Thomas Toczylowski

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The first step of homology-dependent DNA double-strand break (DSB) repair is the 5' strand-specific processing of DNA ends to generate 3' single-strand tails. Despite extensive effort, the nuclease(s) that is directly responsible for the resection of 5' strands in eukaryotic cells remains elusive. Using nucleoplasmic extracts (NPE) derived from the eggs of(More)
Werner syndrome is associated with premature aging and increased risk of cancer. Werner syndrome protein (WRN) is a RecQ-type DNA helicase, which seems to participate in DNA replication, double-strand break (DSB) repair, and telomere maintenance; however, its exact function remains elusive. Using Xenopus egg extracts as the model system, we found that(More)
The first step of homology-dependent repair of DNA double-strand breaks is the strand-specific processing of DNA ends to generate 3' single-strand tails. Despite its importance, the molecular mechanism underlying end processing is poorly understood in eukaryotic cells. We have taken a biochemical approach to investigate DNA end processing in nucleoplasmic(More)
The processing of DNA double-strand breaks (DSBs) into 3' single-stranded tails is the first step of homology-dependent DSB repair. A key player in this process is the highly conserved eukaryotic exonuclease 1 (EXO1), yet its precise mechanism of action has not been rigorously determined. To address this issue, we reconstituted 5'-strand resection in(More)
Replication protein A (RPA), the eukaryotic single-strand deoxyribonucleic acid (DNA [ss-DNA])-binding protein, is involved in DNA replication, nucleotide damage repair, mismatch repair, and DNA damage checkpoint response, but its function in DNA double-strand break (DSB) repair is poorly understood. We investigated the function of RPA in homology-dependent(More)
The resection of DNA double-strand breaks (DSBs) into 3' single-strand tails is the initiating step of homology-dependent repair pathways. A key player in this process is the MRE11-RAD50-NBS1 complex, but its contribution to and mechanistic role in resection are not well understood. In this study, we took advantage of the Xenopus egg extract system to(More)
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