Chromatin remodeling enzymes: who's on first?

A central problem in the regulation of eukaryotic gene expression is unders tanding how gene-specific transcriptional activators orchestrate the recrui tment of the myriad proteins that are required for transcription initiation . An emerging view indicates that activators must first target two types of chromatin remodeling enzyme to the promoter region: an ATP-dependent SWI/S NF-like complex and a histone acetyltransferase, These two enzymes appear t o act synergistically to establish a local chromatin structure that is perm issive for subsequent events. Furthermore, several recent studies indicate that the recruitment of chromatin remodeling enzymes must follow an obligat ory, sequential order of events that is determined by either promoter conte xt or cell-cycle position. Here we review recent developments concerning th e role of chromatin remodeling enzymes in gene regulation, and propose seve ral models to explain how different chromatin remodeling activities can be functionally coupled. (C) 2001 Elsevier Science Ltd. All rights reserved.