Estrogen receptors are the primary regulators of gene function in female reproductive tissues. They do so by recruiting a series of 'coregulators' (coactivators to activate genes, or corepressors to repress genes). Most coregulators are enzymes and many of them are recruited simultaneously to form large complexes bound to a receptor at a given target gene. We know a great deal about the production of the hormone (estrogen) and a good deal about the estrogen receptor. However, much less is known about the complement of coactivators that bind to receptor at a specific target gene. For instance, what specific relative roles the DNA sequence, the posttranslational modifications of the associated proteins, and the compositions of histones play in activating its target gene. We feel we can best contribute specific new information to these questions by studying direct formation of the 'active receptor-coactivator' complexes in vitro, under conditions where we can control the compositions and posttranslational modifications of the components in the complex - all under conditions where we can monitor the final outcome activation of transcriptional expression of the gene into messenger RNA. We plan to approach these questions using biochemical, physical structural and cell-based methodologies. We have developed within the project a means (Cryo-EM) to 'directly visualize' and model the receptor-coactivator complexes that we form in vitro. When we define the DNA bound receptor- complex of coactivators and the histone marks, we then use this information to understand the roles of these molecular reactions in disease states such as reproductive tissue inflammatory diseases and reproductive tissue cancers. When we determine a critical coactivator or histone mark that allows a disease process gene to function aberrantly, we next search for small molecule drugs that will inhibit/activate this molecular targe to favor therapy for the pathology in question. When the cell-free and whole cell studies indicate therapeutic possibilities for a new drug for a disease (e.g., breast cancer), we then test the drugin standard animal models. In preliminary studies described in our grant proposal, we demonstrate this roadmap to therapy can be used successfully to uncover new therapeutic drugs for given diseases of reproductive and oncogenic tissues.