Dynamics of AR-chromatin interactions in living cells
About the project
To understand the molecular details of androgen action, it is critical to explore the mechanisms that regulate AR activity. Since AR is a transcription factor, it is important to delineate the determinants of its interactions with its response element in chromatin and how this results in transcriptional regulation. To that end, we have generated a cell system, modeled on that developed for the glucocorticoid receptor, which makes it possible to study subcellular trafficking and gene targeting by AR in living cells. Using this system and confocal immunoflourescence microscopy coupled to photobleaching techniques, it is possible to investigate the direct interaction of AR with regulatory elements in living cells and the transcriptional consequences of these interactions in real time. It is also possible using this system to study the precise nature of the chromatin structure that AR recognizes, and higher order chromatin transitions that may be induced by AR during gene activation. We have found, for example, that AR has a very dynamic exchange rate with its chromatinized template with a half life of a few seconds, and modification of this may be at the basis of AR response to different ligands, as well as chromatin modifiers. The information that we obtain from this line of work is being compared with global analysis of AR-chromatin interactions as well as those with other members of the nuclear receptor family, such as the glucocorticoid receptor.