1
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Audry J, Zhang H, Kerr C, Berkner KL, Runge KW. Ccq1 restrains Mre11-mediated degradation to distinguish short telomeres from double-strand breaks. Nucleic Acids Res 2024; 52:3722-3739. [PMID: 38321948 DOI: 10.1093/nar/gkae044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 12/21/2023] [Accepted: 01/12/2024] [Indexed: 02/08/2024] Open
Abstract
Telomeres protect chromosome ends and are distinguished from DNA double-strand breaks (DSBs) by means of a specialized chromatin composed of DNA repeats bound by a multiprotein complex called shelterin. We investigated the role of telomere-associated proteins in establishing end-protection by studying viable mutants lacking these proteins. Mutants were studied using a Schizosaccharomyces pombe model system that induces cutting of a 'proto-telomere' bearing telomere repeats to rapidly form a new stable chromosomal end, in contrast to the rapid degradation of a control DSB. Cells lacking the telomere-associated proteins Taz1, Rap1, Poz1 or Rif1 formed a chromosome end that was stable. Surprisingly, cells lacking Ccq1, or impaired for recruiting Ccq1 to the telomere, converted the cleaved proto-telomere to a rapidly degraded DSB. Ccq1 recruits telomerase, establishes heterochromatin and affects DNA damage checkpoint activation; however, these functions were separable from protection of the new telomere by Ccq1. In cells lacking Ccq1, telomere degradation was greatly reduced by eliminating the nuclease activity of Mre11 (part of the Mre11-Rad50-Nbs1/Xrs2 DSB processing complex), and higher amounts of nuclease-deficient Mre11 associated with the new telomere. These results demonstrate a novel function for S. pombe Ccq1 to effect end-protection by restraining Mre11-dependent degradation of the DNA end.
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Affiliation(s)
- Julien Audry
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Haitao Zhang
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Carly Kerr
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Kathleen L Berkner
- Department of Cardiovascular and Metabolic Sciences, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
| | - Kurt W Runge
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, USA
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
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2
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Sang PB, Jaiswal RK, Lyu X, Chai W. Human CST complex restricts excessive PrimPol repriming upon UV induced replication stress by suppressing p21. Nucleic Acids Res 2024; 52:3778-3793. [PMID: 38348929 DOI: 10.1093/nar/gkae078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 01/18/2024] [Accepted: 01/26/2024] [Indexed: 04/25/2024] Open
Abstract
DNA replication stress, caused by various endogenous and exogenous agents, halt or stall DNA replication progression. Cells have developed diverse mechanisms to tolerate and overcome replication stress, enabling them to continue replication. One effective strategy to overcome stalled replication involves skipping the DNA lesion using a specialized polymerase known as PrimPol, which reinitiates DNA synthesis downstream of the damage. However, the mechanism regulating PrimPol repriming is largely unclear. In this study, we observe that knockdown of STN1 or CTC1, components of the CTC1/STN1/TEN1 complex, leads to enhanced replication progression following UV exposure. We find that such increased replication is dependent on PrimPol, and PrimPol recruitment to stalled forks increases upon CST depletion. Moreover, we find that p21 is upregulated in STN1-depleted cells in a p53-independent manner, and p21 depletion restores normal replication rates caused by STN1 deficiency. We identify that p21 interacts with PrimPol, and STN1 depletion stimulates p21-PrimPol interaction and facilitates PrimPol recruitment to stalled forks. Our findings reveal a previously undescribed interplay between CST, PrimPol and p21 in promoting repriming in response to stalled replication, and shed light on the regulation of PrimPol repriming at stalled forks.
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Affiliation(s)
- Pau Biak Sang
- Department of Cancer Biology, Cardinal Bernardin Cancer Center, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
- Department of Microbiology, University of Delhi South Campus, New Delhi, India
| | - Rishi K Jaiswal
- Department of Cancer Biology, Cardinal Bernardin Cancer Center, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
| | - Xinxing Lyu
- Department of Cancer Biology, Cardinal Bernardin Cancer Center, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
| | - Weihang Chai
- Department of Cancer Biology, Cardinal Bernardin Cancer Center, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
- Center for Genetic Diseases, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
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3
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Padmanaban S, Lambacher NJ, Tesmer VM, Zhang J, Shibuya H, Nandakumar J. Caenorhabditis elegans telomere-binding proteins TEBP-1 and TEBP-2 adapt the Myb module to dimerize and bind telomeric DNA. Proc Natl Acad Sci U S A 2024; 121:e2316651121. [PMID: 38588418 PMCID: PMC11032478 DOI: 10.1073/pnas.2316651121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 02/17/2024] [Indexed: 04/10/2024] Open
Abstract
Protecting chromosome ends from misrecognition as double-stranded (ds) DNA breaks is fundamental to eukaryotic viability. The protein complex shelterin prevents a DNA damage response at mammalian telomeres. Mammalian shelterin proteins TRF1 and TRF2 and their homologs in yeast and protozoa protect telomeric dsDNA. N-terminal homodimerization and C-terminal Myb-domain-mediated dsDNA binding are two structural hallmarks of end protection by TRF homologs. Yet our understanding of how Caenorhabditis elegans protects its telomeric dsDNA is limited. Recently identified C. elegans proteins TEBP-1 (also called DTN-1) and TEBP-2 (also called DTN-2) are functional homologs of TRF proteins, but how they bind DNA and whether or how they dimerize is not known. TEBP-1 and TEBP-2 harbor three Myb-containing domains (MCDs) and no obvious dimerization domain. We demonstrate biochemically that only the third MCD binds DNA. We solve the X-ray crystal structure of TEBP-2 MCD3 with telomeric dsDNA to reveal the structural mechanism of telomeric dsDNA protection in C. elegans. Mutagenesis of the DNA-binding site of TEBP-1 and TEBP-2 compromises DNA binding in vitro, and increases DNA damage signaling, lengthens telomeres, and decreases brood size in vivo. Via an X-ray crystal structure, biochemical validation of the dimerization interface, and SEC-MALS analysis, we demonstrate that MCD1 and MCD2 form a composite dimerization module that facilitates not only TEBP-1 and TEBP-2 homodimerization but also heterodimerization. These findings provide fundamental insights into C. elegans telomeric dsDNA protection and highlight how different eukaryotes have evolved distinct strategies to solve the chromosome end protection problem.
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Affiliation(s)
- Shilpa Padmanaban
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI48109
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO63110
| | - Nils J. Lambacher
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden41390
| | - Valerie M. Tesmer
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI48109
| | - Jingjing Zhang
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden41390
| | - Hiroki Shibuya
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden41390
- Laboratory for Gametogenesis, RIKEN Center for Biosystems Dynamics Research, Kobe650-0047, Japan
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI48109
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4
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Pizzul P, Casari E, Rinaldi C, Gnugnoli M, Mangiagalli M, Tisi R, Longhese MP. Rif2 interaction with Rad50 counteracts Tel1 functions in checkpoint signalling and DNA tethering by releasing Tel1 from MRX binding. Nucleic Acids Res 2024; 52:2355-2371. [PMID: 38180815 PMCID: PMC10954470 DOI: 10.1093/nar/gkad1246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2023] [Revised: 12/14/2023] [Accepted: 12/18/2023] [Indexed: 01/07/2024] Open
Abstract
The yeast Rif2 protein is known to inhibit Mre11 nuclease and the activation of Tel1 kinase through a short motif termed MIN, which binds the Rad50 subunit and simulates its ATPase activity in vitro. The mechanism by which Rif2 restrains Tel1 activation and the consequences of this inhibition at DNA double-strand breaks (DSBs) are poorly understood. In this study, we employed AlphaFold-Multimer modelling to pinpoint and validate the interaction surface between Rif2 MIN and Rad50. We also engineered the rif2-S6E mutation that enhances the inhibitory effect of Rif2 by increasing Rif2-Rad50 interaction. Unlike rif2Δ, the rif2-S6E mutation impairs hairpin cleavage. Furthermore, it diminishes Tel1 activation by inhibiting Tel1 binding to DSBs while leaving MRX association unchanged, indicating that Rif2 can directly inhibit Tel1 recruitment to DSBs. Additionally, Rif2S6E reduces Tel1-MRX interaction and increases stimulation of ATPase by Rad50, indicating that Rif2 binding to Rad50 induces an ADP-bound MRX conformation that is not suitable for Tel1 binding. The decreased Tel1 recruitment to DSBs in rif2-S6E cells impairs DSB end-tethering and this bridging defect is suppressed by expressing a Tel1 mutant variant that increases Tel1 persistence at DSBs, suggesting a direct role for Tel1 in the bridging of DSB ends.
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Affiliation(s)
- Paolo Pizzul
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy
| | - Erika Casari
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy
| | - Carlo Rinaldi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy
| | - Marco Gnugnoli
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy
| | - Marco Mangiagalli
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy
| | - Renata Tisi
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy
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5
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Bertrand A, Ba I, Kermasson L, Pirabakaran V, Chable N, Lainey E, Ménard C, Kallel F, Picard C, Hadiji S, Coolen-Allou N, Blanchard E, de Villartay JP, Moshous D, Roelens M, Callebaut I, Kannengiesser C, Revy P. Characterization of novel mutations in the TEL-patch domain of the telomeric factor TPP1 associated with telomere biology disorders. Hum Mol Genet 2024; 33:612-623. [PMID: 38176734 DOI: 10.1093/hmg/ddad210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 12/04/2023] [Accepted: 12/13/2023] [Indexed: 01/06/2024] Open
Abstract
Telomeres are nucleoprotein structures that protect the chromosome ends from degradation and fusion. Telomerase is a ribonucleoprotein complex essential to maintain the length of telomeres. Germline defects that lead to short and/or dysfunctional telomeres cause telomere biology disorders (TBDs), a group of rare and heterogeneous Mendelian diseases including pulmonary fibrosis, dyskeratosis congenita, and Høyeraal-Hreidarsson syndrome. TPP1, a telomeric factor encoded by the gene ACD, recruits telomerase at telomere and stimulates its activity via its TEL-patch domain that directly interacts with TERT, the catalytic subunit of telomerase. TBDs due to TPP1 deficiency have been reported only in 11 individuals. We here report four unrelated individuals with a wide spectrum of TBD manifestations carrying either heterozygous or homozygous ACD variants consisting in the recurrent and previously described in-frame deletion of K170 (K170∆) and three novel missense mutations G179D, L184R, and E215V. Structural and functional analyses demonstrated that the four variants affect the TEL-patch domain of TPP1 and impair telomerase activity. In addition, we identified in the ACD gene several motifs associated with small deletion hotspots that could explain the recurrence of the K170∆ mutation. Finally, we detected in a subset of blood cells from one patient, a somatic TERT promoter-activating mutation that likely provides a selective advantage over non-modified cells, a phenomenon known as indirect somatic genetic rescue. Together, our results broaden the genetic and clinical spectrum of TPP1 deficiency and specify new residues in the TEL-patch domain that are crucial for length maintenance and stability of human telomeres in vivo.
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Affiliation(s)
- Alexis Bertrand
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Ibrahima Ba
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Assistance Publique des Hôpitaux de Paris, Hôpital Bichat, Service de Génétique, Université Paris Diderot, Paris 75018, France
| | - Laëtitia Kermasson
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Vithura Pirabakaran
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Noémie Chable
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Elodie Lainey
- Hematology Laboratory, Robert Debré Hospital-AssistancePublique-Hôpitaux de Paris (APHP), INSERM UMR 1131-Hematology University Institute-Denis Diderot School of Medicine, Paris 75019, France
| | - Christelle Ménard
- Assistance Publique des Hôpitaux de Paris, Hôpital Bichat, Service de Génétique, Université Paris Diderot, Paris 75018, France
| | - Faten Kallel
- Hematology Department, Hedi Chaker Hospital, 3029, Sfax, Tunisia
| | - Capucine Picard
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Department of Pediatric Immunology, Hematology and Rheumatology, Necker-Enfants Malades Hospital, (APHP), Paris 75015, France
- Centre de références des déficits immunitaires Héréditaires (CEREDIH), Necker-Enfants Malades Hospital APHP, Paris 75015, France
- Laboratory of Lymphocyte Activation and Susceptibility to EBV infection, Inserm UMR 1163, Institut Imagine, Paris 75015, France
| | - Sondes Hadiji
- Hematology Department, Hedi Chaker Hospital, 3029, Sfax, Tunisia
| | - Nathalie Coolen-Allou
- Service de Pneumologie, Hôpital Félix Guyon, CHU Réunion, Saint-Denis de la Réunion 97400, France
| | - Elodie Blanchard
- Service de Pneumologie, Hôpital Haut-Lévêque, CHU Bordeaux, Bordeaux 33604, France
| | - Jean-Pierre de Villartay
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
| | - Despina Moshous
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Department of Pediatric Immunology, Hematology and Rheumatology, Necker-Enfants Malades Hospital, (APHP), Paris 75015, France
| | - Marie Roelens
- Université Paris Cité, Imagine Institute, Paris 75015, France
- Centre de références des déficits immunitaires Héréditaires (CEREDIH), Necker-Enfants Malades Hospital APHP, Paris 75015, France
| | - Isabelle Callebaut
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Paris 75005, France
| | - Caroline Kannengiesser
- Assistance Publique des Hôpitaux de Paris, Hôpital Bichat, Service de Génétique, Université Paris Diderot, Paris 75018, France
| | - Patrick Revy
- Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer, INSERM UMR 1163, Imagine Institute, 24 boulevard du Montparnasse, Paris 75015, France
- Université Paris Cité, Imagine Institute, Paris 75015, France
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6
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Takai H, Aria V, Borges P, Yeeles JTP, de Lange T. CST-polymerase α-primase solves a second telomere end-replication problem. Nature 2024; 627:664-670. [PMID: 38418884 DOI: 10.1038/s41586-024-07137-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 01/30/2024] [Indexed: 03/02/2024]
Abstract
Telomerase adds G-rich telomeric repeats to the 3' ends of telomeres1, counteracting telomere shortening caused by loss of telomeric 3' overhangs during leading-strand DNA synthesis ('the end-replication problem'2). Here we report a second end-replication problem that originates from the incomplete duplication of the C-rich telomeric repeat strand (C-strand) by lagging-strand DNA synthesis. This problem is resolved by fill-in synthesis mediated by polymerase α-primase bound to Ctc1-Stn1-Ten1 (CST-Polα-primase). In vitro, priming for lagging-strand DNA replication does not occur on the 3' overhang and lagging-strand synthesis stops in a zone of approximately 150 nucleotides (nt) more than 26 nt from the end of the template. Consistent with the in vitro data, lagging-end telomeres of cells lacking CST-Polα-primase lost 50-60 nt of telomeric CCCTAA repeats per population doubling. The C-strands of leading-end telomeres shortened by around 100 nt per population doubling, reflecting the generation of 3' overhangs through resection. The measured overall C-strand shortening in the absence of CST-Polα-primase fill-in is consistent with the combined effects of incomplete lagging-strand synthesis and 5' resection at the leading ends. We conclude that canonical DNA replication creates two telomere end-replication problems that require telomerase to maintain the G-rich strand and CST-Polα-primase to maintain the C-strand.
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Affiliation(s)
- Hiroyuki Takai
- Laboratory for Cell Biology and Genetics, Rockefeller University, New York, NY, USA
| | - Valentina Aria
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Pamela Borges
- Laboratory for Cell Biology and Genetics, Rockefeller University, New York, NY, USA
| | - Joseph T P Yeeles
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK.
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, Rockefeller University, New York, NY, USA.
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7
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Olson CL, Wuttke DS. Guardians of the Genome: How the Single-Stranded DNA-Binding Proteins RPA and CST Facilitate Telomere Replication. Biomolecules 2024; 14:263. [PMID: 38540683 PMCID: PMC10968030 DOI: 10.3390/biom14030263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/02/2024] [Accepted: 02/20/2024] [Indexed: 04/26/2024] Open
Abstract
Telomeres act as the protective caps of eukaryotic linear chromosomes; thus, proper telomere maintenance is crucial for genome stability. Successful telomere replication is a cornerstone of telomere length regulation, but this process can be fraught due to the many intrinsic challenges telomeres pose to the replication machinery. In addition to the famous "end replication" problem due to the discontinuous nature of lagging strand synthesis, telomeres require various telomere-specific steps for maintaining the proper 3' overhang length. Bulk telomere replication also encounters its own difficulties as telomeres are prone to various forms of replication roadblocks. These roadblocks can result in an increase in replication stress that can cause replication forks to slow, stall, or become reversed. Ultimately, this leads to excess single-stranded DNA (ssDNA) that needs to be managed and protected for replication to continue and to prevent DNA damage and genome instability. RPA and CST are single-stranded DNA-binding protein complexes that play key roles in performing this task and help stabilize stalled forks for continued replication. The interplay between RPA and CST, their functions at telomeres during replication, and their specialized features for helping overcome replication stress at telomeres are the focus of this review.
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Affiliation(s)
- Conner L. Olson
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Deborah S. Wuttke
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80309, USA
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8
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Zhao X, Vogirala VK, Liu M, Zhou Y, Rhodes D, Sandin S, Yan J. Exploring TRF2-Dependent DNA Distortion Through Single-DNA Manipulation Studies. Commun Biol 2024; 7:148. [PMID: 38310140 PMCID: PMC10838314 DOI: 10.1038/s42003-024-05838-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/20/2024] [Indexed: 02/05/2024] Open
Abstract
TRF2 is a component of shelterin, a telomere-specific protein complex that protects the ends of mammalian chromosomes from DNA damage signaling and improper repair. TRF2 functions as a homodimer and its interaction with telomeric DNA has been studied, but its full-length DNA-binding properties are unknown. This study examines TRF2's interaction with single-DNA strands and focuses on the conformation of the TRF2-DNA complex and TRF2's preference for DNA chirality. The results show that TRF2-DNA can switch between extended and compact conformations, indicating multiple DNA-binding modes, and TRF2's binding does not have a strong preference for DNA supercoiling chirality when DNA is under low tension. Instead, TRF2 induces DNA bending under tension. Furthermore, both the N-terminal domain of TRF2 and the Myb domain enhance its affinity for the telomere sequence, highlighting the crucial role of multivalent DNA binding in enhancing its affinity and specificity for telomere sequence. These discoveries offer unique insights into TRF2's interaction with telomeric DNA.
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Affiliation(s)
- Xiaodan Zhao
- Department of Physics, National University of Singapore, 117551, Singapore, Singapore
| | - Vinod Kumar Vogirala
- School of Biological Sciences, Nanyang Technology University, 637551, Singapore, Singapore
- Electron Bio-Imaging Centre (eBIC), Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Meihan Liu
- Mechanobiology Institute, National University of Singapore, 117411, Singapore, Singapore
| | - Yu Zhou
- Mechanobiology Institute, National University of Singapore, 117411, Singapore, Singapore
| | - Daniela Rhodes
- School of Biological Sciences, Nanyang Technology University, 637551, Singapore, Singapore
- NTU Institute of Structural Biology, Nanyang Technology University, 636921, Singapore, Singapore
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK
| | - Sara Sandin
- School of Biological Sciences, Nanyang Technology University, 637551, Singapore, Singapore.
- NTU Institute of Structural Biology, Nanyang Technology University, 636921, Singapore, Singapore.
- Umeå university, KBC-huset (KB), Linnaeus väg 10, Umeå, 90187, Sweden.
| | - Jie Yan
- Department of Physics, National University of Singapore, 117551, Singapore, Singapore.
- Mechanobiology Institute, National University of Singapore, 117411, Singapore, Singapore.
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, 350207, China.
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9
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Rai R, Sodeinde T, Boston A, Chang S. Telomeres cooperate with the nuclear envelope to maintain genome stability. Bioessays 2024; 46:e2300184. [PMID: 38047499 DOI: 10.1002/bies.202300184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/12/2023] [Accepted: 11/14/2023] [Indexed: 12/05/2023]
Abstract
Mammalian telomeres have evolved safeguards to prevent their recognition as DNA double-stranded breaks by suppressing the activation of various DNA sensing and repair proteins. We have shown that the telomere-binding proteins TRF2 and RAP1 cooperate to prevent telomeres from undergoing aberrant homology-directed recombination by mediating t-loop protection. Our recent findings also suggest that mammalian telomere-binding proteins interact with the nuclear envelope to maintain chromosome stability. RAP1 interacts with nuclear lamins through KU70/KU80, and disruption of RAP1 and TRF2 function result in nuclear envelope rupture, promoting telomere-telomere recombination to form structures termed ultrabright telomeres. In this review, we discuss the importance of the interactions between shelterin components and the nuclear envelope to maintain telomere homeostasis and genome stability.
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Affiliation(s)
- Rekha Rai
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Tori Sodeinde
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Ava Boston
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sandy Chang
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut, USA
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10
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Wang LL, Huang SJ, Zhao JT, Liu JY, Xiang MJ. Regulatory role of Mss11 in Candida glabrata virulence: adhesion and biofilm formation. Front Cell Infect Microbiol 2024; 13:1321094. [PMID: 38239503 PMCID: PMC10794409 DOI: 10.3389/fcimb.2023.1321094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 12/11/2023] [Indexed: 01/22/2024] Open
Abstract
Introduction Candida glabrata has emerged as a fungal pathogen with high infection and mortality rates, and its primary virulence factors are related to adhesion and biofilm formation. These virulence factors in C.glabrata are primarily mediated by epithelial adhesins (Epas), most of which are encoded in subtelomeric regions and regulated by subtelomeric silencing mechanisms. The transcription factor Mss11, known for its regulatory role in adhesion, biofilm formation, and filamentous growth in Saccharomyces cerevisiae and Candida albicans, has also been implicated in the expression of EPA6, suggesting its potential influence on C.glabrata virulence. The present study aims to determine the regulatory role of Mss11 in the virulence of C. glabrata. Methods In this work, a Δmss11 null mutant and its complemented strain were constructed from a C.glabrata standard strain. The impact of the transcription factor Mss11 on the virulence of C.glabrata was investigated through a series of phenotypic experiments, including the microbial adhesion to hydrocarbons (MATH) test, adherence assay, biofilm assay, scanning electron microscopy and Galleria mellonella virulence assay. Furthermore, transcriptome sequencing, quantitative reverse transcription polymerase chain reaction (RT-qPCR), and chromatin immunoprecipitation sequencing (ChIP-seq) were employed to investigate the molecular mechanisms behind the regulation of Mss11. Results In C.glabrata, the loss of MSS11 led to a significant reduction in several virulence factors including cell surface hydrophobicity, epithelial cell adhesion, and biofilm formation. These observations were consistent with the decreased virulence of the Δmss11 mutant observed in the Galleria mellonella infection model. Further exploration demonstrated that Mss11 modulates C. glabrata virulence by regulating EPA1 and EPA6 expression. It binds to the upstream regions of EPA1 and EPA6, as well as the promoter regions of the subtelomeric silencing-related genes SIR4, RIF1, and RAP1, indicating the dual regulatory role of Mss11. Conclusion Mss11 plays a crucial role in C. glabrata adhesion and biofilm formation, and thus has a broad influence on virulence. This regulation is achieved by regulating the expression of EPA1 and EPA6 through both promoter-specific regulation and subtelomeric silencing.
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Affiliation(s)
- Lu-Ling Wang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Laboratory Medicine, Ruijin Hospital Luwan Branch, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Si-Jia Huang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Laboratory Medicine, Ruijin Hospital Luwan Branch, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun-Tao Zhao
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jin-Yan Liu
- Department of Laboratory Medicine, Ruijin Hospital Luwan Branch, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ming-Jie Xiang
- Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Laboratory Medicine, Ruijin Hospital Luwan Branch, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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11
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Wong SY, Soman A, Korolev N, Surya W, Chen Q, Shum W, van Noort J, Nordenskiöld L. The shelterin component TRF2 mediates columnar stacking of human telomeric chromatin. EMBO J 2024; 43:87-111. [PMID: 38177309 PMCID: PMC10883271 DOI: 10.1038/s44318-023-00002-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 01/06/2024] Open
Abstract
Telomere repeat binding factor 2 (TRF2) is an essential component of the telomeres and also plays an important role in a number of other non-telomeric processes. Detailed knowledge of the binding and interaction of TRF2 with telomeric nucleosomes is limited. Here, we study the binding of TRF2 to in vitro-reconstituted kilobasepair-long human telomeric chromatin fibres using electron microscopy, single-molecule force spectroscopy and analytical ultracentrifugation sedimentation velocity. Our electron microscopy results revealed that full-length and N-terminally truncated TRF2 promote the formation of a columnar structure of the fibres with an average width and compaction larger than that induced by the addition of Mg2+, in agreement with the in vivo observations. Single-molecule force spectroscopy showed that TRF2 increases the mechanical and thermodynamic stability of the telomeric fibres when stretched with magnetic tweezers. This was in contrast to the result for fibres reconstituted on the 'Widom 601' high-affinity nucleosome positioning sequence, where minor effects on fibre stability were observed. Overall, TRF2 binding induces and stabilises columnar fibres, which may play an important role in telomere maintenance.
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Affiliation(s)
- Sook Yi Wong
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- Department of Emerging Infectious Diseases, Duke-NUS, Medical School, Singapore, 169857, Singapore
| | - Aghil Soman
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Nikolay Korolev
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Wahyu Surya
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Qinming Chen
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- M Diagnostics PTE. LTD, 30 Biopolis Street, Matrix, Singapore, 138671, Singapore
| | - Wayne Shum
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - John van Noort
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- Huygens-Kamerlingh Ones Laboratory, Leiden University, Leiden, 2333 AL, The Netherlands
| | - Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore.
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12
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Braun H, Xu Z, Chang F, Viceconte N, Rane G, Levin M, Lototska L, Roth F, Hillairet A, Fradera-Sola A, Khanchandani V, Sin ZW, Yong WK, Dreesen O, Yang Y, Shi Y, Li F, Butter F, Kappei D. ZNF524 directly interacts with telomeric DNA and supports telomere integrity. Nat Commun 2023; 14:8252. [PMID: 38086788 PMCID: PMC10716145 DOI: 10.1038/s41467-023-43397-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/08/2023] [Indexed: 12/18/2023] Open
Abstract
Telomeres are nucleoprotein structures at the ends of linear chromosomes. In humans, they consist of TTAGGG repeats, which are bound by dedicated proteins such as the shelterin complex. This complex blocks unwanted DNA damage repair at telomeres, e.g. by suppressing nonhomologous end joining (NHEJ) through its subunit TRF2. Here, we describe ZNF524, a zinc finger protein that directly binds telomeric repeats with nanomolar affinity, and reveal base-specific sequence recognition by cocrystallization with telomeric DNA. ZNF524 localizes to telomeres and specifically maintains the presence of the TRF2/RAP1 subcomplex at telomeres without affecting other shelterin members. Loss of ZNF524 concomitantly results in an increase in DNA damage signaling and recombination events. Overall, ZNF524 is a direct telomere-binding protein involved in the maintenance of telomere integrity.
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Affiliation(s)
- Hanna Braun
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
- Institute of Molecular Biology (IMB), Mainz, 55128, Germany
| | - Ziyan Xu
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Fiona Chang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | | | - Grishma Rane
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Michal Levin
- Institute of Molecular Biology (IMB), Mainz, 55128, Germany
| | | | - Franziska Roth
- Institute of Molecular Biology (IMB), Mainz, 55128, Germany
| | - Alexia Hillairet
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | | | - Vartika Khanchandani
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Zi Wayne Sin
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
| | - Wai Khang Yong
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117596, Singapore
| | - Oliver Dreesen
- Cell Aging Laboratory, A*STAR Skin Research Labs, Singapore, 138648, Singapore
| | - Yang Yang
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yunyu Shi
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Fudong Li
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
| | - Falk Butter
- Institute of Molecular Biology (IMB), Mainz, 55128, Germany.
- Institute of Molecular Virology and Cell Biology (IMVZ), Friedrich Loeffler Institute, Greifswald, 17493, Germany.
| | - Dennis Kappei
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore.
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117596, Singapore.
- NUS Center for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117599, Singapore.
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13
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Carvalho Borges PC, Bouabboune C, Escandell JM, Matmati S, Coulon S, Ferreira MG. Pot1 promotes telomere DNA replication via the Stn1-Ten1 complex in fission yeast. Nucleic Acids Res 2023; 51:12325-12336. [PMID: 37953281 PMCID: PMC10711446 DOI: 10.1093/nar/gkad1036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 10/19/2023] [Accepted: 10/31/2023] [Indexed: 11/14/2023] Open
Abstract
Telomeres are nucleoprotein complexes that protect the chromosome-ends from eliciting DNA repair while ensuring their complete duplication. Pot1 is a subunit of telomere capping complex that binds to the G-rich overhang and inhibits the activation of DNA damage checkpoints. In this study, we explore new functions of fission yeast Pot1 by using a pot1-1 temperature sensitive mutant. We show that pot1 inactivation impairs telomere DNA replication resulting in the accumulation of ssDNA leading to the complete loss of telomeric DNA. Recruitment of Stn1 to telomeres, an auxiliary factor of DNA lagging strand synthesis, is reduced in pot1-1 mutants and overexpression of Stn1 rescues loss of telomeres and cell viability at restrictive temperature. We propose that Pot1 plays a crucial function in telomere DNA replication by recruiting Stn1-Ten1 and Polα-primase complex to telomeres via Tpz1, thus promoting lagging-strand DNA synthesis at stalled replication forks.
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Affiliation(s)
| | - Chaïnez Bouabboune
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Equipe labellisée par la Ligue Nationale contre le Cancer, Marseille, F-13009, France
| | | | - Samah Matmati
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Equipe labellisée par la Ligue Nationale contre le Cancer, Marseille, F-13009, France
| | - Stéphane Coulon
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Equipe labellisée par la Ligue Nationale contre le Cancer, Marseille, F-13009, France
| | - Miguel Godinho Ferreira
- Instituto Gulbenkian de Ciência, Oeiras, 2781-901, Portugal
- Institute for Research on Cancer and Aging of Nice (IRCAN), INSERM U1081 UMR7284 CNRS, 06107 Nice, France
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14
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Malzl D, Peycheva M, Rahjouei A, Gnan S, Klein KN, Nazarova M, Schoeberl UE, Gilbert DM, Buonomo SCB, Di Virgilio M, Neumann T, Pavri R. RIF1 regulates early replication timing in murine B cells. Nat Commun 2023; 14:8049. [PMID: 38081811 PMCID: PMC10713614 DOI: 10.1038/s41467-023-43778-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
The mammalian DNA replication timing (RT) program is crucial for the proper functioning and integrity of the genome. The best-known mechanism for controlling RT is the suppression of late origins of replication in heterochromatin by RIF1. Here, we report that in antigen-activated, hypermutating murine B lymphocytes, RIF1 binds predominantly to early-replicating active chromatin and promotes early replication, but plays a minor role in regulating replication origin activity, gene expression and genome organization in B cells. Furthermore, we find that RIF1 functions in a complementary and non-epistatic manner with minichromosome maintenance (MCM) proteins to establish early RT signatures genome-wide and, specifically, to ensure the early replication of highly transcribed genes. These findings reveal additional layers of regulation within the B cell RT program, driven by the coordinated activity of RIF1 and MCM proteins.
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Affiliation(s)
- Daniel Malzl
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090, Lazarettgasse 14, Vienna, Austria
| | - Mihaela Peycheva
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090, Lazarettgasse 14, Vienna, Austria
| | - Ali Rahjouei
- Max-Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Stefano Gnan
- School of Biological Sciences, Institute of Cell Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Kyle N Klein
- San Diego Biomedical Research Institute, San Diego, CA, 92121, USA
| | - Mariia Nazarova
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria
| | - Ursula E Schoeberl
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria
| | - David M Gilbert
- San Diego Biomedical Research Institute, San Diego, CA, 92121, USA
| | - Sara C B Buonomo
- School of Biological Sciences, Institute of Cell Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Michela Di Virgilio
- Max-Delbruck Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
| | - Tobias Neumann
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria.
- Quantro Therapeutics, Vienna Biocenter, 1030, Vienna, Austria.
| | - Rushad Pavri
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, 1030, Vienna, Austria.
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15
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Chib S, Griffin WC, Gao J, Proffitt DR, Byrd AK, Raney KD. Pif1 Helicase Mediates Remodeling of Protein-Nucleic Acid Complexes by Promoting Dissociation of Sub1 from G-Quadruplex DNA and Cdc13 from G-Rich Single-Stranded DNA. Biochemistry 2023; 62:3360-3372. [PMID: 37948114 PMCID: PMC10841737 DOI: 10.1021/acs.biochem.3c00441] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Pif1 is a molecular motor enzyme that is conserved from yeast to mammals. It translocates on ssDNA with a directional bias (5' → 3') and unwinds duplexes using the energy obtained from ATP hydrolysis. Pif1 is involved in dsDNA break repair, resolution of G-quadruplex (G4) structures, negative regulation of telomeres, and Okazaki fragment maturation. An important property of this helicase is to exert force and disrupt protein-DNA complexes, which may otherwise serve as barriers to various cellular pathways. Previously, Pif1 was reported to displace streptavidin from biotinylated DNA, Rap1 from telomeric DNA, and telomerase from DNA ends. Here, we have investigated the ability of S. cerevisiae Pif1 helicase to disrupt protein barriers from G4 and telomeric sites. Yeast chromatin-associated transcription coactivator Sub1 was characterized as a G4 binding protein. We found evidence for a physical interaction between Pif1 helicase and Sub1 protein. Here, we demonstrate that Pif1 is capable of catalyzing the disruption of Sub1-bound G4 structures in an ATP-dependent manner. We also investigated Pif1-mediated removal of yeast telomere-capping protein Cdc13 from DNA ends. Cdc13 exhibits a high-affinity interaction with an 11-mer derived from the yeast telomere sequence. Our results show that Pif1 uses its translocase activity to enhance the dissociation of this telomere-specific protein from its binding site. The rate of dissociation increased with an increase in the helicase loading site length. Additionally, we examined the biochemical mechanism for Pif1-catalyzed protein displacement by mutating the sequence of the telomeric 11-mer on the 5'-end and the 3'-end. The results support a model whereby Pif1 disrupts Cdc13 from the ssDNA in steps.
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Affiliation(s)
- Shubeena Chib
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - Wezley C. Griffin
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - Jun Gao
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - David R. Proffitt
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - Alicia K. Byrd
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
| | - Kevin D. Raney
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205
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16
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Barcenilla BB, Meyers AD, Castillo-González C, Young P, Min JH, Song J, Phadke C, Land E, Canaday E, Perera IY, Bailey SM, Aquilano R, Wyatt SE, Shippen DE. Arabidopsis telomerase takes off by uncoupling enzyme activity from telomere length maintenance in space. Nat Commun 2023; 14:7854. [PMID: 38030615 PMCID: PMC10686995 DOI: 10.1038/s41467-023-41510-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 09/07/2023] [Indexed: 12/01/2023] Open
Abstract
Spaceflight-induced changes in astronaut telomeres have garnered significant attention in recent years. While plants represent an essential component of future long-duration space travel, the impacts of spaceflight on plant telomeres and telomerase have not been examined. Here we report on the telomere dynamics of Arabidopsis thaliana grown aboard the International Space Station. We observe no changes in telomere length in space-flown Arabidopsis seedlings, despite a dramatic increase in telomerase activity (up to 150-fold in roots), as well as elevated genome oxidation. Ground-based follow up studies provide further evidence that telomerase is induced by different environmental stressors, but its activity is uncoupled from telomere length. Supporting this conclusion, genetically engineered super-telomerase lines with enhanced telomerase activity maintain wildtype telomere length. Finally, genome oxidation is inversely correlated with telomerase activity levels. We propose a redox protective capacity for Arabidopsis telomerase that may promote survivability in harsh environments.
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Affiliation(s)
- Borja Barbero Barcenilla
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Alexander D Meyers
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, 45701, USA
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, 45701, USA
- NASA Postdoctoral Program, Oak Ridge Associated Universities, Kennedy Space Center FL, Merritt Island, FL, 32899, USA
| | - Claudia Castillo-González
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Pierce Young
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Ji-Hee Min
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Jiarui Song
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Chinmay Phadke
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA
| | - Eric Land
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Emma Canaday
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, 45701, USA
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, 45701, USA
| | - Imara Y Perera
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695, USA
| | - Susan M Bailey
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Roberto Aquilano
- National Technological University, Rosario Regional Faculty, Zeballos 1341, S2000, Rosario, Argentina
| | - Sarah E Wyatt
- Department of Environmental and Plant Biology, Ohio University, Athens, OH, 45701, USA.
- Molecular and Cellular Biology Program, Ohio University, Athens, OH, 45701, USA.
| | - Dorothy E Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843, USA.
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17
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Zhang Y, Hou K, Tong J, Zhang H, Xiong M, Liu J, Jia S. The Altered Functions of Shelterin Components in ALT Cells. Int J Mol Sci 2023; 24:16830. [PMID: 38069153 PMCID: PMC10706665 DOI: 10.3390/ijms242316830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/23/2023] [Accepted: 11/24/2023] [Indexed: 12/18/2023] Open
Abstract
Telomeres are nucleoprotein complexes that cap the ends of eukaryotic linear chromosomes. Telomeric DNA is bound by shelterin protein complex to prevent telomeric chromosome ends from being recognized as damaged sites for abnormal repair. To overcome the end replication problem, cancer cells mostly preserve their telomeres by reactivating telomerase, but a minority (10-15%) of cancer cells use a homologous recombination-based pathway called alternative lengthening of telomeres (ALT). Recent studies have found that shelterin components play an important role in the ALT mechanism. The binding of TRF1, TRF2, and RAP1 to telomeres attenuates ALT activation, while the maintenance of ALT telomere requires TRF1 and TRF2. POT1 and TPP1 can also influence the occurrence of ALT. The elucidation of how shelterin regulates the initiation of ALT remains elusive. This review presents a comprehensive overview of the current findings on the regulation of ALT by shelterin components, aiming to enhance the insight into the altered functions of shelterin components in ALT cells and to identify potential targets for the treatment of ALT tumor cells.
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Affiliation(s)
| | | | | | | | | | - Jing Liu
- Laboratory of Molecular Genetics of Aging and Tumor, Medical School, Kunming University of Science and Technology, 727 Jing Ming Nan Road, Kunming 650500, China; (Y.Z.); (K.H.); (J.T.); (H.Z.); (M.X.)
| | - Shuting Jia
- Laboratory of Molecular Genetics of Aging and Tumor, Medical School, Kunming University of Science and Technology, 727 Jing Ming Nan Road, Kunming 650500, China; (Y.Z.); (K.H.); (J.T.); (H.Z.); (M.X.)
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18
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Colin L, Reyes C, Berthezene J, Maestroni L, Modolo L, Toselli E, Chanard N, Schaak S, Cuvier O, Gachet Y, Coulon S, Bernard P, Tournier S. Condensin positioning at telomeres by shelterin proteins drives sister-telomere disjunction in anaphase. eLife 2023; 12:RP89812. [PMID: 37988290 PMCID: PMC10662949 DOI: 10.7554/elife.89812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023] Open
Abstract
The localization of condensin along chromosomes is crucial for their accurate segregation in anaphase. Condensin is enriched at telomeres but how and for what purpose had remained elusive. Here, we show that fission yeast condensin accumulates at telomere repeats through the balancing acts of Taz1, a core component of the shelterin complex that ensures telomeric functions, and Mit1, a nucleosome remodeler associated with shelterin. We further show that condensin takes part in sister-telomere separation in anaphase, and that this event can be uncoupled from the prior separation of chromosome arms, implying a telomere-specific separation mechanism. Consistent with a cis-acting process, increasing or decreasing condensin occupancy specifically at telomeres modifies accordingly the efficiency of their separation in anaphase. Genetic evidence suggests that condensin promotes sister-telomere separation by counteracting cohesin. Thus, our results reveal a shelterin-based mechanism that enriches condensin at telomeres to drive in cis their separation during mitosis.
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Affiliation(s)
- Léonard Colin
- CNRS - Laboratory of Biology and Modelling of the CellLyonFrance
- ENS de Lyon, Université Lyon, site Jacques MonodLyonFrance
| | - Celine Reyes
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
| | - Julien Berthezene
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
| | - Laetitia Maestroni
- CNRS, INSERM, Aix Marseille Université, Institut Paoli-Calmettes, CRCM, Equipe labellisée par la Ligue Nationale contre le CancerMarseilleFrance
| | - Laurent Modolo
- CNRS - Laboratory of Biology and Modelling of the CellLyonFrance
- ENS de Lyon, Université Lyon, site Jacques MonodLyonFrance
| | - Esther Toselli
- CNRS - Laboratory of Biology and Modelling of the CellLyonFrance
- ENS de Lyon, Université Lyon, site Jacques MonodLyonFrance
| | - Nicolas Chanard
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
- CBI, MCD-UMR5077, CNRS, Chromatin Dynamics TeamToulouseFrance
| | - Stephane Schaak
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
- CBI, MCD-UMR5077, CNRS, Chromatin Dynamics TeamToulouseFrance
| | - Olivier Cuvier
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
- CBI, MCD-UMR5077, CNRS, Chromatin Dynamics TeamToulouseFrance
| | - Yannick Gachet
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
| | - Stephane Coulon
- CNRS, INSERM, Aix Marseille Université, Institut Paoli-Calmettes, CRCM, Equipe labellisée par la Ligue Nationale contre le CancerMarseilleFrance
| | - Pascal Bernard
- CNRS - Laboratory of Biology and Modelling of the CellLyonFrance
- ENS de Lyon, Université Lyon, site Jacques MonodLyonFrance
| | - Sylvie Tournier
- MCD, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPSToulouseFrance
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19
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Liu L, Luo H, Sheng Y, Kang X, Peng H, Luo H, Fan LL. A novel mutation of CTC1 leads to telomere shortening in a chinese family with interstitial lung disease. Hereditas 2023; 160:37. [PMID: 37978541 PMCID: PMC10656953 DOI: 10.1186/s41065-023-00299-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/25/2023] [Indexed: 11/19/2023] Open
Abstract
Interstitial lung diseases (ILDs), or diffuse pulmonary lung disease, are a subset of lung diseases that primarily affect lung alveoli and the space around interstitial tissue and bronchioles. It clinically manifests as progressive dyspnea, and patients often exhibit a varied decrease in pulmonary diffusion function. Recently, variants in telomere biology-related genes have been identified as genetic lesions of ILDs. Here, we enrolled 82 patients with interstitial pneumonia from 2017 to 2021 in our hospital to explore the candidate gene mutations of these patients via whole-exome sequencing. After data filtering, a novel heterozygous mutation (NM_025099: p.Gly131Arg) of CTC1 was identified in two affected family members. As a component of CST (CTC1-STN1-TEN1) complex, CTC1 is responsible for maintaining telomeric structure integrity and has also been identified as a candidate gene for IPF, a special kind of chronic ILD with insidious onset. Simultaneously, real-time PCR revealed that two affected family members presented with short telomere lengths, which further confirmed the effect of the mutation in the CTC1 gene. Our study not only expanded the mutation spectrum of CTC1 and provided epidemiological data on ILDs caused by CTC1 mutations but also further confirmed the relationship between heterozygous mutations in CTC1 and ILDs, which may further contribute to understanding the mechanisms underlying ILDs.
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Affiliation(s)
- Lv Liu
- Department of Pulmonary and Critical Care Medicine, Research Unit of Respiratory Disease, Hunan Diagnosis and Treatment Center of Respiratory Disease, the Second Xiangya Hospital, Central South University, Changsha, China
- Department of Cell biology, School of Life Science, Central South University, Changsha, China
| | - Hua Luo
- Department of Cardio-Thoracic Surgery, Changsha Medical School, the Affiliated Changsha Central Hospital, University of South China, Changsha, China
| | - Yue Sheng
- Department of Cell biology, School of Life Science, Central South University, Changsha, China
| | - Xi Kang
- Department of Pulmonary and Critical Care Medicine, Research Unit of Respiratory Disease, Hunan Diagnosis and Treatment Center of Respiratory Disease, the Second Xiangya Hospital, Central South University, Changsha, China
| | - Hong Peng
- Department of Pulmonary and Critical Care Medicine, Research Unit of Respiratory Disease, Hunan Diagnosis and Treatment Center of Respiratory Disease, the Second Xiangya Hospital, Central South University, Changsha, China
| | - Hong Luo
- Department of Pulmonary and Critical Care Medicine, Research Unit of Respiratory Disease, Hunan Diagnosis and Treatment Center of Respiratory Disease, the Second Xiangya Hospital, Central South University, Changsha, China.
| | - Liang-Liang Fan
- Department of Cell biology, School of Life Science, Central South University, Changsha, China.
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20
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Hassanpour H, Mirshokraei P, Salehpour M, Amiri K, Ghareghani P, Nasiri L. Canine sperm motility is associated with telomere shortening and changes in expression of shelterin genes. BMC Vet Res 2023; 19:236. [PMID: 37950187 PMCID: PMC10637008 DOI: 10.1186/s12917-023-03795-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 10/28/2023] [Indexed: 11/12/2023] Open
Abstract
BACKGROUND Motion quality is a critical property for essential functions. Several endogenous and exogenous factors are involved in sperm motility. Here, we measured the relative telomere length and evaluated the gene expression of its binding-proteins, shelterin complex (TRF1, TRF2, RAP1, POT1, TIN2, and TPP1) in sperm of dogs using relative quantitative real-time PCR. We compared them between two sperm subpopulations with poor and good motion qualities (separated by swim-up method). Telomere shortening and alterations of shelterin gene expression result from ROS, genotoxic insults, and genetic predisposition. RESULTS Sperm kinematic parameters were measured in two subpopulations and then telomeric index of each parameter was calculated. Telomeric index for linearity, VSL, VCL, STR, BCF, and ALH were significantly higher in sperms with good motion quality than in sperms with poor quality. We demonstrated that poor motion quality is associated with shorter telomere, higher expression of TRF2, POT1, and TIN2 genes, and lower expression of the RAP1 gene in dog sperm. The levels of TRF1 and TPP1 gene expression remained consistent despite variations in sperm quality and telomere length. CONCLUSION Data provided evidence that there are considerable changes in gene expression of many shelterin components (TRF2, TIN2, POT1and RAP1) associated with shortening telomere in the spermatozoa with poor motion quality. Possibly, the poor motion quality is the result of defects in the shelterin complex and telomere length. Our data suggests a new approach in the semen assessment and etiologic investigations of subfertility or infertility in male animals.
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Affiliation(s)
- Hossein Hassanpour
- Department of Gametes and Cloning, Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran.
| | - Pezhman Mirshokraei
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Marzieh Salehpour
- Department of Gametes and Cloning, Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran
| | - Khadije Amiri
- Department of Gametes and Cloning, Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran
| | - Parvin Ghareghani
- Department of Gametes and Cloning, Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran
| | - Leila Nasiri
- Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran
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21
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Gali VK, Monerawela C, Laksir Y, Hiraga SI, Donaldson AD. Checkpoint phosphorylation sites on budding yeast Rif1 protect nascent DNA from degradation by Sgs1-Dna2. PLoS Genet 2023; 19:e1011044. [PMID: 37956214 PMCID: PMC10681312 DOI: 10.1371/journal.pgen.1011044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 11/27/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023] Open
Abstract
In budding yeast the Rif1 protein is important for protecting nascent DNA at blocked replication forks, but the mechanism has been unclear. Here we show that budding yeast Rif1 must interact with Protein Phosphatase 1 to protect nascent DNA. In the absence of Rif1, removal of either Dna2 or Sgs1 prevents nascent DNA degradation, implying that Rif1 protects nascent DNA by targeting Protein Phosphatase 1 to oppose degradation by the Sgs1-Dna2 nuclease-helicase complex. This functional role for Rif1 is conserved from yeast to human cells. Yeast Rif1 was previously identified as a target of phosphorylation by the Tel1/Mec1 checkpoint kinases, but the importance of this phosphorylation has been unclear. We find that nascent DNA protection depends on a cluster of Tel1/Mec1 consensus phosphorylation sites in the Rif1 protein sequence, indicating that the intra-S phase checkpoint acts to protect nascent DNA through Rif1 phosphorylation. Our observations uncover the pathway by which budding yeast Rif1 stabilises newly synthesised DNA, highlighting the crucial role Rif1 plays in maintaining genome stability from lower eukaryotes to humans.
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Affiliation(s)
- Vamsi Krishna Gali
- Chromosome & Cellular Dynamics Section, Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Chandre Monerawela
- Chromosome & Cellular Dynamics Section, Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Yassine Laksir
- Chromosome & Cellular Dynamics Section, Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Shin-Ichiro Hiraga
- Chromosome & Cellular Dynamics Section, Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
| | - Anne D Donaldson
- Chromosome & Cellular Dynamics Section, Institute of Medical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom
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22
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Manzato C, Larini L, Oss Pegorar C, Dello Stritto MR, Jurikova K, Jantsch V, Cusanelli E. TERRA expression is regulated by the telomere-binding proteins POT-1 and POT-2 in Caenorhabditis elegans. Nucleic Acids Res 2023; 51:10681-10699. [PMID: 37713629 PMCID: PMC10602879 DOI: 10.1093/nar/gkad742] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/23/2023] [Accepted: 08/31/2023] [Indexed: 09/17/2023] Open
Abstract
Several aspects of telomere biology are regulated by the telomeric repeat-containing RNA TERRA. While TERRA expression is conserved through evolution, species-specific mechanisms regulate its biogenesis and function. Here we report on the expression of TERRA in Caenorhabditis elegans. We show that C. elegans TERRA is regulated by the telomere-binding proteins POT-1 and POT-2 which repress TERRA in a telomere-specific manner. C. elegans TERRA transcripts are heterogeneous in length and form discrete nuclear foci, as detected by RNA FISH, in both postmitotic and germline cells; a fraction of TERRA foci localizes to telomeres. Interestingly, in germ cells, TERRA is expressed in all stages of meiotic prophase I, and it increases during pachytene, a stage in meiosis when homologous recombination is ongoing. We used the MS2-GFP system to study the spatiotemporal dynamics of single-telomere TERRA molecules. Single particle tracking revealed different types of motilities, suggesting complex dynamics of TERRA transcripts. Finally, we unveiled distinctive features of C. elegans TERRA, which is regulated by telomere shortening in a telomere-specific manner, and it is upregulated in the telomerase-deficient trt-1; pot-2 double mutant prior to activation of the alternative lengthening mechanism ALT. Interestingly, in these worms TERRA displays distinct dynamics with a higher fraction of fast-moving particles.
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Affiliation(s)
- Caterina Manzato
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, 38123, Trento, Italy
| | - Luca Larini
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, 38123, Trento, Italy
| | - Claudio Oss Pegorar
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, 38123, Trento, Italy
| | - Maria Rosaria Dello Stritto
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter 1030, Vienna, Austria
| | - Katarina Jurikova
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, 38123, Trento, Italy
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Mlynská dolina 84215, Bratislava, Slovakia
| | - Verena Jantsch
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter 1030, Vienna, Austria
| | - Emilio Cusanelli
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, 38123, Trento, Italy
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23
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Li Q, Wang X, Liu J, Wu L, Xu S. POT1 involved in telomeric DNA damage repair and genomic stability of cervical cancer cells in response to radiation. Mutat Res Genet Toxicol Environ Mutagen 2023; 891:503670. [PMID: 37770150 DOI: 10.1016/j.mrgentox.2023.503670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 07/25/2023] [Accepted: 08/05/2023] [Indexed: 10/03/2023]
Abstract
Though telomeres play a crucial role in maintaining genomic stability in cancer cells and have emerged as attractive therapeutic targets in anticancer therapy, the relationship between telomere dysfunction and genomic instability induced by irradiation is still unclear. In this study, we identified that protection of telomeres 1 (POT1), a single-stranded DNA (ssDNA)-binding protein, was upregulated in γ-irradiated HeLa cells and in cancer patients who exhibit radiation tolerance. Knockdown of POT1 delayed the repair of radiation-induced telomeric DNA damage which was associated with enhanced H3K9 trimethylation and enhanced the radiosensitivity of HeLa cells. The depletion of POT1 also resulted in significant genomic instability, by showing a significant increase in end-to-end chromosomal fusions, and the formation of anaphase bridges and micronuclei. Furthermore, knockdown of POT1 disturbed telomerase recruitment to telomere, and POT1 could interact with phosphorylated ATM (p-ATM) and POT1 depletion decreased the levels of p-ATM induced by irradiation, suggesting that POT1 could regulate the telomerase recruitment to telomeres to repair irradiation-induced telomeric DNA damage of HeLa cells through interactions with p-ATM. The enhancement of radiosensitivity in cancer cells can be achieved through the combination of POT1 and telomerase inhibitors, presenting a potential approach for radiotherapy in cancer treatment.
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Affiliation(s)
- Qian Li
- School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, PR China
| | - Xiaofei Wang
- School of Biology, Food and Environment, Hefei University, Hefei 230601, PR China
| | - Jie Liu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, PR China
| | - Lijun Wu
- School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei, Anhui 230026, PR China; Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, PR China.
| | - Shengmin Xu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230601, PR China.
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24
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Sullivan DI, Bello FM, Silva AG, Redding KM, Giordano L, Hinchie AM, Loughridge KE, Mora AL, Königshoff M, Kaufman BA, Jurczak MJ, Alder JK. Intact mitochondrial function in the setting of telomere-induced senescence. Aging Cell 2023; 22:e13941. [PMID: 37688329 PMCID: PMC10577573 DOI: 10.1111/acel.13941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/25/2023] [Accepted: 07/07/2023] [Indexed: 09/10/2023] Open
Abstract
Mitochondria play essential roles in metabolic support and signaling within all cells. Congenital and acquired defects in mitochondria are responsible for several pathologies, including premature entrance to cellar senescence. Conversely, we examined the consequences of dysfunctional telomere-driven cellular senescence on mitochondrial biogenesis and function. We drove senescence in vitro and in vivo by deleting the telomere-binding protein TRF2 in fibroblasts and hepatocytes, respectively. Deletion of TRF2 led to a robust DNA damage response, global changes in transcription, and induction of cellular senescence. In vitro, senescent cells had significant increases in mitochondrial respiratory capacity driven by increased cellular and mitochondrial volume. Hepatocytes with dysfunctional telomeres maintained their mitochondrial respiratory capacity in vivo, whether measured in intact cells or purified mitochondria. Induction of senescence led to the upregulation of overlapping and distinct genes in fibroblasts and hepatocytes, but transcripts related to mitochondria were preserved. Our results support that mitochondrial function and activity are preserved in telomere dysfunction-induced senescence, which may facilitate continued cellular functions.
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Affiliation(s)
- Daniel I. Sullivan
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Fiona M. Bello
- Division of Endocrinology and MetabolismUniversity of PittsburghPittsburghPennsylvaniaUSA
- Center for Metabolism and Mitochondrial MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Agustin Gil Silva
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Kevin M. Redding
- Center for Metabolism and Mitochondrial MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
- Heart, Lung, and Blood Vascular Medicine InstituteUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Luca Giordano
- Center for Metabolism and Mitochondrial MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
- Heart, Lung, and Blood Vascular Medicine InstituteUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Angela M. Hinchie
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Kelly E. Loughridge
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Ana L. Mora
- Division of Pulmonary, Critical Care and Sleep Medicine, Davis Heart Lung Research InstituteThe Ohio State UniversityColumbusOhioUSA
| | - Melanie Königshoff
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Brett A. Kaufman
- Center for Metabolism and Mitochondrial MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
- Heart, Lung, and Blood Vascular Medicine InstituteUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Michael J. Jurczak
- Division of Endocrinology and MetabolismUniversity of PittsburghPittsburghPennsylvaniaUSA
- Center for Metabolism and Mitochondrial MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Jonathan K. Alder
- Dorothy P. and Richard P. Simmons Center for Interstitial Lung Disease, Division of Pulmonary, Allergy, and Critical Care MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
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25
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Nakashima K, Kunisaki Y, Hosokawa K, Gotoh K, Yao H, Yuta R, Semba Y, Nogami J, Kikushige Y, Stumpf PS, MacArthur BD, Kang D, Akashi K, Ohga S, Arai F. POT1a deficiency in mesenchymal niches perturbs B-lymphopoiesis. Commun Biol 2023; 6:996. [PMID: 37773433 PMCID: PMC10541440 DOI: 10.1038/s42003-023-05374-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 09/18/2023] [Indexed: 10/01/2023] Open
Abstract
Protection of telomeres 1a (POT1a) is a telomere binding protein. A decrease of POT1a is related to myeloid-skewed haematopoiesis with ageing, suggesting that protection of telomeres is essential to sustain multi-potency. Since mesenchymal stem cells (MSCs) are a constituent of the hematopoietic niche in bone marrow, their dysfunction is associated with haematopoietic failure. However, the importance of telomere protection in MSCs has yet to be elucidated. Here, we show that genetic deletion of POT1a in MSCs leads to intracellular accumulation of fatty acids and excessive ROS and DNA damage, resulting in impaired osteogenic-differentiation. Furthermore, MSC-specific POT1a deficient mice exhibited skeletal retardation due to reduction of IL-7 producing bone lining osteoblasts. Single-cell gene expression profiling of bone marrow from POT1a deficient mice revealed that B-lymphopoiesis was selectively impaired. These results demonstrate that bone marrow microenvironments composed of POT1a deficient MSCs fail to support B-lymphopoiesis, which may underpin age-related myeloid-bias in haematopoiesis.
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Affiliation(s)
- Kentaro Nakashima
- Department of Stem Cell Biology and Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yuya Kunisaki
- Department of Stem Cell Biology and Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
- Center for Cellular and Molecular Medicine, Kyushu University Hospital, Fukuoka, Japan.
- Department of Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.
| | - Kentaro Hosokawa
- Department of Stem Cell Biology and Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazuhito Gotoh
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hisayuki Yao
- Department of Stem Cell Biology and Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Ryosuke Yuta
- Department of Stem Cell Biology and Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yuichiro Semba
- Center for Cellular and Molecular Medicine, Kyushu University Hospital, Fukuoka, Japan
- Department of Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Jumpei Nogami
- Center for Cellular and Molecular Medicine, Kyushu University Hospital, Fukuoka, Japan
- Department of Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Yoshikane Kikushige
- Center for Cellular and Molecular Medicine, Kyushu University Hospital, Fukuoka, Japan
- Department of Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Patrick S Stumpf
- Joint Research Center for Computational Biomedicine, RWTH Aachen University, Aachen, Germany
| | - Ben D MacArthur
- Centre for Human Development, Stem Cells and Regeneration, Faculty of Medicine, University of Southampton, Southampton, UK
- Mathematical Sciences, University of Southampton, Southampton, UK
- The Alan Turing Institute, London, UK
| | - Dongchon Kang
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Koichi Akashi
- Department of Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan
| | - Shouichi Ohga
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Fumio Arai
- Department of Stem Cell Biology and Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
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26
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Takasugi T, Gu P, Liang F, Staco I, Chang S. Pot1b -/- tumors activate G-quadruplex-induced DNA damage to promote telomere hyper-elongation. Nucleic Acids Res 2023; 51:9227-9247. [PMID: 37560909 PMCID: PMC10516629 DOI: 10.1093/nar/gkad648] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/14/2023] [Accepted: 07/22/2023] [Indexed: 08/11/2023] Open
Abstract
Malignant cancers must activate telomere maintenance mechanisms to achieve replicative immortality. Mutations in the human Protection of Telomeres 1 (POT1) gene are frequently detected in cancers with abnormally long telomeres, suggesting that the loss of POT1 function disrupts the regulation of telomere length homeostasis to promote telomere elongation. However, our understanding of the mechanisms leading to elongated telomeres remains incomplete. The mouse genome encodes two POT1 proteins, POT1a and POT1b possessing separation of hPOT1 functions. We performed serial transplantation of Pot1b-/- sarcomas to better understand the role of POT1b in regulating telomere length maintenance. While early-generation Pot1b-/- sarcomas initially possessed shortened telomeres, late-generation Pot1b-/- cells display markedly hyper-elongated telomeres that were recognized as damaged DNA by the Replication Protein A (RPA) complex. The RPA-ATR-dependent DNA damage response at telomeres promotes telomerase recruitment to facilitate telomere hyper-elongation. POT1b, but not POT1a, was able to unfold G-quadruplex present in hyper-elongated telomeres to repress the DNA damage response. Our findings demonstrate that the repression of the RPA-ATR DDR is conserved between POT1b and human POT1, suggesting that similar mechanisms may underly the phenotypes observed in human cancers harboring human POT1 mutations.
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Affiliation(s)
- Taylor Takasugi
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Peili Gu
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Fengshan Liang
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Isabelle Staco
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Sandy Chang
- Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA
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27
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Wolf SE, Shalev I. The shelterin protein expansion of telomere dynamics: Linking early life adversity, life history, and the hallmarks of aging. Neurosci Biobehav Rev 2023; 152:105261. [PMID: 37268182 PMCID: PMC10527177 DOI: 10.1016/j.neubiorev.2023.105261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 04/10/2023] [Accepted: 05/30/2023] [Indexed: 06/04/2023]
Abstract
Aging is characterized by functional decline occurring alongside changes to several hallmarks of aging. One of the hallmarks includes attrition of repeated DNA sequences found at the ends of chromosomes called telomeres. While telomere attrition is linked to morbidity and mortality, whether and how it causally contributes to lifelong rates of functional decline is unclear. In this review, we propose the shelterin-telomere hypothesis of life history, in which telomere-binding shelterin proteins translate telomere attrition into a range of physiological outcomes, the extent of which may be modulated by currently understudied variation in shelterin protein levels. Shelterin proteins may expand the breadth and timing of consequences of telomere attrition, e.g., by translating early life adversity into acceleration of the aging process. We consider how the pleiotropic roles of shelterin proteins provide novel insights into natural variation in physiology, life history, and lifespan. We highlight key open questions that encourage the integrative, organismal study of shelterin proteins that enhances our understanding of the contribution of the telomere system to aging.
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Affiliation(s)
- Sarah E Wolf
- Department of Biobehavioral Health, Penn State University, University Park, PA 16802, USA.
| | - Idan Shalev
- Department of Biobehavioral Health, Penn State University, University Park, PA 16802, USA
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28
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Teano G, Concia L, Wolff L, Carron L, Biocanin I, Adamusová K, Fojtová M, Bourge M, Kramdi A, Colot V, Grossniklaus U, Bowler C, Baroux C, Carbone A, Probst AV, Schrumpfová PP, Fajkus J, Amiard S, Grob S, Bourbousse C, Barneche F. Histone H1 protects telomeric repeats from H3K27me3 invasion in Arabidopsis. Cell Rep 2023; 42:112894. [PMID: 37515769 DOI: 10.1016/j.celrep.2023.112894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 12/02/2022] [Accepted: 07/13/2023] [Indexed: 07/31/2023] Open
Abstract
While the pivotal role of linker histone H1 in shaping nucleosome organization is well established, its functional interplays with chromatin factors along the epigenome are just starting to emerge. Here we show that, in Arabidopsis, as in mammals, H1 occupies Polycomb Repressive Complex 2 (PRC2) target genes where it favors chromatin condensation and H3K27me3 deposition. We further show that, contrasting with its conserved function in PRC2 activation at genes, H1 selectively prevents H3K27me3 accumulation at telomeres and large pericentromeric interstitial telomeric repeat (ITR) domains by restricting DNA accessibility to Telomere Repeat Binding (TRB) proteins, a group of H1-related Myb factors mediating PRC2 cis recruitment. This study provides a mechanistic framework by which H1 avoids the formation of gigantic H3K27me3-rich domains at telomeric sequences and contributes to safeguard nucleus architecture.
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Affiliation(s)
- Gianluca Teano
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France; Université Paris-Saclay, 91190 Orsay, France
| | - Lorenzo Concia
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Léa Wolff
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Léopold Carron
- Sorbonne Université, CNRS, IBPS, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), 75005 Paris, France
| | - Ivona Biocanin
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France; Université Paris-Saclay, 91190 Orsay, France
| | - Kateřina Adamusová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Miloslava Fojtová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Michael Bourge
- Cytometry Facility, Imagerie-Gif, Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Amira Kramdi
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Vincent Colot
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Chris Bowler
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Célia Baroux
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Alessandra Carbone
- Sorbonne Université, CNRS, IBPS, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative (LCQB), 75005 Paris, France
| | - Aline V Probst
- CNRS UMR6293, Université Clermont Auvergne, INSERM U1103, GReD, CRBC, Clermont-Ferrand, France
| | - Petra Procházková Schrumpfová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic; Laboratory of Functional Genomics and Proteomics, NCBR, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Simon Amiard
- CNRS UMR6293, Université Clermont Auvergne, INSERM U1103, GReD, CRBC, Clermont-Ferrand, France
| | - Stefan Grob
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Clara Bourbousse
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Fredy Barneche
- Institut de biologie de l'École normale supérieure (IBENS), École normale supérieure, CNRS, INSERM, Université PSL, Paris, France.
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29
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Tesmer VM, Brenner KA, Nandakumar J. Human POT1 protects the telomeric ds-ss DNA junction by capping the 5' end of the chromosome. Science 2023; 381:771-778. [PMID: 37590346 PMCID: PMC10666826 DOI: 10.1126/science.adi2436] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/19/2023] [Indexed: 08/19/2023]
Abstract
Protection of telomeres 1 (POT1) is the 3' single-stranded overhang-binding telomeric protein that prevents an ataxia telangiectasia and Rad3-related (ATR) DNA damage response (DDR) at chromosome ends. What precludes the DDR machinery from accessing the telomeric double-stranded-single-stranded junction is unknown. We demonstrate that human POT1 binds this junction by recognizing the phosphorylated 5' end of the chromosome. High-resolution crystallographic structures reveal that the junction is capped by POT1 through a "POT-hole" surface, the mutation of which compromises junction protection in vitro and telomeric 5'-end definition and DDR suppression in human cells. Whereas both mouse POT1 paralogs bind the single-stranded overhang, POT1a, not POT1b, contains a POT-hole and binds the junction, which explains POT1a's sufficiency for end protection. Our study shifts the paradigm for DDR suppression at telomeres by highlighting the importance of protecting the double-stranded-single-stranded junction.
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Affiliation(s)
- Valerie M. Tesmer
- Department of Molecular, Cellular and Developmental Biology, University of Michigan; Ann Arbor, 48109, USA
| | - Kirsten A. Brenner
- Department of Molecular, Cellular and Developmental Biology, University of Michigan; Ann Arbor, 48109, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular and Developmental Biology, University of Michigan; Ann Arbor, 48109, USA
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30
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Barbour AT, Wuttke DS. RPA-like single-stranded DNA-binding protein complexes including CST serve as specialized processivity factors for polymerases. Curr Opin Struct Biol 2023; 81:102611. [PMID: 37245465 PMCID: PMC10524659 DOI: 10.1016/j.sbi.2023.102611] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 04/17/2023] [Accepted: 04/25/2023] [Indexed: 05/30/2023]
Abstract
Telomeres and other single-stranded regions of the genome require specialized management to maintain stability and for proper progression of DNA metabolism pathways. Human Replication Protein A and CTC1-STN1-TEN1 are structurally similar heterotrimeric protein complexes that have essential ssDNA-binding roles in DNA replication, repair, and telomeres. Yeast and ciliates have related ssDNA-binding proteins with strikingly conserved structural features to these human heterotrimeric protein complexes. Recent breakthrough structures have extended our understanding of these commonalities by illuminating a common mechanism used by these proteins to act as processivity factors for their partner polymerases through their ability to manage ssDNA.
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Affiliation(s)
- Alexandra T Barbour
- Department of Biochemistry, University of Colorado Bouder, Boulder, CO 80309, USA
| | - Deborah S Wuttke
- Department of Biochemistry, University of Colorado Bouder, Boulder, CO 80309, USA.
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31
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Abstract
It has been known for decades that telomerase extends the 3' end of linear eukaryotic chromosomes and dictates the telomeric repeat sequence based on the template in its RNA. However, telomerase does not mitigate sequence loss at the 5' ends of chromosomes, which results from lagging strand DNA synthesis and nucleolytic processing. Therefore, a second enzyme is needed to keep telomeres intact: DNA polymerase α/Primase bound to Ctc1-Stn1-Ten1 (CST). CST-Polα/Primase maintains telomeres through a fill-in reaction that replenishes the lost sequences at the 5' ends. CST not only serves to maintain telomeres but also determines their length by keeping telomerase from overelongating telomeres. Here we discuss recent data on the evolution, structure, function, and recruitment of mammalian CST-Polα/Primase, highlighting the role of this complex and telomere length control in human disease.
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Affiliation(s)
- Sarah W Cai
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10065, USA
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, New York 10065, USA
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32
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Vaurs M, Naiman K, Bouabboune C, Rai S, Ptasińska K, Rives M, Matmati S, Carr AM, Géli V, Coulon S. Stn1-Ten1 and Taz1 independently promote replication of subtelomeric fragile sequences in fission yeast. Cell Rep 2023; 42:112537. [PMID: 37243596 DOI: 10.1016/j.celrep.2023.112537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 03/01/2023] [Accepted: 05/03/2023] [Indexed: 05/29/2023] Open
Abstract
Efficient replication of terminal DNA is crucial to maintain telomere stability. In fission yeast, Taz1 and the Stn1-Ten1 (ST) complex play prominent roles in DNA-ends replication. However, their function remains elusive. Here, we have analyzed genome-wide replication and show that ST does not affect genome-wide replication but is crucial for the efficient replication of a subtelomeric region called STE3-2. We further show that, when ST function is compromised, a homologous recombination (HR)-based fork restart mechanism becomes necessary for STE3-2 stability. While both Taz1 and Stn1 bind to STE3-2, we find that the STE3-2 replication function of ST is independent of Taz1 but relies on its association with the shelterin proteins Pot1-Tpz1-Poz1. Finally, we demonstrate that the firing of an origin normally inhibited by Rif1 can circumvent the replication defect of subtelomeres when ST function is compromised. Our results help illuminate why fission yeast telomeres are terminal fragile sites.
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Affiliation(s)
- Mélina Vaurs
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Karel Naiman
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France; Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Chaïnez Bouabboune
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Sudhir Rai
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Katarzyna Ptasińska
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Marion Rives
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Samah Matmati
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France
| | - Antony M Carr
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer BN1 9RQ, UK
| | - Vincent Géli
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France.
| | - Stéphane Coulon
- CNRS, INSERM, Aix Marseille Univ, Institut Paoli-Calmettes, CRCM, Ligue Nationale Contre le Cancer (équipe labellisée), Marseille, France.
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33
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Wang H, Ma T, Zhang X, Chen W, Lan Y, Kuang G, Hsu SJ, He Z, Chen Y, Stewart J, Bhattacharjee A, Luo Z, Price C, Feng X. CTC1 OB-B interaction with TPP1 terminates telomerase and prevents telomere overextension. Nucleic Acids Res 2023; 51:4914-4928. [PMID: 37021555 PMCID: PMC10250220 DOI: 10.1093/nar/gkad237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 03/16/2023] [Accepted: 03/31/2023] [Indexed: 04/07/2023] Open
Abstract
CST (CTC1-STN1-TEN1) is a telomere associated complex that binds ssDNA and is required for multiple steps in telomere replication, including termination of G-strand extension by telomerase and synthesis of the complementary C-strand. CST contains seven OB-folds which appear to mediate CST function by modulating CST binding to ssDNA and the ability of CST to recruit or engage partner proteins. However, the mechanism whereby CST achieves its various functions remains unclear. To address the mechanism, we generated a series of CTC1 mutants and studied their effect on CST binding to ssDNA and their ability to rescue CST function in CTC1-/- cells. We identified the OB-B domain as a key determinant of telomerase termination but not C-strand synthesis. CTC1-ΔB expression rescued C-strand fill-in, prevented telomeric DNA damage signaling and growth arrest. However, it caused progressive telomere elongation and the accumulation of telomerase at telomeres, indicating an inability to limit telomerase action. The CTC1-ΔB mutation greatly reduced CST-TPP1 interaction but only modestly affected ssDNA binding. OB-B point mutations also weakened TPP1 association, with the deficiency in TPP1 interaction tracking with an inability to limit telomerase action. Overall, our results indicate that CTC1-TPP1 interaction plays a key role in telomerase termination.
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Affiliation(s)
- Huan Wang
- Department of Pediatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Tengfei Ma
- Department of Pediatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiaotong Zhang
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Wei Chen
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yina Lan
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Guotao Kuang
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Shih-Jui Hsu
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH, USA
| | - Zibin He
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yuxi Chen
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Jason Stewart
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | | | - Zhenhua Luo
- Department of Pediatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Carolyn Price
- Department of Cancer Biology, University of Cincinnati, Cincinnati, OH, USA
| | - Xuyang Feng
- Department of Pediatrics, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
- Institute of Precision Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
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34
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Padmanaban S, Tesmer VM, Nandakumar J. Interaction hub critical for telomerase recruitment and primer-template handling for catalysis. Life Sci Alliance 2023; 6:e202201727. [PMID: 36963832 PMCID: PMC10055720 DOI: 10.26508/lsa.202201727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/26/2023] Open
Abstract
Telomerase processively adds telomeric DNA repeats to chromosome ends using catalytic protein subunit TERT and a template on its RNA subunit TR. Mammalian telomerase is recruited to telomeres by the TEL patch and NOB regions of shelterin component TPP1. Recent cryo-EM structures of human telomerase reveal that a composite TERT TEN-(IFD-TRAP) domain interacts with TPP1. Here, we generate TERT mutants to demonstrate that a three-way TEN-(IFD-TRAP)-TPP1 interaction is critical for telomerase recruitment to telomeres and processive telomere repeat addition. Single mutations of IFD-TRAP at its interface with TR or the DNA primer impair telomerase catalysis. We further reveal the importance of TERT motif 3N and TEN domain loop 99FGF101 in telomerase action. Finally, we demonstrate that TPP1 TEL patch loop residue F172, which undergoes a structural rearrangement to bind telomerase, contributes to the human-mouse species specificity of the telomerase-TPP1 interaction. Our study provides insights into the multiple functions of TERT IFD-TRAP, reveals novel TERT and TPP1 elements critical for function, and helps explain how TPP1 binding licenses robust telomerase action at natural chromosome ends.
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Affiliation(s)
- Shilpa Padmanaban
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Valerie M Tesmer
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Jayakrishnan Nandakumar
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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35
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Zade NH, Khattar E. POT1 mutations cause differential effects on telomere length leading to opposing disease phenotypes. J Cell Physiol 2023; 238:1237-1255. [PMID: 37183325 DOI: 10.1002/jcp.31034] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 03/28/2023] [Accepted: 04/17/2023] [Indexed: 05/16/2023]
Abstract
The protection of telomere protein (POT1) is a telomere-binding protein and is an essential component of the six-membered shelterin complex, which is associated with the telomeres. POT1 directly binds to the 3' single-stranded telomeric overhang and prevents the activation of DNA damage response at telomeres thus preventing the telomere-telomere fusions and genomic instability. POT1 also plays a pivotal role in maintaining telomere length by regulating telomerase-mediated telomere elongation. Mutations in POT1 proteins result in three different telomere phenotypes, which include long, short, or aberrant telomere length. Long telomeres predispose individuals to cancer, while short or aberrant telomere phenotypes result in pro-aging diseases referred to as telomeropathies. Here, we review the function of POT1 proteins in telomere length hemostasis and how the spectrum of mutations reported in POT1 can be segregated toward developing very distinct disease phenotypes of cancer and telomeropathies.
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Affiliation(s)
- Nikita Harish Zade
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be) University, Mumbai, India
| | - Ekta Khattar
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be) University, Mumbai, India
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36
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Ngo K, Gittens TH, Gonzalez DI, Hatmaker EA, Plotkin S, Engle M, Friedman GA, Goldin M, Hoerr RE, Eichman BF, Rokas A, Benton ML, Friedman KL. A comprehensive map of hotspots of de novo telomere addition in Saccharomyces cerevisiae. Genetics 2023; 224:iyad076. [PMID: 37119805 PMCID: PMC10474931 DOI: 10.1093/genetics/iyad076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/15/2023] [Accepted: 04/18/2023] [Indexed: 05/01/2023] Open
Abstract
Telomere healing occurs when telomerase, normally restricted to chromosome ends, acts upon a double-strand break to create a new, functional telomere. De novo telomere addition (dnTA) on the centromere-proximal side of a break truncates the chromosome but, by blocking resection, may allow the cell to survive an otherwise lethal event. We previously identified several sequences in the baker's yeast, Saccharomyces cerevisiae, that act as hotspots of dnTA [termed Sites of Repair-associated Telomere Addition (SiRTAs)], but the distribution and functional relevance of SiRTAs is unclear. Here, we describe a high-throughput sequencing method to measure the frequency and location of telomere addition within sequences of interest. Combining this methodology with a computational algorithm that identifies SiRTA sequence motifs, we generate the first comprehensive map of telomere-addition hotspots in yeast. Putative SiRTAs are strongly enriched in subtelomeric regions where they may facilitate formation of a new telomere following catastrophic telomere loss. In contrast, outside of subtelomeres, the distribution and orientation of SiRTAs appears random. Since truncating the chromosome at most SiRTAs would be lethal, this observation argues against selection for these sequences as sites of telomere addition per se. We find, however, that sequences predicted to function as SiRTAs are significantly more prevalent across the genome than expected by chance. Sequences identified by the algorithm bind the telomeric protein Cdc13, raising the possibility that association of Cdc13 with single-stranded regions generated during the response to DNA damage may facilitate DNA repair more generally.
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Affiliation(s)
- Katrina Ngo
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
| | - Tristen H Gittens
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
| | - David I Gonzalez
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
| | - E Anne Hatmaker
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN 37232 USA
| | - Simcha Plotkin
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
| | - Mason Engle
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
| | - Geofrey A Friedman
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
| | - Melissa Goldin
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
| | - Remington E Hoerr
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
| | - Brandt F Eichman
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232 USA
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN 37232 USA
| | | | - Katherine L Friedman
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232 USA
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37
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Ait Saada A, Guo W, Costa AB, Yang J, Wang J, Lobachev K. Widely spaced and divergent inverted repeats become a potent source of chromosomal rearrangements in long single-stranded DNA regions. Nucleic Acids Res 2023; 51:3722-3734. [PMID: 36919609 PMCID: PMC10164571 DOI: 10.1093/nar/gkad153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/16/2023] Open
Abstract
DNA inverted repeats (IRs) are widespread across many eukaryotic genomes. Their ability to form stable hairpin/cruciform secondary structures is causative in triggering chromosome instability leading to several human diseases. Distance and sequence divergence between IRs are inversely correlated with their ability to induce gross chromosomal rearrangements (GCRs) because of a lesser probability of secondary structure formation and chromosomal breakage. In this study, we demonstrate that structural parameters that normally constrain the instability of IRs are overcome when the repeats interact in single-stranded DNA (ssDNA). We established a system in budding yeast whereby >73 kb of ssDNA can be formed in cdc13-707fs mutants. We found that in ssDNA, 12 bp or 30 kb spaced Alu-IRs show similarly high levels of GCRs, while heterology only beyond 25% suppresses IR-induced instability. Mechanistically, rearrangements arise after cis-interaction of IRs leading to a DNA fold-back and the formation of a dicentric chromosome, which requires Rad52/Rad59 for IR annealing as well as Rad1-Rad10, Slx4, Msh2/Msh3 and Saw1 proteins for nonhomologous tail removal. Importantly, using structural characteristics rendering IRs permissive to DNA fold-back in yeast, we found that ssDNA regions mapped in cancer genomes contain a substantial number of potentially interacting and unstable IRs.
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Affiliation(s)
- Anissia Ait Saada
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Wenying Guo
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Alex B Costa
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Jiaxin Yang
- Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Jianrong Wang
- Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI 48824, USA
| | - Kirill S Lobachev
- School of Biological Sciences and Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
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38
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Lebdy R, Patouillard J, Larroque M, Urbach S, Abou Merhi R, Larroque C, Ribeyre C. The organizer of chromatin topology RIF1 ensures cellular resilience to DNA replication stress. Life Sci Alliance 2023; 6:e202101186. [PMID: 36746532 PMCID: PMC9906048 DOI: 10.26508/lsa.202101186] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 01/23/2023] [Accepted: 01/23/2023] [Indexed: 02/08/2023] Open
Abstract
Eukaryotic genomes are duplicated from thousands of replication origins that fire sequentially forming a defined spatiotemporal pattern of replication clusters. The temporal order of DNA replication is determined by chromatin architecture and, more specifically, by chromatin contacts that are stabilized by RIF1. Here, we show that RIF1 localizes near newly synthesized DNA. In cells exposed to the DNA replication inhibitor aphidicolin, suppression of RIF1 markedly decreased the efficacy of isolation of proteins on nascent DNA, suggesting that the isolation of proteins on nascent DNA procedure is biased by chromatin topology. RIF1 was required to limit the accumulation of DNA lesions induced by aphidicolin treatment and promoted the recruitment of cohesins in the vicinity of nascent DNA. Collectively, the data suggest that the stabilization of chromatin topology by RIF1 limits replication-associated genomic instability.
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Affiliation(s)
- Rana Lebdy
- Institut de Génétique Humaine, CNRS UMR9002, Université de Montpellier, Montpellier, France
- Doctoral School of Sciences and Technology-DSST, Rafic Hariri Campus, Lebanese University, Hadath, Lebanon
| | - Julie Patouillard
- Institut de Génétique Humaine, CNRS UMR9002, Université de Montpellier, Montpellier, France
| | | | - Serge Urbach
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U1191, Université de Montpellier, Montpellier, France
| | - Raghida Abou Merhi
- Doctoral School of Sciences and Technology-DSST, Rafic Hariri Campus, Lebanese University, Hadath, Lebanon
| | - Christian Larroque
- Institut de Recherche en Cancérologie de Montpellier, INSERM U1194, Université de Montpellier, Montpellier, France
| | - Cyril Ribeyre
- Institut de Génétique Humaine, CNRS UMR9002, Université de Montpellier, Montpellier, France
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Storchova R, Palek M, Palkova N, Veverka P, Brom T, Hofr C, Macurek L. Phosphorylation of TRF2 promotes its interaction with TIN2 and regulates DNA damage response at telomeres. Nucleic Acids Res 2023; 51:1154-1172. [PMID: 36651296 PMCID: PMC9943673 DOI: 10.1093/nar/gkac1269] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 11/25/2022] [Accepted: 12/23/2022] [Indexed: 01/19/2023] Open
Abstract
Protein phosphatase magnesium-dependent 1 delta (PPM1D) terminates the cell cycle checkpoint by dephosphorylating the tumour suppressor protein p53. By targeting additional substrates at chromatin, PPM1D contributes to the control of DNA damage response and DNA repair. Using proximity biotinylation followed by proteomic analysis, we identified a novel interaction between PPM1D and the shelterin complex that protects telomeric DNA. In addition, confocal microscopy revealed that endogenous PPM1D localises at telomeres. Further, we found that ATR phosphorylated TRF2 at S410 after induction of DNA double strand breaks at telomeres and this modification increased after inhibition or loss of PPM1D. TRF2 phosphorylation stimulated its interaction with TIN2 both in vitro and at telomeres. Conversely, induced expression of PPM1D impaired localisation of TIN2 and TPP1 at telomeres. Finally, recruitment of the DNA repair factor 53BP1 to the telomeric breaks was strongly reduced after inhibition of PPM1D and was rescued by the expression of TRF2-S410A mutant. Our results suggest that TRF2 phosphorylation promotes the association of TIN2 within the shelterin complex and regulates DNA repair at telomeres.
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Affiliation(s)
- Radka Storchova
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague CZ-14220, Czech Republic
| | - Matous Palek
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague CZ-14220, Czech Republic
| | - Natalie Palkova
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague CZ-14220, Czech Republic
| | - Pavel Veverka
- LifeB, Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno CZ-62500, Czech Republic
| | - Tomas Brom
- LifeB, Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno CZ-62500, Czech Republic
| | - Ctirad Hofr
- LifeB, Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno CZ-62500, Czech Republic
| | - Libor Macurek
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague CZ-14220, Czech Republic
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Ueno M. Exploring Genetic Interactions with Telomere Protection Gene pot1 in Fission Yeast. Biomolecules 2023; 13:biom13020370. [PMID: 36830739 PMCID: PMC9953254 DOI: 10.3390/biom13020370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/18/2023] Open
Abstract
The regulation of telomere length has a significant impact on cancer risk and aging in humans. Circular chromosomes are found in humans and are often unstable during mitosis, resulting in genome instability. Some types of cancer have a high frequency of a circular chromosome. Fission yeast is a good model for studying the formation and stability of circular chromosomes as deletion of pot1 (encoding a telomere protection protein) results in rapid telomere degradation and chromosome fusion. Pot1 binds to single-stranded telomere DNA and is conserved from fission yeast to humans. Loss of pot1 leads to viable strains in which all three fission yeast chromosomes become circular. In this review, I will introduce pot1 genetic interactions as these inform on processes such as the degradation of uncapped telomeres, chromosome fusion, and maintenance of circular chromosomes. Therefore, exploring genes that genetically interact with pot1 contributes to finding new genes and/or new functions of genes related to the maintenance of telomeres and/or circular chromosomes.
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Affiliation(s)
- Masaru Ueno
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima 739-8530, Japan; ; Tel.: +81-82-424-7768
- Hiroshima Research Center for Healthy Aging (HiHA), Hiroshima University, Higashi-Hiroshima 739-8530, Japan
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Sanford SL, Opresko PL. UV light-induced dual promoter mutations dismantle the telomeric guardrails in melanoma. DNA Repair (Amst) 2023; 122:103446. [PMID: 36603239 PMCID: PMC9892262 DOI: 10.1016/j.dnarep.2022.103446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 12/19/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022]
Abstract
Understanding how benign nevi can progress to invasive and metastatic Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, USAelanoma is critical for developing interventions and therapeutics for this most deadly form of skin cancer. UV-induced mutations in the telomerase TERT gene promoter occur in the majority of melanomas but fail to prevent telomere shortening despite telomerase upregulation. This suggests additional "hits" are required to enable telomere maintenance. A new study in Science identified somatic variants in the promoter of the gene that encodes telomere shelterin protein TPP1 in human melanomas. These variants show mutational signatures of UV-induced DNA damage and upregulate TPP1 expression, which synergizes with telomerase to lengthen telomeres. This study provides evidence that TPP1 promoter variants are a critical second hit to prevent telomere shortening and promote immortalization of melanoma cells.
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Affiliation(s)
- Samantha L Sanford
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, USA; UPMC Hillman Cancer Center, University of Pittsburgh, 5117 Centre Avenue, Pittsburgh, PA 15213, USA
| | - Patricia L Opresko
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, USA; UPMC Hillman Cancer Center, University of Pittsburgh, 5117 Centre Avenue, Pittsburgh, PA 15213, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, USA.
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42
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Yu X, Gray S, Ferreira H. POT-3 preferentially binds the terminal DNA-repeat on the telomeric G-overhang. Nucleic Acids Res 2023; 51:610-618. [PMID: 36583365 PMCID: PMC9881156 DOI: 10.1093/nar/gkac1203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 12/01/2022] [Accepted: 12/06/2022] [Indexed: 12/31/2022] Open
Abstract
Eukaryotic chromosomes typically end in 3' telomeric overhangs. The safeguarding of telomeric single-stranded DNA overhangs is carried out by factors related to the protection of telomeres 1 (POT1) protein in humans. Of the three POT1-like proteins in Caenorhabditis elegans, POT-3 was the only member thought to not play a role at telomeres. Here, we provide evidence that POT-3 is a bona fide telomere-binding protein. Using a new loss-of-function mutant, we show that the absence of POT-3 causes telomere lengthening and increased levels of telomeric C-circles. We find that POT-3 directly binds the telomeric G-strand in vitro and map its minimal DNA binding site to the six-nucleotide motif, GCTTAG. We further show that the closely related POT-2 protein binds the same motif, but that POT-3 shows higher sequence selectivity. Crucially, in contrast to POT-2, POT-3 prefers binding sites immediately adjacent to the 3' end of DNA. These differences are significant as genetic analyses reveal that pot-2 and pot-3 do not function redundantly with each other in vivo. Our work highlights the rapid evolution and specialisation of telomere binding proteins and places POT-3 in a unique position to influence activities that control telomere length.
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Affiliation(s)
- Xupeng Yu
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, North Haugh, St Andrews, UK
| | - Sean Gray
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, North Haugh, St Andrews, UK
| | - Helder C Ferreira
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, North Haugh, St Andrews, UK
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43
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Jezek M, Sun W, Negesse MY, Smith ZM, Orosz A, Green EM. Set1 regulates telomere function via H3K4 methylation-dependent and -independent pathways and calibrates the abundance of telomere maintenance factors. Mol Biol Cell 2023; 34:ar6. [PMID: 36416860 PMCID: PMC9816643 DOI: 10.1091/mbc.e22-06-0213] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/05/2022] [Accepted: 11/17/2022] [Indexed: 11/24/2022] Open
Abstract
Set1 is an H3K4 methyltransferase that comprises the catalytic subunit of the COMPASS complex and has been implicated in transcription, DNA repair, cell cycle control, and numerous other genomic functions. Set1 also promotes proper telomere maintenance, as cells lacking Set1 have short telomeres and disrupted subtelomeric gene repression; however, the precise role for Set1 in these processes has not been fully defined. In this study, we have tested mutants of Set1 and the COMPASS complex that differentially alter H3K4 methylation status, and we have attempted to separate catalytic and noncatalytic functions of Set1. Our data reveal that Set1-dependent subtelomeric gene repression relies on its catalytic activity toward H3K4, whereas telomere length is regulated by Set1 catalytic activity but likely independent of the H3K4 substrate. Furthermore, we uncover a role for Set1 in calibrating the abundance of critical telomere maintenance proteins, including components of the telomerase holoenzyme and members of the telomere capping CST (Cdc13-Stn1-Ten1) complex, through both transcriptional and posttranscriptional pathways. Altogether, our data provide new insights into the H3K4 methylation-dependent and -independent roles for Set1 in telomere maintenance in yeast and shed light on possible roles for Set1-related methyltransferases in other systems.
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Affiliation(s)
- Meagan Jezek
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250
| | - Winny Sun
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250
| | - Maraki Y. Negesse
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250
| | - Zachary M. Smith
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250
| | - Alexander Orosz
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250
| | - Erin M. Green
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD 21250
- Marlene and Stewart Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD 21201
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Shiekh S, Jack A, Saurabh A, Mustafa G, Kodikara S, Gyawali P, Hoque M, Pressé S, Yildiz A, Balci H. Shelterin reduces the accessibility of telomeric overhangs. Nucleic Acids Res 2022; 50:12885-12895. [PMID: 36511858 PMCID: PMC9825182 DOI: 10.1093/nar/gkac1176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/25/2022] [Accepted: 11/25/2022] [Indexed: 12/15/2022] Open
Abstract
Telomeres terminate with a 50-300 bases long single-stranded G-rich overhang, which can be misrecognized as a DNA damage repair site. Shelterin plays critical roles in maintaining and protecting telomere ends by regulating access of various physiological agents to telomeric DNA, but the underlying mechanism is not well understood. Here, we measure how shelterin affects the accessibility of long telomeric overhangs by monitoring transient binding events of a short complementary peptide nucleic acid (PNA) probe using FRET-PAINT in vitro. We observed that the POT1 subunit of shelterin reduces the accessibility of the PNA probe by ∼2.5-fold, indicating that POT1 effectively binds to and protects otherwise exposed telomeric sequences. In comparison, a four-component shelterin stabilizes POT1 binding to the overhang by tethering POT1 to the double-stranded telomeric DNA and reduces the accessibility of telomeric overhangs by ∼5-fold. This enhanced protection suggests shelterin restructures the junction between single and double-stranded telomere, which is otherwise the most accessible part of the telomeric overhang.
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Affiliation(s)
- Sajad Shiekh
- Department of Physics, Kent State University, Kent, OH 44242, USA
| | - Amanda Jack
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA
| | - Ayush Saurabh
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, AZ 85287, USA
| | - Golam Mustafa
- Department of Physics, Kent State University, Kent, OH 44242, USA
| | | | - Prabesh Gyawali
- Department of Physics, Kent State University, Kent, OH 44242, USA
| | - Mohammed Enamul Hoque
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Steve Pressé
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, AZ 85287, USA
- School of Molecular Science, Arizona State University, Tempe, AZ 85287, USA
| | - Ahmet Yildiz
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA
- Physics Department, University of California, Berkeley, CA 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Hamza Balci
- Department of Physics, Kent State University, Kent, OH 44242, USA
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45
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Liu Z, Wei X, Gao Y, Gao X, Li X, Zhong Y, Wang X, Liu C, Shi T, Lv J, Liu T. Zbtb34 promotes embryonic stem cell proliferation by elongating telomere length. Aging (Albany NY) 2022; 14:7126-7136. [PMID: 36098743 PMCID: PMC9512507 DOI: 10.18632/aging.204285] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 09/05/2022] [Indexed: 11/25/2022]
Abstract
Zbtb34 is a novel zinc finger protein, which is revealed by biological software analysis to have 3 zinc fingers, but its functions remain unknown. In this study, mouse Zbtb34 cDNA was amplified by PCR and inserted into the plasmid pEGFP-N1 to generate Zbtb34-EGFP fusion protein. The upregulation of Zbtb34 in mouse embryonic stem cells promoted telomere elongation and increased cell proliferation. In order to understand the above phenomena, the telomere co-immunoprecipitation technique was employed to investigate the relationship between Zbtb34 and telomeres. The results indicated that Zbtb34 could bind to the DNA sequences of the telomeres. Alanine substitution of the third zinc finger abolished such binding. Since Pot1 is the only protein binding to the single-stranded DNA at the end of the telomeres, we further investigated the relationship between Zbtb34 and Pot1. The results revealed that the upregulation of Zbtb34 decreased the binding of Pot1b to the telomeres. Through the upregulation of Pot1b, the binding of Zbtb34 to the telomeres was also reduced. In conclusion, we showed that the main biological function of Zbtb34 was to bind telomere DNA via its third ZnF, competing with Pot1b for the binding sites, resulting in telomere elongation and cell proliferation.
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Affiliation(s)
- Zheng Liu
- College of Medical Laboratory Science, Guilin Medical University, Guilin, Guangxi 541004, China
- Guihang Guiyang Hospital Affiliated to Zunyi Medical University, Guiyang, Guizhou 550027, China
| | - Xinran Wei
- College of Medical Laboratory Science, Guilin Medical University, Guilin, Guangxi 541004, China
| | - Yue Gao
- College of Medical Laboratory Science, Guilin Medical University, Guilin, Guangxi 541004, China
| | - Xiaodie Gao
- College of Medical Laboratory Science, Guilin Medical University, Guilin, Guangxi 541004, China
| | - Xia Li
- Clinical Laboratory, Hospital Affiliated to Guilin Medical University, Guilin, Guangxi 541001, China
| | - Yujuan Zhong
- College of Medical Laboratory Science, Guilin Medical University, Guilin, Guangxi 541004, China
| | - Xiujuan Wang
- College of Medical Laboratory Science, Guilin Medical University, Guilin, Guangxi 541004, China
| | - Chong Liu
- College of Medical Laboratory Science, Guilin Medical University, Guilin, Guangxi 541004, China
| | - Tianle Shi
- College of Medical Laboratory Science, Guilin Medical University, Guilin, Guangxi 541004, China
| | - Jiabin Lv
- College of Medical Laboratory Science, Guilin Medical University, Guilin, Guangxi 541004, China
| | - Tao Liu
- Guihang Guiyang Hospital Affiliated to Zunyi Medical University, Guiyang, Guizhou 550027, China
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Choo S, Lorbeer FK, Regalado SG, Short SB, Wu S, Rieser G, Bertuch AA, Hockemeyer D. Editing TINF2 as a potential therapeutic approach to restore telomere length in dyskeratosis congenita. Blood 2022; 140:608-618. [PMID: 35421215 PMCID: PMC9373014 DOI: 10.1182/blood.2021013750] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 03/25/2022] [Indexed: 11/29/2022] Open
Abstract
Mutations in the TINF2 gene, encoding the shelterin protein TIN2, cause telomere shortening and the inherited bone marrow (BM) failure syndrome dyskeratosis congenita (DC). A lack of suitable model systems limits the mechanistic understanding of telomere shortening in the stem cells and thus hinders the development of treatment options for BM failure. Here, we endogenously introduced TIN2-DC mutations in human embryonic stem cells (hESCs) and human hematopoietic stem and progenitor cells (HSPCs) to dissect the disease mechanism and identify a gene-editing strategy that rescued the disease phenotypes. The hESCs with the T284R disease mutation exhibited the short telomere phenotype observed in DC patients. Yet, telomeres in mutant hESCs did not trigger DNA damage responses at telomeres or show exacerbated telomere shortening when differentiated into telomerase-negative cells. Disruption of the mutant TINF2 allele by introducing a frameshift mutation in exon 2 restored telomere length in stem cells and the replicative potential of differentiated cells. Similarly, we introduced TIN2-DC disease variants in human HSPCs to assess the changes in telomere length and proliferative capacity. Lastly, we showed that editing at exon 2 of TINF2 that restored telomere length in hESCs could be generated in TINF2-DC patient HSPCs. Our study demonstrates a simple genetic intervention that rescues the TIN2-DC disease phenotype in stem cells and provides a versatile platform to assess the efficacy of potential therapeutic approaches in vivo.
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Affiliation(s)
- Seunga Choo
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Franziska K Lorbeer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Samuel G Regalado
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Sarah B Short
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Shannon Wu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Gabrielle Rieser
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
| | - Alison A Bertuch
- Department of Pediatrics, Baylor College of Medicine, Houston, TX
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Dirk Hockemeyer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA
- Chan Zuckerberg Biohub, San Francisco, CA; and
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA
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Affiliation(s)
- Conner L Olson
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Alexandra T Barbour
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Deborah S Wuttke
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.
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Jiang L, Yang L, Dai Y, Yang G, Pan S. Expression of POT1-AS1 in GC Tissue, Its Effect on Biological Behavior of Gastric Cancer, and Its Significance on Prognosis of Gastric Cancer. Comput Math Methods Med 2022; 2022:6021994. [PMID: 35936358 PMCID: PMC9355756 DOI: 10.1155/2022/6021994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/20/2022] [Accepted: 06/24/2022] [Indexed: 11/30/2022]
Abstract
Objective To study the correlation between gold in GC and biological indicators of gastric cancer (GC) and its effect on prognosis and correlation of POT1-AS1 with GC cellular growth, and to explore its impact in the processes of GC, to supply histological basis for medical treatment of GC. Methods From September 2019 to December 2021, 80 pairs of GAC specimens and healthy para-carcinoma tissue were immediately stored in paraformaldehyde solution. POT1-AS1 levels in 77 postoperative patients with GC were detected by immunohistochemical method. The correlation of the above indexes and the relationship between the above indexes and the biological behavior and prognosis of GC were analyzed. Results POT1-AS1 was strongly displayed in GAC specimens, and the difference between groups was statistically significant (P < 0.05). After sh-POT1-AS1 plasmid transfection, the relative expression of POT1-AS1 mRNA in SGC-7901 cells was remarkably lower compared to nontransfection group, and the difference between groups was statistically significant (P < 0.05). After POT1-AS1 knockdown, the SGC-7901 proliferation ability and the number of clones of SGC-7901 decreased remarkably. The relative level of cyclin D1 and cyclin-dependent kinase 4 (CDK4) in SGC-7901 reduced remarkably, while relative expression of cyclin-dependent kinase inhibitor 1A (CDKI1A) increased remarkably, and the difference between groups was statistically significant (P < 0.05). The positive expression of POT1-AS1 was found in GC and stromal cells. TIMP-1 in tumor stromal cells was related to the maximum diameter of tumor (P = 0.027), invasion depth (P = 0.001), lymph node metastasis (P = 0.006), and clinical stages (P = 0.006). TIMP-1 had an effect on the prognosis, while the strong positive group had a poor prognosis. The expression of TIMP-1 in GC cells was not related to clinical biological behavior and prognosis of GC. The VEGF level in GC was correlated to tumor maximum diameter (P < 0.05), invasive depth (P < 0.05), and lymph node metastasis (P < 0.05) that was linked to clinical phases, and the difference between groups was statistically significant (P < 0.05), which was positively correlated with Ki67-LI; the correlation coefficient was 0.254 and P = 0.026, which was not related to the positive expression of TIMP-1 in GC cells and stromal cells. VECF has an effect on the prognosis, and the outcomes of the positive group are worse. Conclusion The correlation between TIMP-1 of GASTRIC cancer mesenchymal cells of POT1-AS1 and VEGF and Ki-67-Li suggests that TIMP-1 produced by mesenchymal cells can facilitate tumor progression and lead to poor prognosis by promoting tumor cell proliferation. VEGF can strengthen tumor angiogenesis and then promote tumor cell proliferation, which has an adverse effect on the prognosis. Ki-67-LI is correlated to the medical biological behavior and prognosis of the tumor, reflecting the malignant process of the tumor.
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Affiliation(s)
- Li Jiang
- Department of Pathology, Liyang People's Hospital, 213300, China
| | - Lie Yang
- Department of Pathology, Liyang People's Hospital, 213300, China
| | - Yun Dai
- Department of Pathology, Liyang People's Hospital, 213300, China
| | - Guangming Yang
- Department of Pathology, Liyang People's Hospital, 213300, China
| | - Shuyin Pan
- Department of Pathology, Liyang People's Hospital, 213300, China
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49
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Sun H, Wu Z, Zhou Y, Lu Y, Lu H, Chen H, Shi S, Zeng Z, Wu J, Lei M. Structural insights into Pot1-ssDNA, Pot1-Tpz1 and Tpz1-Ccq1 Interactions within fission yeast shelterin complex. PLoS Genet 2022; 18:e1010308. [PMID: 35849625 PMCID: PMC9333443 DOI: 10.1371/journal.pgen.1010308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 07/28/2022] [Accepted: 06/22/2022] [Indexed: 11/30/2022] Open
Abstract
The conserved shelterin complex caps chromosome ends to protect telomeres and regulate telomere replication. In fission yeast Schizosaccharomyces pombe, shelterin consists of telomeric single- and double-stranded DNA-binding modules Pot1-Tpz1 and Taz1-Rap1 connected by Poz1, and a specific component Ccq1. While individual structures of the two DNA-binding OB folds of Pot1 (Pot1OB1-GGTTAC and Pot1OB2-GGTTACGGT) are available, structural insight into recognition of telomeric repeats with spacers by the complete DNA-binding domain (Pot1DBD) remains an open question. Moreover, structural information about the Tpz1-Ccq1 interaction requires to be revealed for understanding how the specific component Ccq1 of S. pombe shelterin is recruited to telomeres to function as an interacting hub. Here, we report the crystal structures of Pot1DBD-single-stranded-DNA, Pot1372-555-Tpz1185-212 and Tpz1425-470-Ccq1123-439 complexes and propose an integrated model depicting the assembly mechanism of the shelterin complex at telomeres. The structure of Pot1DBD-DNA unveils how Pot1 recognizes S. pombe degenerate telomeric sequences. Our analyses of Tpz1-Ccq1 reveal structural basis for the essential role of the Tpz1-Ccq1 interaction in telomere recruitment of Ccq1 that is required for telomere maintenance and telomeric heterochromatin formation. Overall, our findings provide valuable structural information regarding interactions within fission yeast shelterin complex at 3’ ss telomeric overhang. Telomeres, composed of repetitive DNA sequences and specialized proteins, are protective structures at the ends of linear chromosomes. The telomere structure is essential for the maintenance of genome integrity and stability, and telomere dysfunction has been linked to human development, aging, cancer and a variety of degenerative diseases. An evolutionarily conserved multiple-protein complex called shelterin plays versatile roles in telomere homeostasis regulation, end protection and heterochromatin establishment. However, the highly flexible nature of shelterin complex has greatly impeded our structural and functional understanding for this important complex. In fission yeast, structures of the shelterin dsDNA-binding protein subcomplex Taz1-Rap1 and the bridge subcomplex Tpz1-Poz1-Rap1 are available. Although individual OB-fold subdomains structures have been characterized, structural information about the complete Pot1DBD bound to telomeric repeats with spacers remains to be revealed. Here, by determining the crystal structures of the telomeric overhang binding Pot1DBD-ssDNA, Pot1372-555-Tpz1185-212 and Tpz1425-470-Ccq1123-439 subcomplexes, we provide structural basis not only for the recognition of S. pombe degenerate telomeric sequences by Pot1, but also for the essential function of the Tpz1-Ccq1 interaction in Ccq1 recruitment to telomeres for telomere maintenance and telomeric heterochromatin formation. These findings provide an integrated model depicting the assembly mechanism of the shelterin complex at telomeres and its multiple roles in telomere biology.
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Affiliation(s)
- Hong Sun
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Zhenfang Wu
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
- * E-mail: (ZW); (ZZ); (JW); (ML)
| | - Yuanze Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Yanjia Lu
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Huaisheng Lu
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Hongwen Chen
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, China
| | - Shaohua Shi
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Zhixiong Zeng
- Shandong Provincial Key Laboratory of Microbial Engineering, College of Bioengineering, Qilu University of Technology, Shandong, China
- * E-mail: (ZW); (ZZ); (JW); (ML)
| | - Jian Wu
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
- * E-mail: (ZW); (ZZ); (JW); (ML)
| | - Ming Lei
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- * E-mail: (ZW); (ZZ); (JW); (ML)
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Cho CY, Seller CA, O’Farrell PH. Temporal control of late replication and coordination of origin firing by self-stabilizing Rif1-PP1 hubs in Drosophila. Proc Natl Acad Sci U S A 2022; 119:e2200780119. [PMID: 35733247 PMCID: PMC9245680 DOI: 10.1073/pnas.2200780119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/19/2022] [Indexed: 12/25/2022] Open
Abstract
In the metazoan S phase, coordinated firing of clusters of origins replicates different parts of the genome in a temporal program. Despite advances, neither the mechanism controlling timing nor that coordinating firing of multiple origins is fully understood. Rif1, an evolutionarily conserved inhibitor of DNA replication, recruits protein phosphatase 1 (PP1) and counteracts firing of origins by S-phase kinases. During the midblastula transition (MBT) in Drosophila embryos, Rif1 forms subnuclear hubs at each of the large blocks of satellite sequences and delays their replication. Each Rif1 hub disperses abruptly just prior to the replication of the associated satellite sequences. Here, we show that the level of activity of the S-phase kinase, DDK, accelerated this dispersal program, and that the level of Rif1-recruited PP1 retarded it. Further, Rif1-recruited PP1 supported chromatin association of nearby Rif1. This influence of nearby Rif1 can create a "community effect" counteracting kinase-induced dissociation such that an entire hub of Rif1 undergoes switch-like dispersal at characteristic times that shift in response to the balance of Rif1-PP1 and DDK activities. We propose a model in which the spatiotemporal program of late replication in the MBT embryo is controlled by self-stabilizing Rif1-PP1 hubs, whose abrupt dispersal synchronizes firing of associated late origins.
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Affiliation(s)
- Chun-Yi Cho
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
| | - Charles A. Seller
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
| | - Patrick H. O’Farrell
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
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