Interfering with the dynamics of estrogen receptor-regulated transcription.

In recent years, there has been a growing realization that a static two-dimensional model of gene activation by transcription factors is inadequate. Based on the work from a number of groups (Kang et al. 2002; Liu and Bagchi 2004; Metivier et al. 2003; Park et al. 2005; Reid et al. 2003; Shang et al. 2000; Sharma and Fondell 2002; Vaisanen et al. 2005), it is becoming clear that transcriptional regulation by nuclear receptors is a dynamic and cyclical process (Metivier et al. 2006). There are significant consequences that arise from this shift in understanding, from nuclear receptors as ligand activated factors that bind to a response element to activate expression of a target gene to a process where the receptor repeatedly binds in order to achieve transcription. New insights that arise from viewing the activation process as cyclical and the consequences of this for developing new strategies that modulate the activity of the estrogen receptor are outlined in this chapter.