title: Nucleosome remodeling by the SWI/SNF complex is enhanced by yeast high mobility group box (HMGB) proteins.
abstract: The regulation of gene expression at the level of transcription involves the concerted action of several proteins and protein complexes committed to dynamically alter the surrounding chromatin environment of a gene being activated or repressed. ATP-dependent chromatin remodeling complexes are key factors in chromatin remodeling, and the SWI/SNF complex is the founding member. While many studies have linked the action of these complexes to specific transcriptional regulation of a large number of genes and much is known about their catalytic activity, less is known about the nuclear elements that can enhance or modulate their activity. A number of studies have found that certain High Mobility Group (HMG) proteins are able to stimulate ATP-dependent chromatin remodeling activity, but their influence on the different biochemical outcomes of this activity is still unknown. In this work we studied the influence of the yeast Nhp6A, Nhp6B and Hmo1 proteins (HMGB family members) on different biochemical outcomes of yeast SWI/SNF remodeling activity. We found that all these HMG proteins stimulate the sliding activity of ySWI/SNF, while transient exposure of nucleosomal DNA and octamer transfer catalyzed by this complex are only stimulated by Hmo1. Consistently, only Hmo1 stimulates SWI/SNF binding to the nucleosome. Additionally, the sliding activity of another chromatin remodeling complex, ISW1a, is only stimulated by Hmo1. Further analyses show that these differential stimulatory effects of Hmo1 are dependent on the presence of its C-terminal tail, which contains a stretch of acidic and basic residues.
authors: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile.
authors: Matias I
authors: MI
authors: Hepp
authors: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile.
authors: Valentina
authors: V
authors: Alarcon
authors: Stowers Institute for Medical Research, 1000 E 50th Street, Kansas City 64110, MO, USA.
authors: Arnob
authors: A
authors: Dutta
authors: Stowers Institute for Medical Research, 1000 E 50th Street, Kansas City 64110, MO, USA.
authors: Jerry L
authors: JL
authors: Workman
authors: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, Concepción 4070043, Chile. Electronic address: lgutier@udec.cl.
authors: José L
authors: JL
authors: Gutiérrez
mesh_terms: D042002:Chromatin Assembly and Disassembly; D002868:Chromosomal Proteins, Non-Histone / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000502:physiology; D005656:Fungal Proteins / Q000502:physiology*; D024002:HMGB Proteins / Q000502:physiology*; D024001:HMGN Proteins / Q000502:physiology; D006609:High Mobility Group Proteins / Q000502:physiology; D009707:Nucleosomes / Q000502:physiology*; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D024002:HMGB Proteins; D024001:HMGN Proteins; C103154:HMO1 protein, S cerevisiae; D006609:High Mobility Group Proteins; C086471:NHP6A protein, S cerevisiae; C086472:NHP6B protein, S cerevisiae; D009707:Nucleosomes; D029701:Saccharomyces cerevisiae Proteins
keywords: Chromatin remodeling; HMGB proteins; Hmo1; Nhp6; Nucleosome remodeling; SWI/SNF