Nucleosome Remodeling and Epigenetics
Eukaryotic chromatin is kept flexible and dynamic to respond to environmental, metabolic, and developmental cues through the action of a family of so-called "nucleosome remodeling" ATPases. Consistent with their helicase ancestry, these enzymes experience conformation changes as they bind and hydrolyze ATP. At the same time they interact with DNA and histones, which alters histone -DNA interactions in target nucleosomes. Their action may lead to complete or partial disassembly of nucleosomes, the exchange of histones for variants, the assembly of nucleosomes, or the movement of histone octamers on DNA. "Remodeling" may render DNA sequences accessible to interacting proteins or, conversely, promote packing into tightly folded structures. Remodeling processes participate in every aspect of genome function. Remodeling activities are commonly integrated with other mechanisms such as histone modifications or RNA metabolism to assemble stable, epigenetic states. Outline 1 The discovery of nucleosome remodeling: A historical perspective 2 The nuts and bolts of nucleosome remodeling 3 Diversity of nucleosome remodeling complexes 4 Nucleosome remodeling factors as regulators of transcription 5 Nucleosome remodeling in chromatin assembly and organization 6 Recognition of histone modifications by chromatin remodelers 7 Regulation of remodelers by posttranslational modification 8 Interaction of chromatin remodelers with DNA methylation 9 Chromatin remodelers and histone variants 10 Nucleosome remodeling during development