Kinetic complexity of the global response to glucocorticoid receptor action.

We have characterized the kinetic response of gene targets throughout the murine genome to transcriptional modulation by the glucocorticoid receptor (GR). In contrast to a model in which multiple genes are either repressed or activated during the GR response, the vast majority of responsive genes are subject to complex regulation profiles, frequently with alternate activation and repression phases. We also observe that GR binding at response elements does not always correlate with the target gene response profile. Thus, the cellular response to GR stimulation involves a highly orchestrated series of regulatory actions and not simply a binary response to hormone.