title: Both normal and polyglutamine- expanded ataxin-7 are components of TFTC-type GCN5 histone acetyltransferase- containing complexes.
abstract: SCA7 (spinocerebellar ataxia type 7) is a neurodegenerative disorder caused by a CAG repeat expansion in the SCA7 gene that leads to elongation of a polyglutamine tract in ataxin-7, a protein of unknown function. Sgf73, a putative yeast orthologue of ataxin-7, has been identified as a new component of the yeast SAGA (Spt/Ada/Gcn5 acetyltransferase) multisubunit complex, a co-activator required for the transcription of a subset of RNA polymerase II-dependent genes. We show here that ataxin-7 is an integral component of mammalian SAGA-like complexes, i.e. the TFTC [TBP (TATA-binding protein)-free TAF (TBP-associated factor) complex] and the STAGA (SPT3/TAF9/GCN5 acetyltransferase) complex. In agreement with this, immunoprecipitation of ataxin-7 retained a histone acetyltransferase activity characteristic of TFTC-like complexes. Moreover, polyglutamine expansion in ataxin-7 did not affect its incorporation into TFTCs/STAGA complexes purified from cells from a SCA7 patient. We demonstrate here that ataxin-7 is the human orthologue of a the yeast SAGA Sgf73 subunit, and is a bona fide subunit of human TFTC-like transcriptional complexes.
authors.affiliation: Department of Molecular Pathology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR 7104, CNRS/IN SER M/ULP, BP 10142, 67404 Illkirch Cedex, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Helmlinger
authors.forename: Sara
authors.initials: S
authors.lastname: Hardy
authors.forename: Adrien
authors.initials: A
authors.lastname: Eberlin
authors.forename: Didier
authors.initials: D
authors.lastname: Devys
authors.forename: Làszlò
authors.initials: L
authors.lastname: Tora
mesh_terms: D000067719:Ataxin-7; D018797:Cell Cycle Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D051548:Histone Acetyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D046912:Multiprotein Complexes; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry / Q000235:genetics; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020754:Spinocerebellar Ataxias / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor
chemical_list: D000067719:Ataxin-7; D018797:Cell Cycle Proteins; D051548:Histone Acetyltransferases; D046912:Multiprotein Complexes; D009419:Nerve Tissue Proteins; D010455:Peptides; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C000593829:ATXN7 protein, human; C507785:SAGA complex, S cerevisiae; C097188:polyglutamine