Saccharomyces cerevisiae RecQ helicase, Sgs1, and XPF family endonuclease, Mus81-Mms4, are implicated in processing joint molecule (JM) recombination intermediates. We show that cells lacking either enzyme frequently experience chromosome segregation problems during meiosis and that when both enzymes are absent attempted segregation fails catastrophically. In all cases, segregation appears to be impeded by unresolved JMs. Analysis of the DNA events of recombination indicates that Sgs1 limits aberrant JM structures that result from secondary strand-invasion events and often require Mus81-Mms4 for their normal resolution. Aberrant JMs contain high levels of single Holliday junctions and include intersister JMs, multichromatid JMs comprising three and four chromatids, and newly identified recombinant JMs containing two chromatids, one of which has undergone crossing over. Despite persistent JMs in sgs1 mms4 double mutants, crossover and noncrossover products still form at high levels. We conclude that Sgs1 and Mus81-Mms4 collaborate to eliminate aberrant JMs, whereas as-yet-unidentified enzymes process normal JMs.
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http://dx.doi.org/10.1016/j.molcel.2008.07.006 | DOI Listing |
Methods Mol Biol
December 2024
Department of Biochemistry & Molecular Biophysics, Columbia University, New York, NY, USA.
Homologous recombination (HR) is the principal pathway undertaken by a cell for the error-free repair of DNA double-strand breaks that are frequently encountered by the cell. HR can be initiated at the sites of DNA double-strand breaks by generating long stretches of single-stranded 3' DNA overhang through a process called DNA end resection. In one DNA end resection pathway, this is achieved via the concerted effort of specialized machinery involving the RecQ family helicase BLM, the helicase/endonuclease DNA2, and a single-strand DNA binding protein complex RPA.
View Article and Find Full Text PDFPLoS Genet
December 2024
Department of Microbiology & Immunology, W. R. Hearst Microbiology Research Center, Weill Cornell Medicine, New York, New York, United States of America.
TRF2 is an essential and conserved double-strand telomere binding protein that stabilizes chromosome ends by suppressing DNA damage response and aberrant DNA repair. Herein we investigated the mechanisms and functions of the Trf2 ortholog in the basidiomycete fungus Ustilago maydis, which manifests strong resemblances to metazoans with regards to the telomere and DNA repair machinery. We showed that UmTrf2 binds to Blm in vitro and inhibits Blm-mediated unwinding of telomeric DNA substrates.
View Article and Find Full Text PDFBiochem Biophys Res Commun
December 2024
Graduate School of Integrated Sciences for Life, Hiroshima University, Japan. Electronic address:
Homologous recombination is vital for DNA double-strand break repair. Dysfunction in homologous recombination can lead to cell death, mutations, and cancer. In fission yeast (Schizosaccharomyces pombe), RecQ helicase Rqh1 resolves recombination intermediates.
View Article and Find Full Text PDFBioorg Chem
December 2024
State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang 550014, China; Natural Products Research Center of Guizhou Province, Guiyang 550014, China. Electronic address:
WRN helicase is a crucial target of synthetic death in cancer and has a unique advantage in the treatment of microsatellite unstable cancers. Our previous studies have found that quinazoline derivatives showed the WRN-dependent antiproliferative activity. In this study, a series of new quinazoline derivatives were designed and synthesized by optimizing the structure, and evaluating the targeting and sensitivity to WRN helicase.
View Article and Find Full Text PDFEur J Med Chem
January 2025
Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China; Lingang Laboratory, Shanghai, 200031, China; School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, China; University of Chinese Academy of Sciences, Beijing, 100049, China; School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China. Electronic address:
Werner syndrome RecQ helicase (WRN), a member of the RecQ helicase family, has recently been identified as a synthetic lethal target in microsatellite instability (MSI) tumors. The triazolo-pyrimidine compound HRO761 is the first WRN inhibitor to enter clinical trials, but research on this scaffold remains limited. Here, we designed a series of derivatives to systematically study the structure-activity relationship (SAR) of triazolo-pyrimidine scaffolds, leading to the discovery of compound S35.
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