An efficient procedure for cloning hormone-responsive genes from a specific tissue

Nuclear receptors form a superfamily of ligand-activated transcription factors. In contrast to the significant advances made in recent years to dissect nuclear receptor structure and their corresponding function, progress has been rather slow in the identification of target genes for nuclear receptors, information that is a prerequisite for understanding hormone action. Here, we describe a simple screening protocol that makes it possible to efficiently and effectively clone hormone-responsive genes that are specific to a tissue of interest. When this procedure was used to clone prostate-specific and androgen-responsive genes, approximately 40% of the clones selected at random represented genes that are known to be androgen regulated and are largely specific to prostate for expression, such as prostate specific antigen (PSA). A further 37% are known to be highly enriched in prostate for expression, but their androgen regulation is yet to be studied. The rest of the clones represented novel genes, expressed sequence tags, or known genes whose possible androgen regulation has not yet been assessed. This screening scheme can be applied to any hormone/ligand to clone differentially expressed genes specific to a tissue of interest. Identification of such genes and their characterization should greatly facilitate understanding hormone action in normal and pathological conditions.