title: Stimulation of transcription factor binding and histone displacement by nucleosome assembly protein 1 and nucleoplasmin requires disruption of the histone octamer.
abstract: To investigate the mechanisms by which transcription factors invade nucleosomal DNA and replace histones at control elements, we have examined the response of the histone octamer to transcription factor binding in the presence of histone-binding proteins (i.e., nucleosome assembly factors). We found that yeast nucleosome assembly protein 1 (NAP-1) stimulated transcription factor binding and nucleosome displacement in a manner similar to that of nucleoplasmin. In addition, disruption of the histone octamer was required both for the stimulation of transcription factor binding to nucleosomal DNA and for transcription factor-induced nucleosome displacement mediated by nucleoplasmin or NAP-1. While NAP-1 and nucleoplasmin stimulated the binding of a fusion protein (GAL4-AH) to control nucleosome cores, this stimulation was lost upon covalent histone-histone cross-linking within the histone octamers. In addition, both NAP-1 and nucleoplasmin were able to mediate histone displacement upon the binding of five GAL4-AH dimers to control nucleosome cores; however, this activity was also forfeited when the histone octamers were cross-linked. These data indicate that octamer disruption is required for both stimulation of factor binding and factor-dependent histone displacement by nucleoplasmin and NAP-1. By contrast, transcription factor-induced histone transfer onto nonspecific competitor DNA did not require disruption of the histone octamer. Thus, histone displacement in this instance occurred by transfer of complete histone octamers, a mechanism distinct from that mediated by the histone-binding proteins nucleoplasmin and NAP-1.
authors.affiliation: Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park 16802, USA.
authors.forename: P P
authors.initials: PP
authors.lastname: Walter
authors.forename: T A
authors.initials: TA
authors.lastname: Owen-Hughes
authors.forename: J
authors.initials: J
authors.lastname: Côté
authors.forename: J L
authors.initials: JL
authors.lastname: Workman
mesh_terms: D001483:Base Sequence; D001667:Binding, Competitive; D018797:Cell Cycle Proteins; D015342:DNA Probes / Q000737:chemistry; D004268:DNA-Binding Proteins; D003852:Deoxyribonucleoproteins / Q000737:chemistry; D005656:Fungal Proteins / Q000378:metabolism*; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D056489:Nucleoplasmins; D056490:Nucleosome Assembly Protein 1; D009707:Nucleosomes / Q000648:ultrastructure*; D010750:Phosphoproteins; D011506:Proteins / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors
chemical_list: D018797:Cell Cycle Proteins; D015342:DNA Probes; D004268:DNA-Binding Proteins; D003852:Deoxyribonucleoproteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D006657:Histones; D046911:Macromolecular Substances; C533556:NAP1 protein, S cerevisiae; C533557:NAP1L1 protein, human; D009687:Nuclear Proteins; D056489:Nucleoplasmins; D056490:Nucleosome Assembly Protein 1; D009707:Nucleosomes; D010750:Phosphoproteins; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors