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Oshidari R, Strecker J, Chung DKC, Abraham KJ, Chan JNY, Damaren CJ, Mekhail K. Nuclear microtubule filaments mediate non-linear directional motion of chromatin and promote DNA repair. Nat Commun 2018; 9:2567. [PMID: 29967403 PMCID: PMC6028458 DOI: 10.1038/s41467-018-05009-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 06/07/2018] [Indexed: 12/19/2022] Open
Abstract
Damaged DNA shows increased mobility, which can promote interactions with repair-conducive nuclear pore complexes (NPCs). This apparently random mobility is paradoxically abrogated upon disruption of microtubules or kinesins, factors that typically cooperate to mediate the directional movement of macromolecules. Here, we resolve this paradox by uncovering DNA damage-inducible intranuclear microtubule filaments (DIMs) that mobilize damaged DNA and promote repair. Upon DNA damage, relief of centromeric constraint induces DIMs that cooperate with the Rad9 DNA damage response mediator and Kar3 kinesin motor to capture DNA lesions, which then linearly move along dynamic DIMs. Decreasing and hyper-inducing DIMs respectively abrogates and hyper-activates repair. Accounting for DIM dynamics across cell populations by measuring directional changes of damaged DNA reveals that it exhibits increased non-linear directional behavior in nuclear space. Abrogation of DIM-dependent processes or repair-promoting factors decreases directional behavior. Thus, inducible and dynamic nuclear microtubule filaments directionally mobilize damaged DNA and promote repair. Following DNA damage, different processes come to action to aid repair. The authors here find that microtubule filaments within the cell nucleus capture and non-randomly mobilize damaged chromatin to mediate DNA repair.
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Affiliation(s)
- Roxanne Oshidari
- Department of Laboratory Medicine and Pathobiology, MaRS Centre, University of Toronto, West Tower, 661 University Avenue, Toronto, ON, M5G 1M1, Canada
| | - Jonathan Strecker
- Department of Molecular Genetics, MaRS Centre, University of Toronto, West Tower, 661 University Avenue, Toronto, ON, M5G 1M1, Canada.,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON, M5G 1X5, Canada.,Broad Institute of MIT and Harvard, 75 Ames Street, Cambridge, MA, 02142, USA
| | - Daniel K C Chung
- Department of Laboratory Medicine and Pathobiology, MaRS Centre, University of Toronto, West Tower, 661 University Avenue, Toronto, ON, M5G 1M1, Canada
| | - Karan J Abraham
- Department of Laboratory Medicine and Pathobiology, MaRS Centre, University of Toronto, West Tower, 661 University Avenue, Toronto, ON, M5G 1M1, Canada
| | - Janet N Y Chan
- Department of Laboratory Medicine and Pathobiology, MaRS Centre, University of Toronto, West Tower, 661 University Avenue, Toronto, ON, M5G 1M1, Canada
| | - Christopher J Damaren
- Institute for Aerospace Studies, University of Toronto, 4925 Dufferin Street, Toronto, ON, M3H 5T6, Canada
| | - Karim Mekhail
- Department of Laboratory Medicine and Pathobiology, MaRS Centre, University of Toronto, West Tower, 661 University Avenue, Toronto, ON, M5G 1M1, Canada. .,Canada Research Chairs Program, University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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Mekhail K. Defining the Damaged DNA Mobility Paradox as Revealed by the Study of Telomeres, DSBs, Microtubules and Motors. Front Genet 2018; 9:95. [PMID: 29616083 PMCID: PMC5869915 DOI: 10.3389/fgene.2018.00095] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/07/2018] [Indexed: 11/13/2022] Open
Abstract
Eukaryotic genomes are non-randomly arranged inside the nucleus. Despite this ordered spatial genome organization, damaged DNA exhibits increased random mobility within nuclear space. This increased random movement is thought to promote DNA repair by facilitating homology search, allowing targeting to repair-conducive nuclear domains, or releasing damage from repair-repressive locations. Recent studies focusing on the relationship between telomeres, DNA repair processes, and nuclear organization have revealed that the disruption of motor proteins or microtubules, which typically mediate the directed motion of cargo, disrupts the random mobility of damaged DNA. These findings define a new biological paradox. Here, I define this as the damaged DNA mobility paradox, describe how it uncovers key gaps in knowledge, and highlight key questions to help guide us toward paradox resolution.
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Affiliation(s)
- Karim Mekhail
- Department of Laboratory Medicine and Pathobiology, University of Toronto, MaRS Centre, Toronto, ON, Canada.,Canada Research Chairs Program, University of Toronto, Toronto, ON, Canada
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