1
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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] [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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2
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Identification of a Cancer-Predisposing Germline POT1 p.Ile49Metfs*7 Variant by Targeted Sequencing of a Splenic Marginal Zone Lymphoma. Genes (Basel) 2022; 13:genes13040591. [PMID: 35456397 PMCID: PMC9028718 DOI: 10.3390/genes13040591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/20/2022] [Accepted: 03/23/2022] [Indexed: 11/17/2022] Open
Abstract
Germline disruptive variants in Protection of Telomeres 1 (POT1) predispose to a wide variety of cancers, including melanoma, chronic lymphocytic leukemia (CLL), Hodgkin lymphoma, myeloproliferative neoplasms, and glioma. We report the first case of splenic marginal zone lymphoma (SMZL) arising in a patient with a germline POT1 variant: a 65-year-old male with an extensive history of cancer, including melanoma and papillary thyroid carcinoma, who presented with circulating atypical lymphocytosis. Bone marrow biopsy revealed 20% involvement by a CD5−CD10− B-cell lymphoma that was difficult to classify. During the clinical workup of his low-grade lymphoma, targeted next-generation sequencing (NGS) identified POT1 p.I49Mfs*7 (NM_015450:c. 147delT) at a variant allele frequency (VAF) of 51%. NGS of skin fibroblasts confirmed the POT1 variant was germline. This likely pathogenic POT1 loss-of-function variant has only been reported once before as a germline variant in a patient with glioma and likely represents one of the most deleterious germline POT1 variants ever linked to familial cancer. The spectrum of cancers associated with germline pathogenic POT1 variants (i.e., autosomal dominant POT1 tumor predisposition syndrome) should potentially be expanded to include SMZL, a disease often associated with the loss of chromosome 7q: the location of the POT1 genetic locus (7q31.33).
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3
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Molecular landscape of Hereditary Melanoma. Crit Rev Oncol Hematol 2021; 164:103425. [PMID: 34245855 DOI: 10.1016/j.critrevonc.2021.103425] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 05/20/2021] [Accepted: 07/04/2021] [Indexed: 12/27/2022] Open
Abstract
Melanoma is considered the most lethal skin cancer and its incidence has increased during the past decades. About 10 % of cases are classified as hereditary melanoma. Genetic predisposition usually manifests itself clinically as early onset and multiple cutaneous melanomas. Several genes have been identified as involved to melanoma susceptibility, some of them still with unknown clinical relevance. Beyond melanoma, the affected families are also more prone to develop other malignancies, such as pancreatic cancer. The identification of risk families and involved genes is of great importance, since different forms of oncological surveillance are recommended. However, well established guidelines to standardize both the selection of individuals and the genetic panel to be requested are still lacking. Given the importance of the genetic counseling and testing in the context of clinical suspicion of hereditary melanoma, this paper aims to review the literature regarding genetic panel indications worldwide.
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4
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Active and Passive Destabilization of G-Quadruplex DNA by the Telomere POT1-TPP1 Complex. J Mol Biol 2021; 433:166846. [PMID: 33549587 DOI: 10.1016/j.jmb.2021.166846] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 01/05/2021] [Accepted: 01/22/2021] [Indexed: 11/23/2022]
Abstract
Chromosome ends are protected by guanosine-rich telomere DNA that forms stable G-quadruplex (G4) structures. The heterodimeric POT1-TPP1 complex interacts specifically with telomere DNA to shield it from illicit DNA damage repair and to resolve secondary structure that impedes telomere extension. The mechanism by which POT1-TPP1 accomplishes these tasks is poorly understood. Here, we establish the kinetic framework for POT1-TPP1 binding and unfolding of telomere G4 DNA. Our data identify two modes of POT1-TPP1 destabilization of G4 DNA that are governed by protein concentration. At low concentrations, POT1-TPP1 passively captures transiently unfolded G4s. At higher concentrations, POT1-TPP1 proteins bind to G4s to actively destabilize the DNA structures. Cancer-associated POT1-TPP1 mutations impair multiple reaction steps in this process, resulting in less efficient destabilization of G4 structures. The mechanistic insight highlights the importance of cell cycle dependent expression and localization of the POT1-TPP1 complex and distinguishes diverse functions of this complex in telomere maintenance.
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5
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Fernandes CAH, Morea EGO, Dos Santos GA, da Silva VL, Vieira MR, Viviescas MA, Chatain J, Vadel A, Saintomé C, Fontes MRM, Cano MIN. A multi-approach analysis highlights the relevance of RPA-1 as a telomere end-binding protein (TEBP) in Leishmania amazonensis. Biochim Biophys Acta Gen Subj 2020; 1864:129607. [PMID: 32222548 DOI: 10.1016/j.bbagen.2020.129607] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/21/2020] [Accepted: 03/24/2020] [Indexed: 01/12/2023]
Abstract
BACKGROUND Telomeres are chromosome end structures important in the maintenance of genome homeostasis. They are replenished by the action of telomerase and associated proteins, such as the OB (oligonucleotide/oligosaccharide-binding)-fold containing telomere-end binding proteins (TEBP) which plays an essential role in telomere maintenance and protection. The nature of TEBPs is well known in higher and some primitive eukaryotes, but it remains undetermined in trypanosomatids. Previous in silico searches have shown that there are no homologs of the classical TEPBs in trypanosomatids, including Leishmania sp. However, Replication Protein A subunit 1 (RPA-1), an OB-fold containing DNA-binding protein, was found co-localized with trypanosomatids telomeres and showed a high preference for the telomeric G-rich strand. METHODS AND RESULTS We predicted the absence of structural homologs of OB-fold containing TEBPs in the Leishmania sp. genome using structural comparisons. We demonstrated by molecular docking that the ssDNA binding mode of LaRPA-1 shares features with the higher eukaryotes POT1 and RPA-1 crystal structures ssDNA binding mode. Using fluorescence spectroscopy, protein-DNA interaction assays, and FRET, we respectively show that LaRPA-1 shares some telomeric functions with the classical TEBPs since it can bind at least one telomeric repeat, protect the telomeric G-rich DNA from 3'-5' Exonuclease I digestion, and unfold telomeric G-quadruplex. CONCLUSIONS Our results suggest that RPA-1 emerges as a TEBP in trypanosomatids, and in this context, we present two possible evolutionary landscapes of trypanosomatids RPA-1 that could reflect upon the evolution of OB-fold containing TEBPs from all eukaryotes.
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Affiliation(s)
- Carlos A H Fernandes
- Department of Biophysics and Pharmacology, Biosciences Institute, São Paulo State University (UNESP) - Botucatu, SP, Brazil; Laboratoire de Biologie et Pharmacologie Appliquée, École Normale Supérieure Paris-Saclay, Cachan, France
| | - Edna Gicela O Morea
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Gabriel A Dos Santos
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Vitor L da Silva
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Marina Roveri Vieira
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Maria Alejandra Viviescas
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Jean Chatain
- MNHN CNRS UMR 7196, INSERM U1154, 43 rue Cuvier, 75005 Paris, France
| | - Aurélie Vadel
- MNHN CNRS UMR 7196, INSERM U1154, 43 rue Cuvier, 75005 Paris, France
| | - Carole Saintomé
- MNHN CNRS UMR 7196, INSERM U1154, 43 rue Cuvier, 75005 Paris, France; Sorbonne Université, UFR927, 4 place Jussieu, 75005 Paris, France
| | - Marcos Roberto M Fontes
- Department of Biophysics and Pharmacology, Biosciences Institute, São Paulo State University (UNESP) - Botucatu, SP, Brazil
| | - Maria Isabel Nogueira Cano
- Department of Chemical and Biological Sciences, São Paulo State University (UNESP) - Botucatu, SP, Brazil.
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6
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Bhattacharya P, Dhanyamraju PK, Sarmah A, Jay MP, Jose CM, Dbritto S, Mallavarapu S, Patel TN. Mutational profiling of POT1 gene and its interaction with TPP1 in cancer- A computational approach. INFORMATICS IN MEDICINE UNLOCKED 2020. [DOI: 10.1016/j.imu.2020.100389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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7
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Yu Y, Tan R, Ren Q, Gao B, Sheng Z, Zhang J, Zheng X, Jiang Y, Lan L, Mao Z. POT1 inhibits the efficiency but promotes the fidelity of nonhomologous end joining at non-telomeric DNA regions. Aging (Albany NY) 2019; 9:2529-2543. [PMID: 29227966 PMCID: PMC5764391 DOI: 10.18632/aging.101339] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 12/01/2017] [Indexed: 11/25/2022]
Abstract
Robust DNA double strand break (DSB) repair and stabilized telomeres help maintain genome integrity, preventing the onset of aging or tumorigenesis. POT1 is one of the six factors in the shelterin complex, which protects telomeres from being recognized as DNA damages. TRF1 and TRF2, two other shelterin proteins, have been shown to participate in DNA DSB repair at non-telomeric regions, but whether POT1, which binds to single strand telomeric DNA at chromosomal ends, is involved in DNA DSB repair has not been assessed. Here we found that POT1 arrives at DNA damage sites upon the occurrence of DNA DSBs. It suppresses the efficiency of nonhomologous end joining (NHEJ), the major pathway for fixing DNA DSBs in mammals, but surprisingly promotes NHEJ fidelity. Mechanistic studies indicate that POT1 facilitates the recruitment of Artemis, which is a nuclease and promotes fidelity of NHEJ, to DNA damage sites. In addition, we found that overexpression of POT1 inhibits the protein stability of Lig3, which is the major regulator of alternative NHEJ (alt-NHEJ), therefore suppressing the efficiency of alt-NHEJ. Taken together we propose that POT1 is a key factor regulating the balance between the efficiency and fidelity of NHEJ at non-telomeric DNA regions.
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Affiliation(s)
- Yang Yu
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
| | - Rong Tan
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.,Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - Qian Ren
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Boya Gao
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Zhejin Sheng
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Juanlian Zhang
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Xiaoqing Zheng
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Ying Jiang
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China
| | - Li Lan
- University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Zhiyong Mao
- Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, Shanghai 200092, China.,State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China
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8
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Muoio D, Berardinelli F, Leone S, Coluzzi E, di Masi A, Doria F, Freccero M, Sgura A, Folini M, Antoccia A. Naphthalene diimide-derivatives G-quadruplex ligands induce cell proliferation inhibition, mild telomeric dysfunction and cell cycle perturbation in U251MG glioma cells. FEBS J 2018; 285:3769-3785. [PMID: 30095224 DOI: 10.1111/febs.14628] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 04/30/2018] [Accepted: 08/07/2018] [Indexed: 12/17/2022]
Abstract
In the present paper, the biological effects of three different naphthalene diimides (NDIs) G-quadruplex (G4) ligands (H-NDI-Tyr, H-NDI-NMe2, and tetra-NDI-NMe2) were comparatively evaluated to those exerted by RHPS4, a well-characterized telomeric G4-ligand, in an in vitro model of glioblastoma. Data indicated that NDIs were very effective in blocking cell proliferation at nanomolar concentrations, although displaying a lower specificity for telomere targeting compared to RHPS4. In addition, differently from RHPS4, NDIs failed to enhance the effect of ionizing radiation, thus suggesting that additional targets other than telomeres could be involved in the strong NDI-mediated anti-proliferative effects. In order to test telomeric off-target action of NDIs, a panel of genes involved in tumor progression, DNA repair, telomere maintenance, and cell-cycle regulation were evaluated at transcriptional and translational level. Specifically, the compounds were able to cause a marked reduction of TERT and BCL2 amounts as well as to favor the accumulation of proteins involved in cell cycle control. A detailed cytofluorimetric analysis of cell cycle progression by means of bromodeoxyuridine (BrdU) incorporation and staining of phospho-histone H3 indicated that NDIs greatly reduce the progression through S-phase and lead to G1 accumulation of BrdU-positive cells. Taken together, these data indicated that, besides effects on telomeres and oncogenes such as Tert and Bcl2, nanomolar concentrations of NDIs determined a sustained block of cell proliferation by slowing down cell cycle progression during S-phase. In conclusion, our data indicate that NDIs G4-ligands are powerful antiproliferative agents, which act through mechanisms that ultimately lead to altered cell-cycle control.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Marco Folini
- Dipartimento di Ricerca Applicata e Sviluppo Tecnologico, Fondazione IRCCS Istituto Nazionale dei Tumori di MIlano, Milano, Italy
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9
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Ojha J, Dyagil I, Finch SC, Reiss RF, de Smith AJ, Gonseth S, Zhou M, Hansen HM, Sherborne AL, Nakamura J, Bracci PM, Gudzenko N, Hatch M, Babkina N, Little MP, Chumak VV, Walsh KM, Bazyka D, Wiemels JL, Zablotska LB. Genomic characterization of chronic lymphocytic leukemia (CLL) in radiation-exposed Chornobyl cleanup workers. Environ Health 2018; 17:43. [PMID: 29720177 PMCID: PMC5930419 DOI: 10.1186/s12940-018-0387-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 04/20/2018] [Indexed: 05/29/2023]
Abstract
BACKGROUND Chronic lymphocytic leukemia (CLL) was the predominant leukemia in a recent study of Chornobyl cleanup workers from Ukraine exposed to radiation (UR-CLL). Radiation risks of CLL significantly increased with increasing bone marrow radiation doses. Current analysis aimed to clarify whether the increased risks were due to radiation or to genetic mutations in the Ukrainian population. METHODS A detailed characterization of the genomic landscape was performed in a unique sample of 16 UR-CLL patients and age- and sex-matched unexposed general population Ukrainian-CLL (UN-CLL) and Western-CLL (W-CLL) patients (n = 28 and 100, respectively). RESULTS Mutations in telomere-maintenance pathway genes POT1 and ATM were more frequent in UR-CLL compared to UN-CLL and W-CLL (both p < 0.05). No significant enrichment in copy-number abnormalities at del13q14, del11q, del17p or trisomy12 was identified in UR-CLL compared to other groups. Type of work performed in the Chornobyl zone, age at exposure and at diagnosis, calendar time, and Rai stage were significant predictors of total genetic lesions (all p < 0.05). Tumor telomere length was significantly longer in UR-CLL than in UN-CLL (p = 0.009) and was associated with the POT1 mutation and survival. CONCLUSIONS No significant enrichment in copy-number abnormalities at CLL-associated genes was identified in UR-CLL compared to other groups. The novel associations between radiation exposure, telomere maintenance and CLL prognosis identified in this unique case series provide suggestive, though limited data and merit further investigation.
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Affiliation(s)
- Juhi Ojha
- School of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Iryna Dyagil
- National Research Center for Radiation Medicine, Kyiv, Ukraine
| | - Stuart C. Finch
- Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ USA
| | - Robert F. Reiss
- Department of Pathology and Cell Biology, and Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY USA
| | - Adam J. de Smith
- School of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Semira Gonseth
- School of Public Health, University of California, Berkeley, Berkeley, CA USA
| | - Mi Zhou
- School of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Helen M. Hansen
- School of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Amy L. Sherborne
- School of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Jean Nakamura
- School of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Paige M. Bracci
- School of Medicine, University of California, San Francisco, San Francisco, CA USA
| | | | - Maureen Hatch
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD USA
| | | | - Mark P. Little
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD USA
| | - Vadim V. Chumak
- National Research Center for Radiation Medicine, Kyiv, Ukraine
| | - Kyle M. Walsh
- School of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Dimitry Bazyka
- National Research Center for Radiation Medicine, Kyiv, Ukraine
| | - Joseph L. Wiemels
- School of Medicine, University of California, San Francisco, San Francisco, CA USA
| | - Lydia B. Zablotska
- School of Medicine, University of California, San Francisco, San Francisco, CA USA
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10
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The role of telomere binding molecules for normal and abnormal hematopoiesis. Int J Hematol 2018; 107:646-655. [DOI: 10.1007/s12185-018-2432-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 03/12/2018] [Indexed: 11/26/2022]
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11
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Pavani RS, Vitarelli MO, Fernandes CAH, Mattioli FF, Morone M, Menezes MC, Fontes MRM, Cano MIN, Elias MC. Replication Protein A-1 Has a Preference for the Telomeric G-rich Sequence in Trypanosoma cruzi. J Eukaryot Microbiol 2017; 65:345-356. [PMID: 29044824 DOI: 10.1111/jeu.12478] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/21/2017] [Accepted: 10/09/2017] [Indexed: 01/20/2023]
Abstract
Replication protein A (RPA), the major eukaryotic single-stranded binding protein, is a heterotrimeric complex formed by RPA-1, RPA-2, and RPA-3. RPA is a fundamental player in replication, repair, recombination, and checkpoint signaling. In addition, increasing evidences have been adding functions to RPA in telomere maintenance, such as interaction with telomerase to facilitate its activity and also involvement in telomere capping in some conditions. Trypanosoma cruzi, the etiological agent of Chagas disease is a protozoa parasite that appears early in the evolution of eukaryotes. Recently, we have showed that T. cruziRPA presents canonical functions being involved with DNA replication and DNA damage response. Here, we found by FISH/IF assays that T. cruziRPA localizes at telomeres even outside replication (S) phase. In vitro analysis showed that one telomeric repeat is sufficient to bind RPA-1. Telomeric DNA induces different secondary structural modifications on RPA-1 in comparison with other types of DNA. In addition, RPA-1 presents a higher affinity for telomeric sequence compared to randomic sequence, suggesting that RPA may play specific roles in T. cruzi telomeric region.
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Affiliation(s)
- Raphael Souza Pavani
- Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, SP, 05503-900, Brazil.,Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, SP, 05503-900, Brazil
| | - Marcela O Vitarelli
- Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, SP, 05503-900, Brazil.,Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, SP, 05503-900, Brazil
| | - Carlos A H Fernandes
- Biophysics and Physics Department, Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, 18618970, Brazil
| | - Fabio F Mattioli
- Biophysics and Physics Department, Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, 18618970, Brazil
| | - Mariana Morone
- Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, SP, 05503-900, Brazil.,Laboratório Especial de Toxinologia Aplicada, Instituto Butantan, São Paulo, SP, 05503-900, Brazil
| | - Milene C Menezes
- Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, SP, 05503-900, Brazil.,Laboratório Especial de Toxinologia Aplicada, Instituto Butantan, São Paulo, SP, 05503-900, Brazil
| | - Marcos R M Fontes
- Biophysics and Physics Department, Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, 18618970, Brazil
| | - Maria Isabel N Cano
- Genetics Department, Biosciences Institute, São Paulo State University (UNESP), Botucatu, SP, 18618970, Brazil
| | - Maria Carolina Elias
- Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, SP, 05503-900, Brazil.,Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, SP, 05503-900, Brazil
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12
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Hosokawa K, MacArthur BD, Ikushima YM, Toyama H, Masuhiro Y, Hanazawa S, Suda T, Arai F. The telomere binding protein Pot1 maintains haematopoietic stem cell activity with age. Nat Commun 2017; 8:804. [PMID: 28986560 PMCID: PMC5630588 DOI: 10.1038/s41467-017-00935-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 08/07/2017] [Indexed: 12/11/2022] Open
Abstract
Repeated cell divisions and aging impair stem cell function. However, the mechanisms by which this occurs are not fully understood. Here we show that protection of telomeres 1A (Pot1a), a component of the Shelterin complex that protects telomeres, improves haematopoietic stem cell (HSC) activity during aging. Pot1a is highly expressed in young HSCs, but declines with age. In mouse HSCs, Pot1a knockdown increases DNA damage response (DDR) and inhibits self-renewal. Conversely, Pot1a overexpression or treatment with POT1a protein prevents DDR, maintained self-renewal activity and rejuvenated aged HSCs upon ex vivo culture. Moreover, treatment of HSCs with exogenous Pot1a inhibits the production of reactive oxygen species, suggesting a non-telomeric role for Pot1a in HSC maintenance. Consistent with these results, treatment with exogenous human POT1 protein maintains human HSC activity in culture. Collectively, these results show that Pot1a/POT1 sustains HSC activity and can be used to expand HSC numbers ex vivo.Repeated cell divisions induce DNA damage in haematopoietic stem cells (HSC) and telomeres are sensitive to this damage. Here, the authors show in murine HSCs that the telomere binding protein POT1a inhibited the production of reactive oxygen species, and rejuvenated aged HSCs.
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Affiliation(s)
- Kentaro Hosokawa
- Department of Stem Cell Biology and Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.,Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Ben D MacArthur
- Centre for Human Development, Stem Cells and Regeneration, Faculty of Medicine, University of Southampton, University Road, Southampton, SO17 1BJ, UK
| | - Yoshiko Matsumoto Ikushima
- Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.,National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, 162-8655, Japan
| | - Hirofumi Toyama
- Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Yoshikazu Masuhiro
- Laboratory of Molecular and Cellular Physiology, Department of Applied Biological Sciences, College of Bioresource Sciences, Nihon University, Fujisawa City, Kanagawa, 252-0880, Japan
| | - Shigemasa Hanazawa
- Laboratory of Molecular and Cellular Physiology, Department of Applied Biological Sciences, College of Bioresource Sciences, Nihon University, Fujisawa City, Kanagawa, 252-0880, Japan
| | - Toshio Suda
- Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan. .,Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599, Singapore.
| | - Fumio Arai
- Department of Stem Cell Biology and Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. .,Department of Cell Differentiation, The Sakaguchi Laboratory of Developmental Biology, School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
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