Androgen receptor-binding regions of an androgen-responsive gene.

The interaction of 5 alpha-dihydrotestosterone-receptor complexes with purified DNA fragments representing upstream, coding and intervening sequences of the prostate binding protein C3(1) gene was investigated using a DNA-cellulose competition binding assay. The partially purified androgen-receptor complexes which were used in the assay had proven DNA-binding capabilities. Two fragments were identified with relatively high affinity for androgen-receptor complexes. A 300 bp fragment extending from -220 to +80 and a 500 bp fragment derived entirely from the first intron consistently competed most effectively in the system. The presence of a high affinity site or sites in or near the promoter region of the gene is consistent with current models of transcriptional activation of hormone-responsive genes by steroid receptors. High affinity sites for steroid receptors within introns may indicate a role for receptors in regulation of transcription at other stages, or in post-transcriptional modification.