1
|
Tanshee RR, Mahmud Z, Nabi AHMN, Sayem M. A comprehensive in silico investigation into the pathogenic SNPs in the RTEL1 gene and their biological consequences. PLoS One 2024; 19:e0309713. [PMID: 39240887 PMCID: PMC11379182 DOI: 10.1371/journal.pone.0309713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 08/16/2024] [Indexed: 09/08/2024] Open
Abstract
The Regulator of Telomere Helicase 1 (RTEL1) gene encodes a critical DNA helicase intricately involved in the maintenance of telomeric structures and the preservation of genomic stability. Germline mutations in the RTEL1 gene have been clinically associated with Hoyeraal-Hreidarsson syndrome, a more severe version of Dyskeratosis Congenita. Although various research has sought to link RTEL1 mutations to specific disorders, no comprehensive investigation has yet been conducted on missense mutations. In this study, we attempted to investigate the functionally and structurally deleterious coding and non-coding SNPs of the RTEL1 gene using an in silico approach. Initially, out of 1392 nsSNPs, 43 nsSNPs were filtered out through ten web-based bioinformatics tools. With subsequent analysis using nine in silico tools, these 43 nsSNPs were further shortened to 11 most deleterious nsSNPs. Furthermore, analyses of mutated protein structures, evolutionary conservancy, surface accessibility, domains & PTM sites, cancer susceptibility, and interatomic interaction revealed the detrimental effect of these 11 nsSNPs on RTEL1 protein. An in-depth investigation through molecular docking with the DNA binding sequence demonstrated a striking change in the interaction pattern for F15L, M25V, and G706R mutant proteins, suggesting the more severe consequences of these mutations on protein structure and functionality. Among the non-coding variants, two had the highest likelihood of being regulatory variants, whereas one variant was predicted to affect the target region of a miRNA. Thus, this study lays the groundwork for extensive analysis of RTEL1 gene variants in the future, along with the advancement of precision medicine and other treatment modalities.
Collapse
Affiliation(s)
- Rifah Rownak Tanshee
- Department of Mathematics and Natural Sciences, BRAC University, Badda, Dhaka, Bangladesh
| | - Zimam Mahmud
- Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh
| | - A H M Nurun Nabi
- Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh
| | - Mohammad Sayem
- Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh
| |
Collapse
|
2
|
Cortone G, Graewert MA, Kanade M, Longo A, Hegde R, González‐Magaña A, Chaves‐Arquero B, Blanco FJ, Napolitano LMR, Onesti S. Structural and biochemical characterization of the C-terminal region of the human RTEL1 helicase. Protein Sci 2024; 33:e5093. [PMID: 39180489 PMCID: PMC11344278 DOI: 10.1002/pro.5093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 06/03/2024] [Accepted: 06/16/2024] [Indexed: 08/26/2024]
Abstract
RTEL1 is an essential DNA helicase which plays an important role in various aspects of genome stability, from telomere metabolism to DNA replication, repair and recombination. RTEL1 has been implicated in a number of genetic diseases and cancer development, including glioma, breast, lung and gastrointestinal tumors. RTEL1 is a FeS helicase but, in addition to the helicase core, it comprises a long C-terminal region which includes a number of folded domains connected by intrinsically disordered loops and mediates RTEL1 interaction with factors involved in pivotal cellular pathways. However, information on the architecture and the function of this region is still limited. We expressed and purified a variety of fragments encompassing the folded domains and the unstructured regions. We determined the crystal structure of the second repeat, confirming that it has a fold similar to the harmonin homology domains. SAXS data provide low-resolution information on all the fragments and suggest that the presence of the RING domain affects the overall architecture of the C-terminal region, making the structure significantly more compact. NMR data provide experimental information on the interaction between PCNA and the RTEL1 C-terminal region, revealing a putative low-affinity additional site of interaction. A biochemical analysis shows that the C-terminal region, in addition to a preference for telomeric RNA and DNA G-quadruplexes, has a high affinity for R-loops and D-loops, consistent with the role played by the RTEL1 helicase in homologous recombination, telomere maintenance and preventing replication-transcription conflicts. We further dissected the contribution of each domain in binding different substrates.
Collapse
Affiliation(s)
- Giuseppe Cortone
- Structural Biology LaboratoryElettra‐Sincrotrone TriesteTriesteItaly
- International School for Advanced Studies (SISSA)TriesteItaly
| | | | - Manil Kanade
- Structural Biology LaboratoryElettra‐Sincrotrone TriesteTriesteItaly
| | - Antonio Longo
- Structural Biology LaboratoryElettra‐Sincrotrone TriesteTriesteItaly
- Department of ChemistryUniversità degli Studi di TriesteTriesteItaly
| | - Raghurama Hegde
- Structural Biology LaboratoryElettra‐Sincrotrone TriesteTriesteItaly
| | - Amaia González‐Magaña
- Instituto Biofisika and Departamento de Bioquímica y Biología Molecular (CSIC, UPV/EHU)University of the Basque CountryLeioaSpain
| | | | | | | | - Silvia Onesti
- Structural Biology LaboratoryElettra‐Sincrotrone TriesteTriesteItaly
| |
Collapse
|
3
|
Dixit S, Nagraj T, Bhattacharya D, Saxena S, Sahoo S, Chittela RK, Somyajit K, Nagaraju G. RTEL1 helicase counteracts RAD51-mediated homologous recombination and fork reversal to safeguard replicating genomes. Cell Rep 2024; 43:114594. [PMID: 39116203 DOI: 10.1016/j.celrep.2024.114594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 05/23/2024] [Accepted: 07/22/2024] [Indexed: 08/10/2024] Open
Abstract
Homologous recombination (HR) plays an essential role in the repair of DNA double-strand breaks (DSBs), replication stress responses, and genome maintenance. However, unregulated HR during replication can impair genome duplication and compromise genome stability. The mechanisms underlying HR regulation during DNA replication are obscure. Here, we find that RTEL1 helicase, RAD51, and RAD51 paralogs are enriched at stalled replication sites. The absence of RTEL1 leads to an increase in the RAD51-mediated HR and fork reversal during replication and affects genome-wide replication, which can be rescued by co-depleting RAD51 and RAD51 paralogs. Interestingly, co-depletion of fork remodelers such as SMARCAL1/ZRANB3/HLTF/FBH1 and expression of HR-defective RAD51 mutants also rescues replication defects in RTEL1-deficient cells. The anti-recombinase function of RTEL1 during replication depends on its interaction with PCNA and helicase activity. Together, our data identify the role of RTEL1 helicase in restricting RAD51-mediated fork reversal and HR activity to facilitate error-free genome duplication.
Collapse
Affiliation(s)
- Suruchi Dixit
- Department of Biochemistry Indian Institute of Science, Bangalore 560012, India
| | - Tarun Nagraj
- Department of Biochemistry Indian Institute of Science, Bangalore 560012, India
| | | | - Sneha Saxena
- Department of Biochemistry Indian Institute of Science, Bangalore 560012, India
| | - Satyaranjan Sahoo
- Department of Biochemistry Indian Institute of Science, Bangalore 560012, India
| | - Rajani Kant Chittela
- Applied Genomics Section, Bioscience Group, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Kumar Somyajit
- Department of Biochemistry Indian Institute of Science, Bangalore 560012, India; Functional Genomics & Metabolism Research Unit, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense M 5230, Denmark.
| | - Ganesh Nagaraju
- Department of Biochemistry Indian Institute of Science, Bangalore 560012, India.
| |
Collapse
|
4
|
Smoom R, May CL, Lichtental D, Skordalakes E, Kaestner KH, Tzfati Y. Separation of telomere protection from length regulation by two different point mutations at amino acid 492 of RTEL1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.26.582005. [PMID: 38464183 PMCID: PMC10925190 DOI: 10.1101/2024.02.26.582005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
RTEL1 is an essential DNA helicase that plays multiple roles in genome stability and telomere length regulation. A variant of RTEL1 with a lysine at position 492 is associated with short telomeres in Mus spretus , while a conserved methionine at this position is found in M. musculus , which has ultra-long telomeres. In humans, a missense mutation at this position ( Rtel1 M492I ) causes a fatal telomere biology disease termed Hoyeraal-Hreidarsson syndrome (HHS). Introducing the Rtel1 M492K mutation into M. musculus shortened the telomeres of the resulting strain, termed 'Telomouse', to the length of human telomeres. Here, we report on a mouse strain carrying the Rtel1 M492I mutation, termed 'HHS mouse'. The HHS mouse telomeres are not as short as those of Telomice but nevertheless they display higher levels of telomeric DNA damage, fragility and recombination, associated with anaphase bridges and micronuclei. These observations indicate that the two mutations separate critical functions of RTEL1: M492K mainly reduces the telomere length setpoint, while M492I predominantly disrupts telomere protection. The two mouse models enable dissecting the mechanistic roles of RTEL1 and the different contributions of short telomeres and DNA damage to telomere biology diseases, genomic instability, cancer, and aging.
Collapse
|
5
|
Bolzán AD. Considerations on the scoring of telomere aberrations in vertebrate cells detected by telomere or telomere plus centromere PNA-FISH. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2024; 794:108507. [PMID: 38802042 DOI: 10.1016/j.mrrev.2024.108507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 05/20/2024] [Accepted: 05/21/2024] [Indexed: 05/29/2024]
Abstract
Given that telomeres play a fundamental role in maintaining genomic stability, the study of the chromosomal aberrations involving telomeric sequences is a topic of considerable research interest. In recent years, the scoring of these types of aberrations has been used in vertebrate cells, particularly human cells, to evaluate the effects of genotoxic agents on telomeres and the involvement of telomeric sequences on chromosomal aberrations. Currently, chromosomal aberrations involving telomeric sequences are evaluated in peripheral blood lymphocytes or immortalized cell lines, using telomere or telomere plus centromere fluorescence in situ hybridization (FISH) with Peptide Nucleic Acid (PNA) probes (PNA-FISH). The telomere PNA probe is more efficient in the detection of telomeric sequences than conventional FISH with a telomere DNA probe. In addition, the intensity of the telomeric PNA-FISH probe signal is directly correlated with the number of telomeric repeats. Therefore, use of this type of probe can identify chromosomal aberrations involving telomeres as well as determine the telomere length of the sample. There are several mistakes and inconsistencies in the literature regarding the identification of telomere aberrations, which prevent accurate scoring and data comparison between different publications concerning these types of aberrations. The aim of this review is to clarify these issues, and provide proper terminology and criteria for the identification, scoring, and analysis of telomere aberrations.
Collapse
Affiliation(s)
- Alejandro D Bolzán
- Laboratorio de Citogenética y Mutagénesis, Instituto Multidisciplinario de Biología Celular (IMBICE, CONICET-UNLP-CICPBA), calle 526 y Camino General Belgrano, La Plata, Buenos Aires B1906APO, Argentina; Universidad Nacional de La Plata, Facultad de Ciencias Naturales y Museo, calle 60 y 122, La Plata, Buenos Aires, Argentina.
| |
Collapse
|
6
|
Kumar N, Taneja A, Ghosh M, Rothweiler U, Sundaresan N, Singh M. Harmonin homology domain-mediated interaction of RTEL1 helicase with RPA and DNA provides insights into its recruitment to DNA repair sites. Nucleic Acids Res 2024; 52:1450-1470. [PMID: 38153196 PMCID: PMC10853778 DOI: 10.1093/nar/gkad1208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 12/04/2023] [Accepted: 12/06/2023] [Indexed: 12/29/2023] Open
Abstract
The regulator of telomere elongation helicase 1 (RTEL1) plays roles in telomere DNA maintenance, DNA repair, and genome stability by dismantling D-loops and unwinding G-quadruplex structures. RTEL1 comprises a helicase domain, two tandem harmonin homology domains 1&2 (HHD1 and HHD2), and a Zn2+-binding RING domain. In vitro D-loop disassembly by RTEL1 is enhanced in the presence of replication protein A (RPA). However, the mechanism of RTEL1 recruitment at non-telomeric D-loops remains unknown. In this study, we have unravelled a direct physical interaction between RTEL1 and RPA. Under DNA damage conditions, we showed that RTEL1 and RPA colocalise in the cell. Coimmunoprecipitation showed that RTEL1 and RPA interact, and the deletion of HHDs of RTEL1 significantly reduced this interaction. NMR chemical shift perturbations (CSPs) showed that RPA uses its 32C domain to interact with the HHD2 of RTEL1. Interestingly, HHD2 also interacted with DNA in the in vitro experiments. HHD2 structure was determined using X-ray crystallography, and NMR CSPs mapping revealed that both RPA 32C and DNA competitively bind to HHD2 on an overlapping surface. These results establish novel roles of accessory HHDs in RTEL1's functions and provide mechanistic insights into the RPA-mediated recruitment of RTEL1 to DNA repair sites.
Collapse
Affiliation(s)
- Niranjan Kumar
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
| | - Arushi Taneja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Meenakshi Ghosh
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
| | - Ulli Rothweiler
- The Norwegian Structural Biology Centre, Department of Chemistry, The Arctic University of Norway, N-9037, Tromsø, Norway
| | | | - Mahavir Singh
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
| |
Collapse
|
7
|
Hourvitz N, Awad A, Tzfati Y. The many faces of the helicase RTEL1 at telomeres and beyond. Trends Cell Biol 2024; 34:109-121. [PMID: 37532653 DOI: 10.1016/j.tcb.2023.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 07/01/2023] [Accepted: 07/05/2023] [Indexed: 08/04/2023]
Abstract
Regulator of telomere elongation 1 (RTEL1) is known as a DNA helicase that is important for telomeres and genome integrity. However, the diverse phenotypes of RTEL1 dysfunction, the wide spectrum of symptoms caused by germline RTEL1 mutations, and the association of RTEL1 mutations with cancers suggest that RTEL1 is a complex machine that interacts with DNA, RNA, and proteins, and functions in diverse cellular pathways. We summarize the proposed functions of RTEL1 and discuss their implications for telomere maintenance. Studying RTEL1 is crucial for understanding the complex interplay between telomere maintenance and other nuclear pathways, and how compromising these pathways causes telomere biology diseases, various aging-associated pathologies, and cancer.
Collapse
Affiliation(s)
- Noa Hourvitz
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem 91904, Israel
| | - Aya Awad
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem 91904, Israel
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem 91904, Israel.
| |
Collapse
|
8
|
Lu X, Liu L. Genome stability from the perspective of telomere length. Trends Genet 2024; 40:175-186. [PMID: 37957036 DOI: 10.1016/j.tig.2023.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023]
Abstract
Telomeres and their associated proteins protect the ends of chromosomes to maintain genome stability. Telomeres undergo progressive shortening with each cell division in mammalian somatic cells without telomerase, resulting in genome instability. When telomeres reach a critically short length or are recognized as a damage signal, cells enter a state of senescence, followed by cell cycle arrest, programmed cell death, or immortalization. This review provides an overview of recent advances in the intricate relationship between telomeres and genome instability. Alongside well-established mechanisms such as chromosomal fusion and telomere fusion, we will delve into the perspective on genome stability by examining the role of retrotransposons. Retrotransposons represent an emerging pathway to regulate genome stability through their interactions with telomeres.
Collapse
Affiliation(s)
- Xinyi Lu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China.
| | - Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, Tianjin 300350, China; Frontiers Science Center for Cell Responses, College of Life Science, Nankai University, Tianjin, Tianjin 300071, China; Haihe Laboratory of Cell Ecosystem, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China; Institute of Translational Medicine, Tianjin Union Medical Center, Nankai University, Tianjin 300000, China.
| |
Collapse
|
9
|
Schertzer M, Jullien L, Pinto AL, Calado RT, Revy P, Londoño-Vallejo A. Human RTEL1 Interacts with KPNB1 (Importin β) and NUP153 and Connects Nuclear Import to Nuclear Envelope Stability in S-Phase. Cells 2023; 12:2798. [PMID: 38132118 PMCID: PMC10741959 DOI: 10.3390/cells12242798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 11/29/2023] [Accepted: 12/03/2023] [Indexed: 12/23/2023] Open
Abstract
Regulator of TElomere Length Helicase 1 (RTEL1) is a helicase required for telomere maintenance and genome replication and repair. RTEL1 has been previously shown to participate in the nuclear export of small nuclear RNAs. Here we show that RTEL1 deficiency leads to a nuclear envelope destabilization exclusively in cells entering S-phase and in direct connection to origin firing. We discovered that inhibiting protein import also leads to similar, albeit non-cell cycle-related, nuclear envelope disruptions. Remarkably, overexpression of wild-type RTEL1, or of its C-terminal part lacking the helicase domain, protects cells against nuclear envelope anomalies mediated by protein import inhibition. We identified distinct domains in the C-terminus of RTEL1 essential for the interaction with KPNB1 (importin β) and NUP153, respectively, and we demonstrated that, on its own, the latter domain can promote the dynamic nuclear internalization of peptides that freely diffuse through the nuclear pore. Consistent with putative functions exerted in protein import, RTEL1 can be visualized on both sides of the nuclear pore using high-resolution microscopy. In all, our work points to an unanticipated, helicase-independent, role of RTEL1 in connecting both nucleocytoplasmic trafficking and nuclear envelope integrity to genome replication initiation in S-phase.
Collapse
Affiliation(s)
- Michael Schertzer
- Institut Curie, PSL Research University, CNRS, UMR3244, F-75005 Paris, France;
- Sorbonne Universités, CNRS, UMR3244, F-75005 Paris, France
| | - Laurent Jullien
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue Contre le Cancer, F-75006 Paris, France; (L.J.); (P.R.)
- Paris Descartes–Sorbonne Paris Cité University, Imagine Institute, F-75015 Paris, France
| | - André L. Pinto
- Department of Medical Imaging, Hematology, and Oncology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, Brazil; (A.L.P.); (R.T.C.)
| | - Rodrigo T. Calado
- Department of Medical Imaging, Hematology, and Oncology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto 14049-900, Brazil; (A.L.P.); (R.T.C.)
| | - Patrick Revy
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue Contre le Cancer, F-75006 Paris, France; (L.J.); (P.R.)
- Paris Descartes–Sorbonne Paris Cité University, Imagine Institute, F-75015 Paris, France
| | - Arturo Londoño-Vallejo
- Institut Curie, PSL Research University, CNRS, UMR3244, F-75005 Paris, France;
- Sorbonne Universités, CNRS, UMR3244, F-75005 Paris, France
| |
Collapse
|
10
|
Li B. Telomere maintenance in African trypanosomes. Front Mol Biosci 2023; 10:1302557. [PMID: 38074093 PMCID: PMC10704157 DOI: 10.3389/fmolb.2023.1302557] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/15/2023] [Indexed: 02/12/2024] Open
Abstract
Telomere maintenance is essential for genome integrity and chromosome stability in eukaryotic cells harboring linear chromosomes, as telomere forms a specialized structure to mask the natural chromosome ends from DNA damage repair machineries and to prevent nucleolytic degradation of the telomeric DNA. In Trypanosoma brucei and several other microbial pathogens, virulence genes involved in antigenic variation, a key pathogenesis mechanism essential for host immune evasion and long-term infections, are located at subtelomeres, and expression and switching of these major surface antigens are regulated by telomere proteins and the telomere structure. Therefore, understanding telomere maintenance mechanisms and how these pathogens achieve a balance between stability and plasticity at telomere/subtelomere will help develop better means to eradicate human diseases caused by these pathogens. Telomere replication faces several challenges, and the "end replication problem" is a key obstacle that can cause progressive telomere shortening in proliferating cells. To overcome this challenge, most eukaryotes use telomerase to extend the G-rich telomere strand. In addition, a number of telomere proteins use sophisticated mechanisms to coordinate the telomerase-mediated de novo telomere G-strand synthesis and the telomere C-strand fill-in, which has been extensively studied in mammalian cells. However, we recently discovered that trypanosomes lack many telomere proteins identified in its mammalian host that are critical for telomere end processing. Rather, T. brucei uses a unique DNA polymerase, PolIE that belongs to the DNA polymerase A family (E. coli DNA PolI family), to coordinate the telomere G- and C-strand syntheses. In this review, I will first briefly summarize current understanding of telomere end processing in mammals. Subsequently, I will describe PolIE-mediated coordination of telomere G- and C-strand synthesis in T. brucei and implication of this recent discovery.
Collapse
Affiliation(s)
- Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Arts and Sciences, Cleveland State University, Cleveland, OH, United States
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, United States
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, OH, United States
| |
Collapse
|
11
|
He Q, Sze SK, Ng KS, Koh CG. Paxillin interactome identified by SILAC and label-free approaches coupled to TurboID sheds light on the compositions of focal adhesions in mouse embryonic stem cells. Biochem Biophys Res Commun 2023; 680:73-85. [PMID: 37725837 DOI: 10.1016/j.bbrc.2023.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 08/25/2023] [Accepted: 09/08/2023] [Indexed: 09/21/2023]
Abstract
Self-renewal and differentiation of mouse embryonic stem cells (mESCs) are greatly affected by the extracellular matrix (ECM) environment; the composition and stiffness of which are sensed by the cells via integrin-associated focal adhesions (FAs) which link the cells to the ECM. Although FAs have been studied extensively in differentiated cells, their composition and function in mESCs are not as well elucidated. To gain more detailed knowledge of the molecular compositions of FAs in mESCs, we adopted the proximity-dependent biotinylation (BioID) proteomics approach. Paxillin, a known FA protein (FAP), is fused to the promiscuous biotin ligase TurboID as bait. We employed both SILAC- and label-free (LF)-based quantitative proteomics to strengthen as well as complement individual approach. The mass spectrometry data derived from SILAC and LF identified 38 and 443 proteins, respectively, with 35 overlapping candidates. Fifteen of these shared proteins are known FAPs based on literature-curated adhesome and 7 others are among the reported "meta-adhesome", suggesting the components of FAs are largely conserved between mESCs and differentiated cells. Furthermore, the LF data set contained an additional 18 literature-curated FAPs. Notably, the overlapped proteomics data failed to detect LIM-domain proteins such as zyxin family proteins, which suggests that FAs in mESCs are less mature than differentiated cells. Using the LF approach, we are able to identify PDLIM7, a LIM-domain protein, as a FAP in mESCs. This study illustrates the effectiveness of TurboID in mESCs. Importantly, we found that application of both SILAC and LF methods in combination allowed us to analyze the TurboID proteomics data in an unbiased, stringent and yet comprehensive manner.
Collapse
Affiliation(s)
- Qianqian He
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Kai Soon Ng
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Cheng-Gee Koh
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore.
| |
Collapse
|
12
|
Smoom R, May CL, Ortiz V, Tigue M, Kolev HM, Rowe M, Reizel Y, Morgan A, Egyes N, Lichtental D, Skordalakes E, Kaestner KH, Tzfati Y. Telomouse-a mouse model with human-length telomeres generated by a single amino acid change in RTEL1. Nat Commun 2023; 14:6708. [PMID: 37872177 PMCID: PMC10593777 DOI: 10.1038/s41467-023-42534-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 10/14/2023] [Indexed: 10/25/2023] Open
Abstract
Telomeres, the ends of eukaryotic chromosomes, protect genome integrity and enable cell proliferation. Maintaining optimal telomere length in the germline and throughout life limits the risk of cancer and enables healthy aging. Telomeres in the house mouse, Mus musculus, are about five times longer than human telomeres, limiting the use of this common laboratory animal for studying the contribution of telomere biology to aging and cancer. We identified a key amino acid variation in the helicase RTEL1, naturally occurring in the short-telomere mouse species M. spretus. Introducing this variation into M. musculus is sufficient to reduce the telomere length set point in the germline and generate mice with human-length telomeres. While these mice are fertile and appear healthy, the regenerative capacity of their colonic epithelium is compromised. The engineered Telomouse reported here demonstrates a dominant role of RTEL1 in telomere length regulation and provides a unique model for aging and cancer.
Collapse
Affiliation(s)
- Riham Smoom
- Department of Genetics, The Silberman Institute of Life Sciences, Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Catherine Lee May
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Vivian Ortiz
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Division of Gastroenterology and Hepatology, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Mark Tigue
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Hannah M Kolev
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Melissa Rowe
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Yitzhak Reizel
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Faculty of Biotechnology and Food Engineering, Technion, Haifa, 3200003, Israel
| | - Ashleigh Morgan
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Nachshon Egyes
- Department of Genetics, The Silberman Institute of Life Sciences, Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Dan Lichtental
- Department of Genetics, The Silberman Institute of Life Sciences, Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | - Emmanuel Skordalakes
- Department of Pharmacology and Toxicology, Massey Cancer Center, Virginia Commonwealth University, 401 College St, Richmond, VA, 23298, USA
| | - Klaus H Kaestner
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Sciences, Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
| |
Collapse
|
13
|
Rakotopare J, Toledo F. p53 in the Molecular Circuitry of Bone Marrow Failure Syndromes. Int J Mol Sci 2023; 24:14940. [PMID: 37834388 PMCID: PMC10573108 DOI: 10.3390/ijms241914940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/02/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023] Open
Abstract
Mice with a constitutive increase in p53 activity exhibited features of dyskeratosis congenita (DC), a bone marrow failure syndrome (BMFS) caused by defective telomere maintenance. Further studies confirmed, in humans and mice, that germline mutations affecting TP53 or its regulator MDM4 may cause short telomeres and alter hematopoiesis, but also revealed features of Diamond-Blackfan anemia (DBA) or Fanconi anemia (FA), two BMFSs, respectively, caused by defects in ribosomal function or DNA repair. p53 downregulates several genes mutated in DC, either by binding to promoter sequences (DKC1) or indirectly via the DREAM repressor complex (RTEL1, DCLRE1B), and the p53-DREAM pathway represses 22 additional telomere-related genes. Interestingly, mutations in any DC-causal gene will cause telomere dysfunction and subsequent p53 activation to further promote the repression of p53-DREAM targets. Similarly, ribosomal dysfunction and DNA lesions cause p53 activation, and p53-DREAM targets include the DBA-causal gene TSR2, at least 9 FA-causal genes, and 38 other genes affecting ribosomes or the FA pathway. Furthermore, patients with BMFSs may exhibit brain abnormalities, and p53-DREAM represses 16 genes mutated in microcephaly or cerebellar hypoplasia. In sum, positive feedback loops and the repertoire of p53-DREAM targets likely contribute to partial phenotypic overlaps between BMFSs of distinct molecular origins.
Collapse
Affiliation(s)
- Jeanne Rakotopare
- Genetics of Tumor Suppression, Institut Curie, CEDEX 05, 75248 Paris, France;
- CNRS UMR3244, 75005 Paris, France
- Faculty of Science and Engineering, Sorbonne University, 75005 Paris, France
- Institut Curie, PSL Research University, 75005 Paris, France
| | - Franck Toledo
- Genetics of Tumor Suppression, Institut Curie, CEDEX 05, 75248 Paris, France;
- CNRS UMR3244, 75005 Paris, France
- Faculty of Science and Engineering, Sorbonne University, 75005 Paris, France
- Institut Curie, PSL Research University, 75005 Paris, France
| |
Collapse
|
14
|
Olivier M, Hesketh A, Pouch-Pélissier MN, Pélissier T, Huang Y, Latrasse D, Benhamed M, Mathieu O. RTEL1 is required for silencing and epigenome stability. Nucleic Acids Res 2023; 51:8463-8479. [PMID: 37471026 PMCID: PMC10484728 DOI: 10.1093/nar/gkad610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/13/2023] [Accepted: 07/10/2023] [Indexed: 07/21/2023] Open
Abstract
Transcriptional silencing is an essential mechanism for controlling the expression of genes, transgenes and heterochromatic repeats through specific epigenetic marks on chromatin that are maintained during DNA replication. In Arabidopsis, silenced transgenes and heterochromatic sequences are typically associated with high levels of DNA methylation, while silenced genes are enriched in H3K27me3. Reactivation of these loci is often correlated with decreased levels of these repressive epigenetic marks. Here, we report that the DNA helicase REGULATOR OF TELOMERE ELONGATION 1 (RTEL1) is required for transcriptional silencing. RTEL1 deficiency causes upregulation of many genes enriched in H3K27me3 accompanied by a moderate decrease in this mark, but no loss of DNA methylation at reactivated heterochromatic loci. Instead, heterochromatin exhibits DNA hypermethylation and increased H3K27me3 in rtel1. We further find that loss of RTEL1 suppresses the release of heterochromatin silencing caused by the absence of the MOM1 silencing factor. RTEL1 is conserved among eukaryotes and plays a key role in resolving DNA secondary structures during DNA replication. Inducing such aberrant DNA structures using DNA cross-linking agents also results in a loss of transcriptional silencing. These findings uncover unappreciated roles for RTEL1 in transcriptional silencing and in stabilizing DNA methylation and H3K27me3 patterns.
Collapse
Affiliation(s)
- Margaux Olivier
- Institute of Genetics Reproduction and Development (iGReD), Université Clermont Auvergne, CNRS, Inserm, F-63000 Clermont-Ferrand, France
| | - Amy Hesketh
- Institute of Genetics Reproduction and Development (iGReD), Université Clermont Auvergne, CNRS, Inserm, F-63000 Clermont-Ferrand, France
| | - Marie-Noëlle Pouch-Pélissier
- Institute of Genetics Reproduction and Development (iGReD), Université Clermont Auvergne, CNRS, Inserm, F-63000 Clermont-Ferrand, France
| | - Thierry Pélissier
- Institute of Genetics Reproduction and Development (iGReD), Université Clermont Auvergne, CNRS, Inserm, F-63000 Clermont-Ferrand, France
| | - Ying Huang
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRAE, Université d’Évry, F-91405 Orsay, France
| | - David Latrasse
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRAE, Université d’Évry, F-91405 Orsay, France
| | - Moussa Benhamed
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRAE, Université d’Évry, F-91405 Orsay, France
- Institute of Plant Sciences Paris-Saclay (IPS2), Université de Paris, F-75006 Paris, France
- Institut Universitaire de France (IUF), France
| | - Olivier Mathieu
- Institute of Genetics Reproduction and Development (iGReD), Université Clermont Auvergne, CNRS, Inserm, F-63000 Clermont-Ferrand, France
| |
Collapse
|
15
|
Petronek MS, Allen BG. Maintenance of genome integrity by the late-acting cytoplasmic iron-sulfur assembly (CIA) complex. Front Genet 2023; 14:1152398. [PMID: 36968611 PMCID: PMC10031043 DOI: 10.3389/fgene.2023.1152398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 02/24/2023] [Indexed: 03/29/2023] Open
Abstract
Iron-sulfur (Fe-S) clusters are unique, redox-active co-factors ubiquitous throughout cellular metabolism. Fe-S cluster synthesis, trafficking, and coordination result from highly coordinated, evolutionarily conserved biosynthetic processes. The initial Fe-S cluster synthesis occurs within the mitochondria; however, the maturation of Fe-S clusters culminating in their ultimate insertion into appropriate cytosolic/nuclear proteins is coordinated by a late-acting cytosolic iron-sulfur assembly (CIA) complex in the cytosol. Several nuclear proteins involved in DNA replication and repair interact with the CIA complex and contain Fe-S clusters necessary for proper enzymatic activity. Moreover, it is currently hypothesized that the late-acting CIA complex regulates the maintenance of genome integrity and is an integral feature of DNA metabolism. This review describes the late-acting CIA complex and several [4Fe-4S] DNA metabolic enzymes associated with maintaining genome stability.
Collapse
|
16
|
Nisar H, Khan M, Chaudhry QUN, Iftikhar R, Ghafoor T. Case report: A novel mutation in RTEL1 gene in dyskeratosis congenita. Front Oncol 2023; 13:1098876. [PMID: 36937416 PMCID: PMC10017992 DOI: 10.3389/fonc.2023.1098876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 02/13/2023] [Indexed: 03/06/2023] Open
Abstract
Dyskeratosis congenita (DKC), also known as Zinsser-Cole-Engman syndrome, is a telomeropathy typically presenting as a triad of leukoplakia, nail dystrophy, and reticular hyperpigmentation. Reported genetic mutations linked to DKC include DKC1, TINF2, TERC, TERT, C16orf57, NOLA2, NOLA3, WRAP53/TCAB1, and RTEL1. Homozygous, compound heterozygous, and heterozygous mutations in RTEL1 (RTEL1, regulator of telomere elongation helicase 1) gene on chromosome 20q13 are known to cause autosomal dominant as well as recessive DKC. Pathogenic variants of RTEL1 gene in DKC patients include c.2288G>T (p. Gly763Val), c.3791G>A (p. Arg1264His), and RTEL p. Arg981Trp. We report a novel homozygous variant of RTEL1, transcript ID: ENST00000360203.11, exon 24, c.2060C>T (p.Ala687Val), in a patient of DKC presenting with leukoplakia, dystrophic nails, reticulate pigmentation, and positive family history of a similar phenotype. The novel variant, reported as a variant of uncertain significance, may therefore be considered diagnostic for DKC in a Pakistani population.
Collapse
Affiliation(s)
- Haider Nisar
- Adult and Pediatric Transplant Unit, Armed Forces Bone Marrow Transplant Center/National Institute of Bone Marrow Transplant, Rawalpindi, Pakistan
| | - Memoona Khan
- Pathology Department and Stem Cell Research Lab, Armed Forces Bone Marrow Transplant Center/National Institute of Bone Marrow Transplant, Rawalpindi, Pakistan
- *Correspondence: Memoona Khan,
| | - Qamar Un Nisa Chaudhry
- Adult and Pediatric Transplant Unit, Armed Forces Bone Marrow Transplant Center/National Institute of Bone Marrow Transplant, Rawalpindi, Pakistan
- Pathology Department and Stem Cell Research Lab, Armed Forces Bone Marrow Transplant Center/National Institute of Bone Marrow Transplant, Rawalpindi, Pakistan
| | - Raheel Iftikhar
- Adult and Pediatric Transplant Unit, Armed Forces Bone Marrow Transplant Center/National Institute of Bone Marrow Transplant, Rawalpindi, Pakistan
| | - Tariq Ghafoor
- Adult and Pediatric Transplant Unit, Armed Forces Bone Marrow Transplant Center/National Institute of Bone Marrow Transplant, Rawalpindi, Pakistan
| |
Collapse
|
17
|
Hassani MA, Murid J, Yan J. Regulator of telomere elongation helicase 1 gene and its association with malignancy. Cancer Rep (Hoboken) 2022; 6:e1735. [PMID: 36253342 PMCID: PMC9875622 DOI: 10.1002/cnr2.1735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND With the progression of next-generation sequencing technologies, researchers have identified numerous variants of the regulator of telomere elongation helicase 1 (RTEL1) gene that are associated with a broad spectrum of phenotypic manifestations, including malignancies. At the molecular level, RTEL1 is involved in the regulation of the repair, replication, and transcription of deoxyribonucleic acid (DNA) and the maintenance of telomere length. RTEL1 can act both as a promotor and inhibitor of tumorigenesis. Here, we review the potential mechanisms implicated in the malignant transformation of tissues under conditions of RTEL1 deficiency or its aberrant overexpression. RECENT FINDINGS A major hemostatic challenge during RTEL1 dysfunction could arise from its unbalanced activity for unwinding guanine-rich quadruplex DNA (G4-DNA) structures. In contrast, RTEL1 deficiency leads to alterations in telomeric and genome-wide DNA maintenance mechanisms, ribonucleoprotein metabolism, and the creation of an inflammatory and immune-deficient microenvironment, all promoting malignancy. Additionally, we hypothesize that functionally similar molecules could act to compensate for the deteriorated functions of RTEL1, thereby facilitating the survival of malignant cells. On the contrary, RTEL1 over-expression was directed toward G4-unwinding, by promoting replication fork progression and maintaining intact telomeres, may facilitate malignant transformation and proliferation of various pre-malignant cellular compartments. CONCLUSIONS Therefore, restoring the equilibrium of RTEL1 functions could serve as a therapeutic approach for preventing and treating malignancies.
Collapse
Affiliation(s)
- Mohammad Arian Hassani
- Department of Hematology, Liaoning Medical Center for Hematopoietic Stem Cell Transplantation, Liaoning Key Laboratory of Hematopoietic Stem Cell Transplantation and Translational Medicine, Dalian Key Laboratory of HematologySecond Hospital of Dalian Medical UniversityDalianChina,Department of Hematology, Endocrinology and Rheumatology, Ali Abad Teaching HospitalKabul University of Medical SciencesJamal menaKabulAfghanistan
| | - Jamshid Murid
- Department of Hematology, Endocrinology and Rheumatology, Ali Abad Teaching HospitalKabul University of Medical SciencesJamal menaKabulAfghanistan
| | - Jinsong Yan
- Department of Hematology, Liaoning Medical Center for Hematopoietic Stem Cell Transplantation, Liaoning Key Laboratory of Hematopoietic Stem Cell Transplantation and Translational Medicine, Dalian Key Laboratory of HematologySecond Hospital of Dalian Medical UniversityDalianChina,Diamond Bay Institute of HematologySecond Hospital of Dalian Medical UniversityDalianChina
| |
Collapse
|
18
|
Yang Y, Kong R, Goh FG, Somers WG, Hime GR, Li Z, Cai Y. dRTEL1 is essential for the maintenance of Drosophila male germline stem cells. PLoS Genet 2021; 17:e1009834. [PMID: 34644293 PMCID: PMC8513875 DOI: 10.1371/journal.pgen.1009834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 09/23/2021] [Indexed: 11/19/2022] Open
Abstract
Stem cells have the potential to maintain undifferentiated state and differentiate into specialized cell types. Despite numerous progress has been achieved in understanding stem cell self-renewal and differentiation, many fundamental questions remain unanswered. In this study, we identify dRTEL1, the Drosophila homolog of Regulator of Telomere Elongation Helicase 1, as a novel regulator of male germline stem cells (GSCs). Our genome-wide transcriptome analysis and ChIP-Seq results suggest that dRTEL1 affects a set of candidate genes required for GSC maintenance, likely independent of its role in DNA repair. Furthermore, dRTEL1 prevents DNA damage-induced checkpoint activation in GSCs. Finally, dRTEL1 functions to sustain Stat92E protein levels, the key player in GSC maintenance. Together, our findings reveal an intrinsic role of the DNA helicase dRTEL1 in maintaining male GSC and provide insight into the function of dRTEL1.
Collapse
Affiliation(s)
- Ying Yang
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Department of Pathology, Peking University Health Science Center, Beijing, China
| | - Ruiyan Kong
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Feng Guang Goh
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
| | - W. Gregory Somers
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Australia
| | - Gary R. Hime
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Australia
| | - Zhouhua Li
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Yu Cai
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| |
Collapse
|
19
|
Bolzán AD. Mutagen-induced telomere instability in human cells. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2021; 868-869:503387. [PMID: 34454696 DOI: 10.1016/j.mrgentox.2021.503387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/13/2021] [Accepted: 07/18/2021] [Indexed: 11/27/2022]
Abstract
Telomere instability is one of the main sources of genome instability and may result from chromosome end loss (due to chromosome breakage at one or both ends) or, more frequently, telomere dysfunction. Dysfunctional telomeres arise when they lose their end-capping function or become critically short, which causes chromosomal termini to behave like a DNA double-strand break. Telomere instability may occur at the chromosomal or at the molecular level, giving rise, respectively, to telomere-related chromosomal aberrations or the loss or modification of any of the components of the telomere (telomere DNA, telomere-associated proteins, or telomere RNA). Since telomeres play a fundamental role in maintaining genome stability, the study of telomere instability in cells exposed to mutagens is of great importance to understand the telomere-driven genomic instability present in those cells. In the present review, we will focus on the current knowledge about telomere instability induced by physical, chemical, and biological mutagens in human cells.
Collapse
Affiliation(s)
- Alejandro D Bolzán
- Laboratorio de Citogenética y Mutagénesis, Instituto Multidisciplinario de Biología Celular (IMBICE, CONICET-CICPBA-UNLP), calle 526 y Camino General Belgrano, B1906APO La Plata, Buenos Aires, Argentina; Universidad Nacional de La Plata, Facultad de Ciencias Naturales y Museo, calle 60 y 122, La Plata, Buenos Aires, Argentina.
| |
Collapse
|
20
|
Abstract
In this perspective, we introduce shelterin and the mechanisms of ATM activation and NHEJ at telomeres, before discussing the following questions: How are t-loops proposed to protect chromosome ends and what is the evidence for this model? Can other models explain how TRF2 mediates end protection? Could t-loops be pathological structures? How is end protection achieved in pluripotent cells? What do the insights into telomere end protection in pluripotent cells mean for the t-loop model of end protection? Why might different cell states have evolved different mechanisms of end protection? Finally, we offer support for an updated t-loop model of end protection, suggesting that the data is supportive of a critical role for t-loops in protecting chromosome ends from NHEJ and ATM activation, but that other mechanisms are involved. Finally, we propose that t-loops are likely dynamic, rather than static, structures.
Collapse
Affiliation(s)
- Phil Ruis
- The Francis Crick Institute, London NW1 1AT, United Kingdom
| | | |
Collapse
|
21
|
Dhar S, Datta A, Brosh RM. DNA helicases and their roles in cancer. DNA Repair (Amst) 2020; 96:102994. [PMID: 33137625 DOI: 10.1016/j.dnarep.2020.102994] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 09/28/2020] [Indexed: 12/15/2022]
Abstract
DNA helicases, known for their fundamentally important roles in genomic stability, are high profile players in cancer. Not only are there monogenic helicase disorders with a strong disposition to cancer, it is well appreciated that helicase variants are associated with specific cancers (e.g., breast cancer). Flipping the coin, DNA helicases are frequently overexpressed in cancerous tissues and reduction in helicase gene expression results in reduced proliferation and growth capacity, as well as DNA damage induction and apoptosis of cancer cells. The seminal roles of helicases in the DNA damage and replication stress responses, as well as DNA repair pathways, validate their vital importance in cancer biology and suggest their potential values as targets in anti-cancer therapy. In recent years, many laboratories have characterized the specialized roles of helicase to resolve transcription-replication conflicts, maintain telomeres, mediate cell cycle checkpoints, remodel stalled replication forks, and regulate transcription. In vivo models, particularly mice, have been used to interrogate helicase function and serve as a bridge for preclinical studies that may lead to novel therapeutic approaches. In this review, we will summarize our current knowledge of DNA helicases and their roles in cancer, emphasizing the latest developments.
Collapse
Affiliation(s)
- Srijita Dhar
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Arindam Datta
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Robert M Brosh
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
| |
Collapse
|
22
|
Using telomeric chromosomal aberrations to evaluate clastogen-induced genomic instability in mammalian cells. Chromosome Res 2020; 28:259-276. [DOI: 10.1007/s10577-020-09641-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/06/2020] [Accepted: 09/06/2020] [Indexed: 12/13/2022]
|
23
|
Abstract
Several decades elapsed between the first descriptions of G-quadruplex nucleic acid structures (G4s) assembled in vitro and the emergence of experimental findings indicating that such structures can form and function in living systems. A large body of evidence now supports roles for G4s in many aspects of nucleic acid biology, spanning processes from transcription and chromatin structure, mRNA processing, protein translation, DNA replication and genome stability, and telomere and mitochondrial function. Nonetheless, it must be acknowledged that some of this evidence is tentative, which is not surprising given the technical challenges associated with demonstrating G4s in biology. Here I provide an overview of evidence for G4 biology, focusing particularly on the many potential pitfalls that can be encountered in its investigation, and briefly discuss some of broader biological processes that may be impacted by G4s including cancer.
Collapse
Affiliation(s)
- F. Brad Johnson
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States
| |
Collapse
|
24
|
Awad A, Glousker G, Lamm N, Tawil S, Hourvitz N, Smoom R, Revy P, Tzfati Y. Full length RTEL1 is required for the elongation of the single-stranded telomeric overhang by telomerase. Nucleic Acids Res 2020; 48:7239-7251. [PMID: 32542379 PMCID: PMC7367169 DOI: 10.1093/nar/gkaa503] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 12/17/2022] Open
Abstract
Telomeres cap the ends of eukaryotic chromosomes and distinguish them from broken DNA ends to suppress DNA damage response, cell cycle arrest and genomic instability. Telomeres are elongated by telomerase to compensate for incomplete replication and nuclease degradation and to extend the proliferation potential of germ and stem cells and most cancers. However, telomeres in somatic cells gradually shorten with age, ultimately leading to cellular senescence. Hoyeraal-Hreidarsson syndrome (HHS) is characterized by accelerated telomere shortening and diverse symptoms including bone marrow failure, immunodeficiency, and neurodevelopmental defects. HHS is caused by germline mutations in telomerase subunits, factors essential for its biogenesis and recruitment to telomeres, and in the helicase RTEL1. While diverse phenotypes were associated with RTEL1 deficiency, the telomeric role of RTEL1 affected in HHS is yet unknown. Inducible ectopic expression of wild-type RTEL1 in patient fibroblasts rescued the cells, enabled telomerase-dependent telomere elongation and suppressed the abnormal cellular phenotypes, while silencing its expression resulted in gradual telomere shortening. Our observations reveal an essential role of the RTEL1 C-terminus in facilitating telomerase action at the telomeric 3' overhang. Thus, the common etiology for HHS is the compromised telomerase action, resulting in telomere shortening and reduced lifespan of telomerase positive cells.
Collapse
Affiliation(s)
- Aya Awad
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Galina Glousker
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Noa Lamm
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Shadi Tawil
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Noa Hourvitz
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Riham Smoom
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| | - Patrick Revy
- INSERM UMR 1163, Laboratory of Genome Dynamics in the Immune System, Equipe Labellisée Ligue contre le Cancer and Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel
| |
Collapse
|
25
|
Björkman A, Johansen SL, Lin L, Schertzer M, Kanellis DC, Katsori AM, Christensen ST, Luo Y, Andersen JS, Elsässer SJ, Londono-Vallejo A, Bartek J, Schou KB. Human RTEL1 associates with Poldip3 to facilitate responses to replication stress and R-loop resolution. Genes Dev 2020; 34:1065-1074. [PMID: 32561545 PMCID: PMC7397856 DOI: 10.1101/gad.330050.119] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 05/18/2020] [Indexed: 02/07/2023]
Abstract
In this study from Björkman et al., the authors sought to understand how RTEL1 helicase preserves genomic stability during replication. They demonstrate that RTEL1 and the Polδ subunit Poldip3 form a complex and are mutually dependent in chromatin binding after replication stress, and loss of RTEL1 and Poldip3 leads to marked R-loop accumulation that is confined to sites of active replication, thus highlighting a previously unknown role of RTEL1 and Poldip3 in R-loop suppression at genomic regions where transcription and replication intersect. RTEL1 helicase is a component of DNA repair and telomere maintenance machineries. While RTEL1's role in DNA replication is emerging, how RTEL1 preserves genomic stability during replication remains elusive. Here we used a range of proteomic, biochemical, cell, and molecular biology and gene editing approaches to provide further insights into potential role(s) of RTEL1 in DNA replication and genome integrity maintenance. Our results from complementary human cell culture models established that RTEL1 and the Polδ subunit Poldip3 form a complex and are/function mutually dependent in chromatin binding after replication stress. Loss of RTEL1 and Poldip3 leads to marked R-loop accumulation that is confined to sites of active replication, enhances endogenous replication stress, and fuels ensuing genomic instability. The impact of depleting RTEL1 and Poldip3 is epistatic, consistent with our proposed concept of these two proteins operating in a shared pathway involved in DNA replication control under stress conditions. Overall, our data highlight a previously unsuspected role of RTEL1 and Poldip3 in R-loop suppression at genomic regions where transcription and replication intersect, with implications for human diseases including cancer.
Collapse
Affiliation(s)
- Andrea Björkman
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden
| | - Søren L Johansen
- Department of Cell Biology and Physiology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Lin Lin
- Department of Biomedicine, Aarhus University, Aarhus 8200, Denmark.,Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus 8200, Denmark
| | - Mike Schertzer
- 3UMR 3244 (Telomere and Cancer Laboratory), Centre National de la Recherche Scientifique, Institut Curie, PSL Research University, Sorbonne Universités, Paris 75005, France
| | - Dimitris C Kanellis
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden
| | - Anna-Maria Katsori
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden
| | - Søren T Christensen
- Department of Cell Biology and Physiology, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Yonglun Luo
- Department of Biomedicine, Aarhus University, Aarhus 8200, Denmark.,Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus 8200, Denmark
| | - Jens S Andersen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Simon J Elsässer
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden
| | - Arturo Londono-Vallejo
- 3UMR 3244 (Telomere and Cancer Laboratory), Centre National de la Recherche Scientifique, Institut Curie, PSL Research University, Sorbonne Universités, Paris 75005, France
| | - Jiri Bartek
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden.,Danish Cancer Society Research Centre, DK-2100 Copenhagen, Denmark
| | - Kenneth B Schou
- Division of Genome Biology, Department of Medical Biochemistry and Biophysics, Science for Life Laboratory, Karolinska Institute, Solna 171 77, Sweden
| |
Collapse
|
26
|
SLX4 interacts with RTEL1 to prevent transcription-mediated DNA replication perturbations. Nat Struct Mol Biol 2020; 27:438-449. [PMID: 32398829 DOI: 10.1038/s41594-020-0419-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 03/17/2020] [Indexed: 12/20/2022]
Abstract
The SLX4 tumor suppressor is a scaffold that plays a pivotal role in several aspects of genome protection, including homologous recombination, interstrand DNA crosslink repair and the maintenance of common fragile sites and telomeres. Here, we unravel an unexpected direct interaction between SLX4 and the DNA helicase RTEL1, which, until now, were viewed as having independent and antagonistic functions. We identify cancer and Hoyeraal-Hreidarsson syndrome-associated mutations in SLX4 and RTEL1, respectively, that abolish SLX4-RTEL1 complex formation. We show that both proteins are recruited to nascent DNA, tightly co-localize with active RNA pol II, and that SLX4, in complex with RTEL1, promotes FANCD2/RNA pol II co-localization. Importantly, disrupting the SLX4-RTEL1 interaction leads to DNA replication defects in unstressed cells, which are rescued by inhibiting transcription. Our data demonstrate that SLX4 and RTEL1 interact to prevent replication-transcription conflicts and provide evidence that this is independent of the nuclease scaffold function of SLX4.
Collapse
|
27
|
Tan DQ, Li Y, Yang C, Li J, Tan SH, Chin DWL, Nakamura-Ishizu A, Yang H, Suda T. PRMT5 Modulates Splicing for Genome Integrity and Preserves Proteostasis of Hematopoietic Stem Cells. Cell Rep 2020; 26:2316-2328.e6. [PMID: 30811983 DOI: 10.1016/j.celrep.2019.02.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 12/26/2018] [Accepted: 02/01/2019] [Indexed: 12/15/2022] Open
Abstract
Protein arginine methyltransferase 5 (PRMT5) is essential for hematopoiesis, while PRMT5 inhibition remains a promising therapeutic strategy against various cancers. Here, we demonstrate that hematopoietic stem cell (HSC) quiescence and viability are severely perturbed upon PRMT5 depletion, which also increases HSC size, PI3K/AKT/mechanistic target of rapamycin (mTOR) pathway activity, and protein synthesis rate. We uncover a critical role for PRMT5 in maintaining HSC genomic integrity by modulating splicing of genes involved in DNA repair. We found that reducing PRMT5 activity upregulates exon skipping and intron retention events that impair gene expression. Genes across multiple DNA repair pathways are affected, several of which mediate interstrand crosslink repair and homologous recombination. Consequently, loss of PRMT5 activity leads to endogenous DNA damage that triggers p53 activation, induces apoptosis, and culminates in rapid HSC exhaustion, which is significantly delayed by p53 depletion. Collectively, these findings establish the importance of cell-intrinsic PRMT5 activity in HSCs.
Collapse
Affiliation(s)
- Darren Qiancheng Tan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Ying Li
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Chong Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Jia Li
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Shi Hao Tan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Desmond Wai Loon Chin
- Department of Medicine, Huddinge, Center for Hematology and Regenerative Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Ayako Nakamura-Ishizu
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Toshio Suda
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore.
| |
Collapse
|
28
|
Mota MBS, Carvalho MA, Monteiro ANA, Mesquita RD. DNA damage response and repair in perspective: Aedes aegypti, Drosophila melanogaster and Homo sapiens. Parasit Vectors 2019; 12:533. [PMID: 31711518 PMCID: PMC6849265 DOI: 10.1186/s13071-019-3792-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 11/05/2019] [Indexed: 01/18/2023] Open
Abstract
Background The maintenance of genomic integrity is the responsibility of a complex network, denominated the DNA damage response (DDR), which controls the lesion detection and DNA repair. The main repair pathways are base excision repair (BER), nucleotide excision repair (NER), mismatch repair (MMR), homologous recombination repair (HR) and non-homologous end joining repair (NHEJ). They correct double-strand breaks (DSB), single-strand breaks, mismatches and others, or when the damage is quite extensive and repair insufficient, apoptosis is activated. Methods In this study we used the BLAST reciprocal best-hit methodology to search for DDR orthologs proteins in Aedes aegypti. We also provided a comparison between Ae. aegypti, D. melanogaster and human DDR network. Results Our analysis revealed the presence of ATR and ATM signaling, including the H2AX ortholog, in Ae. aegypti. Key DDR proteins (orthologs to RAD51, Ku and MRN complexes, XP-components, MutS and MutL) were also identified in this insect. Other proteins were not identified in both Ae. aegypti and D. melanogaster, including BRCA1 and its partners from BRCA1-A complex, TP53BP1, PALB2, POLk, CSA, CSB and POLβ. In humans, their absence affects DSB signaling, HR and sub-pathways of NER and BER. Seven orthologs not known in D. melanogaster were found in Ae. aegypti (RNF168, RIF1, WRN, RAD54B, RMI1, DNAPKcs, ARTEMIS). Conclusions The presence of key DDR proteins in Ae. aegypti suggests that the main DDR pathways are functional in this insect, and the identification of proteins not known in D. melanogaster can help fill gaps in the DDR network. The mapping of the DDR network in Ae. aegypti can support mosquito biology studies and inform genetic manipulation approaches applied to this vector.
Collapse
Affiliation(s)
- Maria Beatriz S Mota
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Marcelo Alex Carvalho
- Instituto Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.,Instituto Nacional de Câncer, Divisão de Pesquisa Clínica, Rio de Janeiro, RJ, Brazil
| | - Alvaro N A Monteiro
- Cancer Epidemiology Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Rafael D Mesquita
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil. .,Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| |
Collapse
|
29
|
Lansdorp P, van Wietmarschen N. Helicases FANCJ, RTEL1 and BLM Act on Guanine Quadruplex DNA in Vivo. Genes (Basel) 2019; 10:genes10110870. [PMID: 31683575 PMCID: PMC6896191 DOI: 10.3390/genes10110870] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 10/29/2019] [Accepted: 10/29/2019] [Indexed: 02/03/2023] Open
Abstract
Guanine quadruplex (G4) structures are among the most stable secondary DNA structures that can form in vitro, and evidence for their existence in vivo has been steadily accumulating. Originally described mainly for their deleterious effects on genome stability, more recent research has focused on (potential) functions of G4 structures in telomere maintenance, gene expression, and other cellular processes. The combined research on G4 structures has revealed that properly regulating G4 DNA structures in cells is important to prevent genome instability and disruption of normal cell function. In this short review we provide some background and historical context of our work resulting in the identification of FANCJ, RTEL1 and BLM as helicases that act on G4 structures in vivo. Taken together these studies highlight important roles of different G4 DNA structures and specific G4 helicases at selected genomic locations and telomeres in regulating gene expression and maintaining genome stability.
Collapse
Affiliation(s)
- Peter Lansdorp
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, BC V5Z 1L3, Canada.
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6H 3N1, Canada.
- European Research Institute for the Biology of Ageing, University of Groningen, 9713 AV Groningen, The Netherlands.
| | - Niek van Wietmarschen
- European Research Institute for the Biology of Ageing, University of Groningen, 9713 AV Groningen, The Netherlands.
- Laboratory of Genome Integrity, National Cancer Institute, NIH, Bethesda, MD 20892, USA.
| |
Collapse
|
30
|
Bryan TM. Mechanisms of DNA Replication and Repair: Insights from the Study of G-Quadruplexes. Molecules 2019; 24:E3439. [PMID: 31546714 PMCID: PMC6804030 DOI: 10.3390/molecules24193439] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/18/2019] [Accepted: 09/18/2019] [Indexed: 12/13/2022] Open
Abstract
G-quadruplexes are four-stranded guanine-rich structures that have been demonstrated to occur across the genome in humans and other organisms. They provide regulatory functions during transcription, translation and immunoglobulin gene rearrangement, but there is also a large amount of evidence that they can present a potent barrier to the DNA replication machinery. This mini-review will summarize recent advances in understanding the many strategies nature has evolved to overcome G-quadruplex-mediated replication blockage, including removal of the structure by helicases or nucleases, or circumventing the deleterious effects on the genome through homologous recombination, alternative end-joining or synthesis re-priming. Paradoxically, G-quadruplexes have also recently been demonstrated to provide a positive role in stimulating the initiation of DNA replication. These recent studies have not only illuminated the many roles and consequences of G-quadruplexes, but have also provided fundamental insights into the general mechanisms of DNA replication and its links with genetic and epigenetic stability.
Collapse
Affiliation(s)
- Tracy M Bryan
- Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia.
| |
Collapse
|
31
|
Rababa'h AM, Khabour OF, Alzoubi KH, Al-Momani D, Ababneh M. Assessment of Genotoxicity of Levosimendan in Human Cultured Lymphocytes. Curr Mol Pharmacol 2019; 12:160-165. [PMID: 30848225 DOI: 10.2174/1874467212666190306164926] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 02/16/2019] [Accepted: 02/20/2019] [Indexed: 01/15/2023]
Abstract
BACKGROUND AND OBJECTIVE Levosimendan is a positive inotropic and a vasodilator agent with pleotropic characteristics that include antioxidation, anti-inflammation and smooth muscle vasodilation. METHODS In this study, the effects of levosimendan (0, 0.1, 1, 10, and 20 µg/ml) on oxidative DNA damage and sister-chromatid exchanges (SCEs) were evaluated in human cultured lymphocytes. RESULTS The results showed that levosimendan increased the frequency of SCEs in all examined concentrations (P<0.01) except for 0.1 µg/ml. On the other hand, levosimendan did not induce oxidative DNA damage as measured by the 8-OHdG biomarker (P > 0.05). In addition, neither mitotic arrest nor proliferation index was affected by levosimendan at all examined doses (P > 0.05). CONCLUSION In conclusion, levosimendan might be associated with increases in sister-chromatid exchanges in cultured human lymphocytes. In vivo studies are required to confirm the present findings.
Collapse
Affiliation(s)
- Abeer M Rababa'h
- Department of Clinical Pharmacy; College of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan
| | - Omar F Khabour
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Karem H Alzoubi
- Department of Clinical Pharmacy; College of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan
| | - Dua'a Al-Momani
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Mera Ababneh
- Department of Clinical Pharmacy; College of Pharmacy, Jordan University of Science and Technology, Irbid, Jordan
| |
Collapse
|
32
|
Porreca RM, Glousker G, Awad A, Matilla Fernandez MI, Gibaud A, Naucke C, Cohen SB, Bryan TM, Tzfati Y, Draskovic I, Londoño-Vallejo A. Human RTEL1 stabilizes long G-overhangs allowing telomerase-dependent over-extension. Nucleic Acids Res 2019. [PMID: 29522136 PMCID: PMC5961080 DOI: 10.1093/nar/gky173] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Telomere maintenance protects the cell against genome instability and senescence. Accelerated telomere attrition is a characteristic of premature aging syndromes including Dyskeratosis congenita (DC). Mutations in hRTEL1 are associated with a severe form of DC called Hoyeraal-Hreidarsson syndrome (HHS). HHS patients carry short telomeres and HHS cells display telomere damage. Here we investigated how hRTEL1 contributes to telomere maintenance in human primary as well as tumor cells. Transient depletion of hRTEL1 resulted in rapid telomere shortening only in the context of telomerase-positive cells with very long telomeres and high levels of telomerase. The effect of hRTEL1 on telomere length is telomerase dependent without impacting telomerase biogenesis or targeting of the enzyme to telomeres. Instead, RTEL1 depletion led to a decrease in both G-overhang content and POT1 association with telomeres with limited telomere uncapping. Strikingly, overexpression of POT1 restored telomere length but not the overhang, demonstrating that G-overhang loss is the primary defect caused by RTEL1 depletion. We propose that hRTEL1 contributes to the maintenance of long telomeres by preserving long G-overhangs, thereby facilitating POT1 binding and elongation by telomerase.
Collapse
Affiliation(s)
- Rosa M Porreca
- Institut Curie, PSL Research University, Sorbonne Universités, CNRS UMR3244 Telomere and cancer lab, 75005 Paris, France
| | - Galina Glousker
- Department of Genetics, The Silberman Institute of Life Science, The Hebrew University of Jerusalem, Safra Campus-Givat Ram, Jerusalem 91904, Israel
| | - Aya Awad
- Department of Genetics, The Silberman Institute of Life Science, The Hebrew University of Jerusalem, Safra Campus-Givat Ram, Jerusalem 91904, Israel
| | | | - Anne Gibaud
- Institut Curie, PSL Research University, Sorbonne Universités, CNRS UMR3244 Telomere and cancer lab, 75005 Paris, France
| | - Christian Naucke
- Institut Curie, PSL Research University, Sorbonne Universités, CNRS UMR3244 Telomere and cancer lab, 75005 Paris, France
| | - Scott B Cohen
- Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - Tracy M Bryan
- Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Science, The Hebrew University of Jerusalem, Safra Campus-Givat Ram, Jerusalem 91904, Israel
| | - Irena Draskovic
- Institut Curie, PSL Research University, Sorbonne Universités, CNRS UMR3244 Telomere and cancer lab, 75005 Paris, France
| | - Arturo Londoño-Vallejo
- Institut Curie, PSL Research University, Sorbonne Universités, CNRS UMR3244 Telomere and cancer lab, 75005 Paris, France
| |
Collapse
|
33
|
Chiu V, Hogen R, Sher L, Wadé N, Conti D, Martynova A, Li H, Liang G, O'Connell C. Telomerase Variants in Patients with Cirrhosis Awaiting Liver Transplantation. Hepatology 2019; 69:2652-2663. [PMID: 30964210 PMCID: PMC6594079 DOI: 10.1002/hep.30557] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 01/27/2019] [Indexed: 12/16/2022]
Abstract
Telomeres are repetitive DNA sequences that protect the ends of linear chromosomes, and they are maintained by a ribonucleoprotein complex called telomerase. Variants in genes encoding for telomerase components have been associated with a spectrum of disease in the lung, skin, bone marrow, and liver. Mutations in the telomerase reverse transcriptase and telomerase RNA component genes have been observed at a higher prevalence in patients with liver disease compared with the general population; however, the presence of variants in other components of the telomerase complex and their impact on clinical outcomes has not been explored. We evaluated 86 patients with end-stage liver disease for variants in an expanded panel of eight genes, and found that 17 patients (20%) had likely deleterious variants by in silico analysis. Seven unique likely deleterious variants were identified in the regulator of telomere elongation helicase 1 (RTEL1) gene that encodes for a DNA helicase important in telomere maintenance and genomic stability. In gene burden association analysis of their clinical data, the presence of any RTEL1 variant was associated with a 29% lower baseline white blood cell count (95% confidence interval [CI], -7% to -46%; P Value = 0.01) compared with patients without RTEL1 variants, and the presence of any exonic missense RTEL1 variant was associated with a 42% lower baseline platelet count (95% CI, -5% to -65%: P Value = 0.03). The presence of any telomerase variant was associated with an increased number of readmissions within 1 year after transplantation demonstrated by an incident rate ratio (IRR) of 3.15 (95% CI, 1.22 to 8.57). No association with survival was observed. Conclusion: Among patients who underwent liver transplantation, the presence of any exonic missense variant was associated with a longer postoperative length of stay with an IRR of 2.16 (95% CI, 1.31 to 3.68).
Collapse
Affiliation(s)
- Victor Chiu
- Norris Comprehensive Cancer Center and Hospital, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA,Division of Hematology, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA
| | - Rachel Hogen
- Department of Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA
| | - Linda Sher
- Department of Surgery, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA
| | - Niquelle Wadé
- Department of Preventive Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA
| | - David Conti
- Department of Preventive Medicine, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA
| | - Anastasia Martynova
- Norris Comprehensive Cancer Center and Hospital, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA,Division of Hematology, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA
| | - Hongtao Li
- Department of Urology, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA
| | - Gangning Liang
- Norris Comprehensive Cancer Center and Hospital, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA,Department of Urology, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA
| | - Casey O'Connell
- Norris Comprehensive Cancer Center and Hospital, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA,Division of Hematology, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCA
| |
Collapse
|
34
|
Goffová I, Vágnerová R, Peška V, Franek M, Havlová K, Holá M, Zachová D, Fojtová M, Cuming A, Kamisugi Y, Angelis KJ, Fajkus J. Roles of RAD51 and RTEL1 in telomere and rDNA stability in Physcomitrella patens. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:1090-1105. [PMID: 30834585 DOI: 10.1111/tpj.14304] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 02/21/2019] [Accepted: 02/27/2019] [Indexed: 05/11/2023]
Abstract
Telomeres and ribosomal RNA genes (rDNA) are essential for cell survival and particularly sensitive to factors affecting genome stability. Here, we examine the role of RAD51 and its antagonist, RTEL1, in the moss Physcomitrella patens. In corresponding mutants, we analyse their sensitivity to DNA damage, the maintenance of telomeres and rDNA, and repair of double-stranded breaks (DSBs) induced by genotoxins with various modes of action. While the loss of RTEL1 results in rapid telomere shortening, concurrent loss of both RAD51 genes has no effect on telomere lengths. We further demonstrate here the linked arrangement of 5S and 45S rRNA genes in P. patens. The spacer between 5S and 18S rRNA genes, especially the region downstream from the transcription start site, shows conspicuous clustering of sites with a high propensity to form quadruplex (G4) structures. Copy numbers of 5S and 18S rDNA are reduced moderately in the pprtel1 mutant, and significantly in the double pprad51-1-2 mutant, with no progression during subsequent cultivation. While reductions in 45S rDNA copy numbers observed in pprtel1 and pprad51-1-2 plants apply also to 5S rDNA, changes in transcript levels are different for 45S and 5S rRNA, indicating their independent transcription by RNA polymerase I and III, respectively. The loss of SOL (Sog One-Like), a transcription factor regulating numerous genes involved in DSB repair, increases the rate of DSB repair in dividing as well as differentiated tissue, and through deactivation of G2/M cell-cycle checkpoint allows the cell-cycle progression manifested as a phenotype resistant to bleomycin.
Collapse
Affiliation(s)
- Ivana Goffová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Radka Vágnerová
- The Czech Academy of Sciences, Institute of Experimental Botany, Na Karlovce 1, CZ-16000, Prague, Czech Republic
| | - Vratislav Peška
- The Czech Academy of Sciences, Institute of Biophysics, Královopolská 135, 612 65, Brno, Czech Republic
| | - Michal Franek
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Kateřina Havlová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Marcela Holá
- The Czech Academy of Sciences, Institute of Experimental Botany, Na Karlovce 1, CZ-16000, Prague, Czech Republic
| | - Dagmar Zachová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Miloslava Fojtová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
| | - Andrew Cuming
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Yasuko Kamisugi
- Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Karel J Angelis
- The Czech Academy of Sciences, Institute of Experimental Botany, Na Karlovce 1, CZ-16000, Prague, Czech Republic
| | - Jiří Fajkus
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500, Brno, Czech Republic
- The Czech Academy of Sciences, Institute of Biophysics, Královopolská 135, 612 65, Brno, Czech Republic
| |
Collapse
|
35
|
Griffin WC, Trakselis MA. The MCM8/9 complex: A recent recruit to the roster of helicases involved in genome maintenance. DNA Repair (Amst) 2019; 76:1-10. [PMID: 30743181 DOI: 10.1016/j.dnarep.2019.02.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 02/03/2019] [Indexed: 12/11/2022]
Abstract
There are several DNA helicases involved in seemingly overlapping aspects of homologous and homoeologous recombination. Mutations of many of these helicases are directly implicated in genetic diseases including cancer, rapid aging, and infertility. MCM8/9 are recent additions to the catalog of helicases involved in recombination, and so far, the evidence is sparse, making assignment of function difficult. Mutations in MCM8/9 correlate principally with primary ovarian failure/insufficiency (POF/POI) and infertility indicating a meiotic defect. However, they also act when replication forks collapse/break shuttling products into mitotic recombination and several mutations are found in various somatic cancers. This review puts MCM8/9 in context with other replication and recombination helicases to narrow down its genomic maintenance role. We discuss the known structure/function relationship, the mutational spectrum, and dissect the available cellular and organismal data to better define its role in recombination.
Collapse
Affiliation(s)
- Wezley C Griffin
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas, 76798, USA
| | - Michael A Trakselis
- Department of Chemistry and Biochemistry, Baylor University, Waco, Texas, 76798, USA.
| |
Collapse
|
36
|
Lerner LK, Sale JE. Replication of G Quadruplex DNA. Genes (Basel) 2019; 10:genes10020095. [PMID: 30700033 PMCID: PMC6409989 DOI: 10.3390/genes10020095] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/21/2019] [Accepted: 01/23/2019] [Indexed: 01/03/2023] Open
Abstract
A cursory look at any textbook image of DNA replication might suggest that the complex machine that is the replisome runs smoothly along the chromosomal DNA. However, many DNA sequences can adopt non-B form secondary structures and these have the potential to impede progression of the replisome. A picture is emerging in which the maintenance of processive DNA replication requires the action of a significant number of additional proteins beyond the core replisome to resolve secondary structures in the DNA template. By ensuring that DNA synthesis remains closely coupled to DNA unwinding by the replicative helicase, these factors prevent impediments to the replisome from causing genetic and epigenetic instability. This review considers the circumstances in which DNA forms secondary structures, the potential responses of the eukaryotic replisome to these impediments in the light of recent advances in our understanding of its structure and operation and the mechanisms cells deploy to remove secondary structure from the DNA. To illustrate the principles involved, we focus on one of the best understood DNA secondary structures, G quadruplexes (G4s), and on the helicases that promote their resolution.
Collapse
Affiliation(s)
- Leticia Koch Lerner
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
| | - Julian E Sale
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
| |
Collapse
|
37
|
Telomeres in Plants and Humans: Not So Different, Not So Similar. Cells 2019; 8:cells8010058. [PMID: 30654521 PMCID: PMC6356271 DOI: 10.3390/cells8010058] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/07/2019] [Accepted: 01/07/2019] [Indexed: 01/01/2023] Open
Abstract
Parallel research on multiple model organisms shows that while some principles of telomere biology are conserved among all eukaryotic kingdoms, we also find some deviations that reflect different evolutionary paths and life strategies, which may have diversified after the establishment of telomerase as a primary mechanism for telomere maintenance. Much more than animals, plants have to cope with environmental stressors, including genotoxic factors, due to their sessile lifestyle. This is, in principle, made possible by an increased capacity and efficiency of the molecular systems ensuring maintenance of genome stability, as well as a higher tolerance to genome instability. Furthermore, plant ontogenesis differs from that of animals in which tissue differentiation and telomerase silencing occur during early embryonic development, and the “telomere clock” in somatic cells may act as a preventive measure against carcinogenesis. This does not happen in plants, where growth and ontogenesis occur through the serial division of apical meristems consisting of a small group of stem cells that generate a linear series of cells, which differentiate into an array of cell types that make a shoot and root. Flowers, as generative plant organs, initiate from the shoot apical meristem in mature plants which is incompatible with the human-like developmental telomere shortening. In this review, we discuss differences between human and plant telomere biology and the implications for aging, genome stability, and cell and organism survival. In particular, we provide a comprehensive comparative overview of telomere proteins acting in humans and in Arabidopsis thaliana model plant, and discuss distinct epigenetic features of telomeric chromatin in these species.
Collapse
|
38
|
Relative Telomere Length and Stroke Risk in a Chinese Han Population. J Mol Neurosci 2018; 66:475-481. [PMID: 30345460 DOI: 10.1007/s12031-018-1160-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 08/15/2018] [Indexed: 10/28/2022]
Abstract
This study aimed to further understand the role of relative telomere length (RTL) in susceptibility to stroke and investigate the association regulator of telomere elongation helicase 1 (RETL1) gene polymorphisms and RTL. RTL was measured using the real-time quantitative polymerase chain reaction (qPCR) from 300 stroke patients and 299 healthy controls. Genotyping was performed using the Sequenom MassARRAY platform. The results indicated that stroke patients had significantly shorter median RTL than controls (P < 0.001). Compared with the longer RTL (≥ 0.766), the shorter RTL (< 0.766) was significantly increased the risk of stroke (odds ratio [OR] = 8.44, 95% confidence interval [CI] 5.42-13.14, P < 0.001). The RTL was categorized into tertiles, we found that the shorter RTL (0.515-1.366) (OR = 16.27, 95% CI 7.72-34.29, P < 0.001) and lowest RTL (< 0.515) (OR = 30.63, 95% CI 14.27-65.75, P < 0.001) were significantly increased stroke risk compared with the highest RTL (> 1.366). Stratified analysis showed that the shorter RTL was also significantly increased the risk of stroke compared with the longer RTL in male, age < 60 years and ≥ 60 years, except the female participants. In addition, individuals with the genotypes AA (rs2297441) and GG (rs6089953) have shorter telomeres than the genotypes GG (P = 0.031) and AA (P = 0.032), respectively. Our results suggested that shorter RTL was associated with an increased risk of stroke. The association was found between the genotypes AA (rs2297441) and GG (rs6089953) and shorter RTL in case group. Further studies in larger sample size and biological functional assays are warranted to validate our findings.
Collapse
|
39
|
Dagg RA, Pickett HA, Neumann AA, Napier CE, Henson JD, Teber ET, Arthur JW, Reynolds CP, Murray J, Haber M, Sobinoff AP, Lau LMS, Reddel RR. Extensive Proliferation of Human Cancer Cells with Ever-Shorter Telomeres. Cell Rep 2018. [PMID: 28636942 DOI: 10.1016/j.celrep.2017.05.087] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Acquisition of replicative immortality is currently regarded as essential for malignant transformation. This is achieved by activating a telomere lengthening mechanism (TLM), either telomerase or alternative lengthening of telomeres, to counter normal telomere attrition. However, a substantial proportion of some cancer types, including glioblastomas, liposarcomas, retinoblastomas, and osteosarcomas, are reportedly TLM-negative. As serial samples of human tumors cannot usually be obtained to monitor telomere length changes, it has previously been impossible to determine whether tumors are truly TLM-deficient, there is a previously unrecognized TLM, or the assay results are false-negative. Here, we show that a subset of high-risk neuroblastomas (with ∼50% 5-year mortality) lacked significant TLM activity. Cancer cells derived from these highly aggressive tumors initially had long telomeres and proliferated for >200 population doublings with ever-shorter telomeres. This indicates that prevention of telomere shortening is not always required for oncogenesis, which has implications for inhibiting TLMs for cancer therapy.
Collapse
Affiliation(s)
- Rebecca A Dagg
- Children's Cancer Research Unit, The Children's Hospital at Westmead, University of Sydney, Westmead, NSW 2145, Australia
| | - Hilda A Pickett
- Telomere Length Regulation Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - Axel A Neumann
- Cancer Research Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - Christine E Napier
- Cancer Research Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - Jeremy D Henson
- Cancer Cell Immortality Group, Adult Cancer Program, Prince of Wales Clinical School, University of New South Wales, Randwick, NSW 2052, Australia
| | - Erdahl T Teber
- Bioinformatics Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - Jonathan W Arthur
- Bioinformatics Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - C Patrick Reynolds
- Cancer Center, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Cell Biology and Biochemistry, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Internal Medicine, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Department of Pediatrics, School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Jayne Murray
- Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales Australia, Randwick, NSW 2031, Australia
| | - Michelle Haber
- Children's Cancer Institute, Lowy Cancer Research Centre, University of New South Wales Australia, Randwick, NSW 2031, Australia
| | - Alexander P Sobinoff
- Telomere Length Regulation Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - Loretta M S Lau
- Children's Cancer Research Unit, The Children's Hospital at Westmead, University of Sydney, Westmead, NSW 2145, Australia; Cancer Research Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia
| | - Roger R Reddel
- Cancer Research Unit, Children's Medical Research Institute, University of Sydney, Westmead, NSW 2145, Australia.
| |
Collapse
|
40
|
Margalef P, Kotsantis P, Borel V, Bellelli R, Panier S, Boulton SJ. Stabilization of Reversed Replication Forks by Telomerase Drives Telomere Catastrophe. Cell 2018; 172:439-453.e14. [PMID: 29290468 PMCID: PMC5786504 DOI: 10.1016/j.cell.2017.11.047] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/29/2017] [Accepted: 11/28/2017] [Indexed: 01/09/2023]
Abstract
Telomere maintenance critically depends on the distinct activities of telomerase, which adds telomeric repeats to solve the end replication problem, and RTEL1, which dismantles DNA secondary structures at telomeres to facilitate replisome progression. Here, we establish that reversed replication forks are a pathological substrate for telomerase and the source of telomere catastrophe in Rtel1-/- cells. Inhibiting telomerase recruitment to telomeres, but not its activity, or blocking replication fork reversal through PARP1 inhibition or depleting UBC13 or ZRANB3 prevents the rapid accumulation of dysfunctional telomeres in RTEL1-deficient cells. In this context, we establish that telomerase binding to reversed replication forks inhibits telomere replication, which can be mimicked by preventing replication fork restart through depletion of RECQ1 or PARG. Our results lead us to propose that telomerase inappropriately binds to and inhibits restart of reversed replication forks within telomeres, which compromises replication and leads to critically short telomeres.
Collapse
Affiliation(s)
- Pol Margalef
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | | | - Valerie Borel
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | | | | | - Simon J Boulton
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
| |
Collapse
|
41
|
Sivley RM, Sheehan JH, Kropski JA, Cogan J, Blackwell TS, Phillips JA, Bush WS, Meiler J, Capra JA. Three-dimensional spatial analysis of missense variants in RTEL1 identifies pathogenic variants in patients with Familial Interstitial Pneumonia. BMC Bioinformatics 2018; 19:18. [PMID: 29361909 PMCID: PMC5781290 DOI: 10.1186/s12859-018-2010-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 01/03/2018] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Next-generation sequencing of individuals with genetic diseases often detects candidate rare variants in numerous genes, but determining which are causal remains challenging. We hypothesized that the spatial distribution of missense variants in protein structures contains information about function and pathogenicity that can help prioritize variants of unknown significance (VUS) and elucidate the structural mechanisms leading to disease. RESULTS To illustrate this approach in a clinical application, we analyzed 13 candidate missense variants in regulator of telomere elongation helicase 1 (RTEL1) identified in patients with Familial Interstitial Pneumonia (FIP). We curated pathogenic and neutral RTEL1 variants from the literature and public databases. We then used homology modeling to construct a 3D structural model of RTEL1 and mapped known variants into this structure. We next developed a pathogenicity prediction algorithm based on proximity to known disease causing and neutral variants and evaluated its performance with leave-one-out cross-validation. We further validated our predictions with segregation analyses, telomere lengths, and mutagenesis data from the homologous XPD protein. Our algorithm for classifying RTEL1 VUS based on spatial proximity to pathogenic and neutral variation accurately distinguished 7 known pathogenic from 29 neutral variants (ROC AUC = 0.85) in the N-terminal domains of RTEL1. Pathogenic proximity scores were also significantly correlated with effects on ATPase activity (Pearson r = -0.65, p = 0.0004) in XPD, a related helicase. Applying the algorithm to 13 VUS identified from sequencing of RTEL1 from patients predicted five out of six disease-segregating VUS to be pathogenic. We provide structural hypotheses regarding how these mutations may disrupt RTEL1 ATPase and helicase function. CONCLUSIONS Spatial analysis of missense variation accurately classified candidate VUS in RTEL1 and suggests how such variants cause disease. Incorporating spatial proximity analyses into other pathogenicity prediction tools may improve accuracy for other genes and genetic diseases.
Collapse
Affiliation(s)
- R Michael Sivley
- Department of Biomedical Informatics, Vanderbilt University, Nashville, USA
| | - Jonathan H Sheehan
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, USA
| | | | - Joy Cogan
- Department of Pediatrics, Vanderbilt University, Nashville, USA
| | | | - John A Phillips
- Department of Pediatrics, Vanderbilt University, Nashville, USA
| | - William S Bush
- Department of Quantitative and Population Health Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Jens Meiler
- Department of Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, USA
| | - John A Capra
- Department of Biological Sciences, Vanderbilt Genetics Institute, and Center for Structural Biology, Vanderbilt University, Nashville, USA.
| |
Collapse
|
42
|
Cai Y, Zeng C, Su Q, Zhou J, Li P, Dai M, Wang D, Long F. Association of RTEL1 gene polymorphisms with stroke risk in a Chinese Han population. Oncotarget 2017; 8:114995-115001. [PMID: 29383136 PMCID: PMC5777748 DOI: 10.18632/oncotarget.22980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 11/15/2017] [Indexed: 01/14/2023] Open
Abstract
We investigated the associations between single nucleotide polymorphisms (SNPs) in the regulator of telomere elongation helicase 1 (RTEL1) gene and stroke in the Chinese population. A total of 400 stroke patients and 395 healthy participants were included in this study. Five SNPs in RTEL1 were genotyped and the association with stroke risk was analyzed. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using unconditional logistic regression analysis. Multivariate logistic regression analysis was used to identify SNPs that correlated with stroke. Rs2297441 was associated with an increased risk of stroke in an allele model (odds ratio [OR] = 1.24, 95% confidence interval [95% CI] = 1.01-1.52, p = 0.043). Rs6089953 was associated with an increased risk of stroke under the genotype model ([OR] = 1.862, [CI] = 1.123-3.085, p = 0.016). Rs2297441 was associated with an increased risk of stroke in an additive model (OR = 1.234, 95% CI = 1.005, p = 0.045, Rs6089953, Rs6010620 and Rs6010621 were associated with an increased risk of stroke in the recessive model (Rs6089953:OR = 1.825, 95% CI = 1.121-2.969, p =0.01546; Rs6010620: OR = 1.64, 95% CI = 1.008-2.669, p =0.04656;Rs6010621:OR = 1.661, 95% CI = 1.014-2.722, p =0.04389). Our findings reveal a possible association between SNPs in the RTEL1 gene and stroke risk in Chinese population.
Collapse
Affiliation(s)
- Yi Cai
- Department of Neurosurgery, The Second Affiliated Hospital of Hainan Medical College, Hainan 570311, China
| | - Chaosheng Zeng
- Department of Neurosurgery, The Second Affiliated Hospital of Hainan Medical College, Hainan 570311, China
| | - Qingjie Su
- Department of Neurosurgery, The Second Affiliated Hospital of Hainan Medical College, Hainan 570311, China
| | - Jingxia Zhou
- Department of Neurosurgery, The Second Affiliated Hospital of Hainan Medical College, Hainan 570311, China
| | - Pengxiang Li
- Department of Neurosurgery, The Second Affiliated Hospital of Hainan Medical College, Hainan 570311, China
| | - Mingming Dai
- Department of Neurosurgery, The Second Affiliated Hospital of Hainan Medical College, Hainan 570311, China
| | - Desheng Wang
- Department of Neurosurgery, The Second Affiliated Hospital of Hainan Medical College, Hainan 570311, China
| | - Faqing Long
- Department of Neurosurgery, The Second Affiliated Hospital of Hainan Medical College, Hainan 570311, China
| |
Collapse
|
43
|
Shoeb M, Joseph P, Kodali V, Mustafa G, Farris BY, Umbright C, Roberts JR, Erdely A, Antonini JM. Silica inhalation altered telomere length and gene expression of telomere regulatory proteins in lung tissue of rats. Sci Rep 2017; 7:17284. [PMID: 29230030 PMCID: PMC5725592 DOI: 10.1038/s41598-017-17645-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 11/28/2017] [Indexed: 12/27/2022] Open
Abstract
Exposure to silica can cause lung fibrosis and cancer. Identification of molecular targets is important for the intervention and/or prevention of silica-induced lung diseases. Telomeres consist of tandem repeats of DNA sequences at the end of chromosomes, preventing chromosomal fusion and degradation. Regulator of telomere length-1 (RTEL1) and telomerase reverse transcriptase (TERT), genes involved in telomere regulation and function, play important roles in maintaining telomere integrity and length. The goal of this study was to assess the effect of silica inhalation on telomere length and the regulation of RTEL1 and TERT. Lung tissues and blood samples were collected from rats at 4, 32, and 44 wk after exposure to 15 mg/m3 of silica × 6 h/d × 5 d. Controls were exposed to air. At all-time points, RTEL1 expression was significantly decreased in lung tissue of the silica-exposed animals compared to controls. Also, significant increases in telomere length and TERT were observed in the silica group at 4 and 32 wk. Telomere length, RTEL1 and TERT expression may serve as potential biomarkers related to silica exposure and may offer insight into the molecular mechanism of silica-induced lung disease and tumorigeneses.
Collapse
Affiliation(s)
- Mohammad Shoeb
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA.
| | - Pius Joseph
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Vamsi Kodali
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Gul Mustafa
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Breanne Y Farris
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Christina Umbright
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Jenny R Roberts
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Aaron Erdely
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - James M Antonini
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| |
Collapse
|
44
|
Rong H, He X, Zhu L, Zhu X, Kang L, Wang L, He Y, Yuan D, Jin T. Association between regulator of telomere elongation helicase1 (RTEL1) gene and HAPE risk: A case-control study. Medicine (Baltimore) 2017; 96:e8222. [PMID: 28953687 PMCID: PMC5626330 DOI: 10.1097/md.0000000000008222] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
High altitude pulmonary edema (HAPE) is a paradigm of pulmonary edema. Mutations in regulator of telomere elongation helicase1 (RTEL1) represent an important contributor to risk for pulmonary fibrosis. However, little information is found about the association between RTEL1 and HAPE risk. The present study was undertaken to tentatively explore the potential relation between single-nucleotide polymorphisms (SNPs) in RTEL1 and HAPE risk in Chinese Han population. A total of 265 HAPE patients and 303 healthy controls were included in our case-control study. Four SNPs in RTEL1 were selected and genotyped using the Sequenom MassARRAY method. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated by unconditional logistic regression with adjustment for gender and age. All P values were Bonferroni corrected, and statistical significance was set at P < .0025 (.05/20). In allelic model analysis, we found that the allele "G" of rs6089953 and rs6010621 and the allele "A" of rs2297441 were associated with decreased risk of HAPE. In the genetic model analysis, we found that rs6010621, rs6089953, and rs2297441 were relevant to decreased HAPE risk under dominant model (rs6010621: OR = 0.55; 95% CI = 0.39-0.78; P = .001; rs6089953: OR = 0.68; 95% CI = 0.48-0.96; P = .027; rs2297441: OR = 0.63; 95% CI = 0.45-0.89; P = .008, respectively) and additive model (rs6010621: OR = 0.51; 95% CI = 0.46-0.81; P < .001; rs6089953: OR = 0.72; 95% CI = 0.55-0.95; P = .022; rs2297441: OR = 0.73; 95% CI = 0.57-0.95; P = .019, respectively). SNPs rs6010621 remained significant after Bonferroni correction (P < .0025). In addition, haplotype "GG, GT, AT" of rs6089953-rs6010621 were detected significantly associated with HAPE risk (P < .05), haplotype "GG" remained significant after Bonferroni correction (P < .0025). Our findings provide new evidence for the association between SNPs in RTEL1 and a decreased risk HAPE in the Chinese population. The results need further confirmation.
Collapse
Affiliation(s)
- Hao Rong
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
| | - Xue He
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
| | - Linhao Zhu
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
| | - Xikai Zhu
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
| | - Longli Kang
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
| | - Li Wang
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
| | - Yongjun He
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
| | - Dongya Yuan
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
| | - Tianbo Jin
- Key Laboratory of Molecular Mechanism and Intervention Research for Plateau Diseases of Tibet Autonomous Region
- Key Laboratory of High Altitude Environment and Genes Related to Diseases of Tibet Autonomous Region
- Key Laboratory for Basic Life Science Research of Tibet Autonomous Region, School of Medicine, Xizang Minzu University, Xianyang, Shaanxi
- School of Life Science, Northwest University, Xi’an, China
| |
Collapse
|
45
|
Yalçin Z, Selenz C, Jacobs JJL. Ubiquitination and SUMOylation in Telomere Maintenance and Dysfunction. Front Genet 2017; 8:67. [PMID: 28588610 PMCID: PMC5440461 DOI: 10.3389/fgene.2017.00067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 05/10/2017] [Indexed: 12/14/2022] Open
Abstract
Telomeres are essential nucleoprotein structures at linear chromosomes that maintain genome integrity by protecting chromosome ends from being recognized and processed as damaged DNA. In addition, they limit the cell’s proliferative capacity, as progressive loss of telomeric DNA during successive rounds of cell division eventually causes a state of telomere dysfunction that prevents further cell division. When telomeres become critically short, the cell elicits a DNA damage response resulting in senescence, apoptosis or genomic instability, thereby impacting on aging and tumorigenesis. Over the past years substantial progress has been made in understanding the role of post-translational modifications in telomere-related processes, including telomere maintenance, replication and dysfunction. This review will focus on recent findings that establish an essential role for ubiquitination and SUMOylation at telomeres.
Collapse
Affiliation(s)
- Zeliha Yalçin
- Department of Molecular Oncology, Netherlands Cancer InstituteAmsterdam, Netherlands
| | - Carolin Selenz
- Department of Molecular Oncology, Netherlands Cancer InstituteAmsterdam, Netherlands
| | - Jacqueline J L Jacobs
- Department of Molecular Oncology, Netherlands Cancer InstituteAmsterdam, Netherlands
| |
Collapse
|
46
|
Speckmann C, Sahoo SS, Rizzi M, Hirabayashi S, Karow A, Serwas NK, Hoemberg M, Damatova N, Schindler D, Vannier JB, Boulton SJ, Pannicke U, Göhring G, Thomay K, Verdu-Amoros JJ, Hauch H, Woessmann W, Escherich G, Laack E, Rindle L, Seidl M, Rensing-Ehl A, Lausch E, Jandrasits C, Strahm B, Schwarz K, Ehl SR, Niemeyer C, Boztug K, Wlodarski MW. Clinical and Molecular Heterogeneity of RTEL1 Deficiency. Front Immunol 2017; 8:449. [PMID: 28507545 PMCID: PMC5410638 DOI: 10.3389/fimmu.2017.00449] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 03/31/2017] [Indexed: 12/30/2022] Open
Abstract
Typical features of dyskeratosis congenita (DC) resulting from excessive telomere shortening include bone marrow failure (BMF), mucosal fragility, and pulmonary or liver fibrosis. In more severe cases, immune deficiency and recurring infections can add to disease severity. RTEL1 deficiency has recently been described as a major genetic etiology, but the molecular basis and clinical consequences of RTEL1-associated DC are incompletely characterized. We report our observations in a cohort of six patients: five with novel biallelic RTEL1 mutations p.Trp456Cys, p.Ile425Thr, p.Cys1244ProfsX17, p.Pro884_Gln885ins53X13, and one with novel heterozygous mutation p.Val796AlafsX4. The most unifying features were hypocellular BMF in 6/6 and B-/NK-cell lymphopenia in 5/6 patients. In addition, three patients with homozygous mutations p.Trp456Cys or p.Ile425Thr also suffered from immunodeficiency, cerebellar hypoplasia, and enteropathy, consistent with Hoyeraal-Hreidarsson syndrome. Chromosomal breakage resembling a homologous recombination defect was detected in patient-derived fibroblasts but not in hematopoietic compartment. Notably, in both cellular compartments, differential expression of 1243aa and 1219/1300aa RTEL1 isoforms was observed. In fibroblasts, response to ionizing irradiation and non-homologous end joining were not impaired. Telomeric circles did not accumulate in patient-derived primary cells and lymphoblastoid cell lines, implying alternative pathomechanisms for telomeric loss. Overall, RTEL1-deficient cells exhibited a phenotype of replicative exhaustion, spontaneous apoptosis and senescence. Specifically, CD34+ cells failed to expand in vitro, B-cell development was compromised, and T-cells did not proliferate in long-term culture. Finally, we report on the natural history and outcome of our patients. While two patients died from infections, hematopoietic stem cell transplantation (HSCT) resulted in sustained engraftment in two patients. Whether chemotherapy negatively impacts on the course and onset of other DC-related symptoms remains open at present. Early-onset lung disease occurred in one of our patients after HSCT. In conclusion, RTEL deficiency can show a heterogeneous clinical picture ranging from mild hypocellular BMF with B/NK cell lymphopenia to early-onset, very severe, and rapidly progressing cellular deficiency.
Collapse
Affiliation(s)
- Carsten Speckmann
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Chronic Immunodeficiency, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sushree Sangita Sahoo
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Marta Rizzi
- Center for Chronic Immunodeficiency, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Rheumatology and Clinical Immunology, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Shinsuke Hirabayashi
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Axel Karow
- Department of Paediatrics, Univeristy of Bern, Bern, Switzerland
| | - Nina Kathrin Serwas
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Marc Hoemberg
- Department of Pediatric Hematology and Oncology, Children’s Hospital, University of Cologne, Cologne, Germany
| | - Natalja Damatova
- Department of Medical Genetics, Biozentrum, University of Wuerzburg, Wuerzburg, Germany
| | - Detlev Schindler
- Department of Medical Genetics, Biozentrum, University of Wuerzburg, Wuerzburg, Germany
| | - Jean-Baptiste Vannier
- Telomere Replication and Stability Group, MRC London Institute of Medical Sciences (LMS), London, UK
| | - Simon J. Boulton
- Telomere Replication and Stability Group, MRC London Institute of Medical Sciences (LMS), London, UK
| | - Ulrich Pannicke
- Institute for Transfusion Medicine, Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Service Baden-Wuerttemberg – Hessen, University Ulm, Ulm, Germany
| | - Gudrun Göhring
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - Kathrin Thomay
- Department of Human Genetics, Hannover Medical School, Hannover, Germany
| | - J. J. Verdu-Amoros
- Department of Pediatric Hematology and Oncology, Justus-Liebig-University, Giessen, Germany
| | - Holger Hauch
- Department of Pediatric Hematology and Oncology, Justus-Liebig-University, Giessen, Germany
| | - Wilhelm Woessmann
- Department of Pediatric Hematology and Oncology, Justus-Liebig-University, Giessen, Germany
| | - Gabriele Escherich
- Clinic of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Eckart Laack
- Hemato-Oncology Clinic Hamburg, Hamburg, Germany
| | - Liliana Rindle
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Maximilian Seidl
- Center for Chronic Immunodeficiency, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Medicine, Institute of Pathology, Medical Center, University of Freiburg, Freiburg, Germany
| | - Anne Rensing-Ehl
- Center for Chronic Immunodeficiency, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Ekkehart Lausch
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christine Jandrasits
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Brigitte Strahm
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Klaus Schwarz
- Institute for Transfusion Medicine, Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Service Baden-Wuerttemberg – Hessen, University Ulm, Ulm, Germany
| | - Stephan R. Ehl
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center for Chronic Immunodeficiency, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Charlotte Niemeyer
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- German Cancer Consortium (DKTK), Freiburg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Kaan Boztug
- Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
- St. Anna Kinderspital and Children’s Cancer Research Instutute, Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Marcin W. Wlodarski
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Hematology and Oncology, Medical Centre, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- German Cancer Consortium (DKTK), Freiburg, Germany
- German Cancer Research Center (DKFZ), Heidelberg, Germany
| |
Collapse
|
47
|
DNA Replication Origins and Fork Progression at Mammalian Telomeres. Genes (Basel) 2017; 8:genes8040112. [PMID: 28350373 PMCID: PMC5406859 DOI: 10.3390/genes8040112] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 12/20/2022] Open
Abstract
Telomeres are essential chromosomal regions that prevent critical shortening of linear chromosomes and genomic instability in eukaryotic cells. The bulk of telomeric DNA is replicated by semi-conservative DNA replication in the same way as the rest of the genome. However, recent findings revealed that replication of telomeric repeats is a potential cause of chromosomal instability, because DNA replication through telomeres is challenged by the repetitive telomeric sequences and specific structures that hamper the replication fork. In this review, we summarize current understanding of the mechanisms by which telomeres are faithfully and safely replicated in mammalian cells. Various telomere-associated proteins ensure efficient telomere replication at different steps, such as licensing of replication origins, passage of replication forks, proper fork restart after replication stress, and dissolution of post-replicative structures. In particular, shelterin proteins have central roles in the control of telomere replication. Through physical interactions, accessory proteins are recruited to maintain telomere integrity during DNA replication. Dormant replication origins and/or homology-directed repair may rescue inappropriate fork stalling or collapse that can cause defects in telomere structure and functions.
Collapse
|
48
|
Maestroni L, Matmati S, Coulon S. Solving the Telomere Replication Problem. Genes (Basel) 2017; 8:genes8020055. [PMID: 28146113 PMCID: PMC5333044 DOI: 10.3390/genes8020055] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 01/23/2017] [Indexed: 12/12/2022] Open
Abstract
Telomeres are complex nucleoprotein structures that protect the extremities of linear chromosomes. Telomere replication is a major challenge because many obstacles to the progression of the replication fork are concentrated at the ends of the chromosomes. This is known as the telomere replication problem. In this article, different and new aspects of telomere replication, that can threaten the integrity of telomeres, will be reviewed. In particular, we will focus on the functions of shelterin and the replisome for the preservation of telomere integrity.
Collapse
Affiliation(s)
- Laetitia Maestroni
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Equipe labélisée Ligue Contre le Cancer, 13273 Marseille, France.
| | - Samah Matmati
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Equipe labélisée Ligue Contre le Cancer, 13273 Marseille, France.
| | - Stéphane Coulon
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, Equipe labélisée Ligue Contre le Cancer, 13273 Marseille, France.
| |
Collapse
|
49
|
Liu L. Linking Telomere Regulation to Stem Cell Pluripotency. Trends Genet 2016; 33:16-33. [PMID: 27889084 DOI: 10.1016/j.tig.2016.10.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 10/18/2016] [Accepted: 10/31/2016] [Indexed: 12/31/2022]
Abstract
Embryonic stem cells (ESCs), somatic cell nuclear transfer ESCs, and induced pluripotent stem cells (iPSCs) represent the most studied group of PSCs. Unlimited self-renewal without incurring chromosomal instability and pluripotency are essential for the potential use of PSCs in regenerative therapy. Telomere length maintenance is critical for the unlimited self-renewal, pluripotency, and chromosomal stability of PSCs. While telomerase has a primary role in telomere maintenance, alternative lengthening of telomere pathways involving recombination and epigenetic modifications are also required for telomere length regulation, notably in mouse PSCs. Telomere rejuvenation is part of epigenetic reprogramming to pluripotency. Insights into telomere reprogramming and maintenance in PSCs may have implications for understanding of aging and tumorigenesis. Here, I discuss the link between telomere elongation and homeostasis to the acquisition and maintenance of stem cell pluripotency, and their regulatory mechanisms by epigenetic modifications.
Collapse
Affiliation(s)
- Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Collaborative Innovation Center for Biotherapy, Nankai University, Tianjin 300071, China.
| |
Collapse
|
50
|
p53 downregulates the Fanconi anaemia DNA repair pathway. Nat Commun 2016; 7:11091. [PMID: 27033104 PMCID: PMC4821997 DOI: 10.1038/ncomms11091] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 02/19/2016] [Indexed: 12/12/2022] Open
Abstract
Germline mutations affecting telomere maintenance or DNA repair may, respectively, cause dyskeratosis congenita or Fanconi anaemia, two clinically related bone marrow failure syndromes. Mice expressing p53Δ31, a mutant p53 lacking the C terminus, model dyskeratosis congenita. Accordingly, the increased p53 activity in p53Δ31/Δ31 fibroblasts correlated with a decreased expression of 4 genes implicated in telomere syndromes. Here we show that these cells exhibit decreased mRNA levels for additional genes contributing to telomere metabolism, but also, surprisingly, for 12 genes mutated in Fanconi anaemia. Furthermore, p53Δ31/Δ31 fibroblasts exhibit a reduced capacity to repair DNA interstrand crosslinks, a typical feature of Fanconi anaemia cells. Importantly, the p53-dependent downregulation of Fanc genes is largely conserved in human cells. Defective DNA repair is known to activate p53, but our results indicate that, conversely, an increased p53 activity may attenuate the Fanconi anaemia DNA repair pathway, defining a positive regulatory feedback loop. P53 is regarded as the guardian of the genome, however it is known that mice with increased p53 activity display characteristics of dyskeratosis congenita. Here the authors show that increased p53 activity leads to the repression of telomere maintenance and DNA repair genes.
Collapse
|