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Sember E, Chennakesavula R, Beard B, Opoola M, Hwangbo DS. Dietary restriction fails to extend lifespan of Drosophila model of Werner syndrome. G3 (BETHESDA, MD.) 2024; 14:jkae056. [PMID: 38491858 PMCID: PMC11075538 DOI: 10.1093/g3journal/jkae056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 02/28/2024] [Accepted: 03/04/2024] [Indexed: 03/18/2024]
Abstract
Werner syndrome (WS) is a rare genetic disease in humans, caused by mutations in the WRN gene that encodes a protein containing helicase and exonuclease domains. WS is characterized by symptoms of accelerated aging in multiple tissues and organs, involving increased risk of cancer, heart failure, and metabolic dysfunction. These conditions ultimately lead to the premature mortality of patients with WS. In this study, using the null mutant flies (WRNexoΔ) for the gene WRNexo (CG7670), homologous to the exonuclease domain of WRN in humans, we examined how diets affect the lifespan, stress resistance, and sleep/wake patterns of a Drosophila model of WS. We observed that dietary restriction (DR), one of the most robust nongenetic interventions to extend lifespan in animal models, failed to extend the lifespan of WRNexoΔ mutant flies and even had a detrimental effect in females. Interestingly, the mean lifespan of WRNexoΔ mutant flies was not reduced on a protein-rich diet compared to that of wild-type (WT) flies. Compared to WT control flies, the mutant flies also exhibited altered responses to DR in their resistance to starvation and oxidative stress, as well as changes in sleep/wake patterns. These findings show that the WRN protein is necessary for mediating the effects of DR and suggest that the exonuclease domain of WRN plays an important role in metabolism in addition to its primary role in DNA-repair and genome stability.
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Affiliation(s)
- Eileen Sember
- Department of Biology, University of Louisville, Louisville, KY 40292, USA
| | | | - Breanna Beard
- Department of Biology, University of Louisville, Louisville, KY 40292, USA
| | - Mubaraq Opoola
- Department of Biology, University of Louisville, Louisville, KY 40292, USA
| | - Dae-Sung Hwangbo
- Department of Biology, University of Louisville, Louisville, KY 40292, USA
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2
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Xu X, An H, Wu C, Sang R, Wu L, Lou Y, Yang X, Xi Y. HR repair pathway plays a crucial role in maintaining neural stem cell fate under irradiation stress. Life Sci Alliance 2023; 6:e202201802. [PMID: 37197982 PMCID: PMC10192720 DOI: 10.26508/lsa.202201802] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 05/19/2023] Open
Abstract
Environmental stress can cause mutation or genomic instability in stem cells which, in some cases, leads to tumorigenesis. Mechanisms to monitor and eliminate these mutant stem cells remain elusive. Here, using the Drosophila larval brain as a model, we show that X-ray irradiation (IR) at the early larval stage leads to accumulation of nuclear Prospero (Pros), resulting in premature differentiation of neural stem cells (neuroblasts, NBs). Through NB-specific RNAi screenings, we determined that it is the Mre11-Rad50-Nbs1 complex and the homologous recombination (HR) repair pathway, rather than non-homologous end-joining pathway that plays, a dominant role in the maintenance of NBs under IR stress. The DNA damage sensor ATR/mei-41 is shown to act to prevent IR-induced nuclear Pros in a WRNexo-dependent manner. The accumulation of nuclear Pros in NBs under IR stress, leads to NB cell fate termination, rather than resulting in mutant cell proliferation. Our study reveals an emerging mechanism for the HR repair pathway in maintaining neural stem cell fate under irradiation stress.
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Affiliation(s)
- Xiao Xu
- The Women's Hospital, Institute of Genetics, Zhejiang Provincial Key Laboratory of Genetic & Development Disorders, School of Medicine, Zhejiang University, Hangzhou, China
| | - Huanping An
- The Women's Hospital, Institute of Genetics, Zhejiang Provincial Key Laboratory of Genetic & Development Disorders, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Clinical Molecular Biology of Hanzhong City, Hanzhong Vocational and Technique College, Hanzhong, China
| | - Cheng Wu
- The Women's Hospital, Institute of Genetics, Zhejiang Provincial Key Laboratory of Genetic & Development Disorders, School of Medicine, Zhejiang University, Hangzhou, China
| | - Rong Sang
- The Women's Hospital, Institute of Genetics, Zhejiang Provincial Key Laboratory of Genetic & Development Disorders, School of Medicine, Zhejiang University, Hangzhou, China
| | - Litao Wu
- The Women's Hospital, Institute of Genetics, Zhejiang Provincial Key Laboratory of Genetic & Development Disorders, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yuhan Lou
- The Women's Hospital, Institute of Genetics, Zhejiang Provincial Key Laboratory of Genetic & Development Disorders, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xiaohang Yang
- The Women's Hospital, Institute of Genetics, Zhejiang Provincial Key Laboratory of Genetic & Development Disorders, School of Medicine, Zhejiang University, Hangzhou, China
- Joint Institute of Genetics and Genomic Medicine, Between Zhejiang University and University of Toronto, Zhejiang University, Hangzhou, China
| | - Yongmei Xi
- The Women's Hospital, Institute of Genetics, Zhejiang Provincial Key Laboratory of Genetic & Development Disorders, School of Medicine, Zhejiang University, Hangzhou, China
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3
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Epiney DG, Salameh C, Cassidy D, Zhou LT, Kruithof J, Milutinović R, Andreani TS, Schirmer AE, Bolterstein E. Characterization of Stress Responses in a Drosophila Model of Werner Syndrome. Biomolecules 2021; 11:1868. [PMID: 34944512 PMCID: PMC8699552 DOI: 10.3390/biom11121868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/04/2021] [Accepted: 12/07/2021] [Indexed: 11/16/2022] Open
Abstract
As organisms age, their resistance to stress decreases while their risk of disease increases. This can be shown in patients with Werner syndrome (WS), which is a genetic disease characterized by accelerated aging along with increased risk of cancer and metabolic disease. WS is caused by mutations in WRN, a gene involved in DNA replication and repair. Recent research has shown that WRN mutations contribute to multiple hallmarks of aging including genomic instability, telomere attrition, and mitochondrial dysfunction. However, questions remain regarding the onset and effect of stress on early aging. We used a fly model of WS (WRNexoΔ) to investigate stress response during different life stages and found that stress sensitivity varies according to age and stressor. While larvae and young WRNexoΔ adults are not sensitive to exogenous oxidative stress, high antioxidant activity suggests high levels of endogenous oxidative stress. WRNexoΔ adults are sensitive to stress caused by elevated temperature and starvation suggesting abnormalities in energy storage and a possible link to metabolic dysfunction in WS patients. We also observed higher levels of sleep in aged WRNexoΔ adults suggesting an additional adaptive mechanism to protect against age-related stress. We suggest that stress response in WRNexoΔ is multifaceted and evokes a systemic physiological response to protect against cellular damage. These data further validate WRNexoΔ flies as a WS model with which to study mechanisms of early aging and provide a foundation for development of treatments for WS and similar diseases.
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Affiliation(s)
- Derek G. Epiney
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Charlotte Salameh
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Deirdre Cassidy
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Luhan T. Zhou
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Joshua Kruithof
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Rolan Milutinović
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Tomas S. Andreani
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA;
| | - Aaron E. Schirmer
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
| | - Elyse Bolterstein
- Department of Biology, Northeastern Illinois University, Chicago, IL 60625, USA; (D.G.E.); (C.S.); (D.C.); (L.T.Z.); (J.K.); (R.M.); (A.E.S.)
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4
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Ruchert JM, Brady MM, McMahan S, Lacey KJ, Latta LC, Sekelsky J, Stoffregen EP. Blm helicase facilitates rapid replication of repetitive DNA sequences in early Drosophila development. Genetics 2021; 220:6407149. [PMID: 34849849 DOI: 10.1093/genetics/iyab169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/18/2021] [Indexed: 11/12/2022] Open
Abstract
The absence of functional BLM DNA helicase, a member of the RecQ family of helicases, is responsible for the rare human disorder Bloom Syndrome, which results in developmental abnormalities, DNA repair defects, genomic instability, and a predisposition to cancer. In Drosophila melanogaster, the orthologous Blm protein is essential during early development when the embryo is under the control of maternal gene products. We show that lack of functional maternal Blm during the syncytial cell cycles of Drosophila embryonic development results in severe nuclear defects and lethality. Amongst the small fraction of embryos from Blm mutant mothers that survive to adulthood, a prominent sex-bias favors the class that inherits less repetitive DNA content, which serves as an endogenous source of replication stress. This selection against repetitive DNA content reflects a role for Blm in facilitating replication through repetitive sequences during the rapid S-phases of syncytial cell cycles. During these syncytial cycles, Blm is not required for complex DNA double-strand break repair; however, the progeny sex-bias resulting from the absence of maternal Blm is exacerbated by repetitive DNA sequences and by the slowing of replication fork progression, suggesting that the essential role for Blm during this stage is to manage replication fork stress brought about by impediments to fork progression. Additionally, our data suggest that Blm is only required to manage this replication stress during embryonic development, and likely only during the early, rapid syncytial cell cycles, and not at later developmental stages. These results provide novel insights into Blm function throughout development.
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Affiliation(s)
- Jolee M Ruchert
- Physical, Life, Movement & Sport Sciences, Lewis-Clark State College, Lewiston, ID 83501, USA
| | - Morgan M Brady
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Susan McMahan
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Karly J Lacey
- Physical, Life, Movement & Sport Sciences, Lewis-Clark State College, Lewiston, ID 83501, USA
| | - Leigh C Latta
- Physical, Life, Movement & Sport Sciences, Lewis-Clark State College, Lewiston, ID 83501, USA
| | - Jeff Sekelsky
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA.,Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA.,Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Eric P Stoffregen
- Physical, Life, Movement & Sport Sciences, Lewis-Clark State College, Lewiston, ID 83501, USA.,Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA.,SPIRE Postdoctoral Fellowship Program, University of North Carolina, Chapel Hill, NC 27599, USA
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5
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Aiello FA, Palma A, Malacaria E, Zheng L, Campbell JL, Shen B, Franchitto A, Pichierri P. RAD51 and mitotic function of mus81 are essential for recovery from low-dose of camptothecin in the absence of the WRN exonuclease. Nucleic Acids Res 2020; 47:6796-6810. [PMID: 31114910 PMCID: PMC6648349 DOI: 10.1093/nar/gkz431] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 05/02/2019] [Accepted: 05/07/2019] [Indexed: 11/13/2022] Open
Abstract
Stabilization of stalled replication forks prevents excessive fork reversal or degradation, which can undermine genome integrity. The WRN protein is unique among the other human RecQ family members to possess exonuclease activity. However, the biological role of the WRN exonuclease is poorly defined. Recently, the WRN exonuclease has been linked to protection of stalled forks from degradation. Alternative processing of perturbed forks has been associated to chemoresistance of BRCA-deficient cancer cells. Thus, we used WRN exonuclease-deficiency as a model to investigate the fate of perturbed forks undergoing degradation, but in a BRCA wild-type condition. We find that, upon treatment with clinically-relevant nanomolar doses of the Topoisomerase I inhibitor camptothecin, loss of WRN exonuclease stimulates fork inactivation and accumulation of parental gaps, which engages RAD51. Such mechanism affects reinforcement of CHK1 phosphorylation and causes persistence of RAD51 during recovery from treatment. Notably, in WRN exonuclease-deficient cells, persistence of RAD51 correlates with elevated mitotic phosphorylation of MUS81 at Ser87, which is essential to prevent excessive mitotic abnormalities. Altogether, these findings indicate that aberrant fork degradation, in the presence of a wild-type RAD51 axis, stimulates RAD51-mediated post-replicative repair and engagement of the MUS81 complex to limit genome instability and cell death.
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Affiliation(s)
- Francesca Antonella Aiello
- Mechanisms, Biomarkers and Models Unit, Department of Environment and Health, Istituto Superiore di Sanità, Roma, Italy
| | - Anita Palma
- Mechanisms, Biomarkers and Models Unit, Department of Environment and Health, Istituto Superiore di Sanità, Roma, Italy
| | - Eva Malacaria
- Mechanisms, Biomarkers and Models Unit, Department of Environment and Health, Istituto Superiore di Sanità, Roma, Italy
| | - Li Zheng
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010-3000, USA
| | - Judith L Campbell
- Braun Laboratories, California Institute of Technology, Pasadena, CA 91125, USA
| | - Binghui Shen
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 East Duarte Road, Duarte, CA 91010-3000, USA
| | - Annapaola Franchitto
- Mechanisms, Biomarkers and Models Unit, Department of Environment and Health, Istituto Superiore di Sanità, Roma, Italy
| | - Pietro Pichierri
- Mechanisms, Biomarkers and Models Unit, Department of Environment and Health, Istituto Superiore di Sanità, Roma, Italy.,Istituto Nazionale Biostrutture e Biosistemi, Roma, Italy
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6
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Cassidy D, Epiney DG, Salameh C, Zhou LT, Salomon RN, Schirmer AE, McVey M, Bolterstein E. Evidence for premature aging in a Drosophila model of Werner syndrome. Exp Gerontol 2019; 127:110733. [PMID: 31518666 PMCID: PMC6935377 DOI: 10.1016/j.exger.2019.110733] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 08/29/2019] [Accepted: 09/09/2019] [Indexed: 10/26/2022]
Abstract
Werner syndrome (WS) is an autosomal recessive progeroid disease characterized by patients' early onset of aging, increased risk of cancer and other age-related pathologies. WS is caused by mutations in WRN, a RecQ helicase that has essential roles responding to DNA damage and preventing genomic instability. While human WRN has both an exonuclease and helicase domain, Drosophila WRNexo has high genetic and functional homology to only the exonuclease domain of WRN. Like WRN-deficient human cells, Drosophila WRNexo null mutants (WRNexoΔ) are sensitive to replication stress, demonstrating mechanistic similarities between these two models. Compared to age-matched wild-type controls, WRNexoΔ flies exhibit increased physiological signs of aging, such as shorter lifespans, higher tumor incidence, muscle degeneration, reduced climbing ability, altered behavior, and reduced locomotor activity. Interestingly, these effects are more pronounced in females suggesting sex-specific differences in the role of WRNexo in aging. This and future mechanistic studies will contribute to our knowledge in linking faulty DNA repair mechanisms with the process of aging.
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Affiliation(s)
- Deirdre Cassidy
- Department of Biology, Northeastern Illinois University, 5500 N. Saint Louis Ave, Chicago, IL 60625, United States of America
| | - Derek G Epiney
- Department of Biology, Northeastern Illinois University, 5500 N. Saint Louis Ave, Chicago, IL 60625, United States of America
| | - Charlotte Salameh
- Department of Biology, Northeastern Illinois University, 5500 N. Saint Louis Ave, Chicago, IL 60625, United States of America
| | - Luhan T Zhou
- Department of Biology, Northeastern Illinois University, 5500 N. Saint Louis Ave, Chicago, IL 60625, United States of America
| | - Robert N Salomon
- Department of Pathology, Tufts University School of Medicine, 145 Harrison Ave, Boston, MA 20111, United States of America
| | - Aaron E Schirmer
- Department of Biology, Northeastern Illinois University, 5500 N. Saint Louis Ave, Chicago, IL 60625, United States of America.
| | - Mitch McVey
- Department of Biology, Tufts University, 200 Boston Ave, Ste. 4741, Medford, MA 20155, United States of America.
| | - Elyse Bolterstein
- Department of Biology, Northeastern Illinois University, 5500 N. Saint Louis Ave, Chicago, IL 60625, United States of America.
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7
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A Screen for Synaptic Growth Mutants Reveals Mechanisms That Stabilize Synaptic Strength. J Neurosci 2019; 39:4051-4065. [PMID: 30902873 DOI: 10.1523/jneurosci.2601-18.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 01/28/2023] Open
Abstract
Synapses grow, prune, and remodel throughout development, experience, and disease. This structural plasticity can destabilize information transfer in the nervous system. However, neural activity remains stable throughout life, implying that adaptive countermeasures exist that maintain neurotransmission within proper physiological ranges. Aberrant synaptic structure and function have been associated with a variety of neural diseases, including Fragile X syndrome, autism, and intellectual disability. We have screened 300 mutants in Drosophila larvae of both sexes for defects in synaptic growth at the neuromuscular junction, identifying 12 mutants with severe reductions or enhancements in synaptic growth. Remarkably, electrophysiological recordings revealed that synaptic strength was unchanged in all but one of these mutants compared with WT. We used a combination of genetic, anatomical, and electrophysiological analyses to illuminate three mechanisms that stabilize synaptic strength despite major disparities in synaptic growth. These include compensatory changes in (1) postsynaptic neurotransmitter receptor abundance, (2) presynaptic morphology, and (3) active zone structure. Together, this characterization identifies new mutants with defects in synaptic growth and the adaptive strategies used by synapses to homeostatically stabilize neurotransmission in response.SIGNIFICANCE STATEMENT This study reveals compensatory mechanisms used by synapses to ensure stable functionality during severe alterations in synaptic growth using the neuromuscular junction of Drosophila melanogaster as a model system. Through a forward genetic screen, we identify mutants that exhibit dramatic undergrown or overgrown synapses yet express stable levels of synaptic strength, with three specific compensatory mechanisms discovered. Thus, this study reveals novel insights into the adaptive strategies that constrain neurotransmission within narrow physiological ranges while allowing considerable flexibility in overall synapse number. More broadly, these findings provide insights into how stable synaptic function may be maintained in the nervous system during periods of intensive synaptic growth, pruning, and remodeling.
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8
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Studying Werner syndrome to elucidate mechanisms and therapeutics of human aging and age-related diseases. Biogerontology 2019; 20:255-269. [PMID: 30666569 DOI: 10.1007/s10522-019-09798-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 01/17/2019] [Indexed: 01/22/2023]
Abstract
Aging is a natural and unavoidable part of life. However, aging is also the primary driver of the dominant human diseases, such as cardiovascular disease, cancer, and neurodegenerative diseases, including Alzheimer's disease. Unraveling the sophisticated molecular mechanisms of the human aging process may provide novel strategies to extend 'healthy aging' and the cure of human aging-related diseases. Werner syndrome (WS), is a heritable human premature aging disease caused by mutations in the gene encoding the Werner (WRN) DNA helicase. As a classical premature aging disease, etiological exploration of WS can shed light on the mechanisms of normal human aging and facilitate the development of interventional strategies to improve healthspan. Here, we summarize the latest progress of the molecular understandings of WRN protein, highlight the advantages of using different WS model systems, including Caenorhabditis elegans, Drosophila melanogaster and induced pluripotent stem cell (iPSC) systems. Further studies on WS will propel drug development for WS patients, and possibly also for normal age-related diseases.
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9
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Tvedte ES, Forbes AA, Logsdon JM. Retention of Core Meiotic Genes Across Diverse Hymenoptera. J Hered 2018; 108:791-806. [PMID: 28992199 DOI: 10.1093/jhered/esx062] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 07/13/2017] [Indexed: 12/20/2022] Open
Abstract
The cellular mechanisms of meiosis are critical for proper gamete formation in sexual organisms. Functional studies in model organisms have identified genes essential for meiosis, yet the extent to which this core meiotic machinery is conserved across non-model systems is not fully understood. Moreover, it is unclear whether deviation from canonical modes of sexual reproduction is accompanied by modifications in the genetic components involved in meiosis. We used a robust approach to identify and catalogue meiosis genes in Hymenoptera, an insect order typically characterized by haplodiploid reproduction. Using newly available genome data, we searched for 43 genes involved in meiosis in 18 diverse hymenopterans. Seven of eight genes with roles specific to meiosis were found across a majority of surveyed species, suggesting the preservation of core meiotic machinery in haplodiploid hymenopterans. Phylogenomic analyses of the inventory of meiosis genes and the identification of shared gene duplications and losses provided support for the grouping of species within Proctotrupomorpha, Ichneumonomorpha, and Aculeata clades, along with a paraphyletic Symphyta. The conservation of meiosis genes across Hymenoptera provides a framework for studying transitions between reproductive modes in this insect group.
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Affiliation(s)
- Eric S Tvedte
- Department of Biology, University of Iowa, Iowa City, IA 52242
| | - Andrew A Forbes
- Department of Biology, University of Iowa, Iowa City, IA 52242
| | - John M Logsdon
- Department of Biology, University of Iowa, Iowa City, IA 52242
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10
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Ryu JS, Koo HS. The Caenorhabditis elegans WRN helicase promotes double-strand DNA break repair by mediating end resection and checkpoint activation. FEBS Lett 2017. [PMID: 28640365 DOI: 10.1002/1873-3468.12724] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The protein associated with Werner syndrome (WRN), is involved in DNA repair, checkpoint activation, and telomere maintenance. To better understand the involvement of WRN in double-strand DNA break (DSB) repair, we analyzed the combinatorial role of WRN-1, the Caenorhabditis elegans WRN helicase, in conjunction with EXO-1 and DNA-2 nucleases. We found that WRN-1 cooperates with DNA-2 to resect DSB ends in a pathway acting in parallel to EXO-1. The wrn-1 mutants show an aberrant accumulation of replication protein A (RPA) and RAD-51, and the same pattern of accumulation is also observed in checkpoint-defective strains. We conclude that WRN-1 plays a conserved role in the resection of DSB ends and mediates checkpoint signaling, thereby influencing levels of RPA and RAD-51.
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Affiliation(s)
- Jin-Sun Ryu
- Department of Biochemistry, College of Life Science & Biotechnology, Yonsei University, Seoul, Korea
| | - Hyeon-Sook Koo
- Department of Biochemistry, College of Life Science & Biotechnology, Yonsei University, Seoul, Korea
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11
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Sekelsky J. DNA Repair in Drosophila: Mutagens, Models, and Missing Genes. Genetics 2017; 205:471-490. [PMID: 28154196 PMCID: PMC5289830 DOI: 10.1534/genetics.116.186759] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 10/18/2016] [Indexed: 12/22/2022] Open
Abstract
The numerous processes that damage DNA are counterbalanced by a complex network of repair pathways that, collectively, can mend diverse types of damage. Insights into these pathways have come from studies in many different organisms, including Drosophila melanogaster Indeed, the first ideas about chromosome and gene repair grew out of Drosophila research on the properties of mutations produced by ionizing radiation and mustard gas. Numerous methods have been developed to take advantage of Drosophila genetic tools to elucidate repair processes in whole animals, organs, tissues, and cells. These studies have led to the discovery of key DNA repair pathways, including synthesis-dependent strand annealing, and DNA polymerase theta-mediated end joining. Drosophila appear to utilize other major repair pathways as well, such as base excision repair, nucleotide excision repair, mismatch repair, and interstrand crosslink repair. In a surprising number of cases, however, DNA repair genes whose products play important roles in these pathways in other organisms are missing from the Drosophila genome, raising interesting questions for continued investigations.
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Affiliation(s)
- Jeff Sekelsky
- Department of Biology and Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, North Carolina 27599
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12
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Shaposhnikov M, Proshkina E, Shilova L, Zhavoronkov A, Moskalev A. Lifespan and Stress Resistance in Drosophila with Overexpressed DNA Repair Genes. Sci Rep 2015; 5:15299. [PMID: 26477511 PMCID: PMC4609912 DOI: 10.1038/srep15299] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 09/22/2015] [Indexed: 12/22/2022] Open
Abstract
DNA repair declines with age and correlates with longevity in many animal species. In this study, we investigated the effects of GAL4-induced overexpression of genes implicated in DNA repair on lifespan and resistance to stress factors in Drosophila melanogaster. Stress factors included hyperthermia, oxidative stress, and starvation. Overexpression was either constitutive or conditional and either ubiquitous or tissue-specific (nervous system). Overexpressed genes included those involved in recognition of DNA damage (homologs of HUS1, CHK2), nucleotide and base excision repair (homologs of XPF, XPC and AP-endonuclease-1), and repair of double-stranded DNA breaks (homologs of BRCA2, XRCC3, KU80 and WRNexo). The overexpression of different DNA repair genes led to both positive and negative effects on lifespan and stress resistance. Effects were dependent on GAL4 driver, stage of induction, sex, and role of the gene in the DNA repair process. While the constitutive/neuron-specific and conditional/ubiquitous overexpression of DNA repair genes negatively impacted lifespan and stress resistance, the constitutive/ubiquitous and conditional/neuron-specific overexpression of Hus1, mnk, mei-9, mus210, and WRNexo had beneficial effects. This study demonstrates for the first time the effects of overexpression of these DNA repair genes on both lifespan and stress resistance in D. melanogaster.
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Affiliation(s)
- Mikhail Shaposhnikov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia.,Institute of Biology of Komi Science Center of Ural Branch of RAS, Syktyvkar, 167982, Russia
| | - Ekaterina Proshkina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia.,Institute of Biology of Komi Science Center of Ural Branch of RAS, Syktyvkar, 167982, Russia
| | - Lyubov Shilova
- Institute of Biology of Komi Science Center of Ural Branch of RAS, Syktyvkar, 167982, Russia
| | - Alex Zhavoronkov
- Insilico Medicine, Inc, Johns Hopkins University, ETC, B301, Baltimore, MD, 21218, USA
| | - Alexey Moskalev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
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Ryu JS, Koo HS. Roles of Caenorhabditis elegans WRN Helicase in DNA Damage Responses, and a Comparison with Its Mammalian Homolog: A Mini-Review. Gerontology 2015; 62:296-303. [DOI: 10.1159/000439200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/05/2015] [Indexed: 11/19/2022] Open
Abstract
Werner syndrome protein (WRN) is unusual among RecQ family DNA helicases in having an additional exonuclease activity. WRN is involved in the repair of double-strand DNA breaks via the homologous recombination and nonhomologous end joining pathways, and also in the base excision repair pathway. In addition, the protein promotes the recovery of stalled replication forks. The helicase activity is thought to unwind DNA duplexes, thereby moving replication forks or Holliday junctions. The targets of the exonuclease could be the nascent DNA strands at a replication fork or the ends of double-strand DNA breaks. However, it is not clear which enzyme activities are essential for repairing different types of DNA damage. Model organisms such as mice, flies, and worms deficient in WRN homologs have been investigated to understand the physiological results of defects in WRN activity. Premature aging, the most remarkable characteristic of Werner syndrome, is also seen in the mutant mice and worms, and hypersensitivity to DNA damage has been observed in WRN mutants of all three model organisms, pointing to conservation of the functions of WRN. In the nematode Caenorhabditis elegans, the WRN homolog contains a helicase domain but no exonuclease domain, so that this animal is very useful for studying the in vivo functions of the helicase without interference from the activity of the exonuclease. Here, we review the current status of investigations of C. elegans WRN-1 and discuss its functional differences from the mammalian homologs.
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