Genetic Characterization and Analysis of Cis and Trans-elements That Facilitate Genome Stability in Saccharomyces cerevisiae

Persistent Link:
http://hdl.handle.net/10150/193584
Title:
Genetic Characterization and Analysis of Cis and Trans-elements That Facilitate Genome Stability in Saccharomyces cerevisiae
Author:
Jones, Hope
Issue Date:
2010
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Chromosomal fragile sites are specific loci associated with a high frequency of breakage and recombination. A cell's ability to repair and/or replicate through a lesion is prerequisite to the maintenance of genomic stability. An improved understanding of fragile site biology and its contribution to replication defects and genomic instability is critical for prevention, intervention, and diagnosis of genetic diseases such as cancer. This work seeks to identify and characterize both trans and cis fragile sites associated elements involved in instability onset and progression. An array of Saccharomyces cerevisiae isogenic DNA repair deficient mutants were utilized to identify genes contributing to the stability or instability of a natural fragile site ~ 403 kb from the left telomere on chromosome VII. Findings suggest that the RAD52 epistasis group, the MRX complex, non-homologous end-joining (NHEJ) pathways, MUS81 and SGS1 helicases, translesion polymerases, and a majority of the post replication repair (PRR) proteins are all required for faithful replication of the 403 fragile site and likely other fragile sites as well. In contrast I found that MMS2, previously thought to be specific to the PRR pathway, is required to prevent the fusion of repetitive elements within the 403 site. mgs1 (homolog of the human Werner helicase interacting protein, WHIP) and pol3-13 (a subunit of the DNA polymerase delta) mutants also exhibited reduced instability in checkpoint deficient cells. These findings suggest previously uncharacterized function of Mgs1, Pol3 and Mms2 in regulation of genome regions at risk of replication damage. We further find the presence of inverted repeats (IR) are sufficient to induce instability. Two IR's proximal to the 403 site consistently fuse to generate acentric and dicentric chromosomes involving the 403 fragile site and a newly identified site on chromosome VII as well. The frequency of fusion events is aggravated by chromatin traffic stressors such as tRNA transcription induced fork stalling and replisome termination regions.
Type:
text; Electronic Dissertation
Keywords:
Chromosome instability; Dicentric; DNA replication; Inverted repeats; Transcription
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Molecular & Cellular Biology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Weinert, Ted
Committee Chair:
Weinert, Ted

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleGenetic Characterization and Analysis of Cis and Trans-elements That Facilitate Genome Stability in Saccharomyces cerevisiaeen_US
dc.creatorJones, Hopeen_US
dc.contributor.authorJones, Hopeen_US
dc.date.issued2010en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractChromosomal fragile sites are specific loci associated with a high frequency of breakage and recombination. A cell's ability to repair and/or replicate through a lesion is prerequisite to the maintenance of genomic stability. An improved understanding of fragile site biology and its contribution to replication defects and genomic instability is critical for prevention, intervention, and diagnosis of genetic diseases such as cancer. This work seeks to identify and characterize both trans and cis fragile sites associated elements involved in instability onset and progression. An array of Saccharomyces cerevisiae isogenic DNA repair deficient mutants were utilized to identify genes contributing to the stability or instability of a natural fragile site ~ 403 kb from the left telomere on chromosome VII. Findings suggest that the RAD52 epistasis group, the MRX complex, non-homologous end-joining (NHEJ) pathways, MUS81 and SGS1 helicases, translesion polymerases, and a majority of the post replication repair (PRR) proteins are all required for faithful replication of the 403 fragile site and likely other fragile sites as well. In contrast I found that MMS2, previously thought to be specific to the PRR pathway, is required to prevent the fusion of repetitive elements within the 403 site. mgs1 (homolog of the human Werner helicase interacting protein, WHIP) and pol3-13 (a subunit of the DNA polymerase delta) mutants also exhibited reduced instability in checkpoint deficient cells. These findings suggest previously uncharacterized function of Mgs1, Pol3 and Mms2 in regulation of genome regions at risk of replication damage. We further find the presence of inverted repeats (IR) are sufficient to induce instability. Two IR's proximal to the 403 site consistently fuse to generate acentric and dicentric chromosomes involving the 403 fragile site and a newly identified site on chromosome VII as well. The frequency of fusion events is aggravated by chromatin traffic stressors such as tRNA transcription induced fork stalling and replisome termination regions.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectChromosome instabilityen_US
dc.subjectDicentricen_US
dc.subjectDNA replicationen_US
dc.subjectInverted repeatsen_US
dc.subjectTranscriptionen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineMolecular & Cellular Biologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorWeinert, Teden_US
dc.contributor.chairWeinert, Teden_US
dc.contributor.committeememberParker, Royen_US
dc.contributor.committeememberRay, Dennisen_US
dc.contributor.committeememberTax, Fransen_US
dc.identifier.proquest10849en_US
dc.identifier.oclc659753744en_US
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