The double Holliday junction (dHJ) is generally regarded to be a key intermediate of meiotic recombination, whose resolution is critical for the formation of crossover recombinants. In fission yeast, the Mus81-Eme1 endonuclease has been implicated in resolving dHJs. Consistent with this role, we show that Mus81-Eme1 is required for generating meiotic crossovers. However, purified Mus81-Eme1 prefers to cleave junctions that mimic those formed during the transition from double-strand break to dHJ. Crucially, these junctions are cleaved by Mus81-Eme1 in precisely the right orientation to guarantee the formation of a crossover every time. These data demonstrate how crossovers could arise without forming or resolving dHJs using an enzyme that is widely conserved amongst eukaryotes.
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http://dx.doi.org/10.1016/s1097-2765(03)00343-5 | DOI Listing |
Eur J Pharmacol
July 2024
College of Chemistry, Fuzhou University, Fuzhou, 350108, China. Electronic address:
The emergence of chemoresistance poses a significant challenge to the efficacy of DNA-damaging agents in cancer treatment, in part due to the inherent DNA repair capabilities of cancer cells. The Ku70/80 protein complex (Ku) plays a central role in double-strand breaks (DSBs) repair through the classical non-homologous end joining (c-NHEJ) pathway, and has proven to be one of the most promising drug target for cancer treatment when combined with radiotherapy or chemotherapy. In this study, we conducted a high-throughput screening of small-molecule inhibitors targeting the Ku complex by using a fluorescence polarization-based DNA binding assay.
View Article and Find Full Text PDFMol Cell
February 2024
Department of Oncology, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK. Electronic address:
The Bloom syndrome helicase BLM interacts with topoisomerase IIIα (TOP3A), RMI1, and RMI2 to form the BTR complex, which dissolves double Holliday junctions and DNA replication intermediates to promote sister chromatid disjunction before cell division. In its absence, structure-specific nucleases like the SMX complex (comprising SLX1-SLX4, MUS81-EME1, and XPF-ERCC1) can cleave joint DNA molecules instead, but cells deficient in both BTR and SMX are not viable. Here, we identify a negative genetic interaction between BLM loss and deficiency in the BRCA1-BARD1 tumor suppressor complex.
View Article and Find Full Text PDFBioorg Med Chem
July 2023
College of Chemistry, Fuzhou University, Fuzhou 350108, China; Key Laboratory of Marine Enzyme Engineering, Fuzhou University, Fuzhou, China. Electronic address:
The MUS81-EME1/2 structure-specific endonucleases play a crucial role in the processing of stalled replication forks and recombination intermediates, and have been recognized as an attractive drug target to potentiate the anti-cancer efficacy of DNA-damaging agents. Currently, no bioactive small-molecule inhibitors of MUS81 are available. Here, we performed a high-throughput small-molecule inhibitors screening, using the FRET-based DNA cleavage assay.
View Article and Find Full Text PDFJ Proteome Res
June 2023
Department of Biochemistry, University of Toronto, Toronto, ON M56 1A8, Canada.
The DNA repair scaffold SLX4 has pivotal roles in cellular processes that maintain genome stability, most notably homologous recombination. Germline mutations in are associated with Fanconi anemia, a disease characterized by chromosome instability and cancer susceptibility. The role of mammalian SLX4 in homologous recombination depends critically on binding and activating structure-selective endonucleases, namely SLX1, MUS81-EME1, and XPF-ERCC1.
View Article and Find Full Text PDFDNA Repair (Amst)
September 2021
Department of Biochemistry, University of Toronto, MaRS Centre, 661 University Ave., Toronto, ON, M5G 1M1, Canada; Canada Research Chairs Program, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada. Electronic address:
Nuclear reorganization, including the localization of proteins into discrete subnuclear foci, is a hallmark of the cellular response to DNA damage and replication stress. These foci are thought to represent transient environments or repair factories, in which the lesion is sequestered with molecules and co-factors that catalyze repair. For example, nuclear foci contain signaling proteins that recruit transducer proteins.
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