title: Subunits of the yeast SWI/SNF complex are members of the actin-related protein (ARP) family.
abstract: The yeast SWI/SNF chromatin remodeling complex is comprised of 11 tightly associated polypeptides (SWI1, SWI2, SWI3, SNF5, SNF6, SNF11, SWP82, SWP73, SWP59, SWP61, and SWP29). We have used matrix-assisted laser desorption ionization time-of-flight mass spectrometry to identify the genes that encode the SWP59 and SWP61 subunits. Surprisingly, we find that SWP59 and SWP61 are encoded by the ARP9 and ARP7 genes, respectively, which encode members of the actin-related protein (ARP) family. Sequence analyses have shown that ARP9 and ARP7 are 24-26% identical (48-51% similar) to yeast actin and that they are likely to maintain the overall actin fold. Deletion of either the ARP9 or ARP7 gene causes typical swi/snf phenotypes, including growth defects on media containing galactose, glycerol, or sucrose as sole carbon sources. ARP9 and ARP7 are also required for expression of an HO-lacZ fusion gene and for full transcriptional enhancement by the GAL4 activator. The identification of two ARP family members as crucial subunits of the SWI/SNF complex suggests that the complex may contain a total of three different ATPase subunits; furthermore, the similarity of ARP7 and ARP9 to the HSP and HSC family of ATPases suggests the possibility that chromatin remodeling by SWI/SNF may involve chaperone-like activities.
authors.affiliation: Program in Molecular Medicine and Department of Biochemistry and Molecular Biology, University of Massachusetts Medical Center, Worcester, Massachusetts 01605, USA. craig.peterson@ummed.edu
authors.forename: C L
authors.initials: CL
authors.lastname: Peterson
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.forename: B T
authors.initials: BT
authors.lastname: Chait
mesh_terms: D000199:Actins / Q000235:genetics* / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D002843:Chromatin / Q000235:genetics*; D002868:Chromosomal Proteins, Non-Histone; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics*; D017353:Gene Deletion; D005800:Genes, Fungal; D046911:Macromolecular Substances; D005810:Multigene Family; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics; D010449:Peptide Mapping; D010641:Phenotype; D016133:Polymerase Chain Reaction; D000071796:SMARCB1 Protein; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics
chemical_list: D000199:Actins; D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D017931:DNA Primers; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D046911:Macromolecular Substances; D009687:Nuclear Proteins; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; C094753:SNF11 protein, S cerevisiae; C101683:SNF12 protein, S cerevisiae; C066190:SNF5 protein, S cerevisiae; C078562:SWI1 protein, S cerevisiae; C072981:SWI3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D000251:Adenosine Triphosphatases; C499333:SNF2 protein, S cerevisiae