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Apetroaei MM, Fragkiadaki P, Velescu BȘ, Baliou S, Renieri E, Dinu-Pirvu CE, Drăgănescu D, Vlăsceanu AM, Nedea MI(I, Udeanu DI, Docea AO, Tsatsakis A, Arsene AL. Pharmacotherapeutic Considerations on Telomere Biology: The Positive Effect of Pharmacologically Active Substances on Telomere Length. Int J Mol Sci 2024; 25:7694. [PMID: 39062937 PMCID: PMC11276808 DOI: 10.3390/ijms25147694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 07/06/2024] [Accepted: 07/10/2024] [Indexed: 07/28/2024] Open
Abstract
Telomeres are part of chromatin structures containing repeated DNA sequences, which function as protective caps at the ends of chromosomes and prevent DNA degradation and recombination, thus ensuring the integrity of the genome. While telomere length (TL) can be genetically inherited, TL shortening has been associated with ageing and multiple xenobiotics and bioactive substances. TL has been characterised as a reliable biomarker for the predisposition to developing chronic pathologies and their progression. This narrative review aims to provide arguments in favour of including TL measurements in a complex prognostic and diagnostic panel of chronic pathologies and the importance of assessing the effect of different pharmacologically active molecules on the biology of telomeres. Medicines used in the management of cardiovascular diseases, diabetes, schizophrenia, hormone replacement therapy at menopause, danazol, melatonin, and probiotics have been studied for their positive protective effects against TL shortening. All these classes of drugs are analysed in the present review, with a particular focus on the molecular mechanisms involved.
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Affiliation(s)
- Miruna-Maria Apetroaei
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia Street, 020956 Bucharest, Romania; (M.-M.A.); (C.E.D.-P.); (D.D.); (A.M.V.); (M.I.N.); (D.I.U.); (A.L.A.)
| | - Persefoni Fragkiadaki
- Laboratory of Toxicology and Forensic Sciences, Medical School, University of Crete, Voutes, 71003 Heraklion, Greece; (P.F.); (S.B.); (E.R.); (A.T.)
- Lifeplus S.A., Science & Technological Park of Crete, C Building, Vassilika Vouton, 70013 Heraklion, Greece
| | - Bruno Ștefan Velescu
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia Street, 020956 Bucharest, Romania; (M.-M.A.); (C.E.D.-P.); (D.D.); (A.M.V.); (M.I.N.); (D.I.U.); (A.L.A.)
| | - Stella Baliou
- Laboratory of Toxicology and Forensic Sciences, Medical School, University of Crete, Voutes, 71003 Heraklion, Greece; (P.F.); (S.B.); (E.R.); (A.T.)
- Lifeplus S.A., Science & Technological Park of Crete, C Building, Vassilika Vouton, 70013 Heraklion, Greece
| | - Elisavet Renieri
- Laboratory of Toxicology and Forensic Sciences, Medical School, University of Crete, Voutes, 71003 Heraklion, Greece; (P.F.); (S.B.); (E.R.); (A.T.)
- Lifeplus S.A., Science & Technological Park of Crete, C Building, Vassilika Vouton, 70013 Heraklion, Greece
| | - Cristina Elena Dinu-Pirvu
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia Street, 020956 Bucharest, Romania; (M.-M.A.); (C.E.D.-P.); (D.D.); (A.M.V.); (M.I.N.); (D.I.U.); (A.L.A.)
| | - Doina Drăgănescu
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia Street, 020956 Bucharest, Romania; (M.-M.A.); (C.E.D.-P.); (D.D.); (A.M.V.); (M.I.N.); (D.I.U.); (A.L.A.)
| | - Ana Maria Vlăsceanu
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia Street, 020956 Bucharest, Romania; (M.-M.A.); (C.E.D.-P.); (D.D.); (A.M.V.); (M.I.N.); (D.I.U.); (A.L.A.)
| | - Marina Ionela (Ilie) Nedea
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia Street, 020956 Bucharest, Romania; (M.-M.A.); (C.E.D.-P.); (D.D.); (A.M.V.); (M.I.N.); (D.I.U.); (A.L.A.)
| | - Denisa Ioana Udeanu
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia Street, 020956 Bucharest, Romania; (M.-M.A.); (C.E.D.-P.); (D.D.); (A.M.V.); (M.I.N.); (D.I.U.); (A.L.A.)
| | - Anca Oana Docea
- Department of Toxicology, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania;
| | - Artistidis Tsatsakis
- Laboratory of Toxicology and Forensic Sciences, Medical School, University of Crete, Voutes, 71003 Heraklion, Greece; (P.F.); (S.B.); (E.R.); (A.T.)
- Lifeplus S.A., Science & Technological Park of Crete, C Building, Vassilika Vouton, 70013 Heraklion, Greece
| | - Andreea Letiția Arsene
- Faculty of Pharmacy, Carol Davila University of Medicine and Pharmacy, 6 Traian Vuia Street, 020956 Bucharest, Romania; (M.-M.A.); (C.E.D.-P.); (D.D.); (A.M.V.); (M.I.N.); (D.I.U.); (A.L.A.)
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2
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Keener R, Chhetri SB, Connelly CJ, Taub MA, Conomos MP, Weinstock J, Ni B, Strober B, Aslibekyan S, Auer PL, Barwick L, Becker LC, Blangero J, Bleecker ER, Brody JA, Cade BE, Celedon JC, Chang YC, Cupples LA, Custer B, Freedman BI, Gladwin MT, Heckbert SR, Hou L, Irvin MR, Isasi CR, Johnsen JM, Kenny EE, Kooperberg C, Minster RL, Naseri T, Viali S, Nekhai S, Pankratz N, Peyser PA, Taylor KD, Telen MJ, Wu B, Yanek LR, Yang IV, Albert C, Arnett DK, Ashley-Koch AE, Barnes KC, Bis JC, Blackwell TW, Boerwinkle E, Burchard EG, Carson AP, Chen Z, Chen YDI, Darbar D, de Andrade M, Ellinor PT, Fornage M, Gelb BD, Gilliland FD, He J, Islam T, Kaab S, Kardia SLR, Kelly S, Konkle BA, Kumar R, Loos RJF, Martinez FD, McGarvey ST, Meyers DA, Mitchell BD, Montgomery CG, North KE, Palmer ND, Peralta JM, Raby BA, Redline S, Rich SS, Roden D, Rotter JI, Ruczinski I, Schwartz D, Sciurba F, Shoemaker MB, Silverman EK, Sinner MF, Smith NL, Smith AV, Tiwari HK, Vasan RS, Weiss ST, Williams LK, Zhang Y, Ziv E, Raffield LM, Reiner AP, Arvanitis M, Greider CW, Mathias RA, Battle A. Validation of human telomere length multi-ancestry meta-analysis association signals identifies POP5 and KBTBD6 as human telomere length regulation genes. Nat Commun 2024; 15:4417. [PMID: 38789417 PMCID: PMC11126610 DOI: 10.1038/s41467-024-48394-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 04/26/2024] [Indexed: 05/26/2024] Open
Abstract
Genome-wide association studies (GWAS) have become well-powered to detect loci associated with telomere length. However, no prior work has validated genes nominated by GWAS to examine their role in telomere length regulation. We conducted a multi-ancestry meta-analysis of 211,369 individuals and identified five novel association signals. Enrichment analyses of chromatin state and cell-type heritability suggested that blood/immune cells are the most relevant cell type to examine telomere length association signals. We validated specific GWAS associations by overexpressing KBTBD6 or POP5 and demonstrated that both lengthened telomeres. CRISPR/Cas9 deletion of the predicted causal regions in K562 blood cells reduced expression of these genes, demonstrating that these loci are related to transcriptional regulation of KBTBD6 and POP5. Our results demonstrate the utility of telomere length GWAS in the identification of telomere length regulation mechanisms and validate KBTBD6 and POP5 as genes affecting telomere length regulation.
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Grants
- 5K12GM123914 U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)
- R01AG069120 U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)
- R01 HL105756 NHLBI NIH HHS
- R35GM139580 U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)
- R01 AI132476 NIAID NIH HHS
- R01 DK071891 NIDDK NIH HHS
- R01HL153805 U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)
- R01AG081244 U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)
- R35CA209974 U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)
- R01HL105756 U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- R01HL68959 U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- R01HL079915 U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- R01HL87681 U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (NHLBI)
- R01 HL153805 NHLBI NIH HHS
- R01HL-120393 U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)
- U.S. Department of Health & Human Services | NIH | National Institute of General Medical Sciences (NIGMS)
- U.S. Department of Health & Human Services | NIH | National Heart, Lung, and Blood Institute (NHLBI)
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Affiliation(s)
- Rebecca Keener
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Surya B Chhetri
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Carla J Connelly
- Department of Molecular Biology and Genetics, Johns Hopkins University, Baltimore, MD, USA
| | - Margaret A Taub
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Matthew P Conomos
- Department of Biostatistics, School of Public Health, University of Washington, Seattle, WA, USA
| | - Joshua Weinstock
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Bohan Ni
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA
| | - Benjamin Strober
- Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA
| | | | - Paul L Auer
- Division of Biostatistics, Institute for Health & Equity, and Cancer Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Lucas Barwick
- LTRC Data Coordinating Center, The Emmes Company, LLC, Rockville, MD, USA
| | - Lewis C Becker
- GeneSTAR Research Program, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - John Blangero
- Department of Human Genetics and South Texas Diabetes and Obesity Institute, University of Texas Rio Grande Valley School of Medicine, Brownsville, TX, USA
| | - Eugene R Bleecker
- Department of Medicine, Division of Genetics, Genomics and Precision Medicine, University of Arizona, Tucson, AZ, USA
- Division of Pharmacogenomics, University of Arizona, Tucson, AZ, USA
| | - Jennifer A Brody
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Brian E Cade
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Juan C Celedon
- Division of Pediatric Pulmonary Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yi-Cheng Chang
- Department of Internal Medicine, National Taiwan University, Taipei, Taiwan
- Graduate Institute of Medical Genomics and Proteomics, National Taiwan University, Taipei, Taiwan
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - L Adrienne Cupples
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
- The National Heart, Lung, and Blood Institute, Boston University's Framingham Heart Study, Framingham, MA, USA
| | - Brian Custer
- Vitalant Research Institute, San Francisco, CA, USA
- Department of Laboratory Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Barry I Freedman
- Internal Medicine - Nephrology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Mark T Gladwin
- School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Susan R Heckbert
- Department of Epidemiology, University of Washington, Seattle, WA, USA
| | - Lifang Hou
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Evanston, IL, USA
| | - Marguerite R Irvin
- Department of Epidemiology, University of Alabama Birmingham, Birmingham, AL, USA
| | - Carmen R Isasi
- Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Jill M Johnsen
- Department of Medicine and Institute for Stem Cell & Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Eimear E Kenny
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Center for Genomic Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Charles Kooperberg
- Division of Public Health Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Ryan L Minster
- Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA, USA
| | - Take Naseri
- Naseri & Associates Public Health Consultancy Firm and Family Health Clinic, Apia, Samoa
- International Health Institute, School of Public Health, Brown University, Providence, RI, USA
| | - Satupa'itea Viali
- Oceania University of Medicine, Apia, Samoa
- School of Medicine, National University of Samoa, Apia, Samoa
- Department of Chronic Disease Epidemiology, Yale University School of Public Health, New Haven, CT, USA
| | - Sergei Nekhai
- Center for Sickle Cell Disease and Department of Medicine, College of Medicine, Howard University, Washington DC, USA
| | - Nathan Pankratz
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | - Patricia A Peyser
- Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Kent D Taylor
- The Institute for Translational Genomics and Population Sciences, Department of Pediatrics, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Marilyn J Telen
- Department of Medicine, Duke University Medical Center, Durham, NC, USA
| | - Baojun Wu
- Center for Individualized and Genomic Medicine Research (CIGMA), Department of Internal Medicine, Henry Ford Health System, Detroit, MI, USA
| | - Lisa R Yanek
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ivana V Yang
- Departments of Biomedical Informatics, Medicine, and Epidemiology, University of Colorado, Boulder, CO, USA
| | - Christine Albert
- Harvard Medical School, Boston, MA, USA
- Division of Cardiovascular, Brigham and Women's Hospital, Boston, MA, USA
| | - Donna K Arnett
- Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC, USA
| | | | - Kathleen C Barnes
- Department of Medicine, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA
| | - Joshua C Bis
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA, USA
| | - Thomas W Blackwell
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, MI, USA
- Center for Statistical Genetics, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Eric Boerwinkle
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Esteban G Burchard
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA
| | - April P Carson
- Department of Medicine, University of Mississippi Medical Center, Jackson, MI, USA
| | - Zhanghua Chen
- Department of Population and Public Health Sciences, University of Southern California, Los Angeles, CA, USA
| | - Yii-Der Ida Chen
- The Institute for Translational Genomics and Population Sciences, Department of Pediatrics, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Dawood Darbar
- Division of Cardiology, University of Illinois at Chicago, Chicago, IL, USA
| | - Mariza de Andrade
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA
| | - Patrick T Ellinor
- Cardiovascular Disease Initiative, The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Myriam Fornage
- Institute of Molecular Medicine, McGovern Medical School, the University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Bruce D Gelb
- Mindich Child Health and Development Institute and Departments of Pediatrics and Genetics and Genomic Sciences, Icahn School of Medicine, New York, NY, USA
| | - Frank D Gilliland
- Department of Population and Public Health Sciences, University of Southern California, Los Angeles, CA, USA
| | - Jiang He
- Department of Medicine, Tulane University School of Medicine, New Orleans, LA, USA
| | - Talat Islam
- Department of Population and Public Health Sciences, University of Southern California, Los Angeles, CA, USA
| | - Stefan Kaab
- Department of Cardiology, University Hospital, LMU Munich, Munich, Germany
| | - Sharon L R Kardia
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Shannon Kelly
- Vitalant Research Institute, San Francisco, CA, USA
- University of California San Francisco Benioff Children's Hospital, Oakland, CA, USA
| | - Barbara A Konkle
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - Rajesh Kumar
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- The Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Ruth J F Loos
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Fernando D Martinez
- Asthma & Airway Disease Research Center, University of Arizona, Tucson, AZ, USA
| | - Stephen T McGarvey
- Department of Epidemiology & International Health Institute, Brown University School of Public Health, Providence, RI, USA
| | - Deborah A Meyers
- Department of Medicine, Division of Genetics, Genomics and Precision Medicine, University of Arizona, Tucson, AZ, USA
- Division of Pharmacogenomics, University of Arizona, Tucson, AZ, USA
| | - Braxton D Mitchell
- Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Courtney G Montgomery
- Genes and Human Disease, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Kari E North
- Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Nicholette D Palmer
- Department of Biochemistry, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Juan M Peralta
- Department of Human Genetics and South Texas Diabetes and Obesity Institute, University of Texas Rio Grande Valley School of Medicine, Brownsville, TX, USA
| | - Benjamin A Raby
- Division of Pulmonary and Critical Care, Brigham and Women's Hospital, Boston, MA, USA
- Division of Pulmonary Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Susan Redline
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Stephen S Rich
- Center for Public Health Genomics, Department of Public Health Sciences, University of Virginia, Charlottesville, VA, USA
| | - Dan Roden
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jerome I Rotter
- The Institute for Translational Genomics and Population Sciences, Department of Pediatrics, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Ingo Ruczinski
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - David Schwartz
- Departments of Medicine and Immunology, University of Colorado, Boulder, CO, USA
| | - Frank Sciurba
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - M Benjamin Shoemaker
- Departments of Medicine, Pharmacology, and Biomedical Informatics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Edwin K Silverman
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Moritz F Sinner
- Department of Cardiology, University Hospital, LMU Munich, Munich, Germany
| | - Nicholas L Smith
- Department of Medicine, Tulane University School of Medicine, New Orleans, LA, USA
| | - Albert V Smith
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, USA
| | - Hemant K Tiwari
- Department of Biostatistics, University of Alabama Birmingham, Birmingham, AL, USA
| | | | - Scott T Weiss
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - L Keoki Williams
- Center for Individualized and Genomic Medicine Research (CIGMA), Department of Internal Medicine, Henry Ford Health System, Detroit, MI, USA
| | - Yingze Zhang
- Division of Pulmonary Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Elad Ziv
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Laura M Raffield
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Alexander P Reiner
- Division of Public Health Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Marios Arvanitis
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| | - Carol W Greider
- Department of Molecular Cell and Developmental Biology, University of California Santa Cruz, Santa Cruz, CA, USA
- University Professor Johns Hopkins University, Baltimore, MD, USA
| | - Rasika A Mathias
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Alexis Battle
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
- Department of Computer Science, Johns Hopkins University, Baltimore, MD, USA.
- Department of Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA.
- Malone Center for Engineering in Healthcare, Johns Hopkins University, Baltimore, MD, USA.
- Data Science and AI Institute, Johns Hopkins University, Baltimore, MD, USA.
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3
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Zhong L, Gordillo M, Wang X, Qin Y, Huang Y, Soshnev A, Kumar R, Nanjangud G, James D, David Allis C, Evans T, Carey B, Wen D. Dual role of lipids for genome stability and pluripotency facilitates full potency of mouse embryonic stem cells. Protein Cell 2023; 14:591-602. [PMID: 37029701 PMCID: PMC10392030 DOI: 10.1093/procel/pwad008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Accepted: 01/09/2023] [Indexed: 02/18/2023] Open
Abstract
While Mek1/2 and Gsk3β inhibition ("2i") supports the maintenance of murine embryonic stem cells (ESCs) in a homogenous naïve state, prolonged culture in 2i results in aneuploidy and DNA hypomethylation that impairs developmental potential. Additionally, 2i fails to support derivation and culture of fully potent female ESCs. Here we find that mouse ESCs cultured in 2i/LIF supplemented with lipid-rich albumin (AlbuMAX) undergo pluripotency transition yet maintain genomic stability and full potency over long-term culture. Mechanistically, lipids in AlbuMAX impact intracellular metabolism including nucleotide biosynthesis, lipid biogenesis, and TCA cycle intermediates, with enhanced expression of DNMT3s that prevent DNA hypomethylation. Lipids induce a formative-like pluripotent state through direct stimulation of Erk2 phosphorylation, which also alleviates X chromosome loss in female ESCs. Importantly, both male and female "all-ESC" mice can be generated from de novo derived ESCs using AlbuMAX-based media. Our findings underscore the importance of lipids to pluripotency and link nutrient cues to genome integrity in early development.
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Affiliation(s)
- Liangwen Zhong
- Department of Reproductive Medicine, Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Miriam Gordillo
- Department of Surgery, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA
| | - Xingyi Wang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Yiren Qin
- Department of Reproductive Medicine, Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Yuanyuan Huang
- Department of Reproductive Medicine, Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - Alexey Soshnev
- Laboratory of Chromatin Biology and Epigenetics, The Rockefeller University, New York, NY 10065, USA
- Department of Neuroscience, Developmental and Regenerative Biology, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA
| | - Ritu Kumar
- Department of Surgery, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA
- Gladstone Institutes, 1650 Owens St, San Francisco, CA 94158, USA
| | - Gouri Nanjangud
- Molecular Cytogenetics Core. Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Daylon James
- Department of Reproductive Medicine, Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY 10065, USA
| | - C David Allis
- Laboratory of Chromatin Biology and Epigenetics, The Rockefeller University, New York, NY 10065, USA
| | - Todd Evans
- Department of Surgery, Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA
| | - Bryce Carey
- Laboratory of Chromatin Biology and Epigenetics, The Rockefeller University, New York, NY 10065, USA
| | - Duancheng Wen
- Department of Reproductive Medicine, Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY 10065, USA
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4
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Zhuk AS, Lada AG, Pavlov YI. Polymorphism of Saccharomyces cerevisiae Strains in DNA Metabolism Genes. Int J Mol Sci 2023; 24:ijms24097795. [PMID: 37175502 PMCID: PMC10178279 DOI: 10.3390/ijms24097795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 05/15/2023] Open
Abstract
Baker's yeast, S. cerevisiae, is an excellent model organism exploited for molecular genetic studies of the mechanisms of genome stability in eukaryotes. Genetic peculiarities of commonly used yeast strains impact the processes of DNA replication, repair, and recombination (RRR). We compared the genomic DNA sequence variation of the five strains that are intensively used for RRR studies. We used yeast next-generation sequencing data to detect the extent and significance of variation in 183 RRR genes. We present a detailed analysis of the differences that were found even in closely related strains. Polymorphisms of common yeast strains should be considered when interpreting the outcomes of genome stability studies, especially in cases of discrepancies between laboratories describing the same phenomena.
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Affiliation(s)
- Anna S Zhuk
- Institute of Applied Computer Science, ITMO University, 191002 St. Petersburg, Russia
- Vavilov Institute of General Genetics, St. Petersburg Branch, Russian Academy of Sciences, 199034 St. Petersburg, Russia
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Artem G Lada
- Department of Microbiology and Molecular Genetics, University of California, Davis, CA 95616, USA
| | - Youri I Pavlov
- Eppley Institute for Research in Cancer, Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Departments of Biochemistry and Molecular Biology, Microbiology and Pathology, Genetics Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
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5
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D'Aronco G, Ferraro P, Sassano V, Dagostino C, Biancotto M, Palumbo E, Presot E, Russo A, Bianchi V, Rampazzo C. SAMHD1 restricts the deoxyguanosine triphosphate pool contributing to telomere stability in telomerase-positive cells. FASEB J 2023; 37:e22883. [PMID: 36934410 DOI: 10.1096/fj.202300122r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/26/2023] [Accepted: 03/07/2023] [Indexed: 03/20/2023]
Abstract
SAMHD1 (Sterile alpha motif and histidine/aspartic acid domain-containing protein 1) is a dNTP triphosphohydrolase crucial in the maintenance of balanced cellular dNTP pools, which support genome integrity. In SAMHD1 deficient fibroblasts isolated from Aicardi-Goutières Syndrome (AGS) patients, all four DNA precursors are increased and markedly imbalanced with the largest effect on dGTP, a key player in the modulation of telomerase processivity. Here, we present data showing that SAMHD1, by restricting the dGTP pool, contributes to telomere maintenance in hTERT-immortalized human fibroblasts from AGS patients as well as in telomerase positive cancer cell lines. Only in cells expressing telomerase, the lack of SAMHD1 causes excessive lengthening of telomeres and telomere fragility, whereas primary fibroblasts lacking both SAMHD1 and telomerase enter normally into senescence. Telomere lengthening observed in SAMHD1 deficient but telomerase proficient cells is a gradual process, in accordance with the intrinsic property of telomerase of adding only a few tens of nucleotides for each cycle. Therefore, only a prolonged exposure to high dGTP content causes telomere over-elongation. hTERT-immortalized AGS fibroblasts display also high fragility of chromosome ends, a marker of telomere replication stress. These results not only demonstrate the functional importance of dGTP cellular level but also reveal the critical role played by SAMHD1 in restraining telomerase processivity and safeguarding telomere stability.
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Affiliation(s)
| | - Paola Ferraro
- Department of Biology, University of Padova, Padova, Italy
| | | | | | | | - Elisa Palumbo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Ettore Presot
- Department of Biology, University of Padova, Padova, Italy
| | - Antonella Russo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Vera Bianchi
- Department of Biology, University of Padova, Padova, Italy
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6
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Kaushik R, Arya A, Kumar D, Goel A, Rout PK. Genetic studies of heat stress regulation in goat during hot climatic condition. J Therm Biol 2023; 113:103528. [PMID: 37055132 DOI: 10.1016/j.jtherbio.2023.103528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 02/13/2023] [Accepted: 02/22/2023] [Indexed: 04/15/2023]
Abstract
Various direct and indirect environmental constraints have an impact on livestock performance. The physiological parameters, such as rectal temperature, heart rate, and respiratory rate, are the primary indicators of thermal stress. Under a stressed environment temperature humidity index (THI) had established as a vital measurement to identify the thermal stress in livestock. THI in association with climatic variations can define the environmental effect as stressful or comfortable for livestock. Goats are small ruminants that adapt to a wide range of ecological variations due to their anatomical and physiological characteristics. However, the productivity of animals declines at the individual level during thermal stress. Stress tolerance can be determined through genetic studies associated with at the cellular level using physiological as well as molecular approaches. Information on genetic association with thermal stress in goats is scanty, this severely affects their survival and hence productivity of livestock. The ever-increasing demand for food across the globe needs deciphering novel molecular markers as well as stress indicators that play a vital role in livestock improvement. This review represents an analysis of current knowledge of phenotypic differences during thermal stress and signifies the importance of physiological responses and their association at the cellular level in goats. The regulation of vital genes associated with thermal stress such as Aquaporins (AQP 0, 1, 2, 4, 5, 6, 8), aquaglyceroporins (AQP3, 7, 9, and 10) and super-aquaporins (AQP 11, 12); BAX inhibitors such as PERK (PKR like ER kinase), IRE 1(inositol-requiring-1); Redox regulating genes such as NOX; Transport of Na+ and K+ such as ATPase (ATP1A1) and several heat shock proteins have been implicated in heat-stress related adaptations have been elucidated. As these changes have a significant impact on production performance as well as on livestock productivity. Such efforts may help in the development of molecular markers and will assist the breeders to develop heat-tolerant goats with improved productivity.
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Affiliation(s)
- Rakesh Kaushik
- Animal Genetics and Breeding Division, ICAR- Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, U.P, India; Department of Biotechnology, 17km Stone, NH-2, Mathura-Delhi Road Mathura, Chaumuhan, 281406, U.P, India.
| | - Aditya Arya
- ICMR-National Institute for Malaria Research, Dwarka Sector- 8, New Delhi, 110077, India
| | - Devendra Kumar
- Department of Biotechnology, Keral Verma Subharti College of Science, Swami Vivekanand Subharti University, Meerut, 250005, U.P, India
| | - Anjana Goel
- Department of Biotechnology, 17km Stone, NH-2, Mathura-Delhi Road Mathura, Chaumuhan, 281406, U.P, India
| | - P K Rout
- Animal Genetics and Breeding Division, ICAR- Central Institute for Research on Goats, Makhdoom, Farah, Mathura, 281122, U.P, India.
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7
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Mannherz W, Agarwal S. Thymidine nucleotide metabolism controls human telomere length. Nat Genet 2023; 55:568-580. [PMID: 36959362 PMCID: PMC11000509 DOI: 10.1038/s41588-023-01339-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 02/21/2023] [Indexed: 03/25/2023]
Abstract
Telomere length in humans is associated with lifespan and severe diseases, yet the genetic determinants of telomere length remain incompletely defined. Here we performed genome-wide CRISPR-Cas9 functional telomere length screening and identified thymidine (dT) nucleotide metabolism as a limiting factor in human telomere maintenance. Targeted genetic disruption using CRISPR-Cas9 revealed multiple telomere length control points across the thymidine nucleotide metabolism pathway: decreasing dT nucleotide salvage via deletion of the gene encoding nuclear thymidine kinase (TK1) or de novo production by knockout of the thymidylate synthase gene (TYMS) decreased telomere length, whereas inactivation of the deoxynucleoside triphosphohydrolase-encoding gene SAMHD1 lengthened telomeres. Remarkably, supplementation with dT alone drove robust telomere elongation by telomerase in cells, and thymidine triphosphate stimulated telomerase activity in a substrate-independent manner in vitro. In induced pluripotent stem cells derived from patients with genetic telomere biology disorders, dT supplementation or inhibition of SAMHD1 promoted telomere restoration. Our results demonstrate a critical role of thymidine metabolism in controlling human telomerase and telomere length, which may be therapeutically actionable in patients with fatal degenerative diseases.
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Affiliation(s)
- William Mannherz
- Division of Hematology/Oncology and Stem Cell Program, Boston Children's Hospital, Boston, MA, USA
- Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Biological and Biomedical Sciences Program, Harvard/MIT MD-PhD Program, Harvard Stem Cell Institute, Harvard Initiative for RNA Medicine, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Suneet Agarwal
- Division of Hematology/Oncology and Stem Cell Program, Boston Children's Hospital, Boston, MA, USA.
- Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
- Biological and Biomedical Sciences Program, Harvard/MIT MD-PhD Program, Harvard Stem Cell Institute, Harvard Initiative for RNA Medicine, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
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8
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Sharma S, Kong Z, Jia S, Tran P, Nilsson AK, Chabes A. Quantitative Analysis of Nucleoside Triphosphate Pools in Mouse Muscle Using Hydrophilic Interaction Liquid Chromatography Coupled with Tandem Mass Spectrometry Detection. Methods Mol Biol 2023; 2615:267-280. [PMID: 36807798 DOI: 10.1007/978-1-0716-2922-2_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Defects in deoxyribonucleoside triphosphate (dNTP) metabolism are associated with a number of mitochondrial DNA (mtDNA) depletion syndromes (MDS). These disorders affect the muscles, liver, and brain, and the concentrations of dNTPs in these tissues are already normally low and are, therefore, difficult to measure. Thus, information about the concentrations of dNTPs in tissues of healthy animals and animals with MDS are important for mechanistic studies of mtDNA replication, analysis of disease progression, and the development of therapeutic interventions. Here, we present a sensitive method for the simultaneous analysis of all four dNTPs as well as all four ribonucleoside triphosphates (NTPs) in mouse muscles using hydrophilic interaction liquid chromatography coupled with triple quadrupole mass spectrometry. The simultaneous detection of NTPs allows them to be used as internal standards for the normalization of dNTP concentrations. The method can be applied for measuring dNTP and NTP pools in other tissues and organisms.
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Affiliation(s)
- Sushma Sharma
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Ziqing Kong
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Shaodong Jia
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Phong Tran
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Anna Karin Nilsson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden.
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Asim S, Mansha A, Aslam S, Shahzad A. Study of Interactions Between 3-benzoyl-4-hydroxy-2-methyl-2H-1, 2-benzothiazine and Human DNA by Theoretical, Spectroscopic and Viscometric measurements. J Fluoresc 2023; 33:311-326. [PMID: 36414920 DOI: 10.1007/s10895-022-03045-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 10/15/2022] [Indexed: 11/24/2022]
Abstract
From the last few years mode of interactions between drugs and DNA is an attractive research area as it bridges chemistry, molecular biology and medicinal science. Interactions between small heterocyclic molecules and human DNA is a noteworthy feature in pharmacology for investigation of drugs mechanism and designing of more effective and target specific drugs with fewer side effects. The present research work focuses on the theoretical investigations of 3-benzoyl-4-hydroxy-2-methyl-2H-1, 2-benzothiazine (SASA) by using Gaussian (16 W) software to predict optimized geometry, HOMO-LUMO gap, bond length, bond angle, dihedral angle, electronic and vibrational spectra. Possible reaction site observed in SASA was C7, C9 and C18 as these atoms show maximum charge density. Later the interactions of SASA with human DNA was explored spectroscopic investigations and viscometric investigations at physiological buffers of pH of 4.7 (stomach pH) and 7.4 (blood pH) respectively. Maximum absorbance between SASA-DNA complex was observed in buffer solution of pH 3.4 at wavelength of 370 nm, whereas at 7.4 has maximim absorbance between. Spectroscopic results reflects the bathochromic and hyperchromic shift succeeding the addition of human DNA. During viscosity measurement, intercalation and electrostatic mode of interaction were detected at low and high concentration of drug in solution respectively. Increase in the value of rate constant was observed with the increase in concentration of drug. Larger values of rate constant were observed at pH 7.4 in comparison to pH 3.5. Rate constant, thermodynamic parameters and viscometric analysis prefers the intake of SASA via blood.
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Affiliation(s)
- Sadia Asim
- Department of Chemistry, Government College Women University, Faisalabad, Pakistan.
| | - Asim Mansha
- Department of Chemistry, Government College University, Faisalabad, Pakistan
| | - Sana Aslam
- Department of Chemistry, Government College Women University, Faisalabad, Pakistan
| | - Alina Shahzad
- Department of Chemistry, Government College Women University, Faisalabad, Pakistan
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10
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Borror MB, Girotti M, Kar A, Cain MK, Gao X, MacKay VL, Herron B, Bhaskaran S, Becerra S, Novy N, Ventura N, Johnson TE, Kennedy BK, Rea SL. Inhibition of ATR Reverses a Mitochondrial Respiratory Insufficiency. Cells 2022; 11:1731. [PMID: 35681427 PMCID: PMC9179431 DOI: 10.3390/cells11111731] [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: 04/26/2022] [Revised: 05/15/2022] [Accepted: 05/21/2022] [Indexed: 02/04/2023] Open
Abstract
Diseases that affect the mitochondrial electron transport chain (ETC) often manifest as threshold effect disorders, meaning patients only become symptomatic once a certain level of ETC dysfunction is reached. Cells can invoke mechanisms to circumvent reaching their critical ETC threshold, but it is an ongoing challenge to identify such processes. In the nematode Caenorhabditis elegans, severe reduction of mitochondrial ETC activity shortens life, but mild reduction actually extends it, providing an opportunity to identify threshold circumvention mechanisms. Here, we show that removal of ATL-1, but not ATM-1, worm orthologs of ATR and ATM, respectively, key nuclear DNA damage checkpoint proteins in human cells, unexpectedly lessens the severity of ETC dysfunction. Multiple genetic and biochemical tests show no evidence for increased mutation or DNA breakage in animals exposed to ETC disruption. Reduced ETC function instead alters nucleotide ratios within both the ribo- and deoxyribo-nucleotide pools, and causes stalling of RNA polymerase, which is also known to activate ATR. Unexpectedly, atl-1 mutants confronted with mitochondrial ETC disruption maintain normal levels of oxygen consumption, and have an increased abundance of translating ribosomes. This suggests checkpoint signaling by ATL-1 normally dampens cytoplasmic translation. Taken together, our data suggest a model whereby ETC insufficiency in C. elegans results in nucleotide imbalances leading to the stalling of RNA polymerase, activation of ATL-1, dampening of global translation, and magnification of ETC dysfunction. The loss of ATL-1 effectively reverses the severity of ETC disruption so that animals become phenotypically closer to wild type.
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Affiliation(s)
- Megan B. Borror
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; (M.B.B.); (M.G.); (A.K.); (M.K.C.); (S.B.); (S.B.)
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Milena Girotti
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; (M.B.B.); (M.G.); (A.K.); (M.K.C.); (S.B.); (S.B.)
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Adwitiya Kar
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; (M.B.B.); (M.G.); (A.K.); (M.K.C.); (S.B.); (S.B.)
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Meghan K. Cain
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; (M.B.B.); (M.G.); (A.K.); (M.K.C.); (S.B.); (S.B.)
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Xiaoli Gao
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA;
| | - Vivian L. MacKay
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; (V.L.M.); (B.K.K.)
| | - Brent Herron
- Institute for Behavioral Genetics, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; (B.H.); (T.E.J.)
| | - Shylesh Bhaskaran
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; (M.B.B.); (M.G.); (A.K.); (M.K.C.); (S.B.); (S.B.)
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Sandra Becerra
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; (M.B.B.); (M.G.); (A.K.); (M.K.C.); (S.B.); (S.B.)
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Nathan Novy
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA;
| | - Natascia Ventura
- IUF—Leibniz Research Institute for Environmental Medicine, 103045 Düsseldorf, Germany;
- Institute for Clinical Chemistry and Laboratory Diagnostic, Medical Faculty of the Heinrich Heine University, 103045 Düsseldorf, Germany
| | - Thomas E. Johnson
- Institute for Behavioral Genetics, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309, USA; (B.H.); (T.E.J.)
| | - Brian K. Kennedy
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; (V.L.M.); (B.K.K.)
- Buck Institute for Research on Aging, Novato, CA 94945, USA
- Departments of Biochemistry and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117542, Singapore
| | - Shane L. Rea
- The Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; (M.B.B.); (M.G.); (A.K.); (M.K.C.); (S.B.); (S.B.)
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA;
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11
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Telomere length and telomere repeat-binding protein in children with sickle cell disease. Pediatr Res 2022; 91:539-544. [PMID: 33824452 PMCID: PMC8904250 DOI: 10.1038/s41390-021-01495-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 03/08/2021] [Accepted: 03/11/2021] [Indexed: 02/01/2023]
Abstract
BACKGROUND This study aimed to assess the telomere length and plasma telomere repeat-binding factor 2 (TRF2) levels in addition to other inflammatory markers in children with sickle cell disease (SCD). METHODS We enrolled 106 children (90 SCD and 26 controls) aged 1-15 years from the Hematology unit of King Fahad Medical City (KFMC), Saudi Arabia. Genomic DNA extracted from blood and leukocyte TL was determined using quantitative reverse transcription PCR, whereas TRF2, C-reactive protein, interleukin-6, and DNA oxidative damage were determined by using respective commercially available assays. RESULTS Leukocyte TL was inversely correlated with age in the SCD patients (r = -0.24, P = 0.02) and the controls (r = -0.68, P < 0.0001). In addition, SCD patients had significantly shorter TL (7.74 ± 0.81 kb) (P = 0.003) than controls (8.28 ± 0.73 kb). In contrast, no significant difference in TL among the SCD genotypes (HbSS and HbSβ0) has been observed. A modest, positive correlation was seen between TL and reticulocyte % (r = 0.21; P = 0.06). There were no significant differences in the TL and TRF2 concentrations between subjects with HbSS and HbSβ0 genotypes. CONCLUSIONS Short leukocyte TL was significantly associated with SCD. An inverse association was observed between TL and hemoglobin. Hydroxyurea treatment revealed no impact on TL. IMPACT This study explored the TL and plasma TRF2 in Saudi children with SCD. This is the first documentation that SCD children have shorter TL than their healthy counterparts, and no association between TL and TRF2 has been observed. Hydroxyurea treatment showed no impact on TL in children with SCD. This study is the first of its kind in children with SCD. It will pave the way for another study with a larger sample size in a diverse population to scrutinize these findings better.
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12
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Haluska C, Jin F, Wang Y. Protein phosphatase 2A (PP2A) promotes anaphase entry after DNA replication stress in budding yeast. Mol Biol Cell 2021; 32:ar36. [PMID: 34668760 PMCID: PMC8694091 DOI: 10.1091/mbc.e21-04-0222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 10/01/2021] [Accepted: 10/05/2021] [Indexed: 12/31/2022] Open
Abstract
DNA replication stress activates the S-phase checkpoint that arrests the cell cycle, but it is poorly understood how cells recover from this arrest. Cyclin-dependent kinase (CDK) and protein phosphatase 2A (PP2A) are key cell cycle regulators, and Cdc55 is a regulatory subunit of PP2A in budding yeast. We found that yeast cells lacking functional PP2ACdc55 showed slow growth in the presence of hydroxyurea (HU), a DNA synthesis inhibitor, without obvious viability loss. Moreover, PP2A mutants exhibited delayed anaphase entry and sustained levels of anaphase inhibitor Pds1 after HU treatment. A DNA damage checkpoint Chk1 phosphorylates and stabilizes Pds1. We show that chk1Δ and mutation of the Chk1 phosphorylation sites in Pds1 largely restored efficient anaphase entry in PP2A mutants after HU treatment. In addition, deletion of SWE1, which encodes the inhibitory kinase for CDK or mutation of the Swe1 phosphorylation site in CDK (cdc28F19), also suppressed the anaphase entry delay in PP2A mutants after HU treatment. Our genetic data suggest that Swe1/CDK acts upstream of Pds1. Surprisingly, cdc55Δ showed significant suppression to the viability loss of S-phase checkpoint mutants during DNA synthesis block. Together, our results uncover a PP2A-Swe1-CDK-Chk1-Pds1 axis that promotes recovery from DNA replication stress.
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Affiliation(s)
- Cory Haluska
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306-4300
| | - Fengzhi Jin
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306-4300
| | - Yanchang Wang
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL 32306-4300
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13
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Bose S, Suescún AV, Song J, Castillo-González C, Aklilu BB, Branham E, Lynch R, Shippen DE. tRNA ADENOSINE DEAMINASE 3 is required for telomere maintenance in Arabidopsis thaliana. PLANT CELL REPORTS 2020; 39:1669-1685. [PMID: 32959123 PMCID: PMC7655638 DOI: 10.1007/s00299-020-02594-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/04/2020] [Indexed: 05/05/2023]
Abstract
KEY MESSAGE: tRNA Adenosine Deaminase 3 helps to sustain telomere tracts in a telomerase-independent fashion, likely through regulating cellular metabolism. Telomere length maintenance is influenced by a complex web of chromatin and metabolism-related factors. We previously reported that a lncRNA termed AtTER2 regulates telomerase activity in Arabidopsis thaliana in response to DNA damage. AtTER2 was initially shown to partially overlap with the 5' UTR of the tRNA ADENOSINE DEAMINASE 3 (TAD3) gene. However, updated genome annotation showed that AtTER2 was completely embedded in TAD3, raising the possibility that phenotypes ascribed to AtTER2 could be derived from TAD3. Here we show through strand-specific RNA-Seq, strand-specific qRT-PCR and bioinformatic analyses that AtTER2 does not encode a stable lncRNA. Further examination of the original tad3 (ter2-1/tad3-1) mutant revealed expression of an antisense transcript driven by a cryptic promoter in the T-DNA. Hence, a new hypomorphic allele of TAD3 (tad3-2) was examined. tad3-2 mutants showed hypersensitivity to DNA damage, but no deregulation of telomerase, suggesting that the telomerase phenotype of tad3-1 mutants reflects an off-target effect. Unexpectedly, however, tad3-2 plants displayed progressive loss of telomeric DNA over successive generations that was not accompanied by alteration of terminal architecture or end protection. The phenotype was exacerbated in plants lacking the telomerase processivity factor POT1a, indicating that TAD3 promotes telomere maintenance through a non-canonical, telomerase-independent pathway. The transcriptome of tad3-2 mutants revealed significant dysregulation of genes involved in auxin signaling and glucosinolate biosynthesis, pathways that intersect the stress response, cell cycle regulation and DNA metabolism. These findings indicate that the TAD3 locus indirectly contributes to telomere length homeostasis by altering the metabolic profile in Arabidopsis.
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Affiliation(s)
- Sreyashree Bose
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Ana Victoria Suescún
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
- Facultad de Ciencias, Instituto de Ciencias Ambientales Y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
| | - Jiarui Song
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | | | - Behailu Birhanu Aklilu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
- KWS Gateway Research Center, LLC, 1005 N Warson Rd, BRDG Park, St. Louis, MO, 63132, USA
| | - Erica Branham
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Ryan Lynch
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Dorothy E Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA.
- Department of Biochemistry and Biophysics, 300 Olsen Blvd, Room 413, College Station, TX, 77843-2128, USA.
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14
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Cerritelli SM, El Hage A. RNases H1 and H2: guardians of the stability of the nuclear genome when supply of dNTPs is limiting for DNA synthesis. Curr Genet 2020; 66:1073-1084. [PMID: 32886170 DOI: 10.1007/s00294-020-01086-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/30/2020] [Accepted: 06/01/2020] [Indexed: 11/29/2022]
Abstract
RNA/DNA hybrids are processed by RNases H1 and H2, while single ribonucleoside-monophosphates (rNMPs) embedded in genomic DNA are removed by the error-free, RNase H2-dependent ribonucleotide excision repair (RER) pathway. In the absence of RER, however, topoisomerase 1 (Top1) can cleave single genomic rNMPs in a mutagenic manner. In RNase H2-deficient mice, the accumulation of genomic rNMPs above a threshold of tolerance leads to catastrophic genomic instability that causes embryonic lethality. In humans, deficiencies in RNase H2 induce the autoimmune disorders Aicardi-Goutières syndrome and systemic lupus erythematosus, and cause skin and intestinal cancers. Recently, we reported that in Saccharomyces cerevisiae, the depletion of Rnr1, the major catalytic subunit of ribonucleotide reductase (RNR), which converts ribonucleotides to deoxyribonucleotides, leads to cell lethality in absence of RNases H1 and H2. We hypothesized that under replicative stress and compromised DNA repair that are elicited by an insufficient supply of deoxyribonucleoside-triphosphates (dNTPs), cells cannot survive the accumulation of persistent RNA/DNA hybrids. Remarkably, we found that cells lacking RNase H2 accumulate ~ 5-fold more genomic rNMPs in absence than in presence of Rnr1. When the load of genomic rNMPs is further increased in the presence of a replicative DNA polymerase variant that over-incorporates rNMPs in leading or lagging strand, cells missing both Rnr1 and RNase H2 suffer from severe growth defects. These are reversed in absence of Top1. Thus, in cells lacking RNase H2 and containing a limiting supply of dNTPs, there is a threshold of tolerance for the accumulation of genomic ribonucleotides that is tightly associated with Top1-mediated DNA damage. In this mini-review, we describe the implications of the loss of RNase H2, or RNases H1 and H2, on the integrity of the nuclear genome and viability of budding yeast cells that are challenged with a critically low supply of dNTPs. We further propose that our findings in budding yeast could pave the way for the study of the potential role of mammalian RNR in RNase H2-related diseases.
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Affiliation(s)
- Susana M Cerritelli
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Aziz El Hage
- The Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK.
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15
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Szabó JE, Surányi ÉV, Mébold BS, Trombitás T, Cserepes M, Tóth J. A user-friendly, high-throughput tool for the precise fluorescent quantification of deoxyribonucleoside triphosphates from biological samples. Nucleic Acids Res 2020; 48:e45. [PMID: 32103262 PMCID: PMC7192609 DOI: 10.1093/nar/gkaa116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 02/05/2020] [Accepted: 02/17/2020] [Indexed: 12/24/2022] Open
Abstract
Cells maintain a fine-tuned, dynamic concentration balance in the pool of deoxyribonucleoside 5′-triphosphates (dNTPs). This balance is essential for physiological processes including cell cycle control or antiviral defense. Its perturbation results in increased mutation frequencies, replication arrest and may promote cancer development. An easily accessible and relatively high-throughput method would greatly accelerate the exploration of the diversified consequences of dNTP imbalances. The dNTP incorporation based, fluorescent TaqMan-like assay published by Wilson et al. has the aforementioned advantages over mass spectrometry, radioactive or chromatography based dNTP quantification methods. Nevertheless, the assay failed to produce reliable data in several biological samples. Therefore, we applied enzyme kinetics analysis on the fluorescent dNTP incorporation curves and found that the Taq polymerase exhibits a dNTP independent exonuclease activity that decouples signal generation from dNTP incorporation. Furthermore, we found that both polymerization and exonuclease activities are unpredictably inhibited by the sample matrix. To resolve these issues, we established a kinetics based data analysis method which identifies the signal generated by dNTP incorporation. We automated the analysis process in the nucleoTIDY software which enables even the inexperienced user to calculate the final and accurate dNTP amounts in a 96-well-plate setup within minutes.
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Affiliation(s)
- Judit Eszter Szabó
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest 1117, Hungary.,Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest 1111, Hungary
| | - Éva Viola Surányi
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest 1117, Hungary.,Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest 1111, Hungary
| | - Bence Sándor Mébold
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest 1117, Hungary
| | - Tamás Trombitás
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest 1117, Hungary.,Department of Applied Biotechnology and Food Sciences, Budapest University of Technology and Economics, Budapest 1111, Hungary
| | - Mihály Cserepes
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest 1117, Hungary.,Department of Experimental Pharmacology, National Institute of Oncology, Budapest, Hungary
| | - Judit Tóth
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest 1117, Hungary
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16
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Cerritelli SM, Iranzo J, Sharma S, Chabes A, Crouch RJ, Tollervey D, El Hage A. High density of unrepaired genomic ribonucleotides leads to Topoisomerase 1-mediated severe growth defects in absence of ribonucleotide reductase. Nucleic Acids Res 2020; 48:4274-4297. [PMID: 32187369 PMCID: PMC7192613 DOI: 10.1093/nar/gkaa103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 12/12/2022] Open
Abstract
Cellular levels of ribonucleoside triphosphates (rNTPs) are much higher than those of deoxyribonucleoside triphosphates (dNTPs), thereby influencing the frequency of incorporation of ribonucleoside monophosphates (rNMPs) by DNA polymerases (Pol) into DNA. RNase H2-initiated ribonucleotide excision repair (RER) efficiently removes single rNMPs in genomic DNA. However, processing of rNMPs by Topoisomerase 1 (Top1) in absence of RER induces mutations and genome instability. Here, we greatly increased the abundance of genomic rNMPs in Saccharomyces cerevisiae by depleting Rnr1, the major subunit of ribonucleotide reductase, which converts ribonucleotides to deoxyribonucleotides. We found that in strains that are depleted of Rnr1, RER-deficient, and harbor an rNTP-permissive replicative Pol mutant, excessive accumulation of single genomic rNMPs severely compromised growth, but this was reversed in absence of Top1. Thus, under Rnr1 depletion, limited dNTP pools slow DNA synthesis by replicative Pols and provoke the incorporation of high levels of rNMPs in genomic DNA. If a threshold of single genomic rNMPs is exceeded in absence of RER and presence of limited dNTP pools, Top1-mediated genome instability leads to severe growth defects. Finally, we provide evidence showing that accumulation of RNA/DNA hybrids in absence of RNase H1 and RNase H2 leads to cell lethality under Rnr1 depletion.
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Affiliation(s)
- Susana M Cerritelli
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Jaime Iranzo
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Sushma Sharma
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå SE-901 87, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå SE-901 87, Sweden
| | - Robert J Crouch
- SFR, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - David Tollervey
- The Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Aziz El Hage
- The Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
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17
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Schmidt TT, Sharma S, Reyes GX, Kolodziejczak A, Wagner T, Luke B, Hofer A, Chabes A, Hombauer H. Inactivation of folylpolyglutamate synthetase Met7 results in genome instability driven by an increased dUTP/dTTP ratio. Nucleic Acids Res 2020; 48:264-277. [PMID: 31647103 PMCID: PMC7145683 DOI: 10.1093/nar/gkz1006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 10/11/2019] [Accepted: 10/16/2019] [Indexed: 12/14/2022] Open
Abstract
The accumulation of mutations is frequently associated with alterations in gene function leading to the onset of diseases, including cancer. Aiming to find novel genes that contribute to the stability of the genome, we screened the Saccharomyces cerevisiae deletion collection for increased mutator phenotypes. Among the identified genes, we discovered MET7, which encodes folylpolyglutamate synthetase (FPGS), an enzyme that facilitates several folate-dependent reactions including the synthesis of purines, thymidylate (dTMP) and DNA methylation. Here, we found that Met7-deficient strains show elevated mutation rates, but also increased levels of endogenous DNA damage resulting in gross chromosomal rearrangements (GCRs). Quantification of deoxyribonucleotide (dNTP) pools in cell extracts from met7Δ mutant revealed reductions in dTTP and dGTP that cause a constitutively active DNA damage checkpoint. In addition, we found that the absence of Met7 leads to dUTP accumulation, at levels that allowed its detection in yeast extracts for the first time. Consequently, a high dUTP/dTTP ratio promotes uracil incorporation into DNA, followed by futile repair cycles that compromise both mitochondrial and nuclear DNA integrity. In summary, this work highlights the importance of folate polyglutamylation in the maintenance of nucleotide homeostasis and genome stability.
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Affiliation(s)
- Tobias T Schmidt
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), Heidelberg D-69120, Germany.,Faculty of Bioscience, Heidelberg University, Heidelberg D-69120, Germany
| | - Sushma Sharma
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå SE-901 87 Sweden
| | - Gloria X Reyes
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), Heidelberg D-69120, Germany
| | - Anna Kolodziejczak
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), Heidelberg D-69120, Germany.,Faculty of Bioscience, Heidelberg University, Heidelberg D-69120, Germany
| | - Tina Wagner
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg Universität, 55128 Mainz, Germany
| | - Brian Luke
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg Universität, 55128 Mainz, Germany.,Institute of Molecular Biology (IMB), 55128 Mainz, Germany
| | - Anders Hofer
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå SE-901 87 Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå SE-901 87 Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 87 Umeå, Sweden
| | - Hans Hombauer
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), Heidelberg D-69120, Germany
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18
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Abstract
Stress exposure can leave long-term footprints within the organism, like in telomeres (TLs), protective chromosome caps that shorten during cell replication and following exposure to stressors. Short TLs are considered to indicate lower fitness prospects, but why TLs shorten under stressful conditions is not understood. Glucocorticoid hormones (GCs) increase upon stress exposure and are thought to promote TL shortening by increasing oxidative damage. However, evidence that GCs are pro-oxidants and oxidative stress is causally linked to TL attrition is mixed . Based on new biochemical findings, we propose the metabolic telomere attrition hypothesis: during times of substantially increased energy demands, TLs are shortened as part of the transition into an organismal 'emergency state', which prioritizes immediate survival functions over processes with longer-term benefits. TL attrition during energy shortages could serve multiple roles including amplified signalling of cellular energy debt to re-direct critical resources to immediately important processes. This new view of TL shortening as a strategy to resolve major energetic trade-offs can improve our understanding of TL dynamics. We suggest that TLs are master regulators of cell homeostasis and propose future research avenues to understand the interactions between energy homeostasis, metabolic regulators and TL.
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Affiliation(s)
- Stefania Casagrande
- 1 Research Group Evolutionary Physiology, Max Planck Institute for Ornithology , 82319 Seewiesen , Germany
| | - Michaela Hau
- 1 Research Group Evolutionary Physiology, Max Planck Institute for Ornithology , 82319 Seewiesen , Germany.,2 Department of Biology, University of Konstanz , D-78457 Konstanz , Germany
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19
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Keener R, Connelly CJ, Greider CW. Tel1 Activation by the MRX Complex Is Sufficient for Telomere Length Regulation but Not for the DNA Damage Response in Saccharomyces cerevisiae. Genetics 2019; 213:1271-1288. [PMID: 31645360 PMCID: PMC6893380 DOI: 10.1534/genetics.119.302713] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/17/2019] [Indexed: 12/26/2022] Open
Abstract
Previous models suggested that regulation of telomere length in Saccharomyces cerevisiae by Tel1(ATM) and Mec1(ATR) would parallel the established pathways regulating the DNA damage response. Here, we provide evidence that telomere length regulation differs from the DNA damage response in both the Tel1 and Mec1 pathways. We found that Rad53 mediates a Mec1 telomere length regulation pathway but is dispensable for Tel1 telomere length regulation, whereas in the DNA damage response, Rad53 is regulated by both Mec1 and Tel1 Using epistasis analysis with a Tel1 hypermorphic allele, Tel1-hy909, we found that the MRX complex is not required downstream of Tel1 for telomere elongation but is required downstream of Tel1 for the DNA damage response. Our data suggest that nucleolytic telomere end processing is not a required step for telomerase to elongate telomeres.
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Affiliation(s)
- Rebecca Keener
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Carla J Connelly
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Carol W Greider
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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20
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Schmidt TT, Sharma S, Reyes GX, Gries K, Gross M, Zhao B, Yuan JH, Wade R, Chabes A, Hombauer H. A genetic screen pinpoints ribonucleotide reductase residues that sustain dNTP homeostasis and specifies a highly mutagenic type of dNTP imbalance. Nucleic Acids Res 2019; 47:237-252. [PMID: 30462295 PMCID: PMC6326808 DOI: 10.1093/nar/gky1154] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 10/29/2018] [Indexed: 12/12/2022] Open
Abstract
The balance and the overall concentration of intracellular deoxyribonucleoside triphosphates (dNTPs) are important determinants of faithful DNA replication. Despite the established fact that changes in dNTP pools negatively influence DNA replication fidelity, it is not clear why certain dNTP pool alterations are more mutagenic than others. As intracellular dNTP pools are mainly controlled by ribonucleotide reductase (RNR), and given the limited number of eukaryotic RNR mutations characterized so far, we screened for RNR1 mutations causing mutator phenotypes in Saccharomyces cerevisiae. We identified 24 rnr1 mutant alleles resulting in diverse mutator phenotypes linked in most cases to imbalanced dNTPs. Among the identified rnr1 alleles the strongest mutators presented a dNTP imbalance in which three out of the four dNTPs were elevated (dCTP, dTTP and dGTP), particularly if dGTP levels were highly increased. These rnr1 alleles caused growth defects/lethality in DNA replication fidelity-compromised backgrounds, and caused strong mutator phenotypes even in the presence of functional DNA polymerases and mismatch repair. In summary, this study pinpoints key residues that contribute to allosteric regulation of RNR’s overall activity or substrate specificity. We propose a model that distinguishes between different dNTP pool alterations and provides a mechanistic explanation why certain dNTP imbalances are particularly detrimental.
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Affiliation(s)
- Tobias T Schmidt
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), Heidelberg D-69120, Germany.,Faculty of Bioscience, Heidelberg University, Heidelberg D-69120, Germany
| | - Sushma Sharma
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå SE-901 87 Sweden
| | - Gloria X Reyes
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), Heidelberg D-69120, Germany
| | - Kerstin Gries
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), Heidelberg D-69120, Germany
| | - Maike Gross
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), Heidelberg D-69120, Germany
| | - Boyu Zhao
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), Heidelberg D-69120, Germany.,Faculty of Bioscience, Heidelberg University, Heidelberg D-69120, Germany
| | - Jui-Hung Yuan
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Heidelberg D-69118, Germany
| | - Rebecca Wade
- Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), Heidelberg D-69118, Germany.,Interdisciplinary Center for Scientific Computing (IWR), Heidelberg D-69120, Germany.,Center for Molecular Biology of the University of Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg D-69120, Germany
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå SE-901 87 Sweden.,Laboratory for Molecular Infection Medicine Sweden, Umeå University, Umeå SE-901 87, Sweden
| | - Hans Hombauer
- DNA Repair Mechanisms and Cancer, German Cancer Research Center (DKFZ), Heidelberg D-69120, Germany
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21
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Kong Z, Jia S, Chabes AL, Appelblad P, Lundmark R, Moritz T, Chabes A. Simultaneous determination of ribonucleoside and deoxyribonucleoside triphosphates in biological samples by hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry. Nucleic Acids Res 2019; 46:e66. [PMID: 29554314 PMCID: PMC6009580 DOI: 10.1093/nar/gky203] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 03/08/2018] [Indexed: 11/13/2022] Open
Abstract
Information about the intracellular concentration of dNTPs and NTPs is important for studies of the mechanisms of DNA replication and repair, but the low concentration of dNTPs and their chemical similarity to NTPs present a challenge for their measurement. Here, we describe a new rapid and sensitive method utilizing hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry for the simultaneous determination of dNTPs and NTPs in biological samples. The developed method showed linearity (R2 > 0.99) in wide concentration ranges and could accurately quantify dNTPs and NTPs at low pmol levels. The intra-day and inter-day precision were below 13%, and the relative recovery was between 92% and 108%. In comparison with other chromatographic methods, the current method has shorter analysis times and simpler sample pre-treatment steps, and it utilizes an ion-pair-free mobile phase that enhances mass-spectrometric detection. Using this method, we determined dNTP and NTP concentrations in actively dividing and quiescent mouse fibroblasts.
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Affiliation(s)
- Ziqing Kong
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Shaodong Jia
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Anna Lena Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Patrik Appelblad
- Department of Pharmacology and Clinical Neuroscience, Umeå University, SE-901 87, Umeå, Sweden.,Merck Chemicals and Life Science AB, SE 169-03 Solna, Sweden
| | - Richard Lundmark
- Dept. of Integrative Medical Biology, Umeå University, SE-901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 87 Umeå, Sweden
| | - Thomas Moritz
- Umeå Plant Science Centre (UPSC), Dept. of Forest Genetics and Plant Physiology, SLU, SE-901 87 Umeå, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden.,Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, SE-901 87 Umeå, Sweden
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22
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Upregulation of dNTP Levels After Telomerase Inactivation Influences Telomerase-Independent Telomere Maintenance Pathway Choice in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2018; 8:2551-2558. [PMID: 29848621 PMCID: PMC6071591 DOI: 10.1534/g3.118.200280] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In 10–15% of cancers, telomere length is maintained by a telomerase-independent, recombination-mediated pathway called alternative lengthening of telomeres (ALT). ALT mechanisms were first seen, and have been best studied, in telomerase-null Saccharomyces cerevisiae cells called “survivors”. There are two main types of survivors. Type I survivors amplify Y′ subtelomeric elements while type II survivors, similar to the majority of human ALT cells, amplify the terminal telomeric repeats. Both types of survivors require Rad52, a key homologous recombination protein, and Pol32, a non-essential subunit of DNA polymerase δ. A number of additional proteins have been reported to be important for either type I or type II survivor formation, but it is still unclear how these two pathways maintain telomeres. In this study, we performed a genome-wide screen to identify novel genes that are important for the formation of type II ALT-like survivors. We identified 23 genes that disrupt type II survivor formation when deleted. 17 of these genes had not been previously reported to do so. Several of these genes (DUN1, CCR4, and MOT2) are known to be involved in the regulation of dNTP levels. We find that dNTP levels are elevated early after telomerase inactivation and that this increase favors the formation of type II survivors.
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23
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Barrientos-Moreno M, Murillo-Pineda M, Muñoz-Cabello AM, Prado F. Histone depletion prevents telomere fusions in pre-senescent cells. PLoS Genet 2018; 14:e1007407. [PMID: 29879139 PMCID: PMC5991667 DOI: 10.1371/journal.pgen.1007407] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 05/09/2018] [Indexed: 12/20/2022] Open
Abstract
Upon telomerase inactivation, telomeres gradually shorten with each cell division until cells enter replicative senescence. In Saccharomyces cerevisiae, the kinases Mec1/ATR and Tel1/ATM protect the genome during pre-senescence by preventing telomere-telomere fusions (T-TFs) and the subsequent genetic instability associated with fusion-bridge-breakage cycles. Here we report that T-TFs in mec1Δ tel1Δ cells can be suppressed by reducing the pool of available histones. This protection associates neither with changes in bulk telomere length nor with major changes in the structure of subtelomeric chromatin. We show that the absence of Mec1 and Tel1 strongly augments double-strand break (DSB) repair by non-homologous end joining (NHEJ), which might contribute to the high frequency of T-TFs in mec1Δ tel1Δ cells. However, histone depletion does not prevent telomere fusions by inhibiting NHEJ, which is actually increased in histone-depleted cells. Rather, histone depletion protects telomeres from fusions by homologous recombination (HR), even though HR is proficient in maintaining the proliferative state of pre-senescent mec1Δ tel1Δ cells. Therefore, HR during pre-senescence not only helps stalled replication forks but also prevents T-TFs by a mechanism that, in contrast to the previous one, is promoted by a reduction in the histone pool and can occur in the absence of Rad51. Our results further suggest that the Mec1-dependent depletion of histones that occurs during pre-senescence in cells without telomerase (tlc1Δ) prevents T-TFs by favoring the processing of unprotected telomeres by Rad51-independent HR. Telomere shortening upon telomerase inactivation leads to an irreversible cell division arrest known as replicative senescence, which is considered as a tumor suppressor mechanism. Since pre-senescence is critical for tissue homeostasis, cells are endowed with recombination mechanisms that facilitate the replication of short telomeres and prevent premature entry into senescence. Consequently, pre-senescent cells divide with critically short telomeres, which have lost most of their shelterin proteins. The tumor suppressor genes ATR and ATM, as well as their yeast homologs Mec1 and Tel1, prevent telomere fusions during pre-senescence by unknown mechanisms. Here we show that the absence of Mec1 and Tel1 strongly augments DSB repair by non-homologous end joining, which might explain the high rate of telomere fusions in mec1Δ tel1Δ cells. Moreover, we show that a reduction in the pool of available histones prevents telomere fusions in mec1Δ tel1Δ cells by stimulating Rad51-independent homologous recombination. Our results suggest that the Mec1-dependent process of histone depletion that accompanies pre-senescence in cells lacking telomerase activity is required to prevent telomere fusions by promoting the processing of unprotected telomeres by recombination instead of non-homologous end joining.
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Affiliation(s)
- Marta Barrientos-Moreno
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), CSIC-University of Seville-University Pablo de Olavide, Seville, Spain
| | - Marina Murillo-Pineda
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), CSIC-University of Seville-University Pablo de Olavide, Seville, Spain
| | - Ana M. Muñoz-Cabello
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), CSIC-University of Seville-University Pablo de Olavide, Seville, Spain
| | - Félix Prado
- Department of Genome Biology, Andalusian Molecular Biology and Regenerative Medicine Center (CABIMER), CSIC-University of Seville-University Pablo de Olavide, Seville, Spain
- * E-mail:
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24
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Maicher A, Kupiec M. Rnr1's role in telomere elongation cannot be replaced by Rnr3: a role beyond dNTPs? Curr Genet 2017; 64:547-550. [PMID: 29119271 DOI: 10.1007/s00294-017-0779-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 11/03/2017] [Indexed: 11/29/2022]
Abstract
Telomeres, the nucleoprotein complexes at the end of eukaryotic chromosomes, protect them from degradation and ensure the replicative capacity of cells. In most human tumors and in budding yeast, telomere length is maintained by the activity of telomerase, an enzyme that adds dNTPs according to an internal RNA template. The dNTPs are generated with the help of the ribonucleotide reductase (RNR) complex. We have recently generated strains lacking the large subunit of RNR, Rnr1, which were kept viable by the expression of RNR complexes containing the Rnr1 homolog, Rnr3. Interestingly, we found that these Rnr1-deficient strains have short telomeres that are stably maintained, but cannot become efficiently elongated by telomerase. Thus, a basic maintenance of short telomeres is possible under conditions, where Rnr1 activity is absent, but a sustained elongation of short telomeres fully depends on Rnr1 activity. We show that Rnr3 cannot compensate for this telomeric function of Rnr1 even when overall cellular dNTP values are restored. This suggests that Rnr1 plays a role in telomere elongation beyond increasing cellular dNTP levels. Furthermore, our data indicate that telomerase may act in two different modes, one that is capable of coping with the "end-replication problem" and is functional even in the absence of Rnr1 and another required for the sustained elongation of short telomeres, which fully depends on the presence of Rnr1. Supply of dNTPs for telomere elongation is provided by the Mec1ATR checkpoint, both during regular DNA replication and upon replication fork stalling. We discuss the implications of these results on telomere maintenance in yeast and cancer cells.
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Affiliation(s)
- André Maicher
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel
| | - Martin Kupiec
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, 6997801, Israel.
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25
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Maicher A, Gazy I, Sharma S, Marjavaara L, Grinberg G, Shemesh K, Chabes A, Kupiec M. Rnr1, but not Rnr3, facilitates the sustained telomerase-dependent elongation of telomeres. PLoS Genet 2017; 13:e1007082. [PMID: 29069086 PMCID: PMC5673236 DOI: 10.1371/journal.pgen.1007082] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/06/2017] [Accepted: 10/18/2017] [Indexed: 12/25/2022] Open
Abstract
Ribonucleotide reductase (RNR) provides the precursors for the generation of dNTPs, which are required for DNA synthesis and repair. Here, we investigated the function of the major RNR subunits Rnr1 and Rnr3 in telomere elongation in budding yeast. We show that Rnr1 is essential for the sustained elongation of short telomeres by telomerase. In the absence of Rnr1, cells harbor very short, but functional, telomeres, which cannot become elongated by increased telomerase activity or by tethering of telomerase to telomeres. Furthermore, we demonstrate that Rnr1 function is critical to prevent an early onset of replicative senescence and premature survivor formation in telomerase-negative cells but dispensable for telomere elongation by Homology-Directed-Repair. Our results suggest that telomerase has a "basal activity" mode that is sufficient to compensate for the “end-replication-problem” and does not require the presence of Rnr1 and a different "sustained activity" mode necessary for the elongation of short telomeres, which requires an upregulation of dNTP levels and dGTP ratios specifically through Rnr1 function. By analyzing telomere length and dNTP levels in different mutants showing changes in RNR complex composition and activity we provide evidence that the Mec1ATR checkpoint protein promotes telomere elongation by increasing both dNTP levels and dGTP ratios through Rnr1 upregulation in a mechanism that cannot be replaced by its homolog Rnr3. Telomeres protect the ends of eukaryotic chromosomes and as such determine the replicative capacity of a cell. In budding yeast and approximately 80% of human tumors the enzyme telomerase maintains telomere length by adding newly synthesized repeats to telomeres using dNTPs generated by Ribonucleotide reductase (RNR) complexes. Similarly, telomerase activity can restore telomere length after more severe telomere shortenings that result from collapsed replication forks or lead to telomere over-elongation in the absence of negative regulators of telomerase. Here we provide evidence for two activity modes of telomerase that differentially depend on the major RNR subunit Rnr1. We demonstrate that telomere maintenance and a compensation of the "end-replication-problem" is possible under conditions where Rnr1 activity is absent but that a sustained elongation of short telomeres fully depends on Rnr1 activity. We show that the Rnr1-homolog, Rnr3, cannot compensate for this telomeric function of Rnr1 even when overall cellular dNTP values are restored.
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Affiliation(s)
- André Maicher
- Dept. of Molecular Microbiology & Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Inbal Gazy
- Dept. of Molecular Microbiology & Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Sushma Sharma
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Lisette Marjavaara
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Gilad Grinberg
- Dept. of Molecular Microbiology & Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Keren Shemesh
- Dept. of Molecular Microbiology & Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
| | - Martin Kupiec
- Dept. of Molecular Microbiology & Biotechnology, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
- * E-mail:
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26
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Yi C, Tong J, Lu P, Wang Y, Zhang J, Sun C, Yuan K, Xue R, Zou B, Li N, Xiao S, Dai C, Huang Y, Xu L, Li L, Chen S, Miao D, Deng H, Li H, Yu L. Formation of a Snf1-Mec1-Atg1 Module on Mitochondria Governs Energy Deprivation-Induced Autophagy by Regulating Mitochondrial Respiration. Dev Cell 2017; 41:59-71.e4. [PMID: 28399401 DOI: 10.1016/j.devcel.2017.03.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 10/31/2016] [Accepted: 03/10/2017] [Indexed: 11/28/2022]
Abstract
Autophagy is essential for maintaining glucose homeostasis, but the mechanism by which energy deprivation activates autophagy is not fully understood. We show that Mec1/ATR, a member of the DNA damage response pathway, is essential for glucose starvation-induced autophagy. Mec1, Atg13, Atg1, and the energy-sensing kinase Snf1 are recruited to mitochondria shortly after glucose starvation. Mec1 is recruited through the adaptor protein Ggc1. Snf1 phosphorylates Mec1 on the mitochondrial surface, leading to recruitment of Atg1 to mitochondria. Furthermore, the Snf1-mediated Mec1 phosphorylation and mitochondrial recruitment of Atg1 are essential for maintaining mitochondrial respiration during glucose starvation, and active mitochondrial respiration is required for energy deprivation-activated autophagy. Thus, formation of a Snf1-Mec1-Atg1 module on mitochondria governs energy deprivation-induced autophagy by regulating mitochondrial respiration.
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Affiliation(s)
- Cong Yi
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jingjing Tong
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Puzhong Lu
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yizheng Wang
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jinxie Zhang
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Chen Sun
- The State Key Laboratory of Membrane Biology, School of Life Science, Tsinghua University, Beijing 100084, China
| | - Kangning Yuan
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Renyu Xue
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Bing Zou
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Nianzhong Li
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Shuhua Xiao
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Chong Dai
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yuwei Huang
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Liling Xu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lin Li
- Proteomics Centre, National Institute of Biological Sciences, Beijing 102206, China
| | - She Chen
- Proteomics Centre, National Institute of Biological Sciences, Beijing 102206, China
| | - Di Miao
- Proteomics Facility, School of Life Science, Tsinghua University, Beijing 100084, China
| | - Haiteng Deng
- Proteomics Facility, School of Life Science, Tsinghua University, Beijing 100084, China
| | - Hongliang Li
- Cardiovascular Research Institute of Wuhan University, JieFang Road 238, Wuhan 430060, China
| | - Li Yu
- The State Key Laboratory of Membrane Biology, Tsinghua University-Peking University Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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27
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Wang L. Mitochondrial purine and pyrimidine metabolism and beyond. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2017; 35:578-594. [PMID: 27906631 DOI: 10.1080/15257770.2015.1125001] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Carefully balanced deoxynucleoside triphosphate (dNTP) pools are essential for both nuclear and mitochondrial genome replication and repair. Two synthetic pathways operate in cells to produce dNTPs, e.g., the de novo and the salvage pathways. The key regulatory enzymes for de novo synthesis are ribonucleotide reductase (RNR) and thymidylate synthase (TS), and this process is considered to be cytosolic. The salvage pathway operates both in the cytosol (TK1 and dCK) and the mitochondria (TK2 and dGK). Mitochondrial dNTP pools are separated from the cytosolic ones owing to the double membrane structure of the mitochondria, and are formed by the salvage enzymes TK2 and dGK together with NMPKs and NDPK in postmitotic tissues, while in proliferating cells the mitochondrial dNTPs are mainly imported from the cytosol produced by the cytosolic pathways. Imbalanced mitochondrial dNTP pools lead to mtDNA depletion and/or deletions resulting in serious mitochondrial diseases. The mtDNA depletion syndrome is caused by deficiencies not only in enzymes in dNTP synthesis (TK2, dGK, p53R2, and TP) and mtDNA replication (mtDNA polymerase and twinkle helicase), but also in enzymes in other metabolic pathways such as SUCLA2 and SUCLG1, ABAT and MPV17. Basic questions are why defects in these enzymes affect dNTP synthesis and how important is mitochondrial nucleotide synthesis in the whole cell/organism perspective? This review will focus on recent studies on purine and pyrimidine metabolism, which have revealed several important links that connect mitochondrial nucleotide metabolism with amino acids, glucose, and fatty acid metabolism.
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Affiliation(s)
- Liya Wang
- a Department of Anatomy, Physiology and Biochemistry , Swedish University of Agricultural Sciences , Uppsala , Sweden
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28
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Pai CC, Kearsey SE. A Critical Balance: dNTPs and the Maintenance of Genome Stability. Genes (Basel) 2017; 8:genes8020057. [PMID: 28146119 PMCID: PMC5333046 DOI: 10.3390/genes8020057] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 01/24/2017] [Indexed: 01/14/2023] Open
Abstract
A crucial factor in maintaining genome stability is establishing deoxynucleoside triphosphate (dNTP) levels within a range that is optimal for chromosomal replication. Since DNA replication is relevant to a wide range of other chromosomal activities, these may all be directly or indirectly affected when dNTP concentrations deviate from a physiologically normal range. The importance of understanding these consequences is relevant to genetic disorders that disturb dNTP levels, and strategies that inhibit dNTP synthesis in cancer chemotherapy and for treatment of other disorders. We review here how abnormal dNTP levels affect DNA replication and discuss the consequences for genome stability.
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Affiliation(s)
- Chen-Chun Pai
- CRUK-MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, ORCRB, Roosevelt Drive, Oxford OX3 7DQ, UK.
| | - Stephen E Kearsey
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
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29
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Zubko EI, Shackleton JL, Zubko MK. ATLAS: An advanced PCR-method for routine visualization of telomere length in Saccharomyces cerevisiae. Int J Biol Macromol 2016; 93:1285-1294. [PMID: 27645931 DOI: 10.1016/j.ijbiomac.2016.09.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/20/2016] [Accepted: 09/01/2016] [Indexed: 10/21/2022]
Abstract
Measuring telomere length is essential in telomere biology. Southern blot hybridization is the predominant method for measuring telomere length in the genetic model Saccharomyces cerevisiae. We have further developed and refined a telomere PCR approach, which was rarely used previously (mainly in specific telomeric projects), into a robust method allowing direct visualisation of telomere length differences in routine experiments with S. cerevisiae, and showing a strong correlation of results with data obtained by Southern blot hybridization. In this expanded method denoted as ATLAS (A-dvanced T-elomere L-ength A-nalysis in S. cerevisiae), we have introduced: 1) set of new primers annealing with high specificity to telomeric regions on five different chromosomes; 2) new approach for designing reverse telomere primers that is based on the ligation of an adaptor of a fixed size to telomeric ends. ATLAS can be used at the scale of individual assays and high-throughput approaches. This simple, time/cost-effective and reproducible methodology will complement Southern blot hybridization and facilitate further progress in telomere research.
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Affiliation(s)
- Elena I Zubko
- School of Healthcare Science, Faculty of Science & Engineering, Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, United Kingdom
| | - Jennifer L Shackleton
- School of Healthcare Science, Faculty of Science & Engineering, Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, United Kingdom
| | - Mikhajlo K Zubko
- School of Healthcare Science, Faculty of Science & Engineering, Manchester Metropolitan University, John Dalton Building, Chester St., Manchester, M1 5GD, United Kingdom.
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30
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Multiple Rad52-Mediated Homology-Directed Repair Mechanisms Are Required to Prevent Telomere Attrition-Induced Senescence in Saccharomyces cerevisiae. PLoS Genet 2016; 12:e1006176. [PMID: 27428329 PMCID: PMC4948829 DOI: 10.1371/journal.pgen.1006176] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/15/2016] [Indexed: 12/15/2022] Open
Abstract
Most human somatic cells express insufficient levels of telomerase, which can result in telomere shortening and eventually senescence, both of which are hallmarks of ageing. Homology-directed repair (HDR) is important for maintaining proper telomere function in yeast and mammals. In Saccharomyces cerevisiae, Rad52 is required for almost all HDR mechanisms, and telomerase-null cells senesce faster in the absence of Rad52. However, its role in preventing accelerated senescence has been unclear. In this study, we make use of rad52 separation-of-function mutants to find that multiple Rad52-mediated HDR mechanisms are required to delay senescence, including break-induced replication and sister chromatid recombination. In addition, we show that misregulation of histone 3 lysine 56 acetylation, which is known to be defective in sister chromatid recombination, also causes accelerated senescence. We propose a model where Rad52 is needed to repair telomere attrition-induced replication stress. Telomeres are essential structures located at the ends of chromosomes. The canonical DNA replication machinery is unable to fully replicate DNA at chromosome ends, causing telomeres to shorten with every round of cell division. This shortening can be counteracted by an enzyme called telomerase, but in most human somatic cells, there is insufficient expression of telomerase to prevent telomere shortening. Cells with critically short telomeres can enter an arrested state known as senescence. Telomere attrition has been identified as a hallmark of human ageing. Homologous recombination proteins are important for proper telomere function in yeast and mammals. Yeast lacking both telomerase and Rad52, required for almost all recombination, exhibits accelerated senescence, yet no apparent increase in the rate of telomere shortening. In this study, we explore the role of Rad52 during senescence by taking advantage of rad52 separation-of-function mutants. We find that Rad52 acts in multiple ways to overcome DNA replication problems at telomeres. Impediments to telomere replication can be dealt with by post-replication repair mechanisms, which use a newly synthesized sister chromatid as a template to replicate past the impediment, while telomere truncations, likely caused by the collapse of replication forks, can be extended by break-induced replication.
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31
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Li Y, Guo Z, Jin L, Wang D, Gao Z, Su X, Hou H, Dong Y. Mechanism of the allosteric regulation of Streptococcus mutans 2'-deoxycytidylate deaminase. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2016; 72:883-91. [PMID: 27377385 DOI: 10.1107/s2059798316009153] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 06/07/2016] [Indexed: 01/24/2023]
Abstract
In cells, dUMP is the intermediate precursor of dTTP in its synthesis during deoxynucleotide metabolism. In Gram-positive bacteria and eukaryotes, zinc-dependent deoxycytidylate deaminases (dCDs) catalyze the conversion of dCMP to dUMP. The activity of dCD is allosterically activated by dCTP and inhibited by dTTP. Here, the crystal structure of Streptococcus mutans dCD (SmdCD) complexed with dTTP is presented at 2.35 Å resolution, thereby solving the first pair of activator-bound and inhibitor-bound structures from the same species to provide a more definitive description of the allosteric mechanism. In contrast to the dTTP-bound dCD from the bacteriophage S-TIM5 (S-TIM5-dCD), dTTP-bound SmdCD adopts an inactive conformation similar to the apo form. A structural comparison suggests that the distinct orientations of the triphosphate group in S-TIM5-dCD and SmdCD are a result of the varying protein binding environment. In addition, calorimetric data establish that the modulators bound to dCD can be mutually competitively replaced. The results reveal the mechanism underlying its regulator-specific activity and might greatly enhance the understanding of the allosteric regulation of other dCDs.
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Affiliation(s)
- Yanhua Li
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Zhen Guo
- Key Laboratory of Molecular Biology on Infectious Disease, Chongqing Medical University, YiXueYuanlu-1, Chongqing, People's Republic of China
| | - Li Jin
- Key Laboratory of Molecular Biology on Infectious Disease, Chongqing Medical University, YiXueYuanlu-1, Chongqing, People's Republic of China
| | - Deqiang Wang
- Key Laboratory of Molecular Biology on Infectious Disease, Chongqing Medical University, YiXueYuanlu-1, Chongqing, People's Republic of China
| | - Zengqiang Gao
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Xiaodong Su
- National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Science, Peking University, Beijing 100871, People's Republic of China
| | - Haifeng Hou
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yuhui Dong
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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32
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Ceja-Rangel HA, Sánchez-Suárez P, Castellanos-Juárez E, Peñaroja-Flores R, Arenas-Aranda DJ, Gariglio P, Benítez-Bribiesca L. Shorter telomeres and high telomerase activity correlate with a highly aggressive phenotype in breast cancer cell lines. Tumour Biol 2016; 37:11917-11926. [PMID: 27072825 DOI: 10.1007/s13277-016-5045-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 04/01/2016] [Indexed: 12/12/2022] Open
Abstract
Maintenance of telomere length is one function of human telomerase that is crucial for the survival of cancer cells and cancer progression. Both telomeres and telomerase have been proposed as possible biomarkers of cancer risk and cancer invasiveness; however, their clinical relevance is still under discussion. In order to improve our understanding of the relationship between telomere length and telomerase activity with cancer invasiveness, we studied telomere length as well as telomerase levels, activity, and intracellular localization in breast cancer cell lines with diverse invasive phenotypes. We found an apparently paradoxical coincidence of short telomeres and enhanced telomerase activity in the most invasive breast cancer cell lines. We also observed that hTERT intracellular localization could be correlated with its level of activity. There was no association between human telomerase reverse transcriptase (hTERT) protein expression levels and invasiveness. We propose that simultaneous evaluation of these two biomarkers-telomere length and telomerase activity-could be useful for the assessment of the invasive capacity and aggressiveness of tumor cells from breast cancer patients.
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Affiliation(s)
- Hugo A Ceja-Rangel
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Av. Instituto Politécnico Nacional 2508, 07360, Ciudad de México, Mexico.,Unidad de Investigación Médica en Enfermedades Oncológicas, Hospital de Oncología, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Av. Cuauhtémoc 330, 06725, Ciudad de México, Mexico
| | - Patricia Sánchez-Suárez
- Unidad de Investigación Médica en Enfermedades Oncológicas, Hospital de Oncología, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Av. Cuauhtémoc 330, 06725, Ciudad de México, Mexico
| | - Emilio Castellanos-Juárez
- Unidad de Investigación Médica en Enfermedades Oncológicas, Hospital de Oncología, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Av. Cuauhtémoc 330, 06725, Ciudad de México, Mexico
| | - Rubicelia Peñaroja-Flores
- Unidad de Investigación Médica en Enfermedades Oncológicas, Hospital de Oncología, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Av. Cuauhtémoc 330, 06725, Ciudad de México, Mexico
| | - Diego J Arenas-Aranda
- Unidad de Investigación Médica en Genética Humana, Hospital de Pediatría, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Ciudad de México, Mexico
| | - Patricio Gariglio
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Av. Instituto Politécnico Nacional 2508, 07360, Ciudad de México, Mexico.
| | - Luis Benítez-Bribiesca
- Unidad de Investigación Médica en Enfermedades Oncológicas, Hospital de Oncología, Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social, Av. Cuauhtémoc 330, 06725, Ciudad de México, Mexico.
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33
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van Mourik PM, de Jong J, Agpalo D, Claussin C, Rothstein R, Chang M. Recombination-Mediated Telomere Maintenance in Saccharomyces cerevisiae Is Not Dependent on the Shu Complex. PLoS One 2016; 11:e0151314. [PMID: 26974669 PMCID: PMC4790948 DOI: 10.1371/journal.pone.0151314] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 02/28/2016] [Indexed: 12/22/2022] Open
Abstract
In cells lacking telomerase, telomeres shorten progressively during each cell division due to incomplete end-replication. When the telomeres become very short, cells enter a state that blocks cell division, termed senescence. A subset of these cells can overcome senescence and maintain their telomeres using telomerase-independent mechanisms. In Saccharomyces cerevisiae, these cells are called ‘survivors’ and are dependent on Rad52-dependent homologous recombination and Pol32-dependent break-induced replication. There are two main types of survivors: type I and type II. The type I survivors require Rad51 and maintain telomeres by amplification of subtelomeric elements, while the type II survivors are Rad51-independent, but require the MRX complex and Sgs1 to amplify the C1–3A/TG1–3 telomeric sequences. Rad52, Pol32, Rad51, and Sgs1 are also important to prevent accelerated senescence, indicating that recombination processes are important at telomeres even before the formation of survivors. The Shu complex, which consists of Shu1, Shu2, Psy3, and Csm2, promotes Rad51-dependent homologous recombination and has been suggested to be important for break-induced replication. It also promotes the formation of recombination intermediates that are processed by the Sgs1-Top3-Rmi1 complex, as mutations in the SHU genes can suppress various sgs1, top3, and rmi1 mutant phenotypes. Given the importance of recombination processes during senescence and survivor formation, and the involvement of the Shu complex in many of the same processes during DNA repair, we hypothesized that the Shu complex may also have functions at telomeres. Surprisingly, we find that this is not the case: the Shu complex does not affect the rate of senescence, does not influence survivor formation, and deletion of SHU1 does not suppress the rapid senescence and type II survivor formation defect of a telomerase-negative sgs1 mutant. Altogether, our data suggest that the Shu complex is not important for recombination processes at telomeres.
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Affiliation(s)
- Paula M. van Mourik
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Jannie de Jong
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Danielle Agpalo
- Department of Genetics and Development, Columbia University Medical Center, New York, United States of America
| | - Clémence Claussin
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Rodney Rothstein
- Department of Genetics and Development, Columbia University Medical Center, New York, United States of America
| | - Michael Chang
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- * E-mail:
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34
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Abstract
Cancer was recognized as a genetic disease at least four decades ago, with the realization that the spontaneous mutation rate must increase early in tumorigenesis to account for the many mutations in tumour cells compared with their progenitor pre-malignant cells. Abnormalities in the deoxyribonucleotide pool have long been recognized as determinants of DNA replication fidelity, and hence may contribute to mutagenic processes that are involved in carcinogenesis. In addition, many anticancer agents antagonize deoxyribonucleotide metabolism. Here, we consider the extent to which aspects of deoxyribonucleotide metabolism contribute to our understanding of both carcinogenesis and to the effective use of anticancer agents.
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Affiliation(s)
- Christopher K Mathews
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331-7305, USA
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35
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Colon cancer-associated mutator DNA polymerase δ variant causes expansion of dNTP pools increasing its own infidelity. Proc Natl Acad Sci U S A 2015; 112:E2467-76. [PMID: 25827231 DOI: 10.1073/pnas.1422934112] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Defects in DNA polymerases δ (Polδ) and ε (Polε) cause hereditary colorectal cancer and have been implicated in the etiology of some sporadic colorectal and endometrial tumors. We previously reported that the yeast pol3-R696W allele mimicking a human cancer-associated variant, POLD1-R689W, causes a catastrophic increase in spontaneous mutagenesis. Here, we describe the mechanism of this extraordinary mutator effect. We found that the mutation rate increased synergistically when the R696W mutation was combined with defects in Polδ proofreading or mismatch repair, indicating that pathways correcting DNA replication errors are not compromised in pol3-R696W mutants. DNA synthesis by purified Polδ-R696W was error-prone, but not to the extent that could account for the unprecedented mutator phenotype of pol3-R696W strains. In a search for cellular factors that augment the mutagenic potential of Polδ-R696W, we discovered that pol3-R696W causes S-phase checkpoint-dependent elevation of dNTP pools. Abrogating this elevation by strategic mutations in dNTP metabolism genes eliminated the mutator effect of pol3-R696W, whereas restoration of high intracellular dNTP levels restored the mutator phenotype. Further, the use of dNTP concentrations present in pol3-R696W cells for in vitro DNA synthesis greatly decreased the fidelity of Polδ-R696W and produced a mutation spectrum strikingly similar to the spectrum observed in vivo. The results support a model in which (i) faulty synthesis by Polδ-R696W leads to a checkpoint-dependent increase in dNTP levels and (ii) this increase mediates the hypermutator effect of Polδ-R696W by facilitating the extension of mismatched primer termini it creates and by promoting further errors that continue to fuel the mutagenic pathway.
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36
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Mathews CK. Deoxyribonucleotides as genetic and metabolic regulators. FASEB J 2014; 28:3832-40. [PMID: 24928192 DOI: 10.1096/fj.14-251249] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 06/02/2014] [Indexed: 01/12/2023]
Abstract
For >35 yr, we have known that the accuracy of DNA replication is controlled in large part by the relative concentrations of the 4 canonical deoxyribonucleoside 5'-triphosphates (dNTPs) at the replisome. Since this field was last reviewed, ∼8 yr ago, there has been increased understanding of the mutagenic pathways as they occur in living cells. At the same time, aspects of deoxyribonucleotide metabolism have been shown to be critically involved in processes as diverse as cell cycle control, protooncogene expression, cellular defense against HIV infection, replication rate control, telomere length control, and mitochondrial function. Evidence supports a relationship between dNTP pools and microsatellite repeat instability. Relationships between dNTP synthesis and breakdown in controlling steady-state pools have become better defined. In addition, new experimental approaches have allowed definitive analysis of mutational pathways induced by dNTP pool abnormalities, both in Escherichia coli and in yeast. Finally, ribonucleoside triphosphate (rNTP) pools have been shown to be critical determinants of DNA replication fidelity. These developments are discussed in this review article.
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Affiliation(s)
- Christopher K Mathews
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon, USA
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37
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Rubinstein L, Ungar L, Harari Y, Babin V, Ben-Aroya S, Merenyi G, Marjavaara L, Chabes A, Kupiec M. Telomere length kinetics assay (TELKA) sorts the telomere length maintenance (tlm) mutants into functional groups. Nucleic Acids Res 2014; 42:6314-25. [PMID: 24728996 PMCID: PMC4041441 DOI: 10.1093/nar/gku267] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Genome-wide systematic screens in yeast have uncovered a large gene network (the telomere length maintenance network or TLM), encompassing more than 400 genes, which acts coordinatively to maintain telomere length. Identifying the genes was an important first stage; the next challenge is to decipher their mechanism of action and to organize then into functional groups or pathways. Here we present a new telomere-length measuring program, TelQuant, and a novel assay, telomere length kinetics assay, and use them to organize tlm mutants into functional classes. Our results show that a mutant defective for the relatively unknown MET7 gene has the same telomeric kinetics as mutants defective for the ribonucleotide reductase subunit Rnr1, in charge of the limiting step in dNTP synthesis, or for the Ku heterodimer, a well-established telomere complex. We confirm the epistatic relationship between the mutants and show that physical interactions exist between Rnr1 and Met7. We also show that Met7 and the Ku heterodimer affect dNTP formation, and play a role in non-homologous end joining. Thus, our telomere kinetics assay uncovers new functional groups, as well as complex genetic interactions between tlm mutants.
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Affiliation(s)
- Linda Rubinstein
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Lior Ungar
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Yaniv Harari
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Vera Babin
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Shay Ben-Aroya
- Faculty of Life Sciences Bar-Ilan University, Ramat-Gan, Israel
| | - Gabor Merenyi
- Department of Medical Biochemistry and Biophysics and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå 901 87, Sweden
| | - Lisette Marjavaara
- Department of Medical Biochemistry and Biophysics and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå 901 87, Sweden
| | - Andrei Chabes
- Department of Medical Biochemistry and Biophysics and Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå 901 87, Sweden
| | - Martin Kupiec
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Ramat Aviv 69978, Israel
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The deoxynucleotide triphosphohydrolase SAMHD1 is a major regulator of DNA precursor pools in mammalian cells. Proc Natl Acad Sci U S A 2013; 110:14272-7. [PMID: 23858451 DOI: 10.1073/pnas.1312033110] [Citation(s) in RCA: 186] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Sterile alpha motif and HD-domain containing protein 1 (SAMHD1) is a triphosphohydrolase converting deoxynucleoside triphosphates (dNTPs) to deoxynucleosides. The enzyme was recently identified as a component of the human innate immune system that restricts HIV-1 infection by removing dNTPs required for viral DNA synthesis. SAMHD1 has deep evolutionary roots and is ubiquitous in human organs. Here we identify a general function of SAMHD1 in the regulation of dNTP pools in cultured human cells. The protein was nuclear and variably expressed during the cell cycle, maximally during quiescence and minimally during S-phase. Treatment of lung or skin fibroblasts with specific siRNAs resulted in the disappearence of SAMHD1 accompanied by loss of the cell-cycle regulation of dNTP pool sizes and dNTP imbalance. Cells accumulated in G1 phase with oversized pools and stopped growing. Following removal of the siRNA, the pools were normalized and cell growth restarted, but only after SAMHD1 had reappeared. In quiescent cultures SAMHD1 down-regulation leads to a marked expansion of dNTP pools. In all cases the largest effect was on dGTP, the preferred substrate of SAMHD1. Ribonucleotide reductase, responsible for the de novo synthesis of dNTPs, is a cytosolic enzyme maximally induced in S-phase cells. Thus, in mammalian cells the cell cycle regulation of the two main enzymes controlling dNTP pool sizes is adjusted to the requirements of DNA replication. Synthesis by the reductase peaks during S-phase, and catabolism by SAMHD1 is maximal during G1 phase when large dNTP pools would prevent cells from preparing for a new round of DNA replication.
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Novel connections between DNA replication, telomere homeostasis, and the DNA damage response revealed by a genome-wide screen for TEL1/ATM interactions in Saccharomyces cerevisiae. Genetics 2013; 193:1117-33. [PMID: 23378069 DOI: 10.1534/genetics.113.149849] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tel1 is the budding yeast ortholog of the mammalian tumor suppressor and DNA damage response (DDR) kinase ATM. However, tel1-Δ cells, unlike ATM-deficient cells, do not exhibit sensitivity to DNA-damaging agents, but do display shortened (but stably maintained) telomere lengths. Neither the extent to which Tel1p functions in the DDR nor the mechanism by which Tel1 contributes to telomere metabolism is well understood. To address the first question, we present the results from a comprehensive genome-wide screen for genetic interactions with tel1-Δ that cause sensitivity to methyl methanesulfonate (MMS) and/or ionizing radiation, along with follow-up characterizations of the 13 interactions yielded by this screen. Surprisingly, many of the tel1-Δ interactions that confer DNA damage sensitivity also exacerbate the short telomere phenotype, suggesting a connection between these two phenomena. Restoration of normal telomere length in the tel1-Δ xxx-Δ mutants results in only minor suppression of the DNA damage sensitivity, demonstrating that the sensitivity of these mutants must also involve mechanisms independent of telomere length. In support of a model for increased replication stress in the tel1-Δ xxx-Δ mutants, we show that depletion of dNTP pools through pretreatment with hydroxyurea renders tel1-Δ cells (but not wild type) MMS-sensitive, demonstrating that, under certain conditions, Tel1p does indeed play a critical role in the DDR.
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