Identification of a novel member of the nuclear receptor superfamily which is closely related to Rev-ErbA.

Degenerate PCR primers were designed based upon conserved regions within the DNA and ligand binding domains of several nuclear receptors. PCR was performed using these primers starting with total brain cDNA. Several members of the nuclear receptor superfamily were identified, one of which was novel, but showing a high degree of homology to the previously known orphan receptor Rev-ErbA. This new orphan receptor, Rev-ErbA beta, was further characterised, and a cDNA with an intact open reading frame was isolated from a rat brain cDNA library. Northern blot analysis shows two different sizes of mRNA, 4 and 5.5 kb, respectively, in all tissues analysed. A more detailed study of this orphan was then performed using in situ hybridisation, showing a high expression of the new orphan receptor in particular in the cerebellum, the dentate gyrus of the hippocampus and pituitary gland of adult rats.