NR2C1 and erythroleukemia: Using adult (definitive) murine erythroleukemia (MEL) nuclear cell extracts, we identified the orphan nuclear receptors TR2 (NR2C1) and TR4 (NR2C2) that as a heterodimer was capable of preferential high-affinity binding to the ε- and γ-globin DR1 elements and of recruiting chromatin modifying cofactors to those binding sites [10], [11].