Nuclear remodeling in response to steroid hormone action.

Steroid and similar hormones comprise the broadest class of gene regulatory agents known, spanning vertebrates through the lower animals, and even fungi. Not unexpectedly, therefore, steroid receptors belong to an evolutionarily highly conserved family of proteins. After complexing with their cognate ligands, receptors interact with hormone response elements on target genes and modulate transcription. These actions are multifaceted and only partly understood, and include large-scale changes in the structure and molecular composition of the affected cell nuclei. This chapter examines steroid hormone action and the resultant nuclear remodeling from the following perspectives: (1) Where are the receptors located? (2) Which nuclear domains are most affected? (3) Are there extended or permanent nuclear changes? (4) What is the role of coiled bodies and similar structures in this regard? To address these and related questions, information is drawn from several sources, including vertebrates, insects, and malignant tissues. Entirely new data are presented as well as a review of the literature.