Contextual dependence of steroid receptor function on an androgen-responsive enhancer

• Published in: Molecular and cellular endocrinology 1996-07, Vol.121 (1), p.75-86
• Main Authors: Scheller, Arno, Scheinman, Robert I., Thompson, Elizabeth, Scarlett, Cameron O., Robins, Diane M.
• Format: Article
• Language: English
• Subjects: Androgen; Androgen receptor; Androgens - metabolism; Animals; Base Sequence; Blood Proteins - genetics; Cell Line; Cercopithecus aethiops; Complement C4; Consensus Sequence; Enhancer Elements, Genetic; Glucocorticoid receptor; Glucocorticoids - metabolism; Mice; Molecular Sequence Data; Mutagenesis, Site-Directed; NF-kappa B - metabolism; NF-κB; Oligodeoxyribonucleotides; Rats; Receptors, Steroid - metabolism; Slp; Tumor Cells, Cultured
• ISSN: 0303-7207; 1872-8057
• DOI: 10.1016/0303-7207(96)03854-3

The enhancer of the mouse sex-limited protein ( Slp) gene includes a consensus hormone response element (HRE) that interacts with several auxiliary elements for steroid induction. The 160-bp fragment, C′Δ2, confers response to androgen or glucocorticoid in transfection, while a 120-bp subfragment, C′Δ9, is activated only by androgen in some cells. Site-directed mutants were tested to identify elements affecting differential response of androgen or glucocorticoid receptors (AR, GR). While most mutations of C′Δ2 affected induction by either steroid similarly, disruptions of the consensus HRE or an octamer-like sequence were more severe for GR than AR activity. An HRE half-site was critical to androgen-specific induction of C′Δ9 but had little impact in the nonspecific C′Δ2 context. In DNase I footprinting, full-length AR and GR bound similarly to the consensus HRE but dissimilarly to nonconsensus sites. Intriguingly, NF-κB bound the region of C′Δ2 absent from C′Δ9. Expression of IκB decreased response of C′Δ2, but not C′Δ9, confirming a permissive role of NF-κB in steroid activation. In this case, different factors may associate with receptors in the presence of NF-κB than those that confer androgen specificity in NF-κB's absence, suggesting that exclusion of some factors from a specific transcription complex is as crucial as inclusion of others. This dissection of C′Δ2 and C′Δ9 in vitro reveals subtle distinctions in AR and GR interactions that may underlie specific hormonal response in vivo.