title: Quantification of Ataxin-3 and Ataxin-7 aggregates formed in vivo in Drosophila reveals a threshold of aggregated polyglutamine proteins associated with cellular toxicity.
abstract: Polyglutamine diseases are nine dominantly inherited neurodegenerative pathologies caused by the expansion of a polyglutamine domain in a protein responsible for the disease. This expansion leads to protein aggregation, inclusion formation and toxicity. Despite numerous studies focusing on the subject, whether soluble polyglutamine proteins are responsible for toxicity or not remains debated. To focus on this matter, we evaluated the level of soluble and insoluble truncated pathological Ataxin-3 in vivo in Drosophila, in presence or absence of two suppressors (i.e. Hsp70 and non-pathological Ataxin-3) and along aging. Suppressing truncated Ataxin-3-induced toxicity resulted in a lowered level of aggregated polyglutamine protein. Interestingly, aggregates accumulated as flies aged and reached a maximum level when cell death was detected. Our results were similar with two other pathological polyglutamine proteins, namely truncated Ataxin-7 and full-length Ataxin-3. Our data suggest that accumulation of insoluble aggregates beyond a critical threshold could be responsible for toxicity.
authors.affiliation: Laboratoire de Génétique et Biologie Cellulaire, EA4589, Université Versailles-St-Quentin-en-Yvelines, Ecole Pratique des Hautes Etudes, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bx, France.
authors.forename: Gérald
authors.initials: G
authors.lastname: Vinatier
authors.affiliation: Laboratoire de Génétique et Biologie Cellulaire, EA4589, Université Versailles-St-Quentin-en-Yvelines, Ecole Pratique des Hautes Etudes, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bx, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Corsi
authors.affiliation: Laboratoire de Génétique et Biologie Cellulaire, EA4589, Université Versailles-St-Quentin-en-Yvelines, Ecole Pratique des Hautes Etudes, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bx, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Mignotte
authors.affiliation: Laboratoire de Génétique et Biologie Cellulaire, EA4589, Université Versailles-St-Quentin-en-Yvelines, Ecole Pratique des Hautes Etudes, 2 rue de la source de la Bièvre, 78180 Montigny-le-Bx, France. Electronic address: sebastien.gaumer@uvsq.fr.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Gaumer
mesh_terms: D000375:Aging / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D000818:Animals; D030801:Animals, Genetically Modified; D000067699:Ataxin-3 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000067719:Ataxin-7 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism; D005260:Female; D020271:Heredodegenerative Disorders, Nervous System / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008297:Male; D008959:Models, Neurological; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D066329:Protein Aggregates; D066263:Protein Aggregation, Pathological / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D012995:Solubility
chemical_list: D000067719:Ataxin-7; D050505:Mutant Proteins; D010455:Peptides; D066329:Protein Aggregates; D011994:Recombinant Proteins; D012097:Repressor Proteins; C097188:polyglutamine; C092341:ATXN3 protein, human; D000067699:Ataxin-3
keywords: Drosophila melanogaster; Polyglutamine disease; Protein aggregates; SCA3; SCA7