Nur77 (also designated NGFI-B), Nurr1 (Nur-related factor 1) and NOR-1 (neuron-derived orphan receptor-1) constitute the NGFI-B subfamily within the nuclear receptor superfamily.The human NOR-1 gene maps to chromosome 9q and encodes a protein which is expressed in heart, skeletal muscle, thymus and spleen as well as in brain, where it is developmentally regulated. Therefore, NOR-1 may be involved in regulating neural differentiation. The NOR-1 gene also undergoes chromosomal translocation with the EWS gene to produce a protein thought to affect pre-mRNA splicing.