title: Swi3p controls SWI/SNF assembly and ATP-dependent H2A-H2B displacement.
abstract: Yeast SWI/SNF is a multisubunit, 1.14-MDa ATP-dependent chromatin-remodeling enzyme required for transcription of a subset of inducible genes. Biochemical studies have demonstrated that SWI/SNF uses the energy from ATP hydrolysis to generate superhelical torsion, mobilize mononucleosomes, enhance the accessibility of nucleosomal DNA and remove H2A-H2B dimers from mononucleosomes. Here we describe the ATP-dependent activities of a SWI/SNF sub complex that is composed of only three subunits, Swi2p, Arp7p and Arp9p. Whereas this sub complex is fully functional in most remodeling assays, Swi2p-Arp7p-Arp9p is defective for ATP-dependent removal of H2A-H2B dimers. We identify the acidic N terminus of the Swi3p subunit as a novel H2A-H2B-binding domain required for ATP-dependent dimer loss. Our data indicate that H2A-H2B dimer loss is not an obligatory consequence of ATP-dependent DNA translocation, and furthermore they suggest that SWI/SNF is composed of at least four interdependent modules.
authors.affiliation: Interdisciplinary Graduate Program, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Yang
authors.forename: Roser
authors.initials: R
authors.lastname: Zaurin
authors.forename: Miguel
authors.initials: M
authors.lastname: Beato
authors.forename: Craig L
authors.initials: CL
authors.lastname: Peterson
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly / Q000235:genetics* / Q000502:physiology; D047369:Chromatin Immunoprecipitation; D019281:Dimerization; D006657:Histones / Q000378:metabolism*; D007700:Kinetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*
chemical_list: D006657:Histones; D009687:Nuclear Proteins; D009707:Nucleosomes; C072981:SWI3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D000255:Adenosine Triphosphate