RAR Related Orphan Receptor Gamma (RORg)

RORγ is expressed in many tissues, including thymus, lung, liver, kidney, muscle, and brown fat. While RORγ mRNA is abundantly expressed, attempts to detect RORγ protein have not been successful therefore it is not clear whether RORγ protein is actually expressed. Consistent with this, the main phenotypes identified in RORγ knockout mice (where neither isoform is expressed) are those associated with RORγt immune system function and an isoform specific RORγt knockout displayed a phenotype identical to the RORγ knockout. On the other hand, circadian phenotypes of RORγ mice in tissues where the RORγt isoform is expressed in minute amounts argues for the expression of functional RORγ isoform. Absent protein in previous studies may be due to the high amplitude circadian rhythm of expression of this isoform in some tissues.