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Hatkevich T, Miller DE, Turcotte CA, Miller MC, Sekelsky J. A pathway for error-free non-homologous end joining of resected meiotic double-strand breaks. Nucleic Acids Res 2021; 49:879-890. [PMID: 33406239 PMCID: PMC7826270 DOI: 10.1093/nar/gkaa1205] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/22/2020] [Accepted: 11/25/2020] [Indexed: 12/31/2022] Open
Abstract
Programmed DNA double-strand breaks (DSBs) made during meiosis are repaired by recombination with the homologous chromosome to generate, at selected sites, reciprocal crossovers that are critical for the proper separation of homologs in the first meiotic division. Backup repair processes can compensate when the normal meiotic recombination processes are non-functional. We describe a novel backup repair mechanism that occurs when the homologous chromosome is not available in Drosophila melanogaster meiosis. In the presence of a previously described mutation (Mcm5A7) that disrupts chromosome pairing, DSB repair is initiated by homologous recombination but is completed by non-homologous end joining (NHEJ). Remarkably, this process yields precise repair products. Our results provide support for a recombination intermediate recently proposed in mouse meiosis, in which an oligonucleotide bound to the Spo11 protein that catalyzes DSB formation remains bound after resection. We propose that this oligonucleotide functions as a primer for fill-in synthesis to allow scarless repair by NHEJ. We argue that this is a conserved repair mechanism that is likely to be invoked to overcome occasional challenges in normal meiosis.
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Affiliation(s)
- Talia Hatkevich
- Curriculum in Genetics and Molecular Biology, 120 Mason Farm Road, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Danny E Miller
- Department of Pediatrics, Division of Medical Genetics, University of Washington, Seattle, Washington and Seattle Children's Hospital, Seattle, WA 98105, USA
| | - Carolyn A Turcotte
- Curriculum in Genetics and Molecular Biology, 120 Mason Farm Road, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Margaret C Miller
- Department of Biology, University of North Carolina, 120 South Road, Chapel Hill, NC 27599, USA
| | - Jeff Sekelsky
- Curriculum in Genetics and Molecular Biology, 120 Mason Farm Road, University of North Carolina, Chapel Hill, NC 27599, USA.,Department of Biology, University of North Carolina, 120 South Road, Chapel Hill, NC 27599, USA.,Integrative Program in Biological and Genome Sciences, 250 Bell Tower Drive, University of North Carolina, Chapel Hill, NC 27599, USA
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Hirano R, Interthal H, Huang C, Nakamura T, Deguchi K, Choi K, Bhattacharjee MB, Arimura K, Umehara F, Izumo S, Northrop JL, Salih MAM, Inoue K, Armstrong DL, Champoux JJ, Takashima H, Boerkoel CF. Spinocerebellar ataxia with axonal neuropathy: consequence of a Tdp1 recessive neomorphic mutation? EMBO J 2007; 26:4732-43. [PMID: 17948061 DOI: 10.1038/sj.emboj.7601885] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 09/19/2007] [Indexed: 01/30/2023] Open
Abstract
Tyrosyl-DNA phosphodiesterase 1 (Tdp1) cleaves the phosphodiester bond between a covalently stalled topoisomerase I (Topo I) and the 3' end of DNA. Stalling of Topo I at DNA strand breaks is induced by endogenous DNA damage and the Topo I-specific anticancer drug camptothecin (CPT). The H493R mutation of Tdp1 causes the neurodegenerative disorder spinocerebellar ataxia with axonal neuropathy (SCAN1). Contrary to the hypothesis that SCAN1 arises from catalytically inactive Tdp1, Tdp1-/- mice are indistinguishable from wild-type mice, physically, histologically, behaviorally, and electrophysiologically. However, compared to wild-type mice, Tdp1-/- mice are hypersensitive to CPT and bleomycin but not to etoposide. Consistent with earlier in vitro studies, we show that the H493R Tdp1 mutant protein retains residual activity and becomes covalently trapped on the DNA after CPT treatment of SCAN1 cells. This result provides a direct demonstration that Tdp1 repairs Topo I covalent lesions in vivo and suggests that SCAN1 arises from the recessive neomorphic mutation H493R. This is a novel mechanism for disease since neomorphic mutations are generally dominant.
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Affiliation(s)
- Ryuki Hirano
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
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Dunlop J, Morin X, Corominas M, Serras F, Tear G. glaikit is essential for the formation of epithelial polarity and neuronal development. Curr Biol 2005; 14:2039-45. [PMID: 15556867 DOI: 10.1016/j.cub.2004.10.048] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 09/23/2004] [Accepted: 09/23/2004] [Indexed: 11/28/2022]
Abstract
Epithelial cells have a distinctive polarity based on the restricted distribution of proteins and junctional complexes along an apical-basal axis. Studying the formation of the polarized ectoderm of the Drosophila embryo has identified a number of the molecules that establish this polarity. The Crumbs (Crb) complex is one of three separate complexes that cooperate to control epithelial polarity and the formation of zonula adherens. Here we show that glaikit (gkt), a member of the phospholipase D superfamily, is essential for the formation of epithelial polarity and for neuronal development during Drosophila embryogenesis. In epithelial cells, gkt acts to localize the Crb complex of proteins to the apical lateral membrane. Loss of gkt during neuronal development leads to a severe CNS architecture disruption that is not dependent on the Crb pathway but probably results from the disrupted localization of other membrane proteins. A mutation in the human homolog of gkt causes the neurodegenerative disease spinocerebellar ataxia with neuropathy (SCAN1), making it possible that a failure of membrane protein localization is a cause of this disease.
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Affiliation(s)
- John Dunlop
- Medical Research Council, Centre for Developmental Neurobiology, 4th floor, New Hunts House, Guys Campus, King's College London, London SE1 1UL, United Kingdom.
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