Contribution of DNA Helicases to Genome Stability Public Deposited

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  • March 21, 2019
  • Zapotoczny, Grzegorz
    • Affiliation: School of Medicine, Curriculum in Genetics and Molecular Biology
  • DNA double-strand breaks (DSBs) are one of the most deleterious lesions to the cell. Even a single unrepaired DSB can lead to apoptosis, recombination, loss of heterozygosity, and cancer, thus it is essential for DSBs to be repaired. Synthesis-dependent strand annealing (SDSA) is thought to be a major pathway of DSB repair in mitotically dividing cells, yielding non-recombinant products. Assays that directly measure SDSA have been used to study SDSA in fruit flies and yeast, however, in humans SDSA is poorly understood and the players involved are unknown due to the lack of an SDSA assay. I have developed the first SDSA assay in human cells and present the first direct evidence for SDSA in humans. Furthermore, I report here that human BLM helicase, unlike its Drosophila ortholog is a negative regulator of SDSA. I identified RTEL1 as another negative SDSA regulator. This study provides new insights into the molecular basis of SDSA regulation and shows that BLM and RTEL1-deficient cells exhibit longer synthesis tracts which facilitates SDSA repair. To complement my studies, I utilized a DR-GFP assay to measure GC levels and engineered a crossover-gene conversion (CO-GC) assay and demonstrate here that BLM is responsible for suppression of COs in human cells despite its inhibitory effect on SDSA.
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Rights statement
  • In Copyright
  • Duronio, Robert
  • Ramsden, Dale
  • Copenhaver, Gregory
  • Sekelsky, Jeff
  • Petes, Thomas D.
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill Graduate School
Graduation year
  • 2016

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