Much remains to be learned about cellular signaling and transcriptional regulatory mechanisms. Indeed, both are central to our understanding of normal as well as diseased cells. The glucocorticoid receptor (GR) carries both signaling and transcriptional regulatory functions, and is responsible for the control of development, growth, differentiation and homeostasis in a variety of cellular contexts. The mechanisms by which chromatin structure is disrupted selectively to facilitate transcription of specific genes is unknown. The yeast Swi/Snf chromatin remodeling complex exhibits a functional interdependence with GR, and therefore presents an excellent starting point for analyzing the potential role of targeted transcription factors in the remodeling of chromatin structure, and the role of this interaction in the regulation of gene transcription. In this context, the objective of this proposal is to gain a greater understanding of the functional interdependence of GR and the Swi/Snf complex during transcriptional activation at genomic glucocorticoid response elements (GREs), and to gain insight into how chromatin remodeling is targeted to specific promoters. Specifically, this interaction will be probed using a combination of approaches, including; (i) a chemical crosslinking approach to elucidate contacts between GR and Swi/Snf components; (ii) a mutagensis approach to probe for discrete functional surfaces responsible for interaction; (iii) a biochemical system designed to quantititate Swi/Snf dependent OR activation on a reconstituted MMTV LTR nucleosomal fragment.
