Post-transcriptional Regulation of Steroid Hormone Receptors

Abstract

This review focuses on the post-transcriptional regulation of mRNAs that encode steroid hormone receptors, which exert powerful effects on physiology by regulating gene expression. Recent discoveries in the regulation of gene expression indicate that it is not limited to alterations of the rate of gene transcription. On the contrary, stabilities of specific mRNAs are regulated by cellular signals to profoundly alter their steady state concentrations. The mRNAs encoding steroid hormone receptors are post-transcriptionally regulated by their own hormonal ligands to create autoregulatory feedback loops. Negative and positive autoregulatory feedback loops serve to limit or augment hormonal responses, respectively. Studies of the molecular mechanisms of regulated stabilities of mRNAs encoding steroid hormone receptors continue to identify unique and critical mRNA sequence elements, usually within the 3′ untranslated regions. The binding factors for the mRNA sequence elements are either proteins or microRNAs. Several sequence-specific RNA binding proteins have been identified that either stabilize or destabilize mRNAs encoding steroid hormone receptors, while microRNAs usually destabilize mRNAs and/or inhibit translation of the mRNA. These posttranscriptional effects regulate the expression of steroid hormone receptor genes to impact a large population of hormone-responsive genes. Further elucidation of the molecular mechanisms involved in the post-transcriptional regulation of steroid hormone receptor mRNAs may yield novel approaches to the therapeutic control of hormone actions to augment health.