and the (x) highlights orphan NRs [12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]. NRs with two DBDs are listed as (#), because they do not yet have an unequivocal subfamily status. Like NR0s, NRs with two DBDs do not have the conventional NR structure as shown in Figure 1. The NR7/8 subfamily has been called either NR7 or NR8 [14,22,24]. When information is absent or disputed, cells are left empty.