title: Saccharomyces cerevisiae Sen1 as a model for the study of mutations in human Senataxin that elicit cerebellar ataxia.
abstract: The nuclear RNA and DNA helicase Sen1 is essential in the yeast Saccharomyces cerevisiae and is required for efficient termination of RNA polymerase II transcription of many short noncoding RNA genes. However, the mechanism of Sen1 function is not understood. We created a plasmid-based genetic system to study yeast Sen1 in vivo. Using this system, we show that (1) the minimal essential region of Sen1 corresponds to the helicase domain and one of two flanking nuclear localization sequences; (2) a previously isolated terminator readthrough mutation in the Sen1 helicase domain, E1597K, is rescued by a second mutation designed to restore a salt bridge within the first RecA domain; and (3) the human ortholog of yeast Sen1, Senataxin, cannot functionally replace Sen1 in yeast. Guided by sequence homology between the conserved helicase domains of Sen1 and Senataxin, we tested the effects of 13 missense mutations that cosegregate with the inherited disorder ataxia with oculomotor apraxia type 2 on Sen1 function. Ten of the disease mutations resulted in transcription readthrough of at least one of three Sen1-dependent termination elements tested. Our genetic system will facilitate the further investigation of structure-function relationships in yeast Sen1 and its orthologs.
authors.affiliation: Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706-1532.
authors.forename: Xin
authors.identifier: http://orcid.org/0000-0003-1871-4477
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706-1532.
authors.forename: Ulrika
authors.initials: U
authors.lastname: Müller
authors.affiliation: Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706-1532.
authors.forename: Kaitlin E
authors.initials: KE
authors.lastname: Sundling
authors.affiliation: Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706-1532 dabrow@wisc.edu.
authors.forename: David A
authors.initials: DA
authors.lastname: Brow
mesh_terms: D021581:Active Transport, Cell Nucleus; D020134:Catalytic Domain; D002524:Cerebellar Ataxia / Q000235:genetics*; D004265:DNA Helicases / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D050296:Microbial Viability; D064251:Multifunctional Enzymes; D020125:Mutation, Missense; D020365:RNA Helicases / Q000235:genetics* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D061806:Transcription Termination, Genetic
chemical_list: D064251:Multifunctional Enzymes; C491211:NRD1 protein, S cerevisiae; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins; C542347:SEN1 protein, S cerevisiae; C484368:SETX protein, human; D004265:DNA Helicases; D020365:RNA Helicases
keywords: cerebellar ataxia; helicase; neurodegeneration; transcription termination; yeast genetics