1
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Klump BM, Perez GI, Patrick EM, Adams-Boone K, Cohen SB, Han L, Yu K, Schmidt JC. TCAB1 prevents nucleolar accumulation of the telomerase RNA to facilitate telomerase assembly. Cell Rep 2023; 42:112577. [PMID: 37267110 PMCID: PMC10569210 DOI: 10.1016/j.celrep.2023.112577] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 03/27/2023] [Accepted: 05/12/2023] [Indexed: 06/04/2023] Open
Abstract
Localization of a variety of RNAs to non-membrane-bound cellular compartments such as nucleoli and Cajal bodies is critical for their stability and function. The molecular mechanisms that underly the recruitment and exclusion of RNAs from these phase-separated organelles is incompletely understood. Telomerase is a ribonucleoprotein composed of the reverse transcriptase protein telomerase reverse transcriptase (TERT), the telomerase RNA (TR), and several auxiliary proteins, including TCAB1. Here we show that in the absence of TCAB1, a large fraction of TR is tightly bound to the nucleolus, while TERT is largely excluded from the nucleolus, reducing telomerase assembly. This suggests that nuclear compartmentalization by the non-membrane-bound nucleolus counteracts telomerase assembly, and TCAB1 is required to retain TR in the nucleoplasm. Our work provides insight into the mechanism and functional consequences of RNA recruitment to organelles formed by phase separation and demonstrates that TCAB1 plays an important role in telomerase assembly.
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Affiliation(s)
- Basma M Klump
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA; College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA; Cellular and Molecular Biology Graduate Program, College of Natural Sciences, Michigan State University, East Lansing, MI, USA
| | - Gloria I Perez
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA
| | - Eric M Patrick
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA
| | - Kate Adams-Boone
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA
| | - Scott B Cohen
- Children's Medical Research Institute and University of Sydney, Westmead, NSW 2145, Australia
| | - Li Han
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Kefei Yu
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Jens C Schmidt
- Institute for Quantitative Health Sciences and Engineering, Michigan State University, East Lansing, MI, USA; Department of Obstetrics, Gynecology, and Reproductive Biology, Michigan State University, East Lansing, MI, USA.
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2
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Post-Transcriptional and Post-Translational Modifications in Telomerase Biogenesis and Recruitment to Telomeres. Int J Mol Sci 2023; 24:ijms24055027. [PMID: 36902458 PMCID: PMC10003056 DOI: 10.3390/ijms24055027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
Telomere length is associated with the proliferative potential of cells. Telomerase is an enzyme that elongates telomeres throughout the entire lifespan of an organism in stem cells, germ cells, and cells of constantly renewed tissues. It is activated during cellular division, including regeneration and immune responses. The biogenesis of telomerase components and their assembly and functional localization to the telomere is a complex system regulated at multiple levels, where each step must be tuned to the cellular requirements. Any defect in the function or localization of the components of the telomerase biogenesis and functional system will affect the maintenance of telomere length, which is critical to the processes of regeneration, immune response, embryonic development, and cancer progression. An understanding of the regulatory mechanisms of telomerase biogenesis and activity is necessary for the development of approaches toward manipulating telomerase to influence these processes. The present review focuses on the molecular mechanisms involved in the major steps of telomerase regulation and the role of post-transcriptional and post-translational modifications in telomerase biogenesis and function in yeast and vertebrates.
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Huang Y, Lv J, Zhang Y, Shao Y, Yang D, Cong Y, Huang J, Bian R. Atomic layer deposition (ALD)-constructed TaS 2nanoflakes for cancer-related nucleolin detection. NANOTECHNOLOGY 2023; 34:175701. [PMID: 36645911 DOI: 10.1088/1361-6528/acb35c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 01/16/2023] [Indexed: 06/17/2023]
Abstract
Sensitive detection of nucleolin (NCL) is of great significance for the early diagnosis of cancer. In this work, as a new type of two-dimensional (2D) transition metal dichalcogenides (TMDCs), TaS2nanoflakes (NFs) were precisely constructed by atomic layer deposition (ALD) on carbon fiber paper (CFP) with high specific surface area.In situobservation showed that the nucleation and growth of TaS2nanoflakes were precisely controlled by the number of ALD cycles, thereby regulating their electrochemical properties. The electrochemical performance of TaS2NFs was observed in depth, and compared with that of traditional 2D TMDCs. Due to the high surface area and conductivity, anodic/cathodic current of ∼1570μA of TaS2NFs/CFP can be obtained. Subsequently, an electrochemical biosensor based on ALD-constructed TaS2NFs/CFP for cancer-related NCL detection was fabricated. Due to the excellent electrochemical performance of TaS2NFs/CFP, ultrasensitive detection of NCL in the linear range of 0.1 pM-10 nM with a detection limit of 0.034 pM was achieved.
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Affiliation(s)
- Yazhou Huang
- Industrial Center, Nanjing Institute of Technology, Nanjing 211167, People's Republic of China
| | - Junyan Lv
- Industrial Center, Nanjing Institute of Technology, Nanjing 211167, People's Republic of China
| | - Yunfei Zhang
- Industrial Center, Nanjing Institute of Technology, Nanjing 211167, People's Republic of China
| | - Yinfeng Shao
- Industrial Center, Nanjing Institute of Technology, Nanjing 211167, People's Republic of China
| | - Dongfang Yang
- School of Energy and Power Engineering, Nanjing Institute of Technology, Nanjing 211167, People's Republic of China
| | - Yuan Cong
- School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing 211167, People's Republic of China
| | - Jiacai Huang
- Industrial Center, Nanjing Institute of Technology, Nanjing 211167, People's Republic of China
| | - Rong Bian
- Industrial Center, Nanjing Institute of Technology, Nanjing 211167, People's Republic of China
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4
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Nucleolin; A tumor associated antigen as a potential lung cancer biomarker. Pathol Res Pract 2022; 240:154160. [DOI: 10.1016/j.prp.2022.154160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 08/11/2022] [Accepted: 10/05/2022] [Indexed: 11/06/2022]
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5
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Bellone ML, Fiengo L, Cerchia C, Cotugno R, Bader A, Lavecchia A, De Tommasi N, Piaz FD. Impairment of Nucleolin Activity and Phosphorylation by a Trachylobane Diterpene from Psiadia punctulata in Cancer Cells. Int J Mol Sci 2022; 23:ijms231911390. [PMID: 36232690 PMCID: PMC9570042 DOI: 10.3390/ijms231911390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 11/18/2022] Open
Abstract
Human nucleolin (hNcl) is a multifunctional protein involved in the progression of various cancers and plays a key role in other pathologies. Therefore, there is still unsatisfied demand for hNcl modulators. Recently, we demonstrated that the plant ent-kaurane diterpene oridonin inhibits hNcl but, unfortunately, this compound is quite toxic for healthy cells. Trachylobane diterpene 6,19-dihydroxy-ent-trachiloban-17-oic acid (compound 12) extracted from Psiadia punctulata (DC.) Vatke (Asteraceae) emerged as a ligand of hNcl from a cellular thermal shift assay (CETSA)-based screening of a small library of diterpenes. Effective interaction between this compound and the protein was demonstrated to occur both in vitro and inside two different types of cancer cells. Based on the experimental and computational data, a model of the hNcl/compound 12 complex was built. Because of this binding, hNcl mRNA chaperone activity was significantly reduced, and the level of phosphorylation of the protein was affected. At the biological level, cancer cell incubation with compound 12 produced a cell cycle block in the subG0/G1 phase and induced early apoptosis, whereas no cytotoxicity towards healthy cells was observed. Overall, these results suggested that 6,19-dihydroxy-ent-trachiloban-17-oic could represent a selective antitumoral agent and a promising lead for designing innovative hNcl inhibitors also usable for therapeutic purposes.
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Affiliation(s)
- Maria Laura Bellone
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
| | - Lorenzo Fiengo
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
| | - Carmen Cerchia
- “Drug Discovery” Laboratory, Department of Pharmacy, University of Napoli “Federico II”, Via D. Montesano, 49, 80131 Napoli, Italy
| | - Roberta Cotugno
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
| | - Ammar Bader
- Department of Pharmacognosy, Faculty of Pharmacy, Umm Al-Qura University, Mecca 21995, Saudi Arabia
| | - Antonio Lavecchia
- “Drug Discovery” Laboratory, Department of Pharmacy, University of Napoli “Federico II”, Via D. Montesano, 49, 80131 Napoli, Italy
| | - Nunziatina De Tommasi
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
| | - Fabrizio Dal Piaz
- Department of Medicine, Surgery and Dentistry, University of Salerno, Via S. Allende, 84081 Baronissi, Italy
- Correspondence:
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6
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Shan H, Liu T, Gan H, He S, Deng J, Hu X, Li L, Cai L, He J, Long H, Cai J, Li H, Zhang Q, Wang L, Chen F, Chen Y, Zhang H, Li J, Yang L, Liu Y, Yang J, Kuang DM, Pang P, He H. RNA helicase DDX24 stabilizes LAMB1 to promote hepatocellular carcinoma progression. Cancer Res 2022; 82:3074-3087. [PMID: 35763670 DOI: 10.1158/0008-5472.can-21-3748] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 04/22/2022] [Accepted: 06/23/2022] [Indexed: 11/16/2022]
Abstract
Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies. Elucidating the underlying mechanisms of this disease could provide new therapeutic strategies for treating HCC. Here, we identified a novel role of DEAD-box helicase 24 (DDX24), a member of the DEAD-box protein family, in promoting HCC progression. DDX24 levels were significantly elevated in HCC tissues and were associated with poor prognosis of HCC. Overexpression of DDX24 promoted HCC migration and proliferation in vitro and in vivo, whereas suppression of DDX24 inhibited both functions. Mechanistically, DDX24 bound the mRNA618-624nt of laminin subunit beta 1 (LAMB1) and increased its stability in a manner dependent upon the interaction between nucleolin (NCL) and the C-terminal region of DDX24. Moreover, RFX8 was identified as a DDX24 promoter-binding protein that transcriptionally upregulated DDX24 expression. Collectively, these findings demonstrate that the RFX8/DDX24/LAMB1 axis promotes HCC progression, providing potential therapeutic targets for HCC.
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Affiliation(s)
- Hong Shan
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, Guangdong, China
| | - Tianze Liu
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Hairun Gan
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Simeng He
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Jia Deng
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Xinyan Hu
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Luting Li
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Li Cai
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, China
| | - JianZhong He
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Haoyu Long
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Jianxun Cai
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Hanjie Li
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Qianqian Zhang
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Lijie Wang
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Fangbin Chen
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Yuming Chen
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Haopei Zhang
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Jian Li
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Lukun Yang
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Ye Liu
- Sun Yat-sen University 5th Hospital, Zhuhai, Guangdong province, China
| | | | - Dong-Ming Kuang
- Sun Yat-sen University, Guangzhou, Outside the United States or C, China
| | - Pengfei Pang
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Huanhuan He
- Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
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7
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Akın G, Esbah O, Eröz R. Could nucleolin and nucleophosmin levels be prognostic indicators in non-small cell lung cancer? ACTA FACULTATIS MEDICAE NAISSENSIS 2022. [DOI: 10.5937/afmnai39-35741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Aim: Lung cancer is the leading cause of mortality from cancer across the world. In this study, the use of serum nucleolin (NCL) and nucleophosmin (NPM1) levels as a marker in the diagnosis, prognosis and treatment response evaluation in lung cancer was investigated. Materials and Method: NCL and NPM1 levels of serum samples taken before chemotherapy and after 3-4 courses of chemotherapy from the control group and the patients diagnosed with lung cancer were studied using ELISA method. Results: Serum NCL and NPM1 levels of the patients were higher than of the controls (p = 0.085 for NCL, p = 0.000 for NPM1). NCL and NPM1 levels by histopathologic type were significantly higher in adenocarcinoma than in squamous cell carcinoma (p < 0.05 for each). In view of the treatment responses to chemotherapeutic agents, there was a statistically insignificant difference between the values before and after chemotherapy (p > 0.05 for each). Conclusion: High serum NCL and NPM1 levels were found to correlate with poor prognosis, poor treatment response and low survival rate. It can be concluded that serum NCL and NPM1 levels in lung cancer can be used as diagnostic and prognostic markers for the disease.
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8
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Cruz J, Lemos B. Post-transcriptional diversity in riboproteins and RNAs in aging and cancer. Semin Cancer Biol 2021; 76:292-300. [PMID: 34474152 PMCID: PMC8627441 DOI: 10.1016/j.semcancer.2021.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 08/28/2021] [Accepted: 08/29/2021] [Indexed: 12/19/2022]
Abstract
Post-transcriptional (PtscM) and post-translational (PtrnM) modifications of nucleotides and amino acids are covalent modifications able to change physio-chemical properties of RNAs and proteins. In the ribosome, the adequate assembly of rRNAs and ribosomal protein subunits in the nucleolus ensures suitable translational activity, with protein synthesis tuned according to intracellular demands of energy production, replication, proliferation, and growth. Disruption in the regulatory control of PtscM and PtrnM can impair ribosome biogenesis and ribosome function. Ribosomal impairment may, in turn, impact the synthesis of proteins engaged in functions as varied as telomere maintenance, apoptosis, and DNA repair, as well as intersect with mitochondria and telomerase activity. These cellular processes often malfunction in carcinogenesis and senescence. Here we discuss regulatory mechanisms of PtscMs and PtrnMs on ribosomal function. We also address chemical modification in rRNAs and their impacts on cellular metabolism, replication control, and senescence. Further, we highlight similarities and differences of PtscMs and PtrnMs in ribosomal intermediates during aging and carcinogenesis. Understanding these regulatory mechanisms may uncover critical steps for the development of more efficient oncologic and anti-aging therapies.
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Affiliation(s)
- Jurandir Cruz
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA 02115, USA; Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP 01246, Brazil
| | - Bernardo Lemos
- Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA.
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9
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Constantin D, Dubuis G, Conde-Rubio MDC, Widmann C. APOBEC3C, a nucleolar protein induced by genotoxins, is excluded from DNA damage sites. FEBS J 2021; 289:808-831. [PMID: 34528388 PMCID: PMC9292673 DOI: 10.1111/febs.16202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 08/22/2021] [Accepted: 09/14/2021] [Indexed: 01/23/2023]
Abstract
The human genome contains 11 APOBEC (apolipoprotein B mRNA editing catalytic polypeptide‐like) cytidine deaminases classified into four families. These proteins function mainly in innate antiviral immunity and can also restrict endogenous retrotransposable element multiplication. The present study focuses on APOBEC3C (A3C), a member of the APOBEC3 subfamily. Some APOBEC3 proteins use their enzymatic activity on genomic DNA, inducing mutations and DNA damage, while other members facilitate DNA repair. Our results show that A3C is highly expressed in cells treated with DNA‐damaging agents. Its expression is regulated by p53. Depletion of A3C slightly decreases proliferation and does not affect DNA repair via homologous recombination or nonhomologous end joining. The A3C interactomes obtained from control cells and cells exposed to the genotoxin etoposide indicated that A3C is a nucleolar protein. This was confirmed by the detection of either endogenous or ectopic A3C in nucleoli. Interestingly, we show that A3C is excluded from areas of DNA breaks in live cells. Our data also indicate that the C‐terminal part of A3C is responsible for its nucleolar localization and exclusion from DNA damage sites.
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Affiliation(s)
- Daniel Constantin
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Switzerland
| | - Gilles Dubuis
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Switzerland
| | | | - Christian Widmann
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Switzerland
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10
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Pol α-primase dependent nuclear localization of the mammalian CST complex. Commun Biol 2021; 4:349. [PMID: 33731801 PMCID: PMC7969954 DOI: 10.1038/s42003-021-01845-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 02/11/2021] [Indexed: 01/31/2023] Open
Abstract
The human CST complex composed of CTC1, STN1, and TEN1 is critically involved in telomere maintenance and homeostasis. Specifically, CST terminates telomere extension by inhibiting telomerase access to the telomeric overhang and facilitates lagging strand fill in by recruiting DNA Polymerase alpha primase (Pol α-primase) to the telomeric C-strand. Here we reveal that CST has a dynamic intracellular localization that is cell cycle dependent. We report an increase in nuclear CST several hours after the initiation of DNA replication, followed by exit from the nucleus prior to mitosis. We identify amino acids of CTC1 involved in Pol α-primase binding and nuclear localization. We conclude, the CST complex does not contain a nuclear localization signal (NLS) and suggest that its nuclear localization is reliant on Pol α-primase. Hypomorphic mutations affecting CST nuclear import are associated with telomere syndromes and cancer, emphasizing the important role of this process in health.
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11
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Qin J, Autexier C. Regulation of human telomerase RNA biogenesis and localization. RNA Biol 2021; 18:305-315. [PMID: 32813614 PMCID: PMC7954027 DOI: 10.1080/15476286.2020.1809196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/03/2020] [Accepted: 08/08/2020] [Indexed: 12/16/2022] Open
Abstract
Maintenance of telomeres is essential for genome integrity and replicative capacity in eukaryotic cells. Telomerase, the ribonucleoprotein complex that catalyses telomere synthesis is minimally composed of a reverse transcriptase and an RNA component. The sequence and structural domains of human telomerase RNA (hTR) have been extensively characterized, while the regulation of hTR transcription, maturation, and localization, is not fully understood. Here, we provide an up-to-date review of hTR, with an emphasis on current breakthroughs uncovering the mechanisms of hTR maturation and localization.
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Affiliation(s)
- Jian Qin
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
- Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, Canada
| | - Chantal Autexier
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
- Jewish General Hospital, Lady Davis Institute, Montreal, Quebec, Canada
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12
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Schrumpfová PP, Fajkus J. Composition and Function of Telomerase-A Polymerase Associated with the Origin of Eukaryotes. Biomolecules 2020; 10:biom10101425. [PMID: 33050064 PMCID: PMC7658794 DOI: 10.3390/biom10101425] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/29/2020] [Accepted: 10/01/2020] [Indexed: 12/19/2022] Open
Abstract
The canonical DNA polymerases involved in the replication of the genome are unable to fully replicate the physical ends of linear chromosomes, called telomeres. Chromosomal termini thus become shortened in each cell cycle. The maintenance of telomeres requires telomerase—a specific RNA-dependent DNA polymerase enzyme complex that carries its own RNA template and adds telomeric repeats to the ends of chromosomes using a reverse transcription mechanism. Both core subunits of telomerase—its catalytic telomerase reverse transcriptase (TERT) subunit and telomerase RNA (TR) component—were identified in quick succession in Tetrahymena more than 30 years ago. Since then, both telomerase subunits have been described in various organisms including yeasts, mammals, birds, reptiles and fish. Despite the fact that telomerase activity in plants was described 25 years ago and the TERT subunit four years later, a genuine plant TR has only recently been identified by our group. In this review, we focus on the structure, composition and function of telomerases. In addition, we discuss the origin and phylogenetic divergence of this unique RNA-dependent DNA polymerase as a witness of early eukaryotic evolution. Specifically, we discuss the latest information regarding the recently discovered TR component in plants, its conservation and its structural features.
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Affiliation(s)
- Petra Procházková Schrumpfová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic;
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
- Correspondence:
| | - Jiří Fajkus
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic;
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
- The Czech Academy of Sciences, Institute of Biophysics, Královopolská 135, 612 65 Brno, Czech Republic
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13
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Kroustallaki P, Lirussi L, Carracedo S, You P, Esbensen QY, Götz A, Jobert L, Alsøe L, Sætrom P, Gagos S, Nilsen H. SMUG1 Promotes Telomere Maintenance through Telomerase RNA Processing. Cell Rep 2020; 28:1690-1702.e10. [PMID: 31412240 DOI: 10.1016/j.celrep.2019.07.040] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 05/28/2019] [Accepted: 07/14/2019] [Indexed: 12/13/2022] Open
Abstract
Telomerase biogenesis is a complex process where several steps remain poorly understood. Single-strand-selective uracil-DNA glycosylase (SMUG1) associates with the DKC1-containing H/ACA ribonucleoprotein complex, which is essential for telomerase biogenesis. Herein, we show that SMUG1 interacts with the telomeric RNA component (hTERC) and is required for co-transcriptional processing of the nascent transcript into mature hTERC. We demonstrate that SMUG1 regulates the presence of base modifications in hTERC, in a region between the CR4/CR5 domain and the H box. Increased levels of hTERC base modifications are accompanied by reduced DKC1 binding. Loss of SMUG1 leads to an imbalance between mature hTERC and its processing intermediates, leading to the accumulation of 3'-polyadenylated and 3'-extended intermediates that are degraded in an EXOSC10-independent RNA degradation pathway. Consequently, SMUG1-deprived cells exhibit telomerase deficiency, leading to impaired bone marrow proliferation in Smug1-knockout mice.
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Affiliation(s)
- Penelope Kroustallaki
- Department of Clinical Molecular Biology, University of Oslo, 0318 Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478 Lørenskog, Norway
| | - Lisa Lirussi
- Department of Clinical Molecular Biology, University of Oslo, 0318 Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478 Lørenskog, Norway
| | - Sergio Carracedo
- Department of Clinical Molecular Biology, University of Oslo, 0318 Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478 Lørenskog, Norway
| | - Panpan You
- Department of Clinical Molecular Biology, University of Oslo, 0318 Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478 Lørenskog, Norway
| | - Q Ying Esbensen
- Department of Clinical Molecular Biology, University of Oslo, 0318 Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478 Lørenskog, Norway
| | - Alexandra Götz
- Department of Clinical Molecular Biology, University of Oslo, 0318 Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478 Lørenskog, Norway
| | - Laure Jobert
- Department of Clinical Molecular Biology, University of Oslo, 0318 Oslo, Norway
| | - Lene Alsøe
- Department of Clinical Molecular Biology, University of Oslo, 0318 Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478 Lørenskog, Norway
| | - Pål Sætrom
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, NTNU, 7491 Trondheim, Norway; Department of Computer Science, Norwegian University of Science and Technology, NTNU, 7491 Trondheim, Norway; Bioinformatics Core Facility-BioCore, Norwegian University of Science and Technology, NTNU, 7491 Trondheim, Norway; K.G. Jebsen Center for Genetic Epidemiology, Norwegian University of Science and Technology, NTNU, 7491 Trondheim, Norway
| | - Sarantis Gagos
- Center of Clinical, Experimental Surgery & Translational Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
| | - Hilde Nilsen
- Department of Clinical Molecular Biology, University of Oslo, 0318 Oslo, Norway; Department of Clinical Molecular Biology (EpiGen), Akershus University Hospital, 1478 Lørenskog, Norway.
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14
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Telomerase Biogenesis and Activities from the Perspective of Its Direct Interacting Partners. Cancers (Basel) 2020; 12:cancers12061679. [PMID: 32599885 PMCID: PMC7352425 DOI: 10.3390/cancers12061679] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/20/2020] [Accepted: 06/22/2020] [Indexed: 12/15/2022] Open
Abstract
Telomerase reverse transcriptase (TERT)—the catalytic subunit of telomerase—is reactivated in up to 90% of all human cancers. TERT is observed in heterogenous populations of protein complexes, which are dynamically regulated in a cell type- and cell cycle-specific manner. Over the past two decades, in vitro protein–protein interaction detection methods have discovered a number of endogenous TERT binding partners in human cells that are responsible for the biogenesis and functionalization of the telomerase holoenzyme, including the processes of TERT trafficking between subcellular compartments, assembly into telomerase, and catalytic action at telomeres. Additionally, TERT have been found to interact with protein species with no known telomeric functions, suggesting that these complexes may contribute to non-canonical activities of TERT. Here, we survey TERT direct binding partners and discuss their contributions to TERT biogenesis and functions. The goal is to review the comprehensive spectrum of TERT pro-malignant activities, both telomeric and non-telomeric, which may explain the prevalence of its upregulation in cancer.
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15
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Gao W, Liu Y, Zhang H, Wang Z. Electrochemiluminescence Biosensor for Nucleolin Imaging in a Single Tumor Cell Combined with Synergetic Therapy of Tumor. ACS Sens 2020; 5:1216-1222. [PMID: 32223128 DOI: 10.1021/acssensors.0c00292] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nucleolin, a nuclear biological multifunctional protein, plays significant roles in modulating the proliferation, survival, and apoptosis of tumor cells. Different from the traditional electrochemiluminescence (ECL) method, a new ECL biosensor was built to perform ECL imaging of nucleolin in a single HeLa cell with high sensitivity and throughput. Briefly, mesoporous silica nanoparticles (MSN) loaded with doxorubicin (DOX) and phorbol 12-myristate 13-acetate (PMA) were used as drug carriers and could be specifically opened by nucleolin in a HeLa cell. PMA then induced the HeLa cell to produce reactive oxygen species (ROS) and realized ECL imaging of nucleolin. After that, ROS could damage DNA and proteins of the tumor cell and DOX could induce the apoptosis of HeLa cells by inhibiting genetic material, nucleic acid, synthesis. HeLa cells were then efficiently killed by DOX and ROS in a synergetic pathway. Herein, a new ECL biosensor for ECL imaging of nucleolin in a single HeLa cell and synergetic tumor therapy was built.
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Affiliation(s)
- Wanxia Gao
- Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, College of Chemistry and Chemical Engineering, Qingdao University, Qingdao, Shandong 266071, China
- Collaborative Innovation Center of Tumor Marker Detection Technology, Equipment and Diagnosis-Therapy Integration in Universities of Shandong, Shandong Province Key Laboratory of Detection Technology for Tumor Makers, School of Chemistry and Chemical Engineering, Linyi University, Linyi 276005, China
| | - Yong Liu
- Collaborative Innovation Center of Tumor Marker Detection Technology, Equipment and Diagnosis-Therapy Integration in Universities of Shandong, Shandong Province Key Laboratory of Detection Technology for Tumor Makers, School of Chemistry and Chemical Engineering, Linyi University, Linyi 276005, China
| | - Huairong Zhang
- Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, College of Chemistry and Chemical Engineering, Qingdao University, Qingdao, Shandong 266071, China
- Collaborative Innovation Center of Tumor Marker Detection Technology, Equipment and Diagnosis-Therapy Integration in Universities of Shandong, Shandong Province Key Laboratory of Detection Technology for Tumor Makers, School of Chemistry and Chemical Engineering, Linyi University, Linyi 276005, China
| | - Zonghua Wang
- Shandong Sino-Japanese Center for Collaborative Research of Carbon Nanomaterials, College of Chemistry and Chemical Engineering, Qingdao University, Qingdao, Shandong 266071, China
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16
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Chen J, Stark LA. Insights into the Relationship between Nucleolar Stress and the NF-κB Pathway. Trends Genet 2019; 35:768-780. [PMID: 31434627 DOI: 10.1016/j.tig.2019.07.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/22/2019] [Accepted: 07/24/2019] [Indexed: 02/06/2023]
Abstract
The nuclear organelle the nucleolus and the transcription factor nuclear factor of κ-light-chain-enhancer of activated B cells (NF-κB) are both central to the control of cellular homeostasis, dysregulated in common diseases and implicated in the ageing process. Until recently, it was believed that they acted independently to regulate homeostasis in health and disease. However, there is an emerging body of evidence suggesting that nucleoli and NF-κB signalling converge at multiple levels. Here we will review current understanding of this crosstalk. We will discuss activation of the NF-κB pathway by nucleolar stress and induction of apoptosis by nucleolar sequestration of NF-κB/RelA. We will also discuss the role of TIF-IA, COMMD1, and nucleophosmin, which are key players in this crosstalk, and the therapeutic relevance, particularly with respect to the antitumour effects of aspirin.
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Affiliation(s)
- Jingyu Chen
- University of Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, Western General Hospital, Crewe Road, Edinburgh, Scotland EH4 2XU, UK
| | - Lesley A Stark
- University of Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, Western General Hospital, Crewe Road, Edinburgh, Scotland EH4 2XU, UK.
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17
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Iarovaia OV, Minina EP, Sheval EV, Onichtchouk D, Dokudovskaya S, Razin SV, Vassetzky YS. Nucleolus: A Central Hub for Nuclear Functions. Trends Cell Biol 2019; 29:647-659. [PMID: 31176528 DOI: 10.1016/j.tcb.2019.04.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 04/24/2019] [Accepted: 04/26/2019] [Indexed: 12/19/2022]
Abstract
The nucleolus is the largest and most studied nuclear body, but its role in nuclear function is far from being comprehensively understood. Much work on the nucleolus has focused on its role in regulating RNA polymerase I (RNA Pol I) transcription and ribosome biogenesis; however, emerging evidence points to the nucleolus as an organizing hub for many nuclear functions, accomplished via the shuttling of proteins and nucleic acids between the nucleolus and nucleoplasm. Here, we discuss the cellular mechanisms affected by shuttling of nucleolar components, including the 3D organization of the genome, stress response, DNA repair and recombination, transcription regulation, telomere maintenance, and other essential cellular functions.
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Affiliation(s)
- Olga V Iarovaia
- Institute of Gene Biology of the Russian Academy of Sciences, 119334 Moscow, Russia; LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, 94805 Villejuif, France
| | - Elizaveta P Minina
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Eugene V Sheval
- LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, 94805 Villejuif, France; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Daria Onichtchouk
- Developmental Biology Unit, Department of Biology I, University of Freiburg, Hauptstrasse 1, D-79104 Freiburg, Germany
| | - Svetlana Dokudovskaya
- LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, 94805 Villejuif, France; UMR8126, Université Paris-Sud, CNRS, Institut Gustave Roussy, 94805 Villejuif, France
| | - Sergey V Razin
- Institute of Gene Biology of the Russian Academy of Sciences, 119334 Moscow, Russia; LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, 94805 Villejuif, France; Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Yegor S Vassetzky
- LIA 1066 LFR2O French-Russian Joint Cancer Research Laboratory, 94805 Villejuif, France; Koltzov Institute of Developmental Biology of the Russian Academy of Sciences, 119334 Moscow, Russia; UMR8126, Université Paris-Sud, CNRS, Institut Gustave Roussy, 94805 Villejuif, France.
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18
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Abstract
Telomeres are specialised structures at the end of linear chromosomes. They consist of tandem repeats of the hexanucleotide sequence TTAGGG, as well as a protein complex called shelterin. Together, they form a protective loop structure against chromosome fusion and degradation. Shortening or damage to telomeres and opening of the loop induce an uncapped state that triggers a DNA damage response resulting in senescence or apoptosis.Average telomere length, usually measured in human blood lymphocytes, was thought to be a biomarker for ageing, survival and mortality. However, it becomes obvious that regulation of telomere length is very complex and involves multiple processes. For example, the "end replication problem" during DNA replication as well as oxidative stress are responsible for the shortening of telomeres. In contrast, telomerase activity can potentially counteract telomere shortening when it is able to access and interact with telomeres. However, while highly active during development and in cancer cells, the enzyme is down-regulated in most human somatic cells with a few exceptions such as human lymphocytes. In addition, telomeres can be transcribed, and the transcription products called TERRA are involved in telomere length regulation.Thus, telomere length and their integrity are regulated at many different levels, and we only start to understand this process under conditions of increased oxidative stress, inflammation and during diseases as well as the ageing process.This chapter aims to describe our current state of knowledge on telomeres and telomerase and their regulation in order to better understand their role for the ageing process.
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19
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Schořová Š, Fajkus J, Záveská Drábková L, Honys D, Schrumpfová PP. The plant Pontin and Reptin homologues, RuvBL1 and RuvBL2a, colocalize with TERT and TRB proteins in vivo, and participate in telomerase biogenesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:195-212. [PMID: 30834599 DOI: 10.1111/tpj.14306] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 02/08/2019] [Accepted: 02/26/2019] [Indexed: 05/15/2023]
Abstract
Telomerase maturation and recruitment to telomeres is regulated by several telomerase- and telomere-associated proteins. Among a number of proteins, human Pontin and Reptin play critical roles in telomerase biogenesis. Here we characterized plant orthologues of Pontin and Reptin, RuvBL1 and RuvBL2a, respectively, and show association of Arabidopsis thaliana RuvBL1 (AtRuvBL1) with the catalytic subunit of telomerase (AtTERT) in the nucleolus in vivo. In contrast to mammals, interactions between AtTERT and AtRuvBL proteins in A. thaliana are not direct and they are rather mediated by one of the Arabidopsis thaliana Telomere Repeat Binding (AtTRB) proteins. We further show that plant orthologue of dyskerin, named AtCBF5, is indirectly associated with AtTRB proteins but not with the AtRuvBL proteins in the plant nucleus/nucleolus, and interacts with the Protection of telomere 1 (AtPOT1a) in the nucleolus or cytoplasmic foci. Our genome-wide phylogenetic analyses identify orthologues in RuvBL protein family within the plant kingdom. Dysfunction of AtRuvBL genes in heterozygous T-DNA insertion A. thaliana mutants results in reduced telomerase activity and indicate the involvement of AtRuvBL in plant telomerase biogenesis.
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Affiliation(s)
- Šárka Schořová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Jiří Fajkus
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk University, Brno, Czech Republic
- Institute of Biophysics of the Czech Academy of Sciences, v.v.i., Brno, Czech Republic
| | - Lenka Záveská Drábková
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, v.v.i., Prague, Czech Republic
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, v.v.i., Prague, Czech Republic
| | - Petra Procházková Schrumpfová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Brno, Czech Republic
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20
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Viviescas MA, Cano MIN, Segatto M. Chaperones and Their Role in Telomerase Ribonucleoprotein Biogenesis and Telomere Maintenance. CURR PROTEOMICS 2018. [DOI: 10.2174/1570164615666180713103133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Telomere length maintenance is important for genome stability and cell division. In most
eukaryotes, telomeres are maintained by the telomerase ribonucleoprotein (RNP) complex, minimally
composed of the Telomerase Reverse Transcriptase (TERT) and the telomerase RNA (TER) components.
In addition to TERT and TER, other protein subunits are part of the complex and are involved in
telomerase regulation, assembly, disassembly, and degradation. Among them are some molecular
chaperones such as Hsp90 and its co-chaperone p23 which are found associated with the telomerase
RNP complex in humans, yeast and probably in protozoa. Hsp90 and p23 are necessary for the telomerase
RNP assembly and enzyme activity. In budding yeast, the Hsp90 homolog (Hsp82) is also responsible
for the association and dissociation of telomerase from the telomeric DNA by its direct interaction
with a telomere end-binding protein (Cdc13), responsible for regulating telomerase access to telomeres.
In addition, AAA+ ATPases, such as Pontin and Reptin, which are also considered chaperone-
like proteins, associate with the human telomerase complex by the direct interaction of Pontin with
TERT and dyskerin. They are probably responsible for telomerase RNP assembly since their depletion
impairs the accumulation of the complex. Moreover, various RNA chaperones, are also pivotal in the
assembly and migration of the mature telomerase complex and complex intermediates. In this review,
we will focus on the importance of molecular chaperones for telomerase RNP biogenesis and how they
impact telomere length maintenance and cellular homeostasis.
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Affiliation(s)
- Maria Alejandra Viviescas
- Genetics Department, Biosciences Institute, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
| | | | - Marcela Segatto
- Genetics Department, Biosciences Institute, Sao Paulo State University (UNESP), Botucatu, SP, Brazil
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21
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Kohli JS, Mir H, Wasif A, Chong H, Akhras V, Kumar R, Nagore E, Bennett DC. ETS1, nucleolar and non-nucleolar TERT expression in nevus to melanoma progression. Oncotarget 2017; 8:104408-104417. [PMID: 29262649 PMCID: PMC5732815 DOI: 10.18632/oncotarget.22254] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/03/2017] [Indexed: 11/25/2022] Open
Abstract
TERT (telomerase reverse transcriptase) is the catalytic component of telomerase. TERT shows little expression in normal somatic cells but is commonly re-expressed in cancers, facilitating immortalization. Recently-discovered TERT promoter mutations create binding sites for ETS-family transcription factors to upregulate TERT. ETS1 is reported to be important for TERT upregulation in melanoma. However it is unclear when in melanoma progression TERT and ETS1 proteins are expressed. To elucidate this question, ETS1 and TERT immunohistochemistry were performed on a panel of benign (n=27) and dysplastic nevi (n=34), radial growth phase (n=29), vertical growth phase (n=25) and metastatic melanomas (n=27). Lesions were scored by percentage of positive cells. ETS1 was readily detectable in all lesions, but not in normal melanocytes. TERT was located in either the nucleolus, the nucleoplasm (non-nucleolar) or both. Non-nucleolar TERT increased in prevalence with progression, from 19% of benign nevi to 78% of metastases. It did not however correlate with cell proliferation (Ki-67 immunostaining), nor differ significantly in prevalence between primary melanomas with or without a TERT promoter mutation. These results demonstrate that ETS1 is expressed very early in melanoma progression, and interestingly only non-nucleolar TERT correlates clearly in prevalence with melanoma progression. It can be acquired at various stages and by mechanisms other than promoter mutations.
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Affiliation(s)
- Jaskaren S. Kohli
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London, UK
- Current/Present address: European Research Institute for The Biology of Aging, University Medical Center Groningen, Groningen, The Netherlands
| | - Hira Mir
- Department of Cellular Pathology, St George’s University Hospitals NHS Foundation Trust, London, UK
- Current/Present address: King’s College Hospital Foundation Trust, London, UK
| | - Afsheen Wasif
- Department of Cellular Pathology, St George’s University Hospitals NHS Foundation Trust, London, UK
- Current/Present address: King’s College Hospital Foundation Trust, London, UK
| | - Heung Chong
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London, UK
- Department of Cellular Pathology, St George’s University Hospitals NHS Foundation Trust, London, UK
| | - Victoria Akhras
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London, UK
- Department of Dermatology, St George’s University Hospitals NHS Foundation Trust, London, UK
| | - Rajiv Kumar
- Division of Molecular Genetic Epidemiology, German Cancer Research Center, Heidelberg, Germany
| | - Eduardo Nagore
- Department of Dermatology, Instituto Valenciano de Oncología, Valencia, Spain
| | - Dorothy C. Bennett
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London, UK
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22
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Zhu Z, Tran H, Mathahs MM, Moninger TO, Schmidt WN. HCV Induces Telomerase Reverse Transcriptase, Increases Its Catalytic Activity, and Promotes Caspase Degradation in Infected Human Hepatocytes. PLoS One 2017; 12:e0166853. [PMID: 28056029 PMCID: PMC5215869 DOI: 10.1371/journal.pone.0166853] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 10/17/2016] [Indexed: 01/09/2023] Open
Abstract
Introduction Telomerase repairs the telomeric ends of chromosomes and is active in nearly all malignant cells. Hepatitis C virus (HCV) is known to be oncogenic and potential interactions with the telomerase system require further study. We determined the effects of HCV infection on human telomerase reverse transcriptase (TERT) expression and enzyme activity in primary human hepatocytes and continuous cell lines. Results Primary human hepatocytes and Huh-7.5 hepatoma cells showed early de novo TERT protein expression 2–4 days after infection and these events coincided with increased TERT promoter activation, TERT mRNA, and telomerase activity. Immunoprecipitation studies demonstrated that NS3-4A protease-helicase, in contrast to core or NS5A, specifically bound to the C-terminal region of TERT through interactions between helicase domain 2 and protease sequences. Increased telomerase activity was noted when NS3-4A was transfected into cells, when added to reconstituted mixtures of TERT and telomerase RNA, and when incubated with high molecular weight telomerase ‘holoenzyme’ complexes. The NS3-4A catalytic effect on telomerase was inhibited with primuline or danoprevir, agents that are known to inhibit NS3 helicase and protease activities respectively. In HCV infected cells, NS3-4A could be specifically recovered with telomerase holoenzyme complexes in contrast to NS5A or core protein. HCV infection also activated the effector caspase 7 which is known to target TERT. Activation coincided with the appearance of lower molecular weight carboxy-terminal fragment(s) of TERT, chiefly sized at 45 kD, which could be inhibited with pancaspase or caspase 7 inhibitors. Conclusions HCV infection induces TERT expression and stimulates telomerase activity in addition to triggering Caspase activity that leads to increased TERT degradation. These activities suggest multiple points whereby the virus can influence neoplasia. The NS3-4A protease-helicase can directly bind to TERT, increase telomerase activity, and thus potentially influence telomere repair and host cell neoplastic behavior.
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Affiliation(s)
- Zhaowen Zhu
- Department of Internal Medicine and Research Service, Veterans Affairs Medical Center, Iowa City, IA, United States of America
- Department of Internal Medicine Roy G. and Lucille A. Carver College of Medicine, University of Iowa Iowa City, IA, United States of America
| | - Huy Tran
- Department of Internal Medicine Roy G. and Lucille A. Carver College of Medicine, University of Iowa Iowa City, IA, United States of America
| | - M. Meleah Mathahs
- Department of Internal Medicine and Research Service, Veterans Affairs Medical Center, Iowa City, IA, United States of America
| | - Thomas O. Moninger
- Central Microscopy Research Facility Roy G. and Lucille A. Carver College of Medicine, University of Iowa Iowa City, IA, United States of America
| | - Warren N. Schmidt
- Department of Internal Medicine and Research Service, Veterans Affairs Medical Center, Iowa City, IA, United States of America
- Department of Internal Medicine Roy G. and Lucille A. Carver College of Medicine, University of Iowa Iowa City, IA, United States of America
- * E-mail:
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23
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Abstract
Nucleolin, a multifunctional protein distributed in the nucleolus, participates in many modulations including rDNA transcription, RNA metabolism, and ribosome assembly. Nucleolin is also found in the cytoplasm and on the cell membrane, and surface nucleolin can bind to various ligands to affect many physiological functions. The expression and localization of nucleolin is often abnormal in cancers, as the differential distribution of nucleolin in cancer can influence the carcinogenesis, proliferation, survival, and metastasis of cancer cells, leading to the cancer progression. Thus, nucleolin may be a novel and promising target for anti-cancer treatment. Here, we describe how nucleolin act functions in cancer development and describe nucleolin-dependent anti-cancer therapies.
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Affiliation(s)
- Zhuo Chen
- Department of Oncology, The First College of Clinical Medical Science, China Three Gorges University & Yichang Central People's Hospital, Yichang, China. E-mail.
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24
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Trinkle-Mulcahy L, Sleeman JE. The Cajal body and the nucleolus: "In a relationship" or "It's complicated"? RNA Biol 2016; 14:739-751. [PMID: 27661468 DOI: 10.1080/15476286.2016.1236169] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
From their initial identification as 'nucleolar accessory bodies' more than a century ago, the relationship between Cajal bodies and nucleoli has been a subject of interest and controversy. In this review, we seek to place recent developments in the understanding of the physical and functional relationships between the 2 structures in the context of historical observations. Biophysical models of nuclear body formation, the molecular nature of CB/nucleolus interactions and the increasing list of joint roles for CBs and nucleoli, predominantly in assembling ribonucleoprotein (RNP) complexes, are discussed.
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Affiliation(s)
- Laura Trinkle-Mulcahy
- a Department of Cellular and Molecular Medicine , Ottawa Institute of Systems Biology, University of Ottawa , Ottawa , ON , Canada
| | - Judith E Sleeman
- b BSRC Complex, School of Biology, University of St Andrews , UK
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25
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MacNeil DE, Bensoussan HJ, Autexier C. Telomerase Regulation from Beginning to the End. Genes (Basel) 2016; 7:genes7090064. [PMID: 27649246 PMCID: PMC5042394 DOI: 10.3390/genes7090064] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 08/25/2016] [Accepted: 08/26/2016] [Indexed: 12/11/2022] Open
Abstract
The vast body of literature regarding human telomere maintenance is a true testament to the importance of understanding telomere regulation in both normal and diseased states. In this review, our goal was simple: tell the telomerase story from the biogenesis of its parts to its maturity as a complex and function at its site of action, emphasizing new developments and how they contribute to the foundational knowledge of telomerase and telomere biology.
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Affiliation(s)
- Deanna Elise MacNeil
- Bloomfield Centre for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Côte Ste-Catherine Road, Montréal, QC H3T 1E2, Canada.
- Room M-29, Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montréal, QC H3A 0C7, Canada.
| | - Hélène Jeanne Bensoussan
- Bloomfield Centre for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Côte Ste-Catherine Road, Montréal, QC H3T 1E2, Canada.
- Room M-29, Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montréal, QC H3A 0C7, Canada.
| | - Chantal Autexier
- Bloomfield Centre for Research in Aging, Lady Davis Institute for Medical Research, Jewish General Hospital, 3755 Côte Ste-Catherine Road, Montréal, QC H3T 1E2, Canada.
- Room M-29, Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montréal, QC H3A 0C7, Canada.
- Department of Experimental Medicine, McGill University, 1110 Pins Avenue West, Room 101, Montréal, QC H3A 1A3, Canada.
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26
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Pontvianne F, Carpentier MC, Durut N, Pavlištová V, Jaške K, Schořová Š, Parrinello H, Rohmer M, Pikaard CS, Fojtová M, Fajkus J, Sáez-Vásquez J. Identification of Nucleolus-Associated Chromatin Domains Reveals a Role for the Nucleolus in 3D Organization of the A. thaliana Genome. Cell Rep 2016; 16:1574-1587. [PMID: 27477271 PMCID: PMC5279810 DOI: 10.1016/j.celrep.2016.07.016] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 05/24/2016] [Accepted: 07/03/2016] [Indexed: 11/27/2022] Open
Abstract
The nucleolus is the site of rRNA gene transcription, rRNA processing, and ribosome biogenesis. However, the nucleolus also plays additional roles in the cell. We isolated nucleoli using fluorescence-activated cell sorting (FACS) and identified nucleolus-associated chromatin domains (NADs) by deep sequencing, comparing wild-type plants and null mutants for the nucleolar protein NUCLEOLIN 1 (NUC1). NADs are primarily genomic regions with heterochromatic signatures and include transposable elements (TEs), sub-telomeric regions, and mostly inactive protein-coding genes. However, NADs also include active rRNA genes and the entire short arm of chromosome 4 adjacent to them. In nuc1 null mutants, which alter rRNA gene expression and overall nucleolar structure, NADs are altered, telomere association with the nucleolus is decreased, and telomeres become shorter. Collectively, our studies reveal roles for NUC1 and the nucleolus in the spatial organization of chromosomes as well as telomere maintenance.
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Affiliation(s)
- Frédéric Pontvianne
- CNRS, Laboratoire Génome et Développement des Plantes, UMR5096, 66860 Perpignan, France; Université de Perpignan Via Domitia, Laboratoire Génome et Développement des Plantes, UMR5096, 66860 Perpignan, France; Department of Biology and Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA.
| | - Marie-Christine Carpentier
- CNRS, Laboratoire Génome et Développement des Plantes, UMR5096, 66860 Perpignan, France; Université de Perpignan Via Domitia, Laboratoire Génome et Développement des Plantes, UMR5096, 66860 Perpignan, France
| | - Nathalie Durut
- CNRS, Laboratoire Génome et Développement des Plantes, UMR5096, 66860 Perpignan, France; Université de Perpignan Via Domitia, Laboratoire Génome et Développement des Plantes, UMR5096, 66860 Perpignan, France
| | - Veronika Pavlištová
- Central European Institute of Technology and Faculty of Science, Masaryk University, 62500 Brno, Czech Republic
| | - Karin Jaške
- Central European Institute of Technology and Faculty of Science, Masaryk University, 62500 Brno, Czech Republic
| | - Šárka Schořová
- Central European Institute of Technology and Faculty of Science, Masaryk University, 62500 Brno, Czech Republic
| | | | | | - Craig S Pikaard
- Department of Biology and Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA; Howard Hughes Medical Institute, Indiana University, Bloomington, IN 47405, USA
| | - Miloslava Fojtová
- Central European Institute of Technology and Faculty of Science, Masaryk University, 62500 Brno, Czech Republic
| | - Jiří Fajkus
- Central European Institute of Technology and Faculty of Science, Masaryk University, 62500 Brno, Czech Republic
| | - Julio Sáez-Vásquez
- CNRS, Laboratoire Génome et Développement des Plantes, UMR5096, 66860 Perpignan, France; Université de Perpignan Via Domitia, Laboratoire Génome et Développement des Plantes, UMR5096, 66860 Perpignan, France
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27
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Control of telomerase action at human telomeres. Nat Struct Mol Biol 2016; 22:848-52. [PMID: 26581518 DOI: 10.1038/nsmb.3083] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/04/2015] [Indexed: 12/19/2022]
Abstract
Recent progress has greatly increased the understanding of telomere-bound shelterin proteins and the telomerase holoenzyme, predominantly as separate complexes. Pioneering studies have begun to investigate the requirements for shelterin-telomerase interaction. From this vantage point, focusing on human cells, we review and discuss models for how telomerase and shelterin subunits coordinate to achieve balanced telomere-length homeostasis.
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28
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Hong J, Lee JH, Chung IK. Telomerase activates transcription of cyclin D1 gene through an interaction with NOL1. J Cell Sci 2016; 129:1566-79. [PMID: 26906424 DOI: 10.1242/jcs.181040] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 02/15/2016] [Indexed: 12/28/2022] Open
Abstract
Telomerase is a ribonucleoprotein enzyme that is required for the maintenance of telomere repeats. Although overexpression of telomerase in normal human somatic cells is sufficient to overcome replicative senescence, the ability of telomerase to promote tumorigenesis requires additional activities that are independent of its role in telomere extension. Here, we identify proliferation-associated nucleolar antigen 120 (NOL1, also known as NOP2) as a telomerase RNA component (TERC)-binding protein that is found in association with catalytically active telomerase. Although NOL1 is highly expressed in the majority of human tumor cells, the molecular mechanism by which NOL1 contributes to tumorigenesis remained unclear. We show that NOL1 binds to the T-cell factor (TCF)-binding element of the cyclin D1 promoter and activates its transcription. Interestingly, telomerase is also recruited to the cyclin D1 promoter in a TERC-dependent manner through the interaction with NOL1, further enhancing transcription of the cyclin D1 gene. Depletion of NOL1 suppresses cyclin D1 promoter activity, thereby leading to induction of growth arrest and altered cell cycle distributions. Collectively, our findings suggest that NOL1 represents a new route by which telomerase activates transcription of cyclin D1 gene, thus maintaining cell proliferation capacity.
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Affiliation(s)
- Juyeong Hong
- Department of Integrated Omics for Biomedical Science, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Ji Hoon Lee
- Department of Integrated Omics for Biomedical Science, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - In Kwon Chung
- Department of Integrated Omics for Biomedical Science, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
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29
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Lee JH, Jeong SA, Khadka P, Hong J, Chung IK. Involvement of SRSF11 in cell cycle-specific recruitment of telomerase to telomeres at nuclear speckles. Nucleic Acids Res 2015; 43:8435-51. [PMID: 26286192 PMCID: PMC4787792 DOI: 10.1093/nar/gkv844] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 08/09/2015] [Indexed: 01/13/2023] Open
Abstract
Telomerase, a unique ribonucleoprotein complex that contains the telomerase reverse transcriptase (TERT), the telomerase RNA component (TERC) and the TERC-binding protein dyskerin, is required for continued cell proliferation in stem cells and cancer cells. Here we identify SRSF11 as a novel TERC-binding protein that localizes to nuclear speckles, subnuclear structures that are enriched in pre-messenger RNA splicing factors. SRSF11 associates with active telomerase enzyme through an interaction with TERC and directs it to nuclear speckles specifically during S phase of the cell cycle. On the other hand, a subset of telomeres is shown to be constitutively present at nuclear speckles irrespective of cell cycle phase, suggesting that nuclear speckles could be the nuclear sites for telomerase recruitment to telomeres. SRSF11 also associates with telomeres through an interaction with TRF2, which facilitates translocation of telomerase to telomeres. Depletion of SRSF11 prevents telomerase from associating with nuclear speckles and disrupts telomerase recruitment to telomeres, thereby abrogating telomere elongation by telomerase. These findings suggest that SRSF11 acts as a nuclear speckle-targeting factor that is essential for telomerase association with telomeres through the interactions with TERC and TRF2, and provides a potential target for modulating telomerase activity in cancer.
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Affiliation(s)
- Ji Hoon Lee
- Departments of Systems Biology and Integrated Omics for Biomedical Science, Yonsei University, Seoul 120-749, Korea
| | - Sun Ah Jeong
- Departments of Systems Biology and Integrated Omics for Biomedical Science, Yonsei University, Seoul 120-749, Korea
| | - Prabhat Khadka
- Departments of Systems Biology and Integrated Omics for Biomedical Science, Yonsei University, Seoul 120-749, Korea
| | - Juyeong Hong
- Departments of Systems Biology and Integrated Omics for Biomedical Science, Yonsei University, Seoul 120-749, Korea
| | - In Kwon Chung
- Departments of Systems Biology and Integrated Omics for Biomedical Science, Yonsei University, Seoul 120-749, Korea
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30
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Vogan JM, Collins K. Dynamics of Human Telomerase Holoenzyme Assembly and Subunit Exchange across the Cell Cycle. J Biol Chem 2015; 290:21320-35. [PMID: 26170453 DOI: 10.1074/jbc.m115.659359] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Indexed: 01/04/2023] Open
Abstract
Human telomerase acts on telomeres during the genome synthesis phase of the cell cycle, accompanied by its concentration in Cajal bodies and transient colocalization with telomeres. Whether the regulation of human telomerase holoenzyme assembly contributes to the cell cycle restriction of telomerase function is unknown. We investigated the steady-state levels, assembly, and exchange dynamics of human telomerase subunits with quantitative in vivo cross-linking and other methods. We determined the physical association of telomerase subunits in cells blocked or progressing through the cell cycle as synchronized by multiple protocols. The total level of human telomerase RNA (hTR) was invariant across the cell cycle. In vivo snapshots of telomerase holoenzyme composition established that hTR remains bound to human telomerase reverse transcriptase (hTERT) throughout all phases of the cell cycle, and subunit competition assays suggested that hTERT-hTR interaction is not readily exchangeable. In contrast, the telomerase holoenzyme Cajal body-associated protein, TCAB1, was released from hTR in mitotic cells coincident with TCAB1 delocalization from Cajal bodies. This telomerase holoenzyme disassembly was reversible with cell cycle progression without any change in total TCAB1 protein level. Consistent with differential cell cycle regulation of hTERT-hTR and TCAB1-hTR protein-RNA interactions, overexpression of hTERT or TCAB1 had limited if any influence on hTR assembly of the other subunit. Overall, these findings revealed a cell cycle regulation that disables human telomerase association with telomeres while preserving the co-folded hTERT-hTR ribonucleoprotein catalytic core. Studies here, integrated with previous work, led to a unifying model for telomerase subunit assembly and trafficking in human cells.
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Affiliation(s)
- Jacob M Vogan
- From the Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720
| | - Kathleen Collins
- From the Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720
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31
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Reddel RR. Telomere maintenance mechanisms in cancer: clinical implications. Curr Pharm Des 2015; 20:6361-74. [PMID: 24975603 PMCID: PMC4262939 DOI: 10.2174/1381612820666140630101047] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 06/26/2014] [Indexed: 01/20/2023]
Abstract
The presence of immortal cell populations with an up-regulated telomere maintenance mechanism (TMM) is an almost universal characteristic of cancers, whereas normal somatic cells are unable to prevent proliferation-associated telomere shortening and have a limited proliferative potential. TMMs and related aspects of telomere structure and function therefore appear to be ideal targets for the development of anticancer therapeutics. Such treatments would be targeted to a specific cancer-related molecular abnormality, and also be broad-spectrum in that they would be expected to be potentially applicable to most cancers. However, the telomere biology of normal and malignant human cells is a relatively young research field with large numbers of unanswered questions, so the optimal design of TMM-targeted therapeutic approaches remains unclear. This review outlines the opportunities and challenges presented by telomeres and TMMs for clinical management of cancer.
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Affiliation(s)
- Roger R Reddel
- Children's Medical Research Institute, 214 Hawkesbury Road, Westmead, New South Wales 2145, Australia.
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32
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Jeong SA, Kim K, Lee JH, Cha JS, Khadka P, Cho HS, Chung IK. Akt-mediated phosphorylation increases the binding affinity of hTERT for importin α to promote nuclear translocation. J Cell Sci 2015; 128:2287-301. [DOI: 10.1242/jcs.166132] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 04/10/2015] [Indexed: 01/09/2023] Open
Abstract
ABSTRACT
Telomeres are essential for chromosome integrity and protection, and their maintenance requires the ribonucleoprotein enzyme telomerase. Previously, we have shown that human telomerase reverse transcriptase (hTERT) contains a bipartite nuclear localization signal (NLS; residues 222–240) that is responsible for nuclear import, and that Akt-mediated phosphorylation of residue S227 is important for efficient nuclear import of hTERT. Here, we show that hTERT binds to importin-α proteins through the bipartite NLS and that this heterodimer then forms a complex with importin-β proteins to interact with the nuclear pore complex. Depletion of individual importin-α proteins results in a failure of hTERT nuclear import, and the resulting cytoplasmic hTERT is degraded by ubiquitin-dependent proteolysis. Crystallographic analysis reveals that the bipartite NLS interacts with both the major and minor sites of importin-α proteins. We also show that Akt-mediated phosphorylation of S227 increases the binding affinity for importin-α proteins and promotes nuclear import of hTERT, thereby resulting in increased telomerase activity. These data provide details of a binding mechanism that enables hTERT to interact with the nuclear import receptors and of the control of the dynamic nuclear transport of hTERT through phosphorylation.
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Affiliation(s)
- Sun Ah Jeong
- Department of Integrated Omics for Biomedical Science, Yonsei University, Seoul 120-749, Korea
| | - Kuglae Kim
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Ji Hoon Lee
- Department of Integrated Omics for Biomedical Science, Yonsei University, Seoul 120-749, Korea
| | - Jeong Seok Cha
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - Prabhat Khadka
- Department of Integrated Omics for Biomedical Science, Yonsei University, Seoul 120-749, Korea
| | - Hyun-Soo Cho
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
| | - In Kwon Chung
- Department of Integrated Omics for Biomedical Science, Yonsei University, Seoul 120-749, Korea
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Korea
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33
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Berger CM, Gaume X, Bouvet P. The roles of nucleolin subcellular localization in cancer. Biochimie 2015; 113:78-85. [PMID: 25866190 DOI: 10.1016/j.biochi.2015.03.023] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/29/2015] [Indexed: 01/10/2023]
Abstract
Nucleolin (NCL) is one of the most abundant non ribosomal protein of the nucleolus where it plays a central role in polymerase I transcription. NCL is also found outside of the nucleolus, in the nucleoplasm, cytoplasm as well as on the cell membrane. It acts in all cell compartments to control cellular homeostasis and therefore each cellular pool of NCL can play a different role in cancer development. NCL overexpression and its increased localization at the cell membrane is a common feature of several tumor cells. In cancer cells, NCL overexpression influences cell survival, proliferation and invasion through its action on different cellular pathways. In this review, we describe how the multiple functions of NCL that are associated to its multiple cellular localization can participate to the development of cancer.
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Affiliation(s)
- Caroline Madeleine Berger
- Département de Biologie, Master Biosciences, ENS de Lyon, Lyon, France; Ecole Normale Supérieure de Lyon, Laboratoire Joliot-Curie, CNRS USR 3010, 46 allée d'Italie, 69364 Lyon Cedex 7, France
| | - Xavier Gaume
- Ecole Normale Supérieure de Lyon, Laboratoire Joliot-Curie, CNRS USR 3010, 46 allée d'Italie, 69364 Lyon Cedex 7, France
| | - Philippe Bouvet
- Ecole Normale Supérieure de Lyon, Laboratoire Joliot-Curie, CNRS USR 3010, 46 allée d'Italie, 69364 Lyon Cedex 7, France.
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34
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The Histochemistry and Cell Biology pandect: the year 2014 in review. Histochem Cell Biol 2015; 143:339-68. [PMID: 25744491 DOI: 10.1007/s00418-015-1313-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2015] [Indexed: 02/07/2023]
Abstract
This review encompasses a brief synopsis of the articles published in 2014 in Histochemistry and Cell Biology. Out of the total of 12 issues published in 2014, two special issues were devoted to "Single-Molecule Super-Resolution Microscopy." The present review is divided into 11 categories, providing an easy format for readers to quickly peruse topics of particular interest to them.
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35
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Xiao S, Caglar E, Maldonado P, Das D, Nadeem Z, Chi A, Trinité B, Li X, Saxena A. Induced expression of nucleolin phosphorylation-deficient mutant confers dominant-negative effect on cell proliferation. PLoS One 2014; 9:e109858. [PMID: 25313645 PMCID: PMC4196967 DOI: 10.1371/journal.pone.0109858] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 09/08/2014] [Indexed: 11/25/2022] Open
Abstract
Nucleolin (NCL) is a major nucleolar phosphoprotein that has pleiotropic effects on cell proliferation and is elevated in a variety of tumors. NCL is highly phosphorylated at the N-terminus by two major kinases: interphase casein kinase 2 (CK2) and mitotic cyclin-dependent kinase 1 (CDK1). Earlier we demonstrated that a NCL-mutant that is partly defective in undergoing phosphorylation by CK2 inhibits chromosomal replication through its interactions with Replication Protein A, mimicking the cellular response to DNA damage. We further delineated that the N-terminus of NCL associates with Hdm2, the most common E3 ubiquitin ligase of p53. We reported that NCL antagonizes Hdm2 to stabilize p53 and stimulates p53 transcriptional activity. Although NCL-phosphorylation by CK2 and ribosomal DNA transcription are closely coordinated during interphase, the role of NCL phosphorylation in regulating cell proliferation remains unexplored. We have therefore engineered unique human cells that specifically induce expression of NCL-wild type (WT) or a phosphorylation-deficient NCL-mutant, 6/S*A where all the six CK2 consensus serine sites residing in the N-terminus NCL were mutated to alanine. Here we show that this NCL-mutant is defective in undergoing phosphorylation by CK2. We also demonstrate that NCL-phosphorylation by CK2 is required through the S-phase progression in cell cycle and hence proliferation. Induced expression of NCL with mutated CK2 phosphorylation sites stabilizes p53, results in higher expression of Bcl2 (B-cell lymphoma 2) homology 3 (BH3)-only apoptotic markers and causes a dominant-negative effect on cell viability. Our unique cellular system thus provides the first evidential support to delineate phospho-specific functions of NCL on cell proliferation.
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Affiliation(s)
- Shu Xiao
- Biology Department, Brooklyn College, Brooklyn, New York, United States of America
- City University of New York, Graduate Center, New York, New York, United States of America
| | - Elif Caglar
- Biology Department, Brooklyn College, Brooklyn, New York, United States of America
| | - Priscilla Maldonado
- New York University School of Medicine, New York, New York, United States of America
| | - Dibash Das
- Biology Department, Brooklyn College, Brooklyn, New York, United States of America
- City University of New York, Graduate Center, New York, New York, United States of America
| | - Zaineb Nadeem
- Biology Department, Brooklyn College, Brooklyn, New York, United States of America
| | - Angela Chi
- Great Neck South High School, Great Neck, New York, United States of America
| | - Benjamin Trinité
- New York University College of Dentistry, New York, New York, United States of America
| | - Xin Li
- New York University College of Dentistry, New York, New York, United States of America
| | - Anjana Saxena
- Biology Department, Brooklyn College, Brooklyn, New York, United States of America
- City University of New York, Graduate Center, New York, New York, United States of America
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36
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Telomerase stimulates ribosomal DNA transcription under hyperproliferative conditions. Nat Commun 2014; 5:4599. [PMID: 25118183 DOI: 10.1038/ncomms5599] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 07/07/2014] [Indexed: 12/26/2022] Open
Abstract
In addition to performing its canonical function, Telomerase Reverse Transcriptase (TERT) has been shown to participate in cellular processes independent of telomerase activity. Furthermore, although TERT mainly localizes to Cajal bodies, it is also present within the nucleolus. Because the nucleolus is the site of rDNA transcription, we investigated the possible role of telomerase in regulating RNA polymerase I (Pol I). Here we show that TERT binds to rDNA and stimulates transcription by Pol I during liver regeneration and Ras-induced hyperproliferation. Moreover, the inhibition of telomerase activity by TERT- or TERC-specific RNA interference, the overexpression of dominant-negative-TERT, and the application of the telomerase inhibitor imetelstat reduce Pol I transcription and the growth of tumour cells. In vitro, telomerase can stimulate the formation of the transcription initiation complex. Our results demonstrate how non-canonical features of telomerase may direct Pol I transcription in oncogenic and regenerative hyperproliferation.
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