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Ng YB, Akincilar SC. Shaping DNA damage responses: Therapeutic potential of targeting telomeric proteins and DNA repair factors in cancer. Curr Opin Pharmacol 2024; 76:102460. [PMID: 38776747 DOI: 10.1016/j.coph.2024.102460] [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: 12/10/2022] [Revised: 10/06/2023] [Accepted: 10/11/2023] [Indexed: 05/25/2024]
Abstract
Shelterin proteins regulate genomic stability by preventing inappropriate DNA damage responses (DDRs) at telomeres. Unprotected telomeres lead to persistent DDR causing cell cycle inhibition, growth arrest, and apoptosis. Cancer cells rely on DDR to protect themselves from DNA lesions and exogenous DNA-damaging agents such as chemotherapy and radiotherapy. Therefore, targeting DDR machinery is a promising strategy to increase the sensitivity of cancer cells to existing cancer therapies. However, the success of these DDR inhibitors depends on other mutations, and over time, patients develop resistance to these therapies. This suggests the need for alternative approaches. One promising strategy is co-inhibiting shelterin proteins with DDR molecules, which would offset cellular fitness in DNA repair in a mutation-independent manner. This review highlights the associations and dependencies of the shelterin complex with the DDR proteins and discusses potential co-inhibition strategies that might improve the therapeutic potential of current inhibitors.
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Affiliation(s)
- Yu Bin Ng
- Laboratory of NFκB Signalling, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A∗STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Republic of Singapore
| | - Semih Can Akincilar
- Laboratory of NFκB Signalling, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A∗STAR), 61 Biopolis Drive, Proteos, Singapore 138673, Republic of Singapore.
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2
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Hassanpour H, Mirshokraei P, Salehpour M, Amiri K, Ghareghani P, Nasiri L. Canine sperm motility is associated with telomere shortening and changes in expression of shelterin genes. BMC Vet Res 2023; 19:236. [PMID: 37950187 PMCID: PMC10637008 DOI: 10.1186/s12917-023-03795-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 10/28/2023] [Indexed: 11/12/2023] Open
Abstract
BACKGROUND Motion quality is a critical property for essential functions. Several endogenous and exogenous factors are involved in sperm motility. Here, we measured the relative telomere length and evaluated the gene expression of its binding-proteins, shelterin complex (TRF1, TRF2, RAP1, POT1, TIN2, and TPP1) in sperm of dogs using relative quantitative real-time PCR. We compared them between two sperm subpopulations with poor and good motion qualities (separated by swim-up method). Telomere shortening and alterations of shelterin gene expression result from ROS, genotoxic insults, and genetic predisposition. RESULTS Sperm kinematic parameters were measured in two subpopulations and then telomeric index of each parameter was calculated. Telomeric index for linearity, VSL, VCL, STR, BCF, and ALH were significantly higher in sperms with good motion quality than in sperms with poor quality. We demonstrated that poor motion quality is associated with shorter telomere, higher expression of TRF2, POT1, and TIN2 genes, and lower expression of the RAP1 gene in dog sperm. The levels of TRF1 and TPP1 gene expression remained consistent despite variations in sperm quality and telomere length. CONCLUSION Data provided evidence that there are considerable changes in gene expression of many shelterin components (TRF2, TIN2, POT1and RAP1) associated with shortening telomere in the spermatozoa with poor motion quality. Possibly, the poor motion quality is the result of defects in the shelterin complex and telomere length. Our data suggests a new approach in the semen assessment and etiologic investigations of subfertility or infertility in male animals.
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Affiliation(s)
- Hossein Hassanpour
- Department of Gametes and Cloning, Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran.
| | - Pezhman Mirshokraei
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - Marzieh Salehpour
- Department of Gametes and Cloning, Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran
| | - Khadije Amiri
- Department of Gametes and Cloning, Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran
| | - Parvin Ghareghani
- Department of Gametes and Cloning, Research Institute of Animal Embryo Technology, Shahrekord University, Shahrekord, Iran
| | - Leila Nasiri
- Department of Biology, Faculty of Basic Sciences, Shahed University, Tehran, Iran
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3
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Mannherz W, Agarwal S. Thymidine nucleotide metabolism controls human telomere length. Nat Genet 2023; 55:568-580. [PMID: 36959362 PMCID: PMC11000509 DOI: 10.1038/s41588-023-01339-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 02/21/2023] [Indexed: 03/25/2023]
Abstract
Telomere length in humans is associated with lifespan and severe diseases, yet the genetic determinants of telomere length remain incompletely defined. Here we performed genome-wide CRISPR-Cas9 functional telomere length screening and identified thymidine (dT) nucleotide metabolism as a limiting factor in human telomere maintenance. Targeted genetic disruption using CRISPR-Cas9 revealed multiple telomere length control points across the thymidine nucleotide metabolism pathway: decreasing dT nucleotide salvage via deletion of the gene encoding nuclear thymidine kinase (TK1) or de novo production by knockout of the thymidylate synthase gene (TYMS) decreased telomere length, whereas inactivation of the deoxynucleoside triphosphohydrolase-encoding gene SAMHD1 lengthened telomeres. Remarkably, supplementation with dT alone drove robust telomere elongation by telomerase in cells, and thymidine triphosphate stimulated telomerase activity in a substrate-independent manner in vitro. In induced pluripotent stem cells derived from patients with genetic telomere biology disorders, dT supplementation or inhibition of SAMHD1 promoted telomere restoration. Our results demonstrate a critical role of thymidine metabolism in controlling human telomerase and telomere length, which may be therapeutically actionable in patients with fatal degenerative diseases.
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Affiliation(s)
- William Mannherz
- Division of Hematology/Oncology and Stem Cell Program, Boston Children's Hospital, Boston, MA, USA
- Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Biological and Biomedical Sciences Program, Harvard/MIT MD-PhD Program, Harvard Stem Cell Institute, Harvard Initiative for RNA Medicine, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Suneet Agarwal
- Division of Hematology/Oncology and Stem Cell Program, Boston Children's Hospital, Boston, MA, USA.
- Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA.
- Biological and Biomedical Sciences Program, Harvard/MIT MD-PhD Program, Harvard Stem Cell Institute, Harvard Initiative for RNA Medicine, and Department of Pediatrics, Harvard Medical School, Boston, MA, USA.
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4
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Hassanpour H, Farhadi N, Bahadoran S, Akbari MR. Cardiac telomere attrition following changes in the expression of shelterin genes in pulmonary hypertensive chickens. Br Poult Sci 2023:1-7. [PMID: 36607418 DOI: 10.1080/00071668.2022.2163877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
1. The alterations of relative telomere length and expression of shelterin genes (TRF1, TRF2, RAP1, POT1, and TPP1) were evaluated from the chickens' right heart ventricle in the early and last stages of cold-induced pulmonary hypertension (PHS) at 21 and 42 d of age.2. The relative telomere length in the right ventricular tissues was significantly shorter in the PHS group of broilers than in the control group at 42 d, but did not statistically change at 21 d of age. There was a significant negative correlation between relative telomere length and RV:TV ratio in the broilers at 42 d of age.3. The relative expression of POT1, RAP1 and TPP1 genes in the right ventricular tissues was significantly lower in the PHS group than in the control group at 21 d. The relative expression of the TRF2 gene was only higher in the PHS group of broilers than control at 42 d. The mRNA level of the TRF2 gene exhibited a significant positive correlation with RV:TV ratio at 42 d.4. It was concluded that most shelterin genes are dysregulated in the early stage of PHS (right ventricular hypertrophy) while telomere attrition occurs only at the last stage (heart dilation/failure).
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Affiliation(s)
- H Hassanpour
- Department of Basic Sciences, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran
| | - N Farhadi
- Department of Basic Sciences, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord, Iran
| | - S Bahadoran
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahrekord University, Shaharekord, Iran
| | - M R Akbari
- Department of Animal Sciences, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran
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Tichy ED. Specialized Circuitry of Embryonic Stem Cells Promotes Genomic Integrity. Crit Rev Oncog 2023; 27:1-15. [PMID: 36734869 DOI: 10.1615/critrevoncog.2022042332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Embryonic stem cells (ESCs) give rise to all cell types of the organism. Given the importance of these cells in this process, ESCs must employ robust mechanisms to protect genomic integrity or risk catastrophic propagation of mutations throughout the organism. Should such an event occur in daughter cells that will eventually contribute to the germline, the overall species health could dramatically decline. This review describes several key mechanisms employed by ESCs that are unique to these cells, in order to maintain their genomic integrity. Additionally, the contributions of cell cycle regulators in modulating ESC differentiation, after DNA damage exposure, are also examined. Where data are available, findings reported in ESCs are extended to include observations described in induced pluripotent stem cells (IPSCs).
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Affiliation(s)
- Elisia D Tichy
- Department of Orthopaedic Surgery, Perelman School of Medicine, The University of Pennsylvania, 371 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104-6081
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Jack A, Kim Y, Strom AR, Lee DSW, Williams B, Schaub JM, Kellogg EH, Finkelstein IJ, Ferro LS, Yildiz A, Brangwynne CP. Compartmentalization of telomeres through DNA-scaffolded phase separation. Dev Cell 2022; 57:277-290.e9. [PMID: 35077681 PMCID: PMC8988007 DOI: 10.1016/j.devcel.2021.12.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 08/25/2021] [Accepted: 12/15/2021] [Indexed: 12/20/2022]
Abstract
Telomeres form unique nuclear compartments that prevent degradation and fusion of chromosome ends by recruiting shelterin proteins and regulating access of DNA damage repair factors. To understand how these dynamic components protect chromosome ends, we combine in vivo biophysical interrogation and in vitro reconstitution of human shelterin. We show that shelterin components form multicomponent liquid condensates with selective biomolecular partitioning on telomeric DNA. Tethering and anomalous diffusion prevent multiple telomeres from coalescing into a single condensate in mammalian cells. However, telomeres coalesce when brought into contact via an optogenetic approach. TRF1 and TRF2 subunits of shelterin drive phase separation, and their N-terminal domains specify interactions with telomeric DNA in vitro. Telomeric condensates selectively recruit telomere-associated factors and regulate access of DNA damage repair factors. We propose that shelterin mediates phase separation of telomeric chromatin, which underlies the dynamic yet persistent nature of the end-protection mechanism.
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Affiliation(s)
- Amanda Jack
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA
| | - Yoonji Kim
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Amy R Strom
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Daniel S W Lee
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Byron Williams
- Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
| | - Jeffrey M Schaub
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | | | - Ilya J Finkelstein
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712, USA; Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Luke S Ferro
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
| | - Ahmet Yildiz
- Biophysics Graduate Group, University of California, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA; Physics Department, University of California, Berkeley, CA 94720, USA.
| | - Clifford P Brangwynne
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; Howard Hughes Medical Institute, Princeton University, Princeton NJ 08544, USA.
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Poláková E, Albanaz ATS, Zakharova A, Novozhilova TS, Gerasimov ES, Yurchenko V. Ku80 is involved in telomere maintenance but dispensable for genomic stability in Leishmania mexicana. PLoS Negl Trop Dis 2021; 15:e0010041. [PMID: 34965251 PMCID: PMC8716037 DOI: 10.1371/journal.pntd.0010041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/30/2021] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Telomeres are indispensable for genome stability maintenance. They are maintained by the telomere-associated protein complex, which include Ku proteins and a telomerase among others. Here, we investigated a role of Ku80 in Leishmania mexicana. Leishmania is a genus of parasitic protists of the family Trypanosomatidae causing a vector-born disease called leishmaniasis. METHODOLOGY/PRINCIPAL FINDINGS We used the previously established CRISPR/Cas9 system to mediate ablation of Ku80- and Ku70-encoding genes in L. mexicana. Complete knock-outs of both genes were confirmed by Southern blotting, whole-genome Illumina sequencing, and RT-qPCR. Resulting telomeric phenotypes were subsequently investigated using Southern blotting detection of terminal restriction fragments. The genome integrity in the Ku80- deficient cells was further investigated by whole-genome sequencing. Our work revealed that telomeres in the ΔKu80 L. mexicana are elongated compared to those of the wild type. This is a surprising finding considering that in another model trypanosomatid, Trypanosoma brucei, they are shortened upon ablation of the same gene. A telomere elongation phenotype has been documented in other species and associated with a presence of telomerase-independent alternative telomere lengthening pathway. Our results also showed that Ku80 appears to be not involved in genome stability maintenance in L. mexicana. CONCLUSION/SIGNIFICANCE Ablation of the Ku proteins in L. mexicana triggers telomere elongation, but does not have an adverse impact on genome integrity.
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Affiliation(s)
- Ester Poláková
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Amanda T. S. Albanaz
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Alexandra Zakharova
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | | | - Evgeny S. Gerasimov
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
- Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov University, Moscow, Russia
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8
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RAP1/TERF2IP-A Multifunctional Player in Cancer Development. Cancers (Basel) 2021; 13:cancers13235970. [PMID: 34885080 PMCID: PMC8657031 DOI: 10.3390/cancers13235970] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/24/2021] [Accepted: 11/25/2021] [Indexed: 12/29/2022] Open
Abstract
Simple Summary RAP1 (TERF2IP) is a member of the shelterin complex that protects telomeric DNA and plays a critical role in maintaining chromosome stability. However, mammalian RAP1 was recently found to have additional functions apart from telomeres, acting as a regulator of the NF-κB pathway and transcription factor, and has been suggested that they have putative roles in cancer development. Here, we focus on the main roles of RAP1 in different mechanisms of oncogenesis, progression, and chemoresistance, and consider the clinical significance of findings about its regulation and biological functions. Abstract Mammalian RAP1 (TERF2IP), the most conserved shelterin component, plays a pleiotropic role in the regulation of a variety of cellular processes, including cell metabolism, DNA damage response, and NF-κB signaling, beyond its canonical telomeric role. Moreover, it has been demonstrated to be involved in oncogenesis, progression, and chemoresistance in human cancers. Several mutations and different expression patterns of RAP1 in cancers have been reported. However, the functions and mechanisms of RAP1 in various cancers have not been extensively studied, suggesting the necessity of further investigations. In this review, we summarize the main roles of RAP1 in different mechanisms of cancer development and chemoresistance, with special emphasis on the contribution of RAP1 mutations, expression patterns, and regulation by non-coding RNA, and briefly discuss telomeric and non-telomeric functions.
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9
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Robinson NJ, Miyagi M, Scarborough JA, Scott JG, Taylor DJ, Schiemann WP. SLX4IP promotes RAP1 SUMOylation by PIAS1 to coordinate telomere maintenance through NF-κB and Notch signaling. Sci Signal 2021; 14:eabe9613. [PMID: 34187905 PMCID: PMC8353884 DOI: 10.1126/scisignal.abe9613] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The maintenance of telomere length supports repetitive cell division and therefore plays a central role in cancer development and progression. Telomeres are extended by either the enzyme telomerase or the alternative lengthening of telomeres (ALT) pathway. Here, we found that the telomere-associated protein SLX4IP dictates telomere proteome composition by recruiting and activating the E3 SUMO ligase PIAS1 to the SLX4 complex. PIAS1 SUMOylated the telomere-binding protein RAP1, which disrupted its interaction with the telomere-binding protein TRF2 and facilitated its nucleocytoplasmic shuttling. In the cytosol, RAP1 bound to IκB kinase (IKK), resulting in activation of the transcription factor NF-κB and its induction of Jagged-1 expression, which promoted Notch signaling and the institution of ALT. This axis could be targeted therapeutically in ALT-driven cancers and in tumor cells that develop resistance to antitelomerase therapies. Our results illuminate the mechanisms underlying SLX4IP-dependent telomere plasticity and demonstrate the role of telomere proteins in directly coordinating intracellular signaling and telomere maintenance dynamics.
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Affiliation(s)
- Nathaniel J Robinson
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Masaru Miyagi
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Jessica A Scarborough
- Department of Translational Hematology and Oncology Research, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Jacob G Scott
- Department of Translational Hematology and Oncology Research, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - William P Schiemann
- Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA.
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Khodadadi E, Mir SM, Memar MY, Sadeghi H, Kashiri M, Faeghiniya M, Jamalpoor Z, Sheikh Arabi M. Shelterin complex at telomeres: Roles in cancers. GENE REPORTS 2021. [DOI: 10.1016/j.genrep.2021.101174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Abbasi S, Parmar G, Kelly RD, Balasuriya N, Schild-Poulter C. The Ku complex: recent advances and emerging roles outside of non-homologous end-joining. Cell Mol Life Sci 2021; 78:4589-4613. [PMID: 33855626 PMCID: PMC11071882 DOI: 10.1007/s00018-021-03801-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/29/2021] [Accepted: 02/24/2021] [Indexed: 12/15/2022]
Abstract
Since its discovery in 1981, the Ku complex has been extensively studied under multiple cellular contexts, with most work focusing on Ku in terms of its essential role in non-homologous end-joining (NHEJ). In this process, Ku is well-known as the DNA-binding subunit for DNA-PK, which is central to the NHEJ repair process. However, in addition to the extensive study of Ku's role in DNA repair, Ku has also been implicated in various other cellular processes including transcription, the DNA damage response, DNA replication, telomere maintenance, and has since been studied in multiple contexts, growing into a multidisciplinary point of research across various fields. Some advances have been driven by clarification of Ku's structure, including the original Ku crystal structure and the more recent Ku-DNA-PKcs crystallography, cryogenic electron microscopy (cryoEM) studies, and the identification of various post-translational modifications. Here, we focus on the advances made in understanding the Ku heterodimer outside of non-homologous end-joining, and across a variety of model organisms. We explore unique structural and functional aspects, detail Ku expression, conservation, and essentiality in different species, discuss the evidence for its involvement in a diverse range of cellular functions, highlight Ku protein interactions and recent work concerning Ku-binding motifs, and finally, we summarize the clinical Ku-related research to date.
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Affiliation(s)
- Sanna Abbasi
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Gursimran Parmar
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Rachel D Kelly
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Nileeka Balasuriya
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Caroline Schild-Poulter
- Robarts Research Institute and Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5B7, Canada.
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12
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Chandra A, Rajawat J. Skeletal Aging and Osteoporosis: Mechanisms and Therapeutics. Int J Mol Sci 2021; 22:ijms22073553. [PMID: 33805567 PMCID: PMC8037620 DOI: 10.3390/ijms22073553] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 02/06/2023] Open
Abstract
Bone is a dynamic organ maintained by tightly regulated mechanisms. With old age, bone homeostasis, which is maintained by an intricate balance between bone formation and bone resorption, undergoes deregulation. Oxidative stress-induced DNA damage, cellular apoptosis, and cellular senescence are all responsible for this tissue dysfunction and the imbalance in the bone homeostasis. These cellular mechanisms have become a target for therapeutics to treat age-related osteoporosis. Genetic mouse models have shown the importance of senescent cell clearance in alleviating age-related osteoporosis. Furthermore, we and others have shown that targeting cellular senescence pharmacologically was an effective tool to alleviate age- and radiation-induced osteoporosis. Senescent cells also have an altered secretome known as the senescence associated secretory phenotype (SASP), which may have autocrine, paracrine, or endocrine function. The current review discusses the current and potential pathways which lead to a senescence profile in an aged skeleton and how bone homeostasis is affected during age-related osteoporosis. The review has also discussed existing therapeutics for the treatment of osteoporosis and rationalizes for novel therapeutic options based on cellular senescence and the SASP as an underlying pathogenesis of an aging bone.
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Affiliation(s)
- Abhishek Chandra
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55902, USA
- Department of Internal Medicine, Division of Geriatric Medicine and Gerontology, Mayo Clinic, Rochester, MN 55902, USA
- Robert and Arlene Kogod Aging Center, Mayo Clinic, Rochester, MN 55902, USA
- Correspondence: ; Tel.: +1-507-266-1847
| | - Jyotika Rajawat
- Department of Zoology, University of Lucknow, University Rd, Babuganj, Hasanganj, Lucknow, Uttar Pradesh 226007, India;
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Abbasi S, Schild-Poulter C. Identification of Ku70 Domain-Specific Interactors Using BioID2. Cells 2021; 10:cells10030646. [PMID: 33799447 PMCID: PMC8001828 DOI: 10.3390/cells10030646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/04/2021] [Accepted: 03/10/2021] [Indexed: 11/23/2022] Open
Abstract
Since its inception, proximity-dependent biotin identification (BioID), an in vivo biochemical screening method to identify proximal protein interactors, has seen extensive developments. Improvements and variants of the original BioID technique are being reported regularly, each expanding upon the existing potential of the original technique. While this is advancing our capabilities to study protein interactions under different contexts, we have yet to explore the full potential of the existing BioID variants already at our disposal. Here, we used BioID2 in an innovative manner to identify and map domain-specific protein interactions for the human Ku70 protein. Four HEK293 cell lines were created, each stably expressing various BioID2-tagged Ku70 segments designed to collectively identify factors that interact with different regions of Ku70. Historically, although many interactions have been mapped to the C-terminus of the Ku70 protein, few have been mapped to the N-terminal von Willebrand A-like domain, a canonical protein-binding domain ideally situated as a site for protein interaction. Using this segmented approach, we were able to identify domain-specific interactors as well as evaluate advantages and drawbacks of the BioID2 technique. Our study identifies several potential new Ku70 interactors and validates RNF113A and Spindly as proteins that contact or co-localize with Ku in a Ku70 vWA domain-specific manner.
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14
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Akincilar SC, Chan CHT, Ng QF, Fidan K, Tergaonkar V. Non-canonical roles of canonical telomere binding proteins in cancers. Cell Mol Life Sci 2021; 78:4235-4257. [PMID: 33599797 PMCID: PMC8164586 DOI: 10.1007/s00018-021-03783-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 12/28/2020] [Accepted: 01/29/2021] [Indexed: 02/06/2023]
Abstract
Reactivation of telomerase is a major hallmark observed in 90% of all cancers. Yet paradoxically, enhanced telomerase activity does not correlate with telomere length and cancers often possess short telomeres; suggestive of supplementary non-canonical roles that telomerase might play in the development of cancer. Moreover, studies have shown that aberrant expression of shelterin proteins coupled with their release from shortening telomeres can further promote cancer by mechanisms independent of their telomeric role. While targeting telomerase activity appears to be an attractive therapeutic option, this approach has failed in clinical trials due to undesirable cytotoxic effects on stem cells. To circumvent this concern, an alternative strategy could be to target the molecules involved in the non-canonical functions of telomeric proteins. In this review, we will focus on emerging evidence that has demonstrated the non-canonical roles of telomeric proteins and their impact on tumorigenesis. Furthermore, we aim to address current knowledge gaps in telomeric protein functions and propose future research approaches that can be undertaken to achieve this.
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Affiliation(s)
- Semih Can Akincilar
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Claire Hian Tzer Chan
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Qin Feng Ng
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Kerem Fidan
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Vinay Tergaonkar
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore.
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117593, Singapore.
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15
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Khattar E, Tergaonkar V. Role of Rap1 in DNA damage response: implications in stem cell homeostasis and cancer. Exp Hematol 2020; 90:12-17. [PMID: 32858091 DOI: 10.1016/j.exphem.2020.08.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 08/17/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023]
Abstract
Mammalian Rap1 is a part of the telomere binding complex named shelterin and is one of the most conserved telomeric proteins. With its essential requirement in lower species to its becoming necessary in higher species, it appears to have gained and lost several functions simultaneously evolving with telomeres. Mammalian Rap1 has been reported to play a role in inflammation, metabolism, and oxidative stress. Mammalian Rap1 has also been found to regulate DNA damage response from telomeres in senescent cells. Recently our group uncovered its novel role in stem cell maintenance, and modulation of the chemotherapeutic response. Mechanistically it was found to function as an adaptor via protein-protein interactions and to modulate the response to DNA damage. In the current review we highlight newly identified functions of Rap1 in regulating telomeric and general DNA damage response with its impact at the cellular and organismal levels.
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Affiliation(s)
- Ekta Khattar
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be) University, Mumbai, India.
| | - Vinay Tergaonkar
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A-STAR), Singapore
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16
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Sui J, Zhang S, Chen BPC. DNA-dependent protein kinase in telomere maintenance and protection. Cell Mol Biol Lett 2020; 25:2. [PMID: 31988640 PMCID: PMC6969447 DOI: 10.1186/s11658-020-0199-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 01/02/2020] [Indexed: 12/12/2022] Open
Abstract
This review focuses on DNA-dependent protein kinase (DNA-PK), which is the key regulator of canonical non-homologous end-joining (NHEJ), the predominant mechanism of DNA double-strand break (DSB) repair in mammals. DNA-PK consists of the DNA-binding Ku70/80 heterodimer and the catalytic subunit DNA-PKcs. They assemble at DNA ends, forming the active DNA-PK complex, which initiates NHEJ-mediated DSB repair. Paradoxically, both Ku and DNA-PKcs are associated with telomeres, and they play crucial roles in protecting the telomere against fusions. Herein, we discuss possible mechanisms and contributions of Ku and DNA-PKcs in telomere regulation.
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Affiliation(s)
- Jiangdong Sui
- 1Radiation Oncology Center, Chongqing University Cancer Hospital, Chongqing, 400030 China
| | - Shichuan Zhang
- 2Department of Radiation Oncology, Sichuan Cancer Hospital, Chengdu, China
| | - Benjamin P C Chen
- 3Department of Radiation Oncology, University of Texas Southwestern Medical Center, 2201 Inwood Rd., Dallas, TX 75390-9187 USA
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17
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Khattar E, Maung KZY, Chew CL, Ghosh A, Mok MMH, Lee P, Zhang J, Chor WHJ, Cildir G, Wang CQ, Mohd-Ismail NK, Chin DWL, Lee SC, Yang H, Shin YJ, Nam DH, Chen L, Kumar AP, Deng LW, Ikawa M, Gunaratne J, Osato M, Tergaonkar V. Rap1 regulates hematopoietic stem cell survival and affects oncogenesis and response to chemotherapy. Nat Commun 2019; 10:5349. [PMID: 31836706 PMCID: PMC6911077 DOI: 10.1038/s41467-019-13082-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 10/14/2019] [Indexed: 11/09/2022] Open
Abstract
Increased levels and non-telomeric roles have been reported for shelterin proteins, including RAP1 in cancers. Herein using Rap1 null mice, we provide the genetic evidence that mammalian Rap1 plays a major role in hematopoietic stem cell survival, oncogenesis and response to chemotherapy. Strikingly, this function of RAP1 is independent of its association with the telomere or with its known partner TRF2. We show that RAP1 interacts with many members of the DNA damage response (DDR) pathway. RAP1 depleted cells show reduced interaction between XRCC4/DNA Ligase IV and DNA-PK, and are impaired in DNA Ligase IV recruitment to damaged chromatin for efficient repair. Consistent with its role in DNA damage repair, RAP1 loss decreases double-strand break repair via NHEJ in vivo, and consequently reduces B cell class switch recombination. Finally, we discover that RAP1 levels are predictive of the success of chemotherapy in breast and colon cancer.
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Affiliation(s)
- Ekta Khattar
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Kyaw Ze Ya Maung
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Chen Li Chew
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Arkasubhra Ghosh
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Michelle Meng Huang Mok
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Pei Lee
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jun Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, 210023, Nanjing, P.R. China
| | - Wei Hong Jeff Chor
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Gökhan Cildir
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Chelsia Qiuxia Wang
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Nur Khairiah Mohd-Ismail
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Desmond Wai Loon Chin
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Soo Chin Lee
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Yong-Jae Shin
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Republic of Korea
| | - Do-Hyun Nam
- Institute for Refractory Cancer Research, Samsung Medical Center, Seoul, Republic of Korea
| | - Liming Chen
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, 210023, Nanjing, P.R. China
| | - Alan Prem Kumar
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Lih Wen Deng
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, 565-0871, Japan
- Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Jayantha Gunaratne
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore
| | - Motomi Osato
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Vinay Tergaonkar
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A-STAR), Singapore, Singapore.
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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18
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Barbero Barcenilla B, Shippen DE. Back to the future: The intimate and evolving connection between telomere-related factors and genotoxic stress. J Biol Chem 2019; 294:14803-14813. [PMID: 31434740 DOI: 10.1074/jbc.aw119.008145] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The conversion of circular genomes to linear chromosomes during molecular evolution required the invention of telomeres. This entailed the acquisition of factors necessary to fulfill two new requirements: the need to fully replicate terminal DNA sequences and the ability to distinguish chromosome ends from damaged DNA. Here we consider the multifaceted functions of factors recruited to perpetuate and stabilize telomeres. We discuss recent theories for how telomere factors evolved from existing cellular machineries and examine their engagement in nontelomeric functions such as DNA repair, replication, and transcriptional regulation. We highlight the remarkable versatility of protection of telomeres 1 (POT1) proteins that was fueled by gene duplication and divergence events that occurred independently across several eukaryotic lineages. Finally, we consider the relationship between oxidative stress and telomeres and the enigmatic role of telomere-associated proteins in mitochondria. These findings point to an evolving and intimate connection between telomeres and cellular physiology and the strong drive to maintain chromosome integrity.
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Affiliation(s)
- Borja Barbero Barcenilla
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
| | - Dorothy E Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128
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19
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The role of telomere-binding modulators in pluripotent stem cells. Protein Cell 2019; 11:60-70. [PMID: 31350723 PMCID: PMC6949317 DOI: 10.1007/s13238-019-0651-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/07/2019] [Indexed: 01/24/2023] Open
Abstract
Pluripotent stem cells (PSCs) such as embryonic stem cells (ESCs), ESCs derived by somatic cell nuclear transfer (ntESCs), and induced pluripotent stem cells (iPSCs) have unlimited capacity for self-renewal and pluripotency and can give rise to all types of somatic cells. In order to maintain their self-renewal and pluripotency, PSCs need to preserve their telomere length and homeostasis. In recent years, increasing studies have shown that telomere reprogramming is essential for stem cell pluripotency maintenance and its induced pluripotency process. Telomere-associated proteins are not only required for telomere maintenance in both stem cells, their extra-telomeric functions have also been found to be critical as well. Here, we will discuss how telomeres and telomere-associated factors participate and regulate the maintenance of stem cell pluripotency.
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20
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Lemon LD, Morris DK, Bertuch AA. Loss of Ku's DNA end binding activity affects telomere length via destabilizing telomere-bound Est1 rather than altering TLC1 homeostasis. Sci Rep 2019; 9:10607. [PMID: 31337791 PMCID: PMC6650470 DOI: 10.1038/s41598-019-46840-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/05/2019] [Indexed: 11/21/2022] Open
Abstract
Saccharomyces cerevisiae telomerase, which maintains telomere length, is comprised of an RNA component, TLC1, the reverse transcriptase, Est2, and regulatory subunits, including Est1. The Yku70/Yku80 (Ku) heterodimer, a DNA end binding (DEB) protein, also contributes to telomere length maintenance. Ku binds TLC1 and telomere ends in a mutually exclusive fashion, and is required to maintain levels and nuclear localization of TLC1. Ku also interacts with Sir4, which localizes to telomeres. Here we sought to determine the role of Ku's DEB activity in telomere length maintenance by utilizing yku70-R456E mutant strains, in which Ku has reduced DEB and telomere association but proficiency in TLC1 and Sir4 binding, and TLC1 nuclear retention. Telomere lengths in a yku70-R456E strain were nearly as short as those in yku∆ strains and shorter than in strains lacking either Sir4, Ku:Sir4 interaction, or Ku:TLC1 interaction. TLC1 levels were decreased in the yku70-R456E mutant, yet overexpression of TLC1 failed to restore telomere length. Reduced DEB activity did not impact Est1's ability to associate with telomerase but did result in decreased association of Est1 with the telomere. These findings suggest Ku's DEB activity maintains telomere length homeostasis by preserving Est1's interaction at the telomere rather than altering TLC1 levels.
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Affiliation(s)
- Laramie D Lemon
- Graduate Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Danna K Morris
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Alison A Bertuch
- Graduate Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, 77030, USA.
- Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, USA.
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21
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Abstract
The telomere regulator and transcription factor Rap1 is the only telomere protein conserved in yeasts and mammals. Its functional repertoire in budding yeasts is a particularly interesting field for investigation, given the high evolutionary diversity of this group of unicellular organisms. In the methylotrophic thermotolerant species Hansenula polymorpha DL-1 the RAP1 gene is duplicated (HpRAP1A and HpRAP1B). Here, we report the functional characterization of the two paralogues from H. polymorpha DL-1. We uncover distinct (but overlapping) DNA binding preferences of HpRap1A and HpRap1B proteins. We show that only HpRap1B is able to recognize telomeric DNA directly and to protect it from excessive recombination, whereas HpRap1A is associated with subtelomere regions. Furthermore, we identify specific binding sites for both HpRap1A and HpRap1B within promoters of a large number of ribosomal protein genes (RPGs), implicating Rap1 in the control of the RP regulon in H. polymorpha. Our bioinformatic analysis suggests that RAP1 was duplicated early in the evolution of the “methylotrophs” clade, and the two genes evolved independently. Therefore, our characterization of Rap1 paralogues in H. polymorpha may be relevant to other “methylotrophs”, yielding valuable insights into the evolution of budding yeasts.
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22
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Elbeltagy AR, Bertolini F, Fleming DS, Van Goor A, Ashwell CM, Schmidt CJ, Kugonza DR, Lamont SJ, Rothschild MF. Natural Selection Footprints Among African Chicken Breeds and Village Ecotypes. Front Genet 2019; 10:376. [PMID: 31139205 PMCID: PMC6518202 DOI: 10.3389/fgene.2019.00376] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 04/09/2019] [Indexed: 01/09/2023] Open
Abstract
Natural selection is likely a major factor in shaping genomic variation of the African indigenous rural chicken, driving the development of genetic footprints. Selection footprints are expected to be associated with adaptation to locally prevailing environmental stressors, which may include diverse factors as high altitude, disease resistance, poor nutrition, oxidative and heat stresses. To determine the existence of a selection footprint, 268 birds were randomly sampled from three indigenous ecotypes from East Africa (Rwanda and Uganda) and North Africa (Baladi), and two registered Egyptian breeds (Dandarawi and Fayoumi). Samples were genotyped using the chicken Affymetrix 600K Axiom® Array. A total of 494,332 SNPs were utilized in the downstream analysis after implementing quality control measures. The intra-population runs of homozygosity (ROH) that occurred in >50% of individuals of an ecotype or in >75% of a breed were studied. To identify inter-population differentiation due to genetic structure, FST was calculated for North- vs. East-African populations and Baladi and Fayoumi vs. Dandarawi for overlapping windows (500 kb with a step-size of 250 kb). The ROH and FST mapping detected several selective sweeps on different autosomes. Results reflected selection footprints of the environmental stresses, breed behavior, and management. Intra-population ROH of the Egyptian chickens showed selection footprints bearing genes for adaptation to heat, solar radiation, ion transport and immunity. The high-altitude-adapted East-African populations' ROH showed a selection signature with genes for angiogenesis, oxygen-heme binding and transport. The neuroglobin gene (GO:0019825 and GO:0015671) was detected on a Chromosome 5 ROH of Rwanda-Uganda ecotypes. The sodium-dependent noradrenaline transporter, SLC6A2 on a Chromosome 11 ROH in Fayoumi breed may reflect its active behavior. Inter-population FST among Egyptian populations reflected genetic mechanisms for the Fayoumi resistance to Newcastle Disease Virus (NDV), while FST between Egyptian and Rwanda-Uganda populations indicated the Secreted frizzled related protein 2, SFRP2, (GO:0009314) on Chromosome 4, that contributes to melanogenic activity and most likely enhances the Dandarawi chicken adaptation to high-intensity of solar radiation in Southern Egypt. These results enhance our understanding of the natural selection forces role in shaping genomic structure for adaptation to the stressful African conditions.
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Affiliation(s)
- Ahmed R Elbeltagy
- Department of Animal Science, Iowa State University, Ames, IA, United States.,Department of Animal Biotechnology, Animal Production Research Institute, Giza, Egypt
| | - Francesca Bertolini
- Department of Animal Science, Iowa State University, Ames, IA, United States
| | - Damarius S Fleming
- Department of Animal Science, Iowa State University, Ames, IA, United States.,Virus and Prion Diseases of Livestock Research Unit, National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| | - Angelica Van Goor
- Department of Animal Science, Iowa State University, Ames, IA, United States.,Institute of Food Production and Sustainability, National Institute of Food and Agriculture, United States Department of Agriculture, Washington, DC, United States
| | - Chris M Ashwell
- Department of Poultry Science, North Carolina State University, Raleigh, NC, United States
| | - Carl J Schmidt
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, United States
| | - Donald R Kugonza
- Department of Agricultural Production, Makerere University, Kampala, Uganda
| | - Susan J Lamont
- Department of Animal Science, Iowa State University, Ames, IA, United States
| | - Max F Rothschild
- Department of Animal Science, Iowa State University, Ames, IA, United States
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23
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Fiedler LR, Chapman K, Xie M, Maifoshie E, Jenkins M, Golforoush PA, Bellahcene M, Noseda M, Faust D, Jarvis A, Newton G, Paiva MA, Harada M, Stuckey DJ, Song W, Habib J, Narasimhan P, Aqil R, Sanmugalingam D, Yan R, Pavanello L, Sano M, Wang SC, Sampson RD, Kanayaganam S, Taffet GE, Michael LH, Entman ML, Tan TH, Harding SE, Low CMR, Tralau-Stewart C, Perrior T, Schneider MD. MAP4K4 Inhibition Promotes Survival of Human Stem Cell-Derived Cardiomyocytes and Reduces Infarct Size In Vivo. Cell Stem Cell 2019; 24:579-591.e12. [PMID: 30853557 PMCID: PMC6458995 DOI: 10.1016/j.stem.2019.01.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 12/24/2018] [Accepted: 01/30/2019] [Indexed: 12/17/2022]
Abstract
Heart disease is a paramount cause of global death and disability. Although cardiomyocyte death plays a causal role and its suppression would be logical, no clinical counter-measures target the responsible intracellular pathways. Therapeutic progress has been hampered by lack of preclinical human validation. Mitogen-activated protein kinase kinase kinase kinase-4 (MAP4K4) is activated in failing human hearts and relevant rodent models. Using human induced-pluripotent-stem-cell-derived cardiomyocytes (hiPSC-CMs) and MAP4K4 gene silencing, we demonstrate that death induced by oxidative stress requires MAP4K4. Consequently, we devised a small-molecule inhibitor, DMX-5804, that rescues cell survival, mitochondrial function, and calcium cycling in hiPSC-CMs. As proof of principle that drug discovery in hiPSC-CMs may predict efficacy in vivo, DMX-5804 reduces ischemia-reperfusion injury in mice by more than 50%. We implicate MAP4K4 as a well-posed target toward suppressing human cardiac cell death and highlight the utility of hiPSC-CMs in drug discovery to enhance cardiomyocyte survival.
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Affiliation(s)
- Lorna R Fiedler
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Kathryn Chapman
- Drug Discovery Centre, Department of Medicine, Imperial College London, London SW7 2AZ, UK; Department of Surgery and Cancer, Imperial College London, London W12 0NN, UK; Domainex, Chesterford Research Park, Little Chesterford, Saffron Walden, Essex CB10 1XL, UK
| | - Min Xie
- Michael E. DeBakey Heart Center, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Evie Maifoshie
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Micaela Jenkins
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Pelin Arabacilar Golforoush
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Mohamed Bellahcene
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Michela Noseda
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Dörte Faust
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Ashley Jarvis
- Domainex, Chesterford Research Park, Little Chesterford, Saffron Walden, Essex CB10 1XL, UK
| | - Gary Newton
- Domainex, Chesterford Research Park, Little Chesterford, Saffron Walden, Essex CB10 1XL, UK
| | - Marta Abreu Paiva
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Mutsuo Harada
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Daniel J Stuckey
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Weihua Song
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Josef Habib
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Priyanka Narasimhan
- Domainex, Chesterford Research Park, Little Chesterford, Saffron Walden, Essex CB10 1XL, UK
| | - Rehan Aqil
- Domainex, Chesterford Research Park, Little Chesterford, Saffron Walden, Essex CB10 1XL, UK
| | - Devika Sanmugalingam
- Domainex, Chesterford Research Park, Little Chesterford, Saffron Walden, Essex CB10 1XL, UK
| | - Robert Yan
- Domainex, Chesterford Research Park, Little Chesterford, Saffron Walden, Essex CB10 1XL, UK
| | - Lorenzo Pavanello
- Domainex, Chesterford Research Park, Little Chesterford, Saffron Walden, Essex CB10 1XL, UK
| | - Motoaki Sano
- Michael E. DeBakey Heart Center, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sam C Wang
- Michael E. DeBakey Heart Center, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Robert D Sampson
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Sunthar Kanayaganam
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - George E Taffet
- Michael E. DeBakey Heart Center, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lloyd H Michael
- Michael E. DeBakey Heart Center, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mark L Entman
- Michael E. DeBakey Heart Center, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Tse-Hua Tan
- Immunology Research Center, National Health Research Institutes, Zhunan 35053, Taiwan; Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sian E Harding
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK
| | - Caroline M R Low
- Drug Discovery Centre, Department of Medicine, Imperial College London, London SW7 2AZ, UK
| | | | - Trevor Perrior
- Domainex, Chesterford Research Park, Little Chesterford, Saffron Walden, Essex CB10 1XL, UK
| | - Michael D Schneider
- British Heart Foundation Centre of Research Excellence, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK; Michael E. DeBakey Heart Center, Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA.
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24
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Zhang X, Liu Z, Liu X, Wang S, Zhang Y, He X, Sun S, Ma S, Shyh-Chang N, Liu F, Wang Q, Wang X, Liu L, Zhang W, Song M, Liu GH, Qu J. Telomere-dependent and telomere-independent roles of RAP1 in regulating human stem cell homeostasis. Protein Cell 2019; 10:649-667. [PMID: 30796637 PMCID: PMC6711945 DOI: 10.1007/s13238-019-0610-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 01/03/2019] [Indexed: 01/19/2023] Open
Abstract
RAP1 is a well-known telomere-binding protein, but its functions in human stem cells have remained unclear. Here we generated RAP1-deficient human embryonic stem cells (hESCs) by using CRISPR/Cas9 technique and obtained RAP1-deficient human mesenchymal stem cells (hMSCs) and neural stem cells (hNSCs) via directed differentiation. In both hMSCs and hNSCs, RAP1 not only negatively regulated telomere length but also acted as a transcriptional regulator of RELN by tuning the methylation status of its gene promoter. RAP1 deficiency enhanced self-renewal and delayed senescence in hMSCs, but not in hNSCs, suggesting complicated lineage-specific effects of RAP1 in adult stem cells. Altogether, these results demonstrate for the first time that RAP1 plays both telomeric and nontelomeric roles in regulating human stem cell homeostasis.
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Affiliation(s)
- Xing Zhang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,Advanced Innovation Center for Human Brain Protection, National Clinical Research Center for Geriatric Disorders, Xuanwu Hospital Capital Medical University, Beijing, 100053, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zunpeng Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaoqian Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Si Wang
- Advanced Innovation Center for Human Brain Protection, National Clinical Research Center for Geriatric Disorders, Xuanwu Hospital Capital Medical University, Beijing, 100053, China.,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,Institute for Stem cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yiyuan Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaojuan He
- Advanced Innovation Center for Human Brain Protection, National Clinical Research Center for Geriatric Disorders, Xuanwu Hospital Capital Medical University, Beijing, 100053, China
| | - Shuhui Sun
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Shuai Ma
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ng Shyh-Chang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Institute for Stem cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
| | - Feng Liu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Institute for Stem cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
| | - Qiang Wang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Institute for Stem cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiaoqun Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Institute for Stem cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China
| | - Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China
| | - Weiqi Zhang
- Advanced Innovation Center for Human Brain Protection, National Clinical Research Center for Geriatric Disorders, Xuanwu Hospital Capital Medical University, Beijing, 100053, China. .,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China. .,Institute for Stem cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Moshi Song
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China. .,Institute for Stem cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Guang-Hui Liu
- Advanced Innovation Center for Human Brain Protection, National Clinical Research Center for Geriatric Disorders, Xuanwu Hospital Capital Medical University, Beijing, 100053, China. .,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China. .,Institute for Stem cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China. .,Key Laboratory of Regenerative Medicine of Ministry of Education, Institute of Aging and Regenerative Medicine, Jinan University, Guangzhou, 510632, China. .,Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China.
| | - Jing Qu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China. .,Institute for Stem cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101, China.
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25
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Aksenova AY, Mirkin SM. At the Beginning of the End and in the Middle of the Beginning: Structure and Maintenance of Telomeric DNA Repeats and Interstitial Telomeric Sequences. Genes (Basel) 2019; 10:genes10020118. [PMID: 30764567 PMCID: PMC6410037 DOI: 10.3390/genes10020118] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 02/07/2023] Open
Abstract
Tandem DNA repeats derived from the ancestral (TTAGGG)n run were first detected at chromosome ends of the majority of living organisms, hence the name telomeric DNA repeats. Subsequently, it has become clear that telomeric motifs are also present within chromosomes, and they were suitably called interstitial telomeric sequences (ITSs). It is well known that telomeric DNA repeats play a key role in chromosome stability, preventing end-to-end fusions and precluding the recurrent DNA loss during replication. Recent data suggest that ITSs are also important genomic elements as they confer its karyotype plasticity. In fact, ITSs appeared to be among the most unstable microsatellite sequences as they are highly length polymorphic and can trigger chromosomal fragility and gross chromosomal rearrangements. Importantly, mechanisms responsible for their instability appear to be similar to the mechanisms that maintain the length of genuine telomeres. This review compares the mechanisms of maintenance and dynamic properties of telomeric repeats and ITSs and discusses the implications of these dynamics on genome stability.
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Affiliation(s)
- Anna Y Aksenova
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia.
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02421, USA.
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26
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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.
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27
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Sucularli C, Thomas P, Kocak H, White JS, O'Connor BC, Keegan CE. High-throughput gene expression analysis identifies p53-dependent and -independent pathways contributing to the adrenocortical dysplasia (acd) phenotype. Gene 2018; 679:219-231. [PMID: 30189268 PMCID: PMC6186184 DOI: 10.1016/j.gene.2018.09.002] [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: 06/11/2018] [Revised: 08/24/2018] [Accepted: 09/03/2018] [Indexed: 11/18/2022]
Abstract
In mammalian cells TPP1, encoded by the Acd gene, is a key component of the shelterin complex, which is required for telomere length maintenance and telomere protection. In mice, a hypomorphic mutation in Acd causes the adrenocortical dysplasia (acd) phenotype, which includes limb and body axis anomalies, and perinatal lethality. p53 deficiency partially rescues limb and body axis anomalies in acd mutant embryos, but not perinatal lethality, implicating p53-independent mechanisms in the acd phenotype. Loss of function of most shelterin proteins results in early embryonic lethality. Thus, study of the hypomorphic acd allele provides a unique opportunity to understand telomere dysfunction at an organismal level. The aim of this study was to identify transcriptome alterations in acd mutant and acd, p53 double mutant embryos to understand the p53-dependent and -independent factors that contribute to the mutant phenotypes in the context of the whole organism. Genes involved in developmental processes, cell cycle, metabolic pathways, tight junctions, axon guidance and signaling pathways were regulated by p53-driven mechanisms in acd mutant embryos, while genes functioning in immune response, and RNA processing were altered independently of p53 in acd, p53 double mutant embryos. To our best of knowledge, this is the first study revealing detailed transcriptomic alterations, reflecting novel p53-dependent and -independent pathways contributing to the acd phenotype. Our data confirm the importance of cell cycle and DNA repair pathways, and suggest novel links between telomere dysfunction and immune system regulation and the splicing machinery. Given the broad applicability of telomere maintenance in growth, development, and genome stability, our data will also provide a rich resource for others studying telomere maintenance and DNA damage responses in mammalian model systems.
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Affiliation(s)
- Ceren Sucularli
- Department of Bioinformatics, Institute of Health Sciences, Hacettepe University, 06100 Ankara, Turkey
| | - Peedikayil Thomas
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA; Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Hande Kocak
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA; Department of Medical Biology and Genetics, Istanbul Bilim University, Istanbul, Turkey
| | - James S White
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | | | - Catherine E Keegan
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA; Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA.
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28
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Physical Activity and Nutrition: Two Promising Strategies for Telomere Maintenance? Nutrients 2018; 10:nu10121942. [PMID: 30544511 PMCID: PMC6316700 DOI: 10.3390/nu10121942] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/03/2018] [Accepted: 12/05/2018] [Indexed: 01/01/2023] Open
Abstract
As the world demographic structure is getting older, highlighting strategies to counteract age-related diseases is a major public health concern. Telomeres are nucleoprotein structures that serve as guardians of genome stability by ensuring protection against both cell death and senescence. A hallmark of biological aging, telomere health is determined throughout the lifespan by a combination of both genetic and non-genetic influences. This review summarizes data from recently published studies looking at the effect of lifestyle variables such as nutrition and physical activity on telomere dynamics.
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29
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Kalathiya U, Padariya M, Baginski M. The structurally similar TRFH domain of TRF1 and TRF2 dimers shows distinct behaviour towards TIN2. Arch Biochem Biophys 2018; 642:52-62. [PMID: 29428209 DOI: 10.1016/j.abb.2018.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 02/06/2018] [Accepted: 02/07/2018] [Indexed: 01/25/2023]
Abstract
The telomere repeat binding-factor 1 and 2 (TRF1 and TRF2) proteins of the shelterin complex bind to duplex telomeric DNA as homodimers, and the homodimerization is mediated by their TRFH (TRF-homology) domains. We performed molecular dynamic (MD) simulations of the dimer forms of TRF1TRFH and TRF2TRFH in the presence/absence of the TIN2TBM (TIN2, TRF-interacting nuclear protein 2, TBM, TRF-binding motif) peptide. The MD results suggest that TIN2TBM is necessary to ensure the stability of TRF1TRFH homodimer but not the TRF2TRFH homodimer. In TRF1-TIN2-TRF2 complex, the peptide enhances the protein-protein interactions to yield a stable heterodimer. Both monomers in TRF1TRFH homodimer interact almost equally with the peptide, whereas in TRF2TRFH homodimer, monomer TRF2TRFH(M1) exhibits more dominant interactions than the TRF2TRFH(M2). The common residues of TRF1/2TRFH(M1) that form interactions with TIN2TBM in all peptide-bound systems originate from the H3 (helix) and L3 (loop) regions. Additionally, in the homodimer systems, residues of TRF1/2TRFH(M2) also interact with the peptide. The residue pair E71-K213 is responsible for different conformations of TRF1TRFH homodimers; specifically, this residue pair enhances the protein-peptide/protein interactions in peptide-bound/unbound systems, respectively. TRF1TRFH and TRF2TRFH proteins have a conserved but different interface responsible for the protein-protein/peptide interactions that exist in the corresponding dimers.
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Affiliation(s)
- Umesh Kalathiya
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Narutowicza St 11/12, 80-233 Gdansk, Poland.
| | - Monikaben Padariya
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Narutowicza St 11/12, 80-233 Gdansk, Poland
| | - Maciej Baginski
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Narutowicza St 11/12, 80-233 Gdansk, Poland
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30
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Lian S, Meng L, Yang Y, Ma T, Xing X, Feng Q, Song Q, Liu C, Tian Z, Qu L, Shou C. PRL-3 promotes telomere deprotection and chromosomal instability. Nucleic Acids Res 2017; 45:6546-6571. [PMID: 28482095 PMCID: PMC5499835 DOI: 10.1093/nar/gkx392] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 04/26/2017] [Indexed: 12/24/2022] Open
Abstract
Phosphatase of regenerating liver (PRL-3) promotes cell invasiveness, but its role in genomic integrity remains unknown. We report here that shelterin component RAP1 mediates association between PRL-3 and TRF2. In addition, TRF2 and RAP1 assist recruitment of PRL-3 to telomeric DNA. Silencing of PRL-3 in colon cancer cells does not affect telomere integrity or chromosomal stability, but induces reactive oxygen species-dependent DNA damage response and senescence. However, overexpression of PRL-3 in colon cancer cells and primary fibroblasts promotes structural abnormalities of telomeres, telomere deprotection, DNA damage response, chromosomal instability and senescence. Furthermore, PRL-3 dissociates RAP1 and TRF2 from telomeric DNA in vitro and in cells. PRL-3-promoted telomere deprotection, DNA damage response and senescence are counteracted by disruption of PRL-3–RAP1 complex or expression of ectopic TRF2. Examination of clinical samples showed that PRL-3 status positively correlates with telomere deprotection and senescence. PRL-3 transgenic mice exhibit hallmarks of telomere deprotection and senescence and are susceptible to dextran sodium sulfate-induced colon malignancy. Our results uncover a novel role of PRL-3 in tumor development through its adverse impact on telomere homeostasis.
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Affiliation(s)
- Shenyi Lian
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China.,Department of Pathology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Lin Meng
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Yongyong Yang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Ting Ma
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Xiaofang Xing
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Qin Feng
- Central Laboratory, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Qian Song
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Caiyun Liu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Zhihua Tian
- Central Laboratory, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Like Qu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
| | - Chengchao Shou
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Biochemistry and Molecular Biology, Peking University Cancer Hospital & Institute, Beijing 100142, China
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31
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Expression of Telomere-Associated Proteins is Interdependent to Stabilize Native Telomere Structure and Telomere Dysfunction by G-Quadruplex Ligand Causes TERRA Upregulation. Cell Biochem Biophys 2017; 76:311-319. [DOI: 10.1007/s12013-017-0835-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 09/18/2017] [Indexed: 11/26/2022]
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32
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Cai Y, Kandula V, Kosuru R, Ye X, Irwin MG, Xia Z. Decoding telomere protein Rap1: Its telomeric and nontelomeric functions and potential implications in diabetic cardiomyopathy. Cell Cycle 2017; 16:1765-1773. [PMID: 28853973 PMCID: PMC5628636 DOI: 10.1080/15384101.2017.1371886] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mammalian Rap1, the most conserved telomere-interacting protein, beyond its role within nucleus for the maintenance of telomeric functions, is also well known for its pleiotropic functions in various physiological and pathological conditions associated with metabolism, inflammation and oxidative stress. For all these, nowadays Rap1 is the subject of critical investigations aimed to unveil its molecular signaling pathways and to scrutinize the applicability of its modulation as a promising therapeutic strategy with clinical relevance. However, the underlying intimate mechanisms of Rap1 are not extensively studied, but any modulation of this protein level has been associated with pathologies like inflammation, oxidative stress and deregulated metabolism. This is considerably important in light of the recent discovery of Rap1 modulation in diseases like cancer and cardiac metabolic disorders. In this review, we focus on both the telomeric and nontelomeric functions of Rap1 and its modulation in various health risks, especially on the heart.
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Affiliation(s)
- Yin Cai
- a Department of Anaesthesiology , The University of Hong Kong , Hong Kong SAR , China
| | - Vidya Kandula
- a Department of Anaesthesiology , The University of Hong Kong , Hong Kong SAR , China
| | - Ramoji Kosuru
- a Department of Anaesthesiology , The University of Hong Kong , Hong Kong SAR , China
| | - Xiaodong Ye
- a Department of Anaesthesiology , The University of Hong Kong , Hong Kong SAR , China
| | - Michael G Irwin
- a Department of Anaesthesiology , The University of Hong Kong , Hong Kong SAR , China
| | - Zhengyuan Xia
- a Department of Anaesthesiology , The University of Hong Kong , Hong Kong SAR , China
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33
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Berardinelli F, Coluzzi E, Sgura A, Antoccia A. Targeting telomerase and telomeres to enhance ionizing radiation effects in in vitro and in vivo cancer models. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 773:204-219. [PMID: 28927529 DOI: 10.1016/j.mrrev.2017.02.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 02/13/2017] [Accepted: 02/14/2017] [Indexed: 01/05/2023]
Abstract
One of the hallmarks of cancer consists in the ability of tumor cells to divide indefinitely, and to maintain stable telomere lengths throughout the activation of specific telomere maintenance mechanisms (TMM). Therefore in the last fifteen years, researchers proposed to target telomerase or telomeric structure in order to block limitless replicative potential of cancer cells providing a fascinating strategy for a broad-spectrum cancer therapy. In the present review, we report in vitro and in vivo evidence regarding the use of chemical agents targeting both telomerase or telomere structure and showing promising antitumor effects when used in combination with ionizing radiation (IR). RNA interference, antisense oligonucleotides (e.g., GRN163L), non-nucleoside inhibitors (e.g., BIBR1532) and nucleoside analogs (e.g., AZT) represent some of the most potent strategies to inhibit telomerase activity used in combination with IR. Furthermore, radiosensitizing effects were demonstrated also for agents acting directly on the telomeric structure such as G4-ligands (e.g., RHPS4 and Telomestatin) or telomeric-oligos (T-oligos). To date, some of these compounds are under clinical evaluation (e.g., GRN163L and KML001). Advantages of Telomere/Telomerase Targeting Compounds (T/TTCs) coupled with radiotherapy may be relevant in the treatment of radioresistant tumors and in the development of new optimized treatment plans with reduced dose adsorbed by patients and consequent attenuation of short- end long-term side effects. Pros and cons of possible future applications in cancer therapy based on the combination of T/TCCs and radiation treatment are discussed.
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Affiliation(s)
- F Berardinelli
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy.
| | - E Coluzzi
- Dipartimento di Scienze, Università Roma Tre, Rome Italy
| | - A Sgura
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy
| | - A Antoccia
- Dipartimento di Scienze, Università Roma Tre, Rome Italy; Istituto Nazionale di Fisica Nucleare, INFN, Sezione di Roma Tre, Rome, Italy
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34
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Martínez P, Gómez-López G, Pisano DG, Flores JM, Blasco MA. A genetic interaction between RAP1 and telomerase reveals an unanticipated role for RAP1 in telomere maintenance. Aging Cell 2016; 15:1113-1125. [PMID: 27586969 PMCID: PMC5114719 DOI: 10.1111/acel.12517] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2016] [Indexed: 11/30/2022] Open
Abstract
RAP1 is one of the components of shelterin, the capping complex at chromosome ends or telomeres, although its role in telomere length maintenance and protection has remained elusive. RAP1 also binds subtelomeric repeats and along chromosome arms, where it regulates gene expression and has been shown to function in metabolism control. Telomerase is the enzyme that elongates telomeres, and its deficiency causes a premature aging in humans and mice. We describe an unanticipated genetic interaction between RAP1 and telomerase. While RAP1 deficiency alone does not impact on mouse survival, mice lacking both RAP1 and telomerase show a progressively decreased survival with increasing mouse generations compared to telomerase single mutants. Telomere shortening is more pronounced in Rap1−/−Terc−/− doubly deficient mice than in the single‐mutant Terc−/− counterparts, leading to an earlier onset of telomere‐induced DNA damage and degenerative pathologies. Telomerase deficiency abolishes obesity and liver steatohepatitis provoked by RAP1 deficiency. Using genomewide ChIP sequencing, we find that progressive telomere shortening owing to telomerase deficiency leads to re‐localization of RAP1 from telomeres and subtelomeric regions to extratelomeric sites in a genomewide manner. These findings suggest that although in the presence of sufficient telomere reserve RAP1 is not a key factor for telomere maintenance and protection, it plays a crucial role in the context of telomerase deficiency, thus in agreement with its evolutionary conservation as a telomere component from yeast to humans.
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Affiliation(s)
- Paula Martínez
- Telomeres and Telomerase Group; Molecular Oncology Program; Spanish National Cancer Centre (CNIO); Melchor Fernández Almagro 3 Madrid E-28029 Spain
| | - Gonzalo Gómez-López
- Bioinformatics Core Unit; Structural Biology and Biocomputing Program; Spanish National Cancer Centre (CNIO); Melchor Fernández Almagro 3 Madrid E-28029 Spain
| | - David G. Pisano
- Bioinformatics Core Unit; Structural Biology and Biocomputing Program; Spanish National Cancer Centre (CNIO); Melchor Fernández Almagro 3 Madrid E-28029 Spain
| | - Juana M. Flores
- Animal Surgery and Medicine Department; Faculty of Veterinarian; Complutense University of Madrid; Madrid 28029 Spain
| | - Maria A. Blasco
- Telomeres and Telomerase Group; Molecular Oncology Program; Spanish National Cancer Centre (CNIO); Melchor Fernández Almagro 3 Madrid E-28029 Spain
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35
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Menendez JA, Rubio MA, Campisi J, Lupu R. Heregulin, a new regulator of telomere length in human cells. Oncotarget 2016; 6:39422-36. [PMID: 26318724 PMCID: PMC4741836 DOI: 10.18632/oncotarget.4964] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 07/12/2015] [Indexed: 01/12/2023] Open
Abstract
The growth factor heregulin (HRG) promotes breast cancer (BC) tumorigenesis and metastasis and differentially modulates BC cell responses to DNA-damaging agents via its dual extracellular and nuclear localization. Given the central role of telomere dysfunction to drive carcinogenesis and to alter the chemotherapeutic profile of transformed cells, we hypothesized that an unanticipated nuclear function of HRG might be to regulate telomere length. Engineered overexpression of the HRGβ2 isoform in non-aggressive, HRG-negative MCF-7 BC cells resulted in a significant shortening of telomeres (up to 1.3 kb) as measured by Southern blotting of telomere terminal restriction fragments. Conversely, antisense-mediated suppression of HRGβ2 in highly aggressive, HRG-overexpressing MDA-MB-231 and Hs578T cells increased telomere length up to 3.0 kb. HRGβ2 overexpression promoted a marked upregulation of telomere-binding protein 2 (TRF2) protein expression, whereas its knockdown profoundly decreased TRF2 expression. Double staining of endogenous HRGβ2 with telomere-specific peptide nucleic acid probe/fluorescence in situ hybridization (PNA/FISH) revealed the partial localization of HRG at the chromosome ends. Moreover, a predominantly nucleoplasmic staining pattern of endogenous HRGβ2 appeared to co-localize with TRF2 and, concomitantly with RAP1, a telomere regulator that specifically interacts with TRF2. Small interfering RNA-mediated knockdown of HRG decreased the expression of TRF2 and RAP1, decreased their presence at chromosome ends, and coincidentally resulted in the formation of longer telomeres. This study uncovers a new function for HRGβ2 in controlling telomere length, in part due to its ability to regulate and interact with the telomere-associated proteins TRF2 and RAP1.
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Affiliation(s)
- Javier A Menendez
- ProCURE (Program Against Cancer Therapeutic Resistance), Metabolism & Cancer Group, Catalan Institute of Oncology (ICO), Girona, Spain.,Girona Biomedical Research Institute (IDIBGI), Girona, Spain
| | - Miguel A Rubio
- Laboratory of Hematology Service, Institut d'Investigació Biomèdica Sant Pau, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Judith Campisi
- Lawrence Berkeley National Laboratory, Life Sciences Division, Berkeley, CA, USA.,Buck Institute for Research on Aging, Novato, CA, USA
| | - Ruth Lupu
- Mayo Clinic, Department of Laboratory Medicine and Pathology, Division of Experimental Pathology, Rochester, MN, USA.,Mayo Clinic Cancer Center, Rochester, MN, USA
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36
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Heregulin, a new interactor of the telosome/shelterin complex in human telomeres. Oncotarget 2016; 6:39408-21. [PMID: 26327598 PMCID: PMC4741835 DOI: 10.18632/oncotarget.4962] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 07/10/2015] [Indexed: 01/03/2023] Open
Abstract
Telomere length, shape and function depend on a complex of six core telomere-associated proteins referred to as the telosome or shelterin complex. We here demonstrate that the isoform β2 of the heregulin family of growth factors (HRGβ2) is a novel interactor of the telosome/shelterin complex in human telomeres. Analysis of protein-protein interactions using a high-throughput yeast two-hybrid (Y2H) screen identified RAP1, the only telomere protein that is conserved from yeasts to mammals, as a novel interacting partner of HRGβ2. Deletion analysis of RAP1 revealed that the linker domain, a region previously suggested to recruit negative regulators of telomere length, interacts specifically with HRGβ2. Co-immunoprecipitation and imaging experiments demonstrated that, in addition to RAP1, HRGβ2 could associate with the RAP1-associated telomeric repeat binding factor 2 (TRF2). Deletion analysis of HRGβ2 confirmed that a putative nuclear localization signal (NLS) was necessary for nuclear HRGβ2 to exert a negative regulation of telomere length whereas the N-terminus (extracellular) amino acids of HRGβ2 were sufficient to interact with RAP1/TRF2 and promote telomere shortening. Taken together, our studies identify nuclear HRGβ2 as one of the previously unknown regulators predicted to be recruited by the RAP1 linker domain to negatively regulate telomere length in human cells. Our current findings reveal that a new, but likely not the last, unexpected visitor has arrived to the “telosome/shelterin town”.
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Rajavel M, Orban T, Xu M, Hernandez-Sanchez W, de la Fuente M, Palczewski K, Taylor DJ. Dynamic peptides of human TPP1 fulfill diverse functions in telomere maintenance. Nucleic Acids Res 2016; 44:10467-10479. [PMID: 27655633 PMCID: PMC5137443 DOI: 10.1093/nar/gkw846] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 09/12/2016] [Accepted: 09/14/2016] [Indexed: 12/12/2022] Open
Abstract
Telomeres are specialized nucleoprotein complexes that comprise the ends of linear chromosomes. Human telomeres end in a short, single-stranded DNA (ssDNA) overhang that is recognized and bound by two telomere proteins, POT1 and TPP1. Whereas POT1 binds directly to telomere ssDNA, its interaction with TPP1 is essential for localization of POT1 to the telomere. TPP1 also provides enhanced binding and sequence discrimination that regulates POT1-TPP1 interactions exclusively with telomere ssDNA. Finally, TPP1 recruits telomerase, the enzyme responsible for synthesis of telomere DNA, to the telomere. While the oligosaccharide-oligonucleotide-binding (OB)-fold domain of TPP1 has been solved by X-ray crystallography, the molecular interactions within the POT1-TPP1-ssDNA ternary complex and the conformational changes that contribute to its diverse functions remain ambiguous. We employed hydrogen/deuterium exchange combined with mass spectrometry to identify three peptides, all residing within the OB-fold of TPP1, that exhibit altered exchange rates upon complex formation or ssDNA binding. Mutation of these regions combined with functional assays revealed the diverse contributions of each moiety in protein-protein interactions, regulating telomerase activity or DNA-binding. Together, these functional data combined with biophysical analyses and homology modeling provide a molecular understanding of the diverse contributions of TPP1 in telomere maintenance.
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Affiliation(s)
- Malligarjunan Rajavel
- Department of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Tivadar Orban
- Department of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Mengyuan Xu
- Department of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Wilnelly Hernandez-Sanchez
- Department of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Maria de la Fuente
- Department of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA .,Department of Biochemistry, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA
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Expression of Telomere Binding Proteins (RAP1 and POT1) in Renal Cell Carcinoma and Their Correlation with Clinicopathological Parameters. Indian J Clin Biochem 2016; 32:301-305. [PMID: 28811689 DOI: 10.1007/s12291-016-0611-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 08/18/2016] [Indexed: 01/20/2023]
Abstract
Telomere stability is indispensable for continuous proliferation of cells. Telomere structure is maintained by group of six proteins termed as shelterin. RAP1 and POT1 proteins are significant members of shelterin complex. Expression of RAP1 and POT1 are crucial for telomere maintenance and hence uncontrolled division of cells. Notably, expression of RAP1 and POT1 is unknown in renal cell carcinoma (RCC). In view of these facts, the present study was initiated to investigate the expression of RAP1 and POT1 in RCC and their relationships with clinicopathological features. In total 65 histopathologically confirmed RCC cases and their adjacent normal renal parenchyma were analyzed for gene expression. The mRNA expression of telomere binding proteins RAP1 and POT1 were measured using RT-PCR. Expression of RAP1 was observed to be significantly increased in tumour tissues as compared to corresponding normal renal tissues (P = 0.004). The gene expression of RAP1 was documented to be related to grades of RCC (P = 0.002) and subtypes of RCC (P = 0.01). Although, POT1 expression was up-regulated in RCC tissue, however it was not statistically significant. Also, POT1 expression was not related to grades, stages and subtypes of RCC. This is the first study which shows correlation RAP1 with grades and subtypes of RCC.
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Rybaczek D. Hydroxyurea-induced replication stress causes poly(ADP-ribose) polymerase-2 accumulation and changes its intranuclear location in root meristems of Vicia faba. JOURNAL OF PLANT PHYSIOLOGY 2016; 198:89-102. [PMID: 27155387 DOI: 10.1016/j.jplph.2016.03.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 03/29/2016] [Accepted: 03/30/2016] [Indexed: 06/05/2023]
Abstract
Replication stress induced by 24 and 48h exposure to 2.5mM hydroxyurea (HU) increased the activity of poly(ADP-ribose) polymerase-2 (PARP-2; EC 2.4.2.30) in root meristem cells of Vicia faba. An increase in the number of PARP-2 foci was accompanied by their delocalization from peripheral areas to the interior of the nucleus. Our results indicate that the increase in PARP-2 was connected with an increase in S139-phosphorylated H2AX histones. The findings suggest the possible role of PARP-2 in replication stress. We also confirm that the intranuclear location of PARP-2 depends on the duration of HU-induced replication stress, confirming the role of PARP-2 as an indicator of stress intensity. Finally, we conclude that the more intense the HU-mediated replication stress, the greater the probability of PARP-2 activation or H2AXS139 phosphorylation, but also the greater the chance of increasing the efficiency of repair processes and a return to normal cell cycle progression.
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Affiliation(s)
- Dorota Rybaczek
- Department of Cytophysiology, Institute of Experimental Biology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90236 Łódź, Poland.
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TRF2-RAP1 is required to protect telomeres from engaging in homologous recombination-mediated deletions and fusions. Nat Commun 2016; 7:10881. [PMID: 26941064 PMCID: PMC4785230 DOI: 10.1038/ncomms10881] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 01/29/2016] [Indexed: 12/27/2022] Open
Abstract
Repressor/activator protein 1 (RAP1) is a highly conserved telomere-interacting protein. Yeast Rap1 protects telomeres from non-homologous end joining (NHEJ), plays important roles in telomere length control and is involved in transcriptional gene regulation. However, a role for mammalian RAP1 in telomere end protection remains controversial. Here we present evidence that mammalian RAP1 is essential to protect telomere from homology directed repair (HDR) of telomeres. RAP1 cooperates with the basic domain of TRF2 (TRF2B) to repress PARP1 and SLX4 localization to telomeres. Without RAP1 and TRF2B, PARP1 and SLX4 HR factors promote rapid telomere resection, resulting in catastrophic telomere loss and the generation of telomere-free chromosome fusions in both mouse and human cells. The RAP1 Myb domain is required to repress both telomere loss and formation of telomere-free fusions. Our results highlight the importance of the RAP1-TRF2 heterodimer in protecting telomeres from inappropriate processing by the HDR pathway. While yeast Rap1 regulates telomere length and protects telomeres from non-homologous end joining, its role in higher eukaryotes is controversial. Here the authors present evidence that in mammals, RAP1 cooperates with TRF2 to prevent homologous recombination-mediated repair of telomeres.
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Berthelot V, Mouta-Cardoso G, Hégarat N, Guillonneau F, François JC, Giovannangeli C, Praseuth D, Rusconi F. The human DNA ends proteome uncovers an unexpected entanglement of functional pathways. Nucleic Acids Res 2016; 44:4721-33. [PMID: 26921407 PMCID: PMC4889927 DOI: 10.1093/nar/gkw121] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 02/17/2016] [Indexed: 01/06/2023] Open
Abstract
DNA ends get exposed in cells upon either normal or dysfunctional cellular processes or molecular events. Telomeres need to be protected by the shelterin complex to avoid junctions occurring between chromosomes while failing topoisomerases or clustered DNA damage processing may produce double-strand breaks, thus requiring swift repair to avoid cell death. The rigorous study of the great many proteins involved in the maintenance of DNA integrity is a challenging task because of the innumerous unspecific electrostatic and/or hydrophobic DNA—protein interactions that arise due to the chemical nature of DNA. We devised a technique that discriminates the proteins recruited specifically at DNA ends from those that bind to DNA because of a generic affinity for the double helix. Our study shows that the DNA ends proteome comprises proteins of an unexpectedly wide functional spectrum, ranging from DNA repair to ribosome biogenesis and cytoskeleton, including novel proteins of undocumented function. A global mapping of the identified proteome on published DNA repair protein networks demonstrated the excellent specificity and functional coverage of our purification technique. Finally, the native nucleoproteic complexes that assembled specifically onto DNA ends were shown to be endowed with a highly efficient DNA repair activity.
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Affiliation(s)
- Vivien Berthelot
- Laboratoire de chimie physique, UMR CNRS 8000, University of Paris-Sud, F-91400 Orsay, France
| | - Gildas Mouta-Cardoso
- Structure et Instabilité des Génomes, INSERM U1154, UMR CNRS/MNHN 7196, F-75005 Paris, France
| | - Nadia Hégarat
- Structure et Instabilité des Génomes, INSERM U1154, UMR CNRS/MNHN 7196, F-75005 Paris, France
| | - François Guillonneau
- Plateforme de spectrométrie de masse 3P5, Institut Cochin, F-75014 Paris, France
| | - Jean-Christophe François
- Inserm and Sorbonne Universities, UPMC, UMR_S 938, Research Center Saint-Antoine, F-75012 Paris, France
| | - Carine Giovannangeli
- Structure et Instabilité des Génomes, INSERM U1154, UMR CNRS/MNHN 7196, F-75005 Paris, France
| | - Danièle Praseuth
- Structure et Instabilité des Génomes, INSERM U1154, UMR CNRS/MNHN 7196, F-75005 Paris, France
| | - Filippo Rusconi
- Laboratoire de chimie physique, UMR CNRS 8000, University of Paris-Sud, F-91400 Orsay, France
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Lustig AJ. Hypothesis: Paralog Formation from Progenitor Proteins and Paralog Mutagenesis Spur the Rapid Evolution of Telomere Binding Proteins. Front Genet 2016; 7:10. [PMID: 26904098 PMCID: PMC4748036 DOI: 10.3389/fgene.2016.00010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 01/22/2016] [Indexed: 12/31/2022] Open
Abstract
Through elegant studies in fungal cells and complex organisms, we propose a unifying paradigm for the rapid evolution of telomere binding proteins (TBPs) that associate with either (or both) telomeric DNA and telomeric proteins. TBPs protect and regulate telomere structure and function. Four critical factors are involved. First, TBPs that commonly bind to telomeric DNA include the c-Myb binding proteins, OB-fold single-stranded binding proteins, and G-G base paired Hoogsteen structure (G4) binding proteins. Each contributes independently or, in some cases, cooperatively, to provide a minimum level of telomere function. As a result of these minimal requirements and the great abundance of homologs of these motifs in the proteome, DNA telomere-binding activity may be generated more easily than expected. Second, telomere dysfunction gives rise to genome instability, through the elevation of recombination rates, genome ploidy, and the frequency of gene mutations. The formation of paralogs that diverge from their progenitor proteins ultimately can form a high frequency of altered TBPs with altered functions. Third, TBPs that assemble into complexes (e.g., mammalian shelterin) derive benefits from the novel emergent functions. Fourth, a limiting factor in the evolution of TBP complexes is the formation of mutually compatible interaction surfaces amongst the TBPs. These factors may have different degrees of importance in the evolution of different phyla, illustrated by the apparently simpler telomeres in complex plants. Selective pressures that can utilize the mechanisms of paralog formation and mutagenesis to drive TBP evolution along routes dependent on the requisite physiologic changes.
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Affiliation(s)
- Arthur J Lustig
- Department of Biochemistry and Molecular Biology, Tulane University, New Orleans LA, USA
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Design of High-Affinity Stapled Peptides To Target the Repressor Activator Protein 1 (RAP1)/Telomeric Repeat-Binding Factor 2 (TRF2) Protein-Protein Interaction in the Shelterin Complex. J Med Chem 2015; 59:328-34. [PMID: 26673461 DOI: 10.1021/acs.jmedchem.5b01465] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Shelterin, a six-protein complex, plays a fundamental role in protecting both the length and the stability of telomeres. Repressor activator protein 1 (RAP1) and telomeric repeat-binding factor 2 (TRF2) are two subunits in shelterin that interact with each other. Small-molecule inhibitors that block the RAP1/TRF2 protein-protein interaction can disrupt the structure of shelterin and may be employed as pharmacological tools to investigate the biology of shelterin. On the basis of the cocrystal structure of RAP1/TRF2 complex, we have developed first-in-class triazole-stapled peptides that block the protein-protein interaction between RAP1 and TRF2. Our most potent stapled peptide binds to RAP1 protein with a Ki value of 7 nM and is >100 times more potent than the corresponding wild-type TRF2 peptide. On the basis of our high-affinity peptides, we have developed and optimized a competitive, fluorescence polarization (FP) assay for accurate and rapid determination of the binding affinities of our designed compounds and this assay may also assist in the discovery of non-peptide, small-molecule inhibitors capable of blocking the RAP1/TRF2 protein-protein interaction.
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Telomere length and recurrence risk after curative resection in patients with early-stage non-small-cell lung cancer: a prospective cohort study. J Thorac Oncol 2015; 10:302-8. [PMID: 25299235 DOI: 10.1097/jto.0000000000000398] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND We hypothesized that telomere length in peripheral blood would have significant predictive value for risk of recurrence after curative resection in non-small-cell lung cancer (NSCLC). METHODS This prospective study included 473 patients with histologically confirmed early stage NSCLC who underwent curative therapy at MD Anderson Cancer Center between 1995 and 2008. Relative telomere length (RTL) of peripheral leukocytes was measured by real-time polymerase chain reaction. The risk of recurrence was estimated as hazard ratios (HRs) and 95% confidence intervals (CIs) using a multivariable Cox proportional hazard regression model. RESULTS Median duration of follow-up was 61 months, and 151 patients (32%) had developed recurrence at time of analysis. Patients who developed recurrence had significantly longer mean RTL compared with those without recurrence (1.13 versus 1.07, p = 0.046). A subgroup analysis indicates that women had longer RTL compared with men (1.12 versus 1.06, p = 0.025), and the patients with adenocarcinoma demonstrated longer RTL compared with those with other histologic types (1.11 versus 1.05, p = 0.042). To determine whether longer RTL in women and adenocarcinoma subgroup would predict risk of recurrence, multivariate Cox analysis adjusting for age, sex, stage, pack year and treatment regimens was performed. Longer telomeres were significantly associated with higher risk of developing recurrence in women (hazard ratio [HR], 2.25; 95% confidence interval [CI], 1.02-4.96, p = 0.044) and adenocarcinoma subgroups (HR, 2.19; 95% CI, 1.05-4.55, p = 0.036). The increased risk of recurrence due to long RTL was more apparent in women with adenocarcinoma (HR, 2.67; 95% CI, 1.19-6.03, p = 0.018). CONCLUSIONS This is the first prospective study to suggest that long RTL is associated with recurrence in early stage NSCLC after curative resection. Women and adenocarcinoma seem to be special subgroups in which telomere biology may play an important role.
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Lee K, Gollahon LS. ZSCAN4 and TRF1: A functionally indirect interaction in cancer cells independent of telomerase activity. Biochem Biophys Res Commun 2015; 466:644-9. [PMID: 26403970 DOI: 10.1016/j.bbrc.2015.09.107] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 09/19/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE Recently, the newly identified embryonic stem cell marker, Zinc finger and SCAN domain containing 4 gene (ZSCAN4), which plays a key role in genomic stability by regulating telomere elongation, was shown to co-localize with TRF1 foci. This suggests that the interaction of ZSCAN4 with TRF1 functions in regulation of telomere elongation in ESC. Based on these studies, we hypothesized that ZSCAN4 binds to TRF1 in cancer cells to function in regulating telomere length. The purpose of this study was to determine whether this interaction occurred across different cell lineage-derived cancers and whether telomerase status impacted this relationship. To that end, telomerase positive cervical cancer cells (HeLa) and breast cancer cells (MCF7), and telomerase negative osteosarcoma cells (SaOS2), were analyzed for ZSCAN4 and TRF1 interactions. RESULTS Immunocytochemistry demonstrated co-localization of ZSCAN4 and TRF1 to the nucleus. This functional relationship was confirmed using BiFC imaging analysis based on distance in situ. Co-immunoprecipitation and pull-down assay results demonstrated that ZSCAN4 binds with TRF1 in vitro indirectly. All three cell types showed similar results. CONCLUSIONS In this study, we revealed, for the first time, that ZSCAN4 indirectly interacts with TRF1 (functional association protein) in cancer cells. Furthermore, we show that ZSCAN4 plays an important role independent of telomere maintenance pathways (telomerase positive and ALT) or cell lineage.
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Affiliation(s)
- Kyungwoo Lee
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA.
| | - Lauren S Gollahon
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA; Texas Tech University Imaging Center, Lubbock, TX, 79409, USA.
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RecQ helicases and PARP1 team up in maintaining genome integrity. Ageing Res Rev 2015; 23:12-28. [PMID: 25555679 DOI: 10.1016/j.arr.2014.12.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Revised: 12/18/2014] [Accepted: 12/22/2014] [Indexed: 01/04/2023]
Abstract
Genome instability represents a primary hallmark of aging and cancer. RecQL helicases (i.e., RECQL1, WRN, BLM, RECQL4, RECQL5) as well as poly(ADP-ribose) polymerases (PARPs, in particular PARP1) represent two central quality control systems to preserve genome integrity in mammalian cells. Consistently, both enzymatic families have been linked to mechanisms of aging and carcinogenesis in mice and humans. This is in accordance with clinical and epidemiological findings demonstrating that defects in three RecQL helicases, i.e., WRN, BLM, RECQL4, are related to human progeroid and cancer predisposition syndromes, i.e., Werner, Bloom, and Rothmund Thomson syndrome, respectively. Moreover, PARP1 hypomorphy is associated with a higher risk for certain types of cancer. On a molecular level, RecQL helicases and PARP1 are involved in the control of DNA repair, telomere maintenance, and replicative stress. Notably, over the last decade, it became apparent that all five RecQL helicases physically or functionally interact with PARP1 and/or its enzymatic product poly(ADP-ribose) (PAR). Furthermore, a profound body of evidence revealed that the cooperative function of RECQLs and PARP1 represents an important factor for maintaining genome integrity. In this review, we summarize the status quo of this molecular cooperation and discuss open questions that provide a basis for future studies to dissect the cooperative functions of RecQL helicases and PARP1 in aging and carcinogenesis.
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Robles-Espinoza CD, Velasco-Herrera MDC, Hayward NK, Adams DJ. Telomere-regulating genes and the telomere interactome in familial cancers. Mol Cancer Res 2015; 13:211-22. [PMID: 25244922 PMCID: PMC4278843 DOI: 10.1158/1541-7786.mcr-14-0305] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Telomeres are repetitive sequence structures at the ends of linear chromosomes that consist of double-stranded DNA repeats followed by a short single-stranded DNA protrusion. Telomeres need to be replicated in each cell cycle and protected from DNA-processing enzymes, tasks that cells execute using specialized protein complexes such as telomerase (that includes TERT), which aids in telomere maintenance and replication, and the shelterin complex, which protects chromosome ends. These complexes are also able to interact with a variety of other proteins, referred to as the telomere interactome, to fulfill their biological functions and control signaling cascades originating from telomeres. Given their essential role in genomic maintenance and cell-cycle control, germline mutations in telomere-regulating proteins and their interacting partners have been found to underlie a variety of diseases and cancer-predisposition syndromes. These syndromes can be characterized by progressively shortening telomeres, in which carriers can present with organ failure due to stem cell senescence among other characteristics, or can also present with long or unprotected telomeres, providing an alternative route for cancer formation. This review summarizes the critical roles that telomere-regulating proteins play in cell-cycle control and cell fate and explores the current knowledge on different cancer-predisposing conditions that have been linked to germline defects in these proteins and their interacting partners.
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Affiliation(s)
| | | | - Nicholas K Hayward
- Oncogenomics Laboratory, QIMR Berghofer Medical Research Institute, Herston, Brisbane, Queensland, Australia
| | - David J Adams
- Experimental Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
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Kabir S, Hockemeyer D, de Lange T. TALEN gene knockouts reveal no requirement for the conserved human shelterin protein Rap1 in telomere protection and length regulation. Cell Rep 2014; 9:1273-80. [PMID: 25453752 DOI: 10.1016/j.celrep.2014.10.014] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/02/2014] [Accepted: 10/03/2014] [Indexed: 10/24/2022] Open
Abstract
The conserved protein Rap1 functions at telomeres in fungi, protozoa, and vertebrates. Like yeast Rap1, human Rap1 has been implicated in telomere length regulation and repression of nonhomologous end-joining (NHEJ) at telomeres. However, mouse telomeres lacking Rap1 do not succumb to NHEJ. To determine the functions of human Rap1, we generated several transcription activator-like effector nuclease (TALEN)-mediated human cell lines lacking Rap1. Loss of Rap1 did not affect the other components of shelterin, the modification of telomeric histones, the subnuclear position of telomeres, or the 3' telomeric overhang. Telomeres lacking Rap1 did not show a DNA damage response, NHEJ, or consistent changes in their length, indicating that Rap1 does not have an important function in protection or length regulation of human telomeres. As human Rap1, like its mouse and unicellular orthologs, affects gene expression, we propose that the conservation of Rap1 reflects its role in transcriptional regulation rather than a function at telomeres.
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Affiliation(s)
- Shaheen Kabir
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY 10065, USA
| | - Dirk Hockemeyer
- Department of Molecular and Cellular Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY 10065, USA.
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Bosch-Presegué L, Vaquero A. Sirtuin-dependent epigenetic regulation in the maintenance of genome integrity. FEBS J 2014; 282:1745-67. [DOI: 10.1111/febs.13053] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 09/09/2014] [Accepted: 09/12/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Laia Bosch-Presegué
- Chromatin Biology Laboratory; Cancer Epigenetics and Biology Program; Institut d'Investigació Biomèdica de Bellvitge; Barcelona Spain
| | - Alejandro Vaquero
- Chromatin Biology Laboratory; Cancer Epigenetics and Biology Program; Institut d'Investigació Biomèdica de Bellvitge; Barcelona Spain
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The Ku heterodimer: function in DNA repair and beyond. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2014; 763:15-29. [PMID: 25795113 DOI: 10.1016/j.mrrev.2014.06.002] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/07/2014] [Accepted: 06/25/2014] [Indexed: 01/11/2023]
Abstract
Ku is an abundant, highly conserved DNA binding protein found in both prokaryotes and eukaryotes that plays essential roles in the maintenance of genome integrity. In eukaryotes, Ku is a heterodimer comprised of two subunits, Ku70 and Ku80, that is best characterized for its central role as the initial DNA end binding factor in the "classical" non-homologous end joining (C-NHEJ) pathway, the main DNA double-strand break (DSB) repair pathway in mammals. Ku binds double-stranded DNA ends with high affinity in a sequence-independent manner through a central ring formed by the intertwined strands of the Ku70 and Ku80 subunits. At the break, Ku directly and indirectly interacts with several C-NHEJ factors and processing enzymes, serving as the scaffold for the entire DNA repair complex. There is also evidence that Ku is involved in signaling to the DNA damage response (DDR) machinery to modulate the activation of cell cycle checkpoints and the activation of apoptosis. Interestingly, Ku is also associated with telomeres, where, paradoxically to its DNA end-joining functions, it protects the telomere ends from being recognized as DSBs, thereby preventing their recombination and degradation. Ku, together with the silent information regulator (Sir) complex is also required for transcriptional silencing through telomere position effect (TPE). How Ku associates with telomeres, whether it is through direct DNA binding, or through protein-protein interactions with other telomere bound factors remains to be determined. Ku is central to the protection of organisms through its participation in C-NHEJ to repair DSBs generated during V(D)J recombination, a process that is indispensable for the establishment of the immune response. Ku also functions to prevent tumorigenesis and senescence since Ku-deficient mice show increased cancer incidence and early onset of aging. Overall, Ku function is critical to the maintenance of genomic integrity and to proper cellular and organismal development.
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