1
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Yasukawa M, Ando Y, Yamashita T, Matsuda Y, Shoji S, Morioka MS, Kawaji H, Shiozawa K, Machitani M, Abe T, Yamada S, Kaneko MK, Kato Y, Furuta Y, Kondo T, Shirouzu M, Hayashizaki Y, Kaneko S, Masutomi K. CDK1 dependent phosphorylation of hTERT contributes to cancer progression. Nat Commun 2020; 11:1557. [PMID: 32214089 PMCID: PMC7096428 DOI: 10.1038/s41467-020-15289-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 03/03/2020] [Indexed: 12/24/2022] Open
Abstract
The telomerase reverse transcriptase is upregulated in the majority of human cancers and contributes directly to cell transformation. Here we report that hTERT is phosphorylated at threonine 249 during mitosis by the serine/threonine kinase CDK1. Clinicopathological analyses reveal that phosphorylation of hTERT at threonine 249 occurs more frequently in aggressive cancers. Using CRISPR/Cas9 genome editing, we introduce substitution mutations at threonine 249 in the endogenous hTERT locus and find that phosphorylation of threonine 249 is necessary for hTERT-mediated RNA dependent RNA polymerase (RdRP) activity but dispensable for reverse transcriptase and terminal transferase activities. Cap Analysis of Gene Expression (CAGE) demonstrates that hTERT phosphorylation at 249 regulates the expression of specific genes that are necessary for cancer cell proliferation and tumor formation. These observations indicate that phosphorylation at threonine 249 regulates hTERT RdRP and contributes to cancer progression in a telomere independent manner. Regulated telomerase reverse transcriptase (hTERT) activity is common in human tumors. Here, the authors show that hTERT is phosphorylated by CDK1 and that this event is necessary for hTERT-mediated RNA dependent RNA polymerase activity but not for reverse transcriptase and terminal transferase activities.
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Affiliation(s)
- Mami Yasukawa
- Division of Cancer Stem Cell, National Cancer Center Research Institute, Tokyo, 104-0045, Japan
| | - Yoshinari Ando
- Division of Cancer Stem Cell, National Cancer Center Research Institute, Tokyo, 104-0045, Japan
| | - Taro Yamashita
- Department of Gastroenterology, Kanazawa University Graduate School of Medical Science, Kanazawa, 920-8641, Japan
| | - Yoko Matsuda
- Department of Pathology, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, 173-0015, Japan.,Oncology Pathology, Department of Pathology and Host-Defense, Kagawa University, Kagawa, 761-0793, Japan
| | - Shisako Shoji
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, 230-0045, Japan
| | - Masaki Suimye Morioka
- Preventive Medicine and Applied Genomics Unit, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan
| | - Hideya Kawaji
- Preventive Medicine and Applied Genomics Unit, RIKEN Center for Integrative Medical Sciences, Yokohama, 230-0045, Japan.,RIKEN Preventive Medicine and Diagnosis Innovation Program, Wako, 351-0198, Japan
| | - Kumiko Shiozawa
- Division of Rare Cancer Research, National Cancer Center Research Institute, Tokyo, 104-0045, Japan
| | - Mitsuhiro Machitani
- Division of Cancer Stem Cell, National Cancer Center Research Institute, Tokyo, 104-0045, Japan
| | - Takaya Abe
- Animal Resource Development Unit, RIKEN Center for Life Science Technologies, Kobe, 650-0047, Japan.,Genetic Engineering Team, RIKEN Center for Life Science Technologies, Kobe, 650-0047, Japan
| | - Shinji Yamada
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Mika K Kaneko
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan
| | - Yukinari Kato
- Department of Antibody Drug Development, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan.,New Industry Creation Hatchery Center, Tohoku University, Sendai, 980-8579, Japan
| | - Yasuhide Furuta
- Animal Resource Development Unit, RIKEN Center for Life Science Technologies, Kobe, 650-0047, Japan.,Genetic Engineering Team, RIKEN Center for Life Science Technologies, Kobe, 650-0047, Japan
| | - Tadashi Kondo
- Division of Rare Cancer Research, National Cancer Center Research Institute, Tokyo, 104-0045, Japan
| | - Mikako Shirouzu
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, 230-0045, Japan
| | | | - Shuichi Kaneko
- Department of Gastroenterology, Kanazawa University Graduate School of Medical Science, Kanazawa, 920-8641, Japan
| | - Kenkichi Masutomi
- Division of Cancer Stem Cell, National Cancer Center Research Institute, Tokyo, 104-0045, Japan.
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2
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Shintomi K, Inoue F, Watanabe H, Ohsumi K, Ohsugi M, Hirano T. Mitotic chromosome assembly despite nucleosome depletion in Xenopus egg extracts. Science 2017; 356:1284-1287. [PMID: 28522692 DOI: 10.1126/science.aam9702] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 05/08/2017] [Indexed: 12/23/2022]
Abstract
The nucleosome is the fundamental structural unit of eukaryotic chromatin. During mitosis, duplicated nucleosome fibers are organized into a pair of rod-shaped structures (chromatids) within a mitotic chromosome. However, it remains unclear whether nucleosome assembly is indeed an essential prerequisite for mitotic chromosome assembly. We combined mouse sperm nuclei and Xenopus cell-free egg extracts depleted of the histone chaperone Asf1 and found that chromatid-like structures could be assembled even in the near absence of nucleosomes. The resultant "nucleosome-depleted" chromatids contained discrete central axes positive for condensins, although they were more fragile than normal nucleosome-containing chromatids. Combinatorial depletion experiments underscored the central importance of condensins in mitotic chromosome assembly, which sheds light on their functional cross-talk with nucleosomes in this process.
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Affiliation(s)
- Keishi Shintomi
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Fukashi Inoue
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan.,TAK-Circulator Corporation, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiroshi Watanabe
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Keita Ohsumi
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
| | - Miho Ohsugi
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Tatsuya Hirano
- Chromosome Dynamics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan.
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3
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Kappei D, Scheibe M, Paszkowski-Rogacz M, Bluhm A, Gossmann TI, Dietz S, Dejung M, Herlyn H, Buchholz F, Mann M, Butter F. Phylointeractomics reconstructs functional evolution of protein binding. Nat Commun 2017; 8:14334. [PMID: 28176777 PMCID: PMC5309834 DOI: 10.1038/ncomms14334] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 12/16/2016] [Indexed: 12/27/2022] Open
Abstract
Molecular phylogenomics investigates evolutionary relationships based on genomic data. However, despite genomic sequence conservation, changes in protein interactions can occur relatively rapidly and may cause strong functional diversification. To investigate such functional evolution, we here combine phylogenomics with interaction proteomics. We develop this concept by investigating the molecular evolution of the shelterin complex, which protects telomeres, across 16 vertebrate species from zebrafish to humans covering 450 million years of evolution. Our phylointeractomics screen discovers previously unknown telomere-associated proteins and reveals how homologous proteins undergo functional evolution. For instance, we show that TERF1 evolved as a telomere-binding protein in the common stem lineage of marsupial and placental mammals. Phylointeractomics is a versatile and scalable approach to investigate evolutionary changes in protein function and thus can provide experimental evidence for phylogenomic relationships.
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Affiliation(s)
- Dennis Kappei
- Cancer Science Institute of Singapore, National University of Singapore, 14 Medical Drive, Singapore 117599, Singapore.,Medical Systems Biology, UCC, University Hospital and Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstraße 74, Dresden D-01307, Germany
| | - Marion Scheibe
- Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, Mainz D-55128, Germany.,Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried D-82152, Germany
| | - Maciej Paszkowski-Rogacz
- Medical Systems Biology, UCC, University Hospital and Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstraße 74, Dresden D-01307, Germany
| | - Alina Bluhm
- Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, Mainz D-55128, Germany
| | - Toni Ingolf Gossmann
- Department of Animal &Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Sabrina Dietz
- Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, Mainz D-55128, Germany
| | - Mario Dejung
- Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, Mainz D-55128, Germany
| | - Holger Herlyn
- Institute of Anthropology, University of Mainz, Anselm-Franz-von-Bentzel-Weg 7, Mainz D-55099, Germany
| | - Frank Buchholz
- Medical Systems Biology, UCC, University Hospital and Medical Faculty Carl Gustav Carus, TU Dresden, Fetscherstraße 74, Dresden D-01307, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, Dresden D-01307, Germany.,German Cancer Research Center (DKFZ), Neuenheimer Feld 280, 69120 Heidelberg, Germany.,German Cancer Consortium (DKTK) partner site, Fetscherstr. 74, 01307 Dresden Germany.,National Center for Tumor Diseases (NCT), University Hospital Carl Gustav Carus, TU Dresden, Dresden D-01307, Germany
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Am Klopferspitz 18, Martinsried D-82152, Germany
| | - Falk Butter
- Institute of Molecular Biology (IMB) gGmbH, Ackermannweg 4, Mainz D-55128, Germany
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4
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Lan J, Zhu Y, Xu L, Yu H, Yu J, Liu X, Fu C, Wang X, Ke Y, Huang H, Dou Z. The 68-kDa telomeric repeat binding factor 1 (TRF1)-associated protein (TAP68) interacts with and recruits TRF1 to the spindle pole during mitosis. J Biol Chem 2014; 289:14145-56. [PMID: 24692559 PMCID: PMC4022882 DOI: 10.1074/jbc.m113.526244] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 03/20/2014] [Indexed: 01/19/2023] Open
Abstract
The telomere capping protein TRF1 is a component of the multiprotein complex "shelterin," which organizes the telomere into a high order structure. Besides telomere maintenance, telomere-associated proteins also have nontelomeric functions. For example, tankyrase 1 and TRF1 are required for the maintenance of faithful mitotic progression. However, the functional relevance of their centrosomal localization has not been established. Here, we report the identification of a TRF1-binding protein, TAP68, that interacts with TRF1 in mitotic cells. TAP68 contains two coiled-coil domains and a structural maintenance of chromosome motifs and co-localizes with TRF1 to telomeres during interphase. Immediately after nuclear envelope breakdown, TAP68 translocates toward the spindle poles followed by TRF1. Dissociation of TAP68 from the telomere is concurrent with the Nek2A-dependent phosphorylation at Thr-221. Biochemical characterization demonstrated that the first coiled-coil domain of TAP68 binds and recruits TRF1 to the centrosome. Inhibition of TAP68 expression by siRNA blocked the localization of TRF1 and tankyrase 1 to the centrosome. Furthermore, siRNA-mediated depletion of TAP68 perturbed faithful chromosome segregation and genomic stability. These findings suggest that TAP68 functions in mediating TRF1-tankyrase 1 localization to the centrosome and in mitotic regulation.
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Affiliation(s)
- Jianping Lan
- From the Department of Hematology and Hematopoietic Stem Cell Transplant Center, Zhejiang Provincial People's Hospital, Hangzhou 310014
| | - Yuanyuan Zhu
- the Department of Hematology and Bone Marrow Transplant Center, 1st Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, and
| | - Leilei Xu
- the Anhui Key Laboratory of Cellular Dynamics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230027, China
| | - Huijuan Yu
- the Anhui Key Laboratory of Cellular Dynamics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230027, China
| | - Jian Yu
- the Department of Hematology and Bone Marrow Transplant Center, 1st Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, and
| | - Xing Liu
- the Anhui Key Laboratory of Cellular Dynamics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230027, China
| | - Chuanhai Fu
- the Anhui Key Laboratory of Cellular Dynamics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230027, China
| | - Xiaogang Wang
- From the Department of Hematology and Hematopoietic Stem Cell Transplant Center, Zhejiang Provincial People's Hospital, Hangzhou 310014
| | - Yuwen Ke
- the Anhui Key Laboratory of Cellular Dynamics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230027, China
| | - He Huang
- the Department of Hematology and Bone Marrow Transplant Center, 1st Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, and
| | - Zhen Dou
- the Anhui Key Laboratory of Cellular Dynamics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei 230027, China
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5
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Lisaingo K, Uringa EJ, Lansdorp PM. Resolution of telomere associations by TRF1 cleavage in mouse embryonic stem cells. Mol Biol Cell 2014; 25:1958-68. [PMID: 24829382 PMCID: PMC4072570 DOI: 10.1091/mbc.e13-10-0564] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Telomere associations have been observed during key cellular processes such as mitosis, meiosis, and carcinogenesis and must be resolved before cell division to prevent genome instability. Here we establish that telomeric repeat-binding factor 1 (TRF1), a core component of the telomere protein complex, is a mediator of telomere associations in mammalian cells. Using live-cell imaging, we show that expression of TRF1 or yellow fluorescent protein (YFP)-TRF1 fusion protein above endogenous levels prevents proper telomere resolution during mitosis. TRF1 overexpression results in telomere anaphase bridges and aggregates containing TRF1 protein and telomeric DNA. Site-specific protein cleavage of YFP-TRF1 by tobacco etch virus protease resolves telomere aggregates, indicating that telomere associations are mediated by TRF1. This study provides novel insight into the formation and resolution of telomere associations.
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Affiliation(s)
- Kathleen Lisaingo
- Terry Fox Laboratory, BC Cancer Research Centre, University of British Columbia, Vancouver, BC V5Z 1L3, Canada
| | - Evert-Jan Uringa
- Terry Fox Laboratory, BC Cancer Research Centre, University of British Columbia, Vancouver, BC V5Z 1L3, CanadaEuropean Research Institute for the Biology of Ageing, University of Groningen, University Medical CentreGroningen, NL-9713 AV Groningen, Netherlands
| | - Peter M Lansdorp
- Terry Fox Laboratory, BC Cancer Research Centre, University of British Columbia, Vancouver, BC V5Z 1L3, CanadaEuropean Research Institute for the Biology of Ageing, University of Groningen, University Medical CentreGroningen, NL-9713 AV Groningen, Netherlands
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6
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Involvement of telomerase reverse transcriptase in heterochromatin maintenance. Mol Cell Biol 2014; 34:1576-93. [PMID: 24550003 DOI: 10.1128/mcb.00093-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
In the fission yeast Schizosaccharomyces pombe, centromeric heterochromatin is maintained by an RNA-directed RNA polymerase complex (RDRC) and the RNA-induced transcriptional silencing (RITS) complex in a manner that depends on the generation of short interfering RNA. In association with the telomerase RNA component (TERC), the telomerase reverse transcriptase (TERT) forms telomerase and counteracts telomere attrition, and without TERC, TERT has been implicated in the regulation of heterochromatin at locations distinct from telomeres. Here, we describe a complex composed of human TERT (hTERT), Brahma-related gene 1 (BRG1), and nucleostemin (NS) that contributes to heterochromatin maintenance at centromeres and transposons. This complex produced double-stranded RNAs homologous to centromeric alpha-satellite (alphoid) repeat elements and transposons that were processed into small interfering RNAs targeted to these heterochromatic regions. These small interfering RNAs promoted heterochromatin assembly and mitotic progression in a manner dependent on the RNA interference machinery. These observations implicate the hTERT/BRG1/NS (TBN) complex in heterochromatin assembly at particular sites in the mammalian genome.
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7
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Walker JR, Zhu XD. Post-translational modifications of TRF1 and TRF2 and their roles in telomere maintenance. Mech Ageing Dev 2012; 133:421-34. [PMID: 22634377 DOI: 10.1016/j.mad.2012.05.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 04/27/2012] [Accepted: 05/04/2012] [Indexed: 11/29/2022]
Abstract
Telomeres, heterochromatic structures, found at the ends of linear eukaryotic chromosomes, function to protect natural chromosome ends from nucleolytic attack. Human telomeric DNA is bound by a telomere-specific six-subunit protein complex, termed shelterin/telosome. The shelterin subunits TRF1 and TRF2 bind in a sequence-specific manner to double-stranded telomeric DNA, providing a vital platform for recruitment of additional shelterin proteins as well as non-shelterin factors crucial for the maintenance of telomere length and structure. Both TRF1 and TRF2 are engaged in multiple roles at telomeres including telomere protection, telomere replication, sister telomere resolution and telomere length maintenance. Regulation of TRF1 and TRF2 in these various processes is controlled by post-translational modifications, at times in a cell-cycle-dependent manner, affecting key functions such as DNA binding, dimerization, localization, degradation and interactions with other proteins. Here we review the post-translational modifications of TRF1 and TRF2 and discuss the mechanisms by which these modifications contribute to the function of these two proteins.
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Affiliation(s)
- John R Walker
- Department of Biology, LSB438, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
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8
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Peuscher MH, Jacobs JJL. Posttranslational control of telomere maintenance and the telomere damage response. Cell Cycle 2012; 11:1524-34. [PMID: 22433952 DOI: 10.4161/cc.19847] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Telomeres help maintain genome integrity by protecting natural chromosome ends from being recognized as damaged DNA. When telomeres become dysfunctional, they limit replicative lifespan and prevent outgrowth of potentially cancerous cells by activating a DNA damage response that forces cells into senescence or apoptosis. On the other hand, chromosome ends devoid of proper telomere protection are subject to DNA repair activities that cause end-to-end fusions and, when cells divide, extensive genomic instability that can promote cancer. While telomeres represent unique chromatin structures with important roles in cancer and aging, we have limited understanding of the way telomeres and the response to their malfunction are controlled at the level of chromatin. Accumulating evidence indicates that different types of posttranslational modifications act in both telomere maintenance and the response to telomere uncapping. Here, we discuss the latest insights on posttranslational control of telomeric chromatin, with emphasis on ubiquitylation and SUMOylation events.
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Affiliation(s)
- Marieke H Peuscher
- Division of Molecular Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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9
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Muraki K, Nabetani A, Nishiyama A, Ishikawa F. Essential roles of Xenopus TRF2 in telomere end protection and replication. Genes Cells 2011; 16:728-39. [DOI: 10.1111/j.1365-2443.2011.01520.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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10
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Wang C, Yu J, Yuan K, Lan J, Jin C, Huang H. Plk1-mediated mitotic phosphorylation of PinX1 regulates its stability. Eur J Cell Biol 2010; 89:748-56. [PMID: 20573420 DOI: 10.1016/j.ejcb.2010.05.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 05/11/2010] [Accepted: 05/18/2010] [Indexed: 02/05/2023] Open
Abstract
PinX1 was originally identified as a Pin2/TRF1-interacting protein that suppresses telomerase activity via its telomerase inhibitor domain (TID) and regulates the nucleolar localization of TRF1 in telomerase-positive cells. In addition to its telomeric localization, PinX1 can be found in the nucleoli of human cells. Our recent studies have shown that PinX1 localizes to the chromosome periphery and kinetochores in mitosis. Depletion of PinX1 results in lagging chromosomes in mitosis and micronuclei in interphase. However, less is known about the post-translational modification of PinX1 in mitosis. Here, we show that Polo-like kinase 1 (Plk1) is a novel interacting protein of PinX1. Plk1 interacts with and phosphorylates PinX1 in vivo and in vitro. Overexpression of Plk1 promotes protein turnover of PinX1, a process that depends on ubiquitin-associated proteasomal degradation. Depletion of Plk1 using siRNA increases the stability of PinX1 at protein level in mitosis. Moreover, Plk1-mediated phosphorylation of PinX1 at five phosphorylation sites is essential for its Plk1-induced degradation. These findings suggest that Plk1 may negatively regulate the stability of PinX1 by mitotic phosphorylation.
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Affiliation(s)
- Chong Wang
- The First Affiliated Hospital of Zhejiang University Medical School, Hangzhou 310003, China
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11
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Wawrousek KE, Fortini BK, Polaczek P, Chen L, Liu Q, Dunphy WG, Campbell JL. Xenopus DNA2 is a helicase/nuclease that is found in complexes with replication proteins And-1/Ctf4 and Mcm10 and DSB response proteins Nbs1 and ATM. Cell Cycle 2010; 9:1156-66. [PMID: 20237432 DOI: 10.4161/cc.9.6.11049] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We have used the Xenopus laevis egg extract system to study the roles of vertebrate Dna2 in DNA replication and double-strand-break (DSB) repair. We first establish that Xenopus Dna2 is a helicase, as well as a nuclease. We further show that Dna2 is a nuclear protein that is actively recruited to DNA only after replication origin licensing. Dna2 co-localizes in foci with RPA and is found in a complex with replication fork components And-1 and Mcm10. Dna2 interacts with the DSB repair and checkpoint proteins Nbs1 and ATM. We also determine the order of arrival of ATM, MRN, Dna2, TopBP1, and RPA to duplex DNA ends and show that it is the same both in S phase and M phase extracts. Interestingly, Dna2 can bind to DNA ends independently of MRN, but efficient nucleolytic resection, as measured by RPA recruitment, requires both MRN and Dna2. The nuclease activity of Mre11 is required, since its inhibition delays both full Dna2 recruitment and resection. Dna2 depletion inhibits but does not block resection, and Chk1 and Chk2 induction occurs in the absence of Dna2.
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Affiliation(s)
- Karen E Wawrousek
- Division of Biology, California Institute of Technology, Pasadena, CA, USA
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12
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Kurth I, Gautier J. Origin-dependent initiation of DNA replication within telomeric sequences. Nucleic Acids Res 2009; 38:467-76. [PMID: 19906732 PMCID: PMC2811021 DOI: 10.1093/nar/gkp929] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Replication of telomeres requires the action of telomerase, the semi-conservative replication machinery and the stabilization of the replication fork during passage through telomeric DNA. Whether vertebrate telomeres support initiation of replication has not been experimentally addressed. Using Xenopus cell free extracts we established a system to study replication initiation within linear telomeric DNA substrates. We show binding of TRF2 to telomeric DNA, indicating that exogenous DNA exclusively composed of telomeric repeats is recognized by shelterin components. Interaction with telomere binding proteins is not sufficient to prevent a DNA damage response. Notably, we observe regulated assembly of the pre-replicative complex proteins ORC2, MCM6 and Cdc6 to telomeric DNA. Most importantly, we detect origin-dependent replication of telomeric substrates under conditions that inhibit checkpoint activation. These results indicate that pre-replicative complexes assemble within telomeric DNA and can be converted into functional origins.
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Affiliation(s)
- Isabel Kurth
- Institute for Cancer Genetics, Department of Genetics and Development and Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY 10032, USA
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13
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Zhu Q, Meng L, Hsu JK, Lin T, Teishima J, Tsai RYL. GNL3L stabilizes the TRF1 complex and promotes mitotic transition. ACTA ACUST UNITED AC 2009; 185:827-39. [PMID: 19487455 PMCID: PMC2711588 DOI: 10.1083/jcb.200812121] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Telomeric repeat binding factor 1 (TRF1) is a component of the multiprotein complex "shelterin," which organizes the telomere into a high-order structure. TRF1 knockout embryos suffer from severe growth defects without apparent telomere dysfunction, suggesting an obligatory role for TRF1 in cell cycle control. To date, the mechanism regulating the mitotic increase in TRF1 protein expression and its function in mitosis remains unclear. Here, we identify guanine nucleotide-binding protein-like 3 (GNL3L), a GTP-binding protein most similar to nucleostemin, as a novel TRF1-interacting protein in vivo. GNL3L binds TRF1 in the nucleoplasm and is capable of promoting the homodimerization and telomeric association of TRF1, preventing promyelocytic leukemia body recruitment of telomere-bound TRF1, and stabilizing TRF1 protein by inhibiting its ubiquitylation and binding to FBX4, an E3 ubiquitin ligase for TRF1. Most importantly, the TRF1 protein-stabilizing activity of GNL3L mediates the mitotic increase of TRF1 protein and promotes the metaphase-to-anaphase transition. This work reveals novel aspects of TRF1 modulation by GNL3L.
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Affiliation(s)
- Qubo Zhu
- Center for Cancer and Stem Cell Biology, Alkek Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX 77030, USA
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14
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Vizlin-Hodzic D, Ryme J, Simonsson S, Simonsson T. Developmental studies of Xenopus shelterin complexes: the message to reset telomere length is already present in the egg. FASEB J 2009; 23:2587-94. [PMID: 19329760 DOI: 10.1096/fj.09-129619] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The 6-protein complex shelterin protects the telomeres of human chromosomes. The recent discovery that telomeres are important for epigenetic gene regulation and vertebrate embryonic development calls for the establishment of model organisms to study shelterin and telomere function under normal developmental conditions. Here, we report the sequences of the shelterin-encoding genes in Xenopus laevis and its close relation Xenopus tropicalis. In vitro expression and biochemical characterization of the Xenopus shelterin proteins TRF1, TRF2, POT1, TIN2, RAP1, TPP1, and the shelterin accessory factor PINX1 indicate that all main functions of their human orthologs are conserved in Xenopus. The XlTRF1 and XtTRF1 proteins bind double-stranded telomeric DNA sequence specifically and interact with XlTIN2 and XtTIN2, respectively. Similarly, the XlTRF2 and XtTRF2 proteins bind double-stranded telomeric DNA and interact with XlRAP1 and XtRAP1, respectively, whereas the XlPOT1 and XtPOT1 proteins bind single-stranded telomeric DNA. Real-time PCR further reveals the gene expression profiles for telomerase and the shelterin genes during embryogenesis. Notably, the composition of shelterin and the formation of its subcomplexes appear to be temporally regulated during embryonic development. Moreover, unexpectedly high telomerase and shelterin gene expression during early embryogenesis may reflect a telomere length-resetting mechanism, similar to that reported for induced pluripotent stem cells and for animals cloned through somatic nuclear transfer.
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Affiliation(s)
- Dzeneta Vizlin-Hodzic
- University of Gothenburg, Department of Biomedicine, Medical Biochemistry and Cell Biology Division, P.O. Box 440, SE 405 30 Gothenburg, Sweden
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15
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Her YR, Chung IK. Ubiquitin Ligase RLIM Modulates Telomere Length Homeostasis through a Proteolysis of TRF1. J Biol Chem 2009; 284:8557-66. [PMID: 19164295 DOI: 10.1074/jbc.m806702200] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The telomeric protein TRF1 negatively regulates telomere length by inhibiting telomerase access at the telomere termini, suggesting that the protein level of TRF1 at telomeres is tightly regulated. Regulation of TRF1 protein abundance is essential for proper telomere function and occurs primarily through post-translational modifications of TRF1. Here we describe RLIM, a RING H2 zinc finger protein with intrinsic ubiquitin ligase activity, as a TRF1-interacting protein. RLIM increases TRF1 turnover by targeting it for degradation by the proteasome in a ubiquitin-dependent manner, independently of Fbx4, which is known to interact with and negatively regulate TRF1. Whereas overexpression of RLIM decreases the level of TRF1 protein, depletion of endogenous RLIM expression by small hairpin RNA increases the level of TRF1 and leads to telomere shortening, thereby impairing cell growth. These results demonstrate that RLIM is involved in the negative regulation of TRF1 function through physical interaction and ubiquitin-mediated proteolysis. Hence, RLIM represents a new pathway for telomere maintenance by modulating the level of TRF1 at telomeres.
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Affiliation(s)
- Yoon Ra Her
- Department of Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
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16
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Wu ZQ, Yang X, Weber G, Liu X. Plk1 phosphorylation of TRF1 is essential for its binding to telomeres. J Biol Chem 2008; 283:25503-25513. [PMID: 18625707 PMCID: PMC2533076 DOI: 10.1074/jbc.m803304200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Revised: 07/08/2008] [Indexed: 11/06/2022] Open
Abstract
In a search for Polo-like kinase 1 (Plk1) interaction proteins, we have identified TRF1 (telomeric repeat binding factor 1) as a potential Plk1 target. In this communication we report further characterization of the interaction. We show that Plk1 associates with TRF1, and Plk1 phosphorylates TRF1 at Ser-435 in vivo. Moreover, Cdk1, serving as a priming kinase, phosphorylates TRF1 to generate a docking site for Plk1 toward TRF1. In the presence of nocodazole, ectopic expression of wild type TRF1 but not TRF1 with alanine mutation in the Plk1 phosphorylation site induces apoptosis in cells containing short telomeres but not in cells containing long telomeres. Unexpectedly, down-regulation of TRF1 by RNA interference affects cell proliferation and results in obvious apoptosis in cells with short telomeres but not in cells with long telomeres. Importantly, we observe that telomeric DNA binding ability of TRF1 is cell cycle-regulated and reaches a peak during mitosis. Upon phosphorylation by Plk1 in vivo and in vitro, the ability of TRF1 to bind telomeric DNA is dramatically increased. These results demonstrate that Plk1 interacts with and phosphorylates TRF1 and suggest that Plk1-mediated phosphorylation is involved in both TRF1 overexpression-induced apoptosis and its telomeric DNA binding ability.
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Affiliation(s)
- Zhao-Qiu Wu
- Department of Biochemistry and the Cancer Center, Purdue University, West Lafayette, Indiana 47907
| | - Xiaoming Yang
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Gregory Weber
- Department of Biochemistry and the Cancer Center, Purdue University, West Lafayette, Indiana 47907
| | - Xiaoqi Liu
- Department of Biochemistry and the Cancer Center, Purdue University, West Lafayette, Indiana 47907.
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Kim MK, Kang MR, Nam HW, Bae YS, Kim YS, Chung IK. Regulation of Telomeric Repeat Binding Factor 1 Binding to Telomeres by Casein Kinase 2-mediated Phosphorylation. J Biol Chem 2008; 283:14144-52. [DOI: 10.1074/jbc.m710065200] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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18
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Grandin N, Charbonneau M. Protection against chromosome degradation at the telomeres. Biochimie 2008; 90:41-59. [PMID: 17764802 DOI: 10.1016/j.biochi.2007.07.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Accepted: 07/17/2007] [Indexed: 10/23/2022]
Abstract
Telomeres, the ends of linear chromosomes, contain repeated TG-rich sequences which, in dividing cells, must be constantly replenished in order to avoid chromosome erosion and, hence, genomic instability. Moreover, unprotected telomeres are prone to end-to-end fusions. Telomerase, a specialized reverse transcriptase with a built-in RNA template, or, in the absence of telomerase, alternative pathways of telomere maintenance are required for continuous cell proliferation in actively dividing cells as well as in cancerous cells emerging in deregulated somatic tissues. The challenge is to keep these free DNA ends masked from the nucleolytic attacks that will readily operate on any DNA double-strand break in the cell, while also allowing the recruitment of telomerase at intervals. Specialized telomeric proteins, as well as DNA repair and checkpoint proteins with a dual role in telomere maintenance and DNA damage signaling/repair, protect the telomere ends from degradation and some of them also function in telomerase recruitment or other aspects of telomere length homeostasis. Phosphorylation of some telomeric proteins by checkpoint protein kinases appears to represent a mode of regulation of telomeric mechanisms. Finally, recent studies have allowed starting to understand the coupling between progression of the replication forks through telomeric regions and the subsequent telomere replication by telomerase, as well as retroaction of telomerase in cis on the firing of nearby replication origins.
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Affiliation(s)
- Nathalie Grandin
- UMR CNRS no. 5239, Ecole Normale Supérieure de Lyon, IFR128 BioSciences Gerland-Lyon Sud, 46, allée d'Italie, 69364 Lyon, France
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19
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Muramatsu Y, Tahara H, Ono T, Tsuruo T, Seimiya H. Telomere elongation by a mutant tankyrase 1 without TRF1 poly(ADP-ribosyl)ation. Exp Cell Res 2007; 314:1115-24. [PMID: 18221737 DOI: 10.1016/j.yexcr.2007.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2007] [Revised: 11/08/2007] [Accepted: 12/07/2007] [Indexed: 11/16/2022]
Abstract
Telomeres are the capping structures of the eukaryotic chromosome ends. Tankyrase 1 is a poly(ADP-ribose) polymerase that elongates telomeres in a telomerase-dependent manner. This function of tankyrase 1 is mediated by down-regulation of TRF1, a negative regulator of telomere access to telomerase. Namely, tankyrase 1 poly(ADP-ribosyl)ates (PARsylates) TRF1, which in turn dissociates TRF1 from telomeres. The resulting telomeres become better substrates for telomerase-mediated DNA extension. Tankyrase 1 has five independent TRF1 binding sites, ARC (ANK repeat cluster) I to V. Among them, the most C-terminal ARC V is required for TRF1 PARsylation and its release from telomeres. By contrast, functional significance of other four ARCs remains elusive. In this study, we generated a mutant tankyrase 1 that had inactive ARC IV and lacked ARC V but elongated telomeres without TRF1 PARsylation. Consistent with the failure in PARsylation, this mutant only marginally released TRF1 from telomeres. Still, it decreased telomere binding of POT1, a downstream effector of TRF1-mediated telomere length control, and elongated the telomeric 3'-overhang as the wild-type tankyrase 1 did. Thus even without TRF1 PARsylation, this mutant tankyrase 1 seemed to loosen the closed structure of the telomeric heterochromatin. These findings suggest a new role for multiple ARCs in telomere extension by tankyrase 1.
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Affiliation(s)
- Yukiko Muramatsu
- Division of Molecular Biotherapy, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research, Tokyo, Japan
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20
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Abstract
Telomeres are among the most important structures in eukaryotic cells. Creating the physical ends of linear chromosomes, they play a crucial role in maintaining genome stability, control of cell division, cell growth and senescence. In vertebrates, telomeres consist of G-rich repetitive DNA sequences (TTAGGG)n and specific proteins, creating a specialized structure called the telosome that through mutual interactions with many other factors in the cell give rise to dynamic regulation of chromosome maintenance. In this review, we survey the structural and mechanistic aspects of telomere length regulation and how these processes lead to alterations in normal and immortal cell growth.
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Affiliation(s)
- M Matulić
- Ruder Bosković Institute, Department of Molecular Biology, Zagreb, Croatia
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