title: Chromatin opening and stable perturbation of core histone:DNA contacts by FoxO1.
abstract: FoxO1, a member of the forkhead rabdomyosarcoma (FoxO) subfamily of transcription factors, binds DNA via a highly conserved winged-helix "forkhead box" motif used by other regulatory proteins to mediate their effects through chromatin binding and remodeling. To examine how FoxO1 regulates target genes in chromatin, we studied the binding of purified recombinant FoxO1 protein to nucleosome particles and chromatin arrays containing the insulin-like growth factor-binding protein 1 promoter. We found that FoxO1 is able to bind to its cognate sites within the insulin-like growth factor-binding protein 1 promoter on a nucleosome. This binding stably perturbs core histone:DNA contacts extending up- and downstream from sites of FoxO1 binding without disrupting the underlying core particle. FoxO1 is able to harness these capabilities to bind to and de-condense linker histone-compacted chromatin arrays. Chromatin opening by FoxO1 requires both the N and C termini of the protein, which are also required for high affinity core histone binding and, in the case of the N terminus, nucleosome perturbation. We suggest that the chromatin binding and remodeling functions revealed here for FoxO1 endow all FoxO factors with the ability to initiate and dynamically modulate active chromatin states, enabling their diverse roles as gene regulatory factors in metabolism, cell survival, apoptosis, cell cycle progression, DNA repair, and protection against oxidative stress.
authors.affiliation: Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Mitsutoki
authors.initials: M
authors.lastname: Hatta
authors.forename: Lisa Ann
authors.initials: LA
authors.lastname: Cirillo
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002453:Cell Cycle / Q000502:physiology; D002470:Cell Survival / Q000502:physiology; D002474:Cell-Free System / Q000378:metabolism; D042002:Chromatin Assembly and Disassembly / Q000502:physiology*; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair / Q000502:physiology; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000502:physiology; D011485:Protein Binding / Q000502:physiology; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; C467200:Foxo1 protein, mouse; D006657:Histones; D018970:Insulin-Like Growth Factor Binding Protein 1; D009707:Nucleosomes; D011994:Recombinant Proteins; D004247:DNA