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/th yroid hormone receptor superfamily, from a rat neuronal cell cDNA libr ary. NOR-1 has strong amino acid sequence homology to orphan receptors NGFI-B and Nurrl, and is expressed predominantly in the brain tissue in vivo. In the present study, we examined NOR-1 gene expression in va rious cultured cells with distinct properties of neuronal cells (PC12) , glial cells (C-6), endocrine cells (GH(3), AtT-20 and Y-1), or fibro blasts (NIH3T3 and L), by reverse transcription-polymerase chain react ion and nucleotide sequencing. NOR-1 transcripts were induced with for skolin and 12-O-tetradecanoylphorbol-13-acetate in all cell lines exam ined. The nerve growth factor induced not only NGFI-B but also NOR-1 a nd Nurrl transcripts in PC12 cells. These findings suggest that NOR-1 gene expression is induced by various stimuli in diverse cell types.