Nuclear receptors coordinate the activities of chromatin remodeling complexes and coactivators to facilitate initiation of transcription

Recent advances in the field of in vitro chromatin assembly have led to in vitro transcription systems which reproduce in the test tube, in vivo chara cteristics of ligand-dependent transcriptional activation by nuclear recept ors. Dissection of these systems has begun to provide us with information c oncerning the underlying molecular mechanisms. Through recruitment of coact ivator proteins, nuclear receptors act first to remodel chromatin within th e promoter region and then to recruit the transcriptional machinery to the promoter region in order to initiate transcription. Here we present a possi ble sequential mechanism for ligand-dependent transcriptional activation by nuclear receptors and discuss the in vitro and in vivo data that support t his model.