Effects of BRCA1 Loss on the Fidelity of DNA Double-Strand Break Repair

Persistent Link:
http://hdl.handle.net/10150/145104
Title:
Effects of BRCA1 Loss on the Fidelity of DNA Double-Strand Break Repair
Author:
Thompson, Eric
Issue Date:
2011
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:
The tumor suppressor Breast Cancer Susceptibility Protein 1 (BRCA1) protects our cells from genomic instability in part by facilitating the efficient repair of DNA double-strand breaks. Other functions of BRCA1 include transcriptional regulation, apoptosis, DNA damage signaling, chromatin remodeling and protein ubiquitination. The major contribution of BRCA1 to maintaining genomic stability is thought to be through its role in DNA repair. BRCA1 promotes the error-free repair of double-strand breaks by homologous recombination, and is also implicated in the regulation of non-homologous end joining repair. Here we investigated the role of BRCA1 in maintaining the fidelity of non-homologous end joining repair following a double-strand break. We also examined the frequency of microhomology-mediated end joining (MMEJ) and the fidelity of double-strand break repair relative to BRCA1 protein levels in both control and tumorigenic breast epithelial cells. In addition to altered BRCA1 protein levels, we tested the effects of cellular exposure to mirin, an inhibitor of Meiotic recombination enzyme 11 (Mre11) 3' to 5' exonuclease activity. Knockdown or loss of BRCA1 protein resulted in an increased frequency of overall plasmid DNA repair mutagenesis and MMEJ following a double-strand break. Inhibition of Mre11 exonuclease activity with mirin significantly decreased the occurrence of MMEJ, but did not considerably affect the overall mutagenic frequency of plasmid double-strand break repair, although some of our data indicate that the size of sequence deletions may be reduced by mirin inhibition. The results suggest that BRCA1 protects DNA from mutagenesis during non-homologous double strand break repair in plasmid-based assays. The increased frequency of double-strand break mutagenesis and MMEJ repair in the absence of BRCA1 suggests a potential mechanism for carcinogenesis.
Type:
Electronic Dissertation; text
Keywords:
BRCA1; DNA; Double-strand break; Mirin
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Molecular & Cellular Biology
Degree Grantor:
University of Arizona
Advisor:
Fares, Johnny

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleEffects of BRCA1 Loss on the Fidelity of DNA Double-Strand Break Repairen_US
dc.creatorThompson, Ericen_US
dc.contributor.authorThompson, Ericen_US
dc.date.issued2011-
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.abstractThe tumor suppressor Breast Cancer Susceptibility Protein 1 (BRCA1) protects our cells from genomic instability in part by facilitating the efficient repair of DNA double-strand breaks. Other functions of BRCA1 include transcriptional regulation, apoptosis, DNA damage signaling, chromatin remodeling and protein ubiquitination. The major contribution of BRCA1 to maintaining genomic stability is thought to be through its role in DNA repair. BRCA1 promotes the error-free repair of double-strand breaks by homologous recombination, and is also implicated in the regulation of non-homologous end joining repair. Here we investigated the role of BRCA1 in maintaining the fidelity of non-homologous end joining repair following a double-strand break. We also examined the frequency of microhomology-mediated end joining (MMEJ) and the fidelity of double-strand break repair relative to BRCA1 protein levels in both control and tumorigenic breast epithelial cells. In addition to altered BRCA1 protein levels, we tested the effects of cellular exposure to mirin, an inhibitor of Meiotic recombination enzyme 11 (Mre11) 3' to 5' exonuclease activity. Knockdown or loss of BRCA1 protein resulted in an increased frequency of overall plasmid DNA repair mutagenesis and MMEJ following a double-strand break. Inhibition of Mre11 exonuclease activity with mirin significantly decreased the occurrence of MMEJ, but did not considerably affect the overall mutagenic frequency of plasmid double-strand break repair, although some of our data indicate that the size of sequence deletions may be reduced by mirin inhibition. The results suggest that BRCA1 protects DNA from mutagenesis during non-homologous double strand break repair in plasmid-based assays. The increased frequency of double-strand break mutagenesis and MMEJ repair in the absence of BRCA1 suggests a potential mechanism for carcinogenesis.en_US
dc.typeElectronic Dissertationen_US
dc.typetexten_US
dc.subjectBRCA1en_US
dc.subjectDNAen_US
dc.subjectDouble-strand breaken_US
dc.subjectMirinen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineMolecular & Cellular Biologyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorFares, Johnnyen_US
dc.contributor.committeememberZarnescu, Danielaen_US
dc.contributor.committeememberTsao, Tsu-Shuenen_US
dc.contributor.committeememberSchroeder, Joyceen_US
dc.contributor.committeememberKrieg, Paulen_US
dc.identifier.proquest11522-
dc.identifier.oclc752261386-
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