Gene expression of NOR-1, a neuron-derived orphan receptor, is inducible in neuronal and other cell lineages in culture.

We recently isolated a cDNA of NOR-1, a novel member of the steroid/thyroid hormone receptor superfamily, from a rat neuronal cell cDNA library. NOR-1 has strong amino acid sequence homology to orphan receptors NGFI-B and Nurr1, and is expressed predominantly in the brain tissue in vivo. In the present study, we examined NOR-1 gene expression in various cultured cells with distinct properties of neuronal cells (PC12), glial cells (C6), endocrine cells (GH3, AtT-20 and Y-1), or fibroblasts (NIH3T3 and L), by reverse transcription-polymerase chain reaction and nucleotide sequencing. NOR-1 transcripts were induced with forskolin and 12-O-tetradecanoylphorbol-13-acetate in all cell lines examined. The nerve growth factor induced not only NGFI-B but also NOR-1 and Nurr1 transcripts in PC12 cells. These findings suggest that NOR-1 gene expression is induced by various stimuli in diverse cell types.