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Zhao X, Vogirala VK, Liu M, Zhou Y, Rhodes D, Sandin S, Yan J. Exploring TRF2-Dependent DNA Distortion Through Single-DNA Manipulation Studies. Commun Biol 2024; 7:148. [PMID: 38310140 PMCID: PMC10838314 DOI: 10.1038/s42003-024-05838-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/20/2024] [Indexed: 02/05/2024] Open
Abstract
TRF2 is a component of shelterin, a telomere-specific protein complex that protects the ends of mammalian chromosomes from DNA damage signaling and improper repair. TRF2 functions as a homodimer and its interaction with telomeric DNA has been studied, but its full-length DNA-binding properties are unknown. This study examines TRF2's interaction with single-DNA strands and focuses on the conformation of the TRF2-DNA complex and TRF2's preference for DNA chirality. The results show that TRF2-DNA can switch between extended and compact conformations, indicating multiple DNA-binding modes, and TRF2's binding does not have a strong preference for DNA supercoiling chirality when DNA is under low tension. Instead, TRF2 induces DNA bending under tension. Furthermore, both the N-terminal domain of TRF2 and the Myb domain enhance its affinity for the telomere sequence, highlighting the crucial role of multivalent DNA binding in enhancing its affinity and specificity for telomere sequence. These discoveries offer unique insights into TRF2's interaction with telomeric DNA.
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Affiliation(s)
- Xiaodan Zhao
- Department of Physics, National University of Singapore, 117551, Singapore, Singapore
| | - Vinod Kumar Vogirala
- School of Biological Sciences, Nanyang Technology University, 637551, Singapore, Singapore
- Electron Bio-Imaging Centre (eBIC), Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
| | - Meihan Liu
- Mechanobiology Institute, National University of Singapore, 117411, Singapore, Singapore
| | - Yu Zhou
- Mechanobiology Institute, National University of Singapore, 117411, Singapore, Singapore
| | - Daniela Rhodes
- School of Biological Sciences, Nanyang Technology University, 637551, Singapore, Singapore
- NTU Institute of Structural Biology, Nanyang Technology University, 636921, Singapore, Singapore
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, UK
| | - Sara Sandin
- School of Biological Sciences, Nanyang Technology University, 637551, Singapore, Singapore.
- NTU Institute of Structural Biology, Nanyang Technology University, 636921, Singapore, Singapore.
- Umeå university, KBC-huset (KB), Linnaeus väg 10, Umeå, 90187, Sweden.
| | - Jie Yan
- Department of Physics, National University of Singapore, 117551, Singapore, Singapore.
- Mechanobiology Institute, National University of Singapore, 117411, Singapore, Singapore.
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, 350207, China.
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2
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Wong SY, Soman A, Korolev N, Surya W, Chen Q, Shum W, van Noort J, Nordenskiöld L. The shelterin component TRF2 mediates columnar stacking of human telomeric chromatin. EMBO J 2024; 43:87-111. [PMID: 38177309 PMCID: PMC10883271 DOI: 10.1038/s44318-023-00002-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 01/06/2024] Open
Abstract
Telomere repeat binding factor 2 (TRF2) is an essential component of the telomeres and also plays an important role in a number of other non-telomeric processes. Detailed knowledge of the binding and interaction of TRF2 with telomeric nucleosomes is limited. Here, we study the binding of TRF2 to in vitro-reconstituted kilobasepair-long human telomeric chromatin fibres using electron microscopy, single-molecule force spectroscopy and analytical ultracentrifugation sedimentation velocity. Our electron microscopy results revealed that full-length and N-terminally truncated TRF2 promote the formation of a columnar structure of the fibres with an average width and compaction larger than that induced by the addition of Mg2+, in agreement with the in vivo observations. Single-molecule force spectroscopy showed that TRF2 increases the mechanical and thermodynamic stability of the telomeric fibres when stretched with magnetic tweezers. This was in contrast to the result for fibres reconstituted on the 'Widom 601' high-affinity nucleosome positioning sequence, where minor effects on fibre stability were observed. Overall, TRF2 binding induces and stabilises columnar fibres, which may play an important role in telomere maintenance.
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Affiliation(s)
- Sook Yi Wong
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- Department of Emerging Infectious Diseases, Duke-NUS, Medical School, Singapore, 169857, Singapore
| | - Aghil Soman
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Nikolay Korolev
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Wahyu Surya
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Qinming Chen
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- M Diagnostics PTE. LTD, 30 Biopolis Street, Matrix, Singapore, 138671, Singapore
| | - Wayne Shum
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - John van Noort
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- Huygens-Kamerlingh Ones Laboratory, Leiden University, Leiden, 2333 AL, The Netherlands
| | - Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore.
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3
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Pan Y, Hu C, Hou LJ, Chen YL, Shi J, Liu JC, Zhou JQ. Swc4 protects nucleosome-free rDNA, tDNA and telomere loci to inhibit genome instability. DNA Repair (Amst) 2023; 127:103512. [PMID: 37230009 DOI: 10.1016/j.dnarep.2023.103512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 04/17/2023] [Accepted: 05/11/2023] [Indexed: 05/27/2023]
Abstract
In the baker's yeast Saccharomyces cerevisiae, NuA4 and SWR1-C, two multisubunit complexes, are involved in histone acetylation and chromatin remodeling, respectively. Eaf1 is the assembly platform subunit of NuA4, Swr1 is the assembly platform and catalytic subunit of SWR1-C, while Swc4, Yaf9, Arp4 and Act1 form a functional module, and is present in both NuA4 and SWR1 complexes. ACT1 and ARP4 are essential for cell survival. Deletion of SWC4, but not YAF9, EAF1 or SWR1 results in a severe growth defect, but the underlying mechanism remains largely unknown. Here, we show that swc4Δ, but not yaf9Δ, eaf1Δ, or swr1Δ cells display defects in DNA ploidy and chromosome segregation, suggesting that the defects observed in swc4Δ cells are independent of NuA4 or SWR1-C integrity. Swc4 is enriched in the nucleosome-free regions (NFRs) of the genome, including characteristic regions of RDN5s, tDNAs and telomeres, independently of Yaf9, Eaf1 or Swr1. In particular, rDNA, tDNA and telomere loci are more unstable and prone to recombination in the swc4Δ cells than in wild-type cells. Taken together, we conclude that the chromatin associated Swc4 protects nucleosome-free chromatin of rDNA, tDNA and telomere loci to ensure genome integrity.
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Affiliation(s)
- Yue Pan
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Can Hu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lin-Jun Hou
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yu-Long Chen
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jiantao Shi
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jia-Cheng Liu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
| | - Jin-Qiu Zhou
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China; Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China.
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Forsyth RG, Krenács T, Athanasou N, Hogendoorn PCW. Cell Biology of Giant Cell Tumour of Bone: Crosstalk between m/wt Nucleosome H3.3, Telomeres and Osteoclastogenesis. Cancers (Basel) 2021; 13:5119. [PMID: 34680268 PMCID: PMC8534144 DOI: 10.3390/cancers13205119] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/06/2021] [Accepted: 10/08/2021] [Indexed: 12/14/2022] Open
Abstract
Giant cell tumour of bone (GCTB) is a rare and intriguing primary bone neoplasm. Worrisome clinical features are its local destructive behaviour, its high tendency to recur after surgical therapy and its ability to create so-called benign lung metastases (lung 'plugs'). GCTB displays a complex and difficult-to-understand cell biological behaviour because of its heterogenous morphology. Recently, a driver mutation in histone H3.3 was found. This mutation is highly conserved in GCTB but can also be detected in glioblastoma. Denosumab was recently introduced as an extra option of medical treatment next to traditional surgical and in rare cases, radiotherapy. Despite these new insights, many 'old' questions about the key features of GCTB remain unanswered, such as the presence of telomeric associations (TAs), the reactivation of hTERT, and its slight genomic instability. This review summarises the recent relevant literature of histone H3.3 in relation to the GCTB-specific G34W mutation and pays specific attention to the G34W mutation in relation to the development of TAs, genomic instability, and the characteristic morphology of GCTB. As pieces of an etiogenetic puzzle, this review tries fitting all these molecular features and the unique H3.3 G34W mutation together in GCTB.
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Affiliation(s)
- Ramses G. Forsyth
- Department of Pathology, University Hospital Brussels (UZB), Laarbeeklaan 101, 1090 Brussels, Belgium;
- Labaratorium for Experimental Pathology (EXPA), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium
| | - Tibor Krenács
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Üllöi ut 26, 1085 Budapest, Hungary;
| | - Nicholas Athanasou
- Department of Histopathology, Nuffield Orthopaedic Centre, University of Oxford, NDORMS, Oxford OX3 7HE, UK;
| | - Pancras C. W. Hogendoorn
- Department of Pathology, University Hospital Brussels (UZB), Laarbeeklaan 101, 1090 Brussels, Belgium;
- Labaratorium for Experimental Pathology (EXPA), Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels, Belgium
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Üllöi ut 26, 1085 Budapest, Hungary;
- Department of Histopathology, Nuffield Orthopaedic Centre, University of Oxford, NDORMS, Oxford OX3 7HE, UK;
- Department of Pathology, Leiden University Medical Center (LUMC), Albinusdreef 2, 2300 RC Leiden, The Netherlands
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5
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Kato H, Shimizu M, Urano T. Chemical map-based prediction of nucleosome positioning using the Bioconductor package nuCpos. BMC Bioinformatics 2021; 22:322. [PMID: 34120589 PMCID: PMC8201924 DOI: 10.1186/s12859-021-04240-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 06/06/2021] [Indexed: 11/10/2022] Open
Abstract
Background Assessing the nucleosome-forming potential of specific DNA sequences is important for understanding complex chromatin organization. Methods for predicting nucleosome positioning include bioinformatics and biophysical approaches. An advantage of bioinformatics methods, which are based on in vivo nucleosome maps, is the use of natural sequences that may contain previously unknown elements involved in nucleosome positioning in vivo. The accuracy of such prediction attempts reflects the genomic coordinate resolution of the nucleosome maps applied. Nucleosome maps are constructed using micrococcal nuclease digestion followed by high-throughput sequencing (MNase-seq). However, as MNase has a strong preference for A/T-rich sequences, MNase-seq may not be appropriate for this purpose. In addition to MNase-seq-based maps, base pair-resolution chemical maps of in vivo nucleosomes from three different species (budding and fission yeasts, and mice) are currently available. However, these chemical maps have yet to be integrated into publicly available computational methods. Results We developed a Bioconductor package (named nuCpos) to demonstrate the superiority of chemical maps in predicting nucleosome positioning. The accuracy of chemical map-based prediction in rotational settings was higher than that of the previously developed MNase-seq-based approach. With our method, predicted nucleosome occupancy reasonably matched in vivo observations and was not affected by A/T nucleotide frequency. Effects of genetic alterations on nucleosome positioning that had been observed in living yeast cells could also be predicted. nuCpos calculates individual histone binding affinity (HBA) scores for given 147-bp sequences to examine their suitability for nucleosome formation. We also established local HBA as a new parameter to predict nucleosome formation, which was calculated for 13 overlapping nucleosomal DNA subsequences. HBA and local HBA scores for various sequences agreed well with previous in vitro and in vivo studies. Furthermore, our results suggest that nucleosomal subsegments that are disfavored in different rotational settings contribute to the defined positioning of nucleosomes. Conclusions Our results demonstrate that chemical map-based statistical models are beneficial for studying nucleosomal DNA features. Studies employing nuCpos software can enhance understanding of chromatin regulation and the interpretation of genetic alterations and facilitate the design of artificial sequences. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-021-04240-2.
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Affiliation(s)
- Hiroaki Kato
- Department of Biochemistry, Shimane University School of Medicine, 89-1 Enya-cho, Izumo, Shimane, 693-8501, Japan.
| | - Mitsuhiro Shimizu
- Department of Chemistry, Graduate School of Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo, 191-8506, Japan
| | - Takeshi Urano
- Department of Biochemistry, Shimane University School of Medicine, 89-1 Enya-cho, Izumo, Shimane, 693-8501, Japan
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6
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Thakur J, Packiaraj J, Henikoff S. Sequence, Chromatin and Evolution of Satellite DNA. Int J Mol Sci 2021; 22:ijms22094309. [PMID: 33919233 PMCID: PMC8122249 DOI: 10.3390/ijms22094309] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 12/15/2022] Open
Abstract
Satellite DNA consists of abundant tandem repeats that play important roles in cellular processes, including chromosome segregation, genome organization and chromosome end protection. Most satellite DNA repeat units are either of nucleosomal length or 5–10 bp long and occupy centromeric, pericentromeric or telomeric regions. Due to high repetitiveness, satellite DNA sequences have largely been absent from genome assemblies. Although few conserved satellite-specific sequence motifs have been identified, DNA curvature, dyad symmetries and inverted repeats are features of various satellite DNAs in several organisms. Satellite DNA sequences are either embedded in highly compact gene-poor heterochromatin or specialized chromatin that is distinct from euchromatin. Nevertheless, some satellite DNAs are transcribed into non-coding RNAs that may play important roles in satellite DNA function. Intriguingly, satellite DNAs are among the most rapidly evolving genomic elements, such that a large fraction is species-specific in most organisms. Here we describe the different classes of satellite DNA sequences, their satellite-specific chromatin features, and how these features may contribute to satellite DNA biology and evolution. We also discuss how the evolution of functional satellite DNA classes may contribute to speciation in plants and animals.
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Affiliation(s)
- Jitendra Thakur
- Department of Biology, Emory University, Atlanta, GA 30322, USA;
- Correspondence:
| | - Jenika Packiaraj
- Department of Biology, Emory University, Atlanta, GA 30322, USA;
| | - Steven Henikoff
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA;
- Fred Hutchinson Cancer Research Center, Howard Hughes Medical Institute, Seattle, WA 98109, USA
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7
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Lim CJ, Cech TR. Shaping human telomeres: from shelterin and CST complexes to telomeric chromatin organization. Nat Rev Mol Cell Biol 2021; 22:283-298. [PMID: 33564154 DOI: 10.1038/s41580-021-00328-y] [Citation(s) in RCA: 115] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2021] [Indexed: 01/14/2023]
Abstract
The regulation of telomere length in mammals is crucial for chromosome end-capping and thus for maintaining genome stability and cellular lifespan. This process requires coordination between telomeric protein complexes and the ribonucleoprotein telomerase, which extends the telomeric DNA. Telomeric proteins modulate telomere architecture, recruit telomerase to accessible telomeres and orchestrate the conversion of the newly synthesized telomeric single-stranded DNA tail into double-stranded DNA. Dysfunctional telomere maintenance leads to telomere shortening, which causes human diseases including bone marrow failure, premature ageing and cancer. Recent studies provide new insights into telomerase-related interactions (the 'telomere replisome') and reveal new challenges for future telomere structural biology endeavours owing to the dynamic nature of telomere architecture and the great number of structures that telomeres form. In this Review, we discuss recently determined structures of the shelterin and CTC1-STN1-TEN1 (CST) complexes, how they may participate in the regulation of telomere replication and chromosome end-capping, and how disease-causing mutations in their encoding genes may affect specific functions. Major outstanding questions in the field include how all of the telomere components assemble relative to each other and how the switching between different telomere structures is achieved.
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Affiliation(s)
- Ci Ji Lim
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA. .,Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA. .,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA.
| | - Thomas R Cech
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA. .,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA. .,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA.
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8
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Zhang HH, Zhao LD, Zuo P, Yin BC, Ye BC. A telomerase-responsive nanoprobe with theranostic properties in tumor cells. Talanta 2020; 215:120898. [PMID: 32312443 DOI: 10.1016/j.talanta.2020.120898] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/01/2020] [Accepted: 03/03/2020] [Indexed: 12/11/2022]
Abstract
Multidrug resistance (MDR) is the main cause of treatment failure in clinical cancer chemotherapy due to the presence of P-glycoproteins (P-gp), which widely exist in stubborn drug-resistant tumor membranes and actively pump drugs from inside the tumor cell to the outside. In this study, we report a novel telomerase-responsive nanoprobe with theranostic properties for inhibiting P-gp expression and reversing MDR by gene silencing. This nanoprobe is composed of an AuNP assembled with telomerase primer, antisense oligonucleotide (ASO), and doxorubicin (Dox). When the designed nanoprobe is uptaken by the MDR cancer cells, the Dox and ASO are specifically released due to the extension of telomerase primer triggered by telomerase. The released ASO specifically hybridizes with multidrug resistance 1 (MDR1) mRNA sequence, which encodes the P-gp. As a result, the expression of P-gp is inhibited and the efflux of Dox is prevented with reduced MDR in cancerous cells. The results demonstrate that the nanoprobe based on telomerase switching for drug release and gene silencing, can both target cancer cells for delivering drugs and overcome the effect of efflux pumps. This work presents a novel paradigm for theranostics of MDR cancer and enhances the efficacy of chemotherapeutics.
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Affiliation(s)
- He-Hua Zhang
- Lab of Biosystem and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Li-Dong Zhao
- Lab of Biosystem and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Peng Zuo
- Lab of Biosystem and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Bin-Cheng Yin
- Lab of Biosystem and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China; Institute of Engineering Biology and Health, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, China; School of Chemistry and Chemical Engineering, Shihezi University, Shihezi, 832000, Xinjiang, China.
| | - Bang-Ce Ye
- Lab of Biosystem and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China; Institute of Engineering Biology and Health, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, 310014, Zhejiang, China; School of Chemistry and Chemical Engineering, Shihezi University, Shihezi, 832000, Xinjiang, China.
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9
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Aksenova AY, Mirkin SM. At the Beginning of the End and in the Middle of the Beginning: Structure and Maintenance of Telomeric DNA Repeats and Interstitial Telomeric Sequences. Genes (Basel) 2019; 10:genes10020118. [PMID: 30764567 PMCID: PMC6410037 DOI: 10.3390/genes10020118] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 02/07/2023] Open
Abstract
Tandem DNA repeats derived from the ancestral (TTAGGG)n run were first detected at chromosome ends of the majority of living organisms, hence the name telomeric DNA repeats. Subsequently, it has become clear that telomeric motifs are also present within chromosomes, and they were suitably called interstitial telomeric sequences (ITSs). It is well known that telomeric DNA repeats play a key role in chromosome stability, preventing end-to-end fusions and precluding the recurrent DNA loss during replication. Recent data suggest that ITSs are also important genomic elements as they confer its karyotype plasticity. In fact, ITSs appeared to be among the most unstable microsatellite sequences as they are highly length polymorphic and can trigger chromosomal fragility and gross chromosomal rearrangements. Importantly, mechanisms responsible for their instability appear to be similar to the mechanisms that maintain the length of genuine telomeres. This review compares the mechanisms of maintenance and dynamic properties of telomeric repeats and ITSs and discusses the implications of these dynamics on genome stability.
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Affiliation(s)
- Anna Y Aksenova
- Laboratory of Amyloid Biology, St. Petersburg State University, 199034 St. Petersburg, Russia.
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02421, USA.
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10
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Fuse T, Yanagida A, Shimizu M. The Yeast Minichromosome System Consisting of Highly Positioned Nucleosomes in Vivo. Biol Pharm Bull 2019; 42:289-294. [DOI: 10.1248/bpb.b18-00732] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Tomohiro Fuse
- Department of Chemistry, Graduate School of Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University
| | - Akio Yanagida
- School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
| | - Mitsuhiro Shimizu
- Department of Chemistry, Graduate School of Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University
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11
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Ichikawa Y, Saitoh N, Kaufman PD. An asymmetric centromeric nucleosome. eLife 2018; 7:37911. [PMID: 30136924 PMCID: PMC6125124 DOI: 10.7554/elife.37911] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/22/2018] [Indexed: 02/03/2023] Open
Abstract
Nucleosomes contain two copies of each core histone, held together by a naturally symmetric, homodimeric histone H3-H3 interface. This symmetry has complicated efforts to determine the regulatory potential of this architecture. Through molecular design and in vivo selection, we recently generated obligately heterodimeric H3s, providing a powerful tool for discovery of the degree to which nucleosome symmetry regulates chromosomal functions in living cells (Ichikawa et al., 2017). We now have extended this tool to the centromeric H3 isoform (Cse4/CENP-A) in budding yeast. These studies indicate that a single Cse4 N- or C-terminal extension per pair of Cse4 molecules is sufficient for kinetochore function, and validate previous experiments indicating that an octameric centromeric nucleosome is required for viability in this organism. These data also support the generality of the H3 asymmetric interface for probing general questions in chromatin biology.
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Affiliation(s)
- Yuichi Ichikawa
- Department of Molecular, Cell, and Cancer Biology, University of Massachusetts Medical School, Worcester, United States.,Division of Cancer Biology, The Cancer Institute of JFCR, Tokyo, Japan
| | - Noriko Saitoh
- Division of Cancer Biology, The Cancer Institute of JFCR, Tokyo, Japan
| | - Paul D Kaufman
- Department of Molecular, Cell, and Cancer Biology, University of Massachusetts Medical School, Worcester, United States
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12
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Fuse T, Katsumata K, Morohoshi K, Mukai Y, Ichikawa Y, Kurumizaka H, Yanagida A, Urano T, Kato H, Shimizu M. Parallel mapping with site-directed hydroxyl radicals and micrococcal nuclease reveals structural features of positioned nucleosomes in vivo. PLoS One 2017; 12:e0186974. [PMID: 29073207 PMCID: PMC5658119 DOI: 10.1371/journal.pone.0186974] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 10/11/2017] [Indexed: 12/17/2022] Open
Abstract
Micrococcal nuclease (MNase) has been widely used for analyses of nucleosome locations in many organisms. However, due to its sequence preference, the interpretations of the positions and occupancies of nucleosomes using MNase have remained controversial. Next-generation sequencing (NGS) has also been utilized for analyses of MNase-digests, but some technical biases are commonly present in the NGS experiments. Here, we established a gel-based method to map nucleosome positions in Saccharomyces cerevisiae, using isolated nuclei as the substrate for the histone H4 S47C-site-directed chemical cleavage in parallel with MNase digestion. The parallel mapping allowed us to compare the chemically and enzymatically cleaved sites by indirect end-labeling and primer extension mapping, and thus we could determine the nucleosome positions and the sizes of the nucleosome-free regions (or nucleosome-depleted regions) more accurately, as compared to nucleosome mapping by MNase alone. The analysis also revealed that the structural features of the nucleosomes flanked by the nucleosome-free region were different from those within regularly arrayed nucleosomes, showing that the structures and dynamics of individual nucleosomes strongly depend on their locations. Moreover, we demonstrated that the parallel mapping results were generally consistent with the previous genome-wide chemical mapping and MNase-Seq results. Thus, the gel-based parallel mapping will be useful for the analysis of a specific locus under various conditions.
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Affiliation(s)
- Tomohiro Fuse
- Department of Chemistry, Graduate School of Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, Hino, Tokyo, Japan
| | - Koji Katsumata
- Department of Chemistry, Graduate School of Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, Hino, Tokyo, Japan
| | - Koya Morohoshi
- Department of Chemistry, Graduate School of Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, Hino, Tokyo, Japan
| | - Yukio Mukai
- Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, Japan
| | - Yuichi Ichikawa
- Graduate School of Advanced Science and Engineering/RISE/IMSB, Waseda University, Shinjuku-ku, Tokyo, Japan
| | - Hitoshi Kurumizaka
- Graduate School of Advanced Science and Engineering/RISE/IMSB, Waseda University, Shinjuku-ku, Tokyo, Japan
| | - Akio Yanagida
- School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Tokyo, Japan
| | - Takeshi Urano
- Department of Biochemistry, Shimane University School of Medicine, Izumo, Shimane, Japan
| | - Hiroaki Kato
- Department of Biochemistry, Shimane University School of Medicine, Izumo, Shimane, Japan
| | - Mitsuhiro Shimizu
- Department of Chemistry, Graduate School of Science and Engineering, Program in Chemistry and Life Science, School of Science and Engineering, Meisei University, Hino, Tokyo, Japan
- * E-mail:
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13
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Bandaria JN, Qin P, Berk V, Chu S, Yildiz A. Shelterin Protects Chromosome Ends by Compacting Telomeric Chromatin. Cell 2016; 164:735-46. [PMID: 26871633 DOI: 10.1016/j.cell.2016.01.036] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/28/2015] [Accepted: 01/22/2016] [Indexed: 12/12/2022]
Abstract
Telomeres, repetitive DNA sequences at chromosome ends, are shielded against the DNA damage response (DDR) by the shelterin complex. To understand how shelterin protects telomere ends, we investigated the structural organization of telomeric chromatin in human cells using super-resolution microscopy. We found that telomeres form compact globular structures through a complex network of interactions between shelterin subunits and telomeric DNA, but not by DNA methylation, histone deacetylation, or histone trimethylation at telomeres and subtelomeric regions. Mutations that abrogate shelterin assembly or removal of individual subunits from telomeres cause up to a 10-fold increase in telomere volume. Decompacted telomeres accumulate DDR signals and become more accessible to telomere-associated proteins. Recompaction of telomeric chromatin using an orthogonal method displaces DDR signals from telomeres. These results reveal the chromatin remodeling activity of shelterin and demonstrate that shelterin-mediated compaction of telomeric chromatin provides robust protection of chromosome ends against the DDR machinery.
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Affiliation(s)
- Jigar N Bandaria
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Peiwu Qin
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Veysel Berk
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Steven Chu
- Department of Physics, Stanford University, Stanford, CA 94305, USA
| | - Ahmet Yildiz
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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14
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Ichikawa Y, Morohashi N, Tomita N, Mitchell AP, Kurumizaka H, Shimizu M. Sequence-directed nucleosome-depletion is sufficient to activate transcription from a yeast core promoter in vivo. Biochem Biophys Res Commun 2016; 476:57-62. [PMID: 27208777 DOI: 10.1016/j.bbrc.2016.05.063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 05/12/2016] [Indexed: 11/18/2022]
Abstract
Nucleosome-depleted regions (NDRs) (also called nucleosome-free regions or NFRs) are often found in the promoter regions of many yeast genes, and are formed by multiple mechanisms, including the binding of activators and enhancers, the actions of chromatin remodeling complexes, and the specific DNA sequences themselves. However, it remains unclear whether NDR formation per se is essential for transcriptional activation. Here, we examined the relationship between nucleosome organization and gene expression using a defined yeast reporter system, consisting of the CYC1 minimal core promoter and the lacZ gene. We introduced simple repeated sequences that should be either incorporated in nucleosomes or excluded from nucleosomes in the site upstream of the TATA boxes. The (CTG)12, (GAA)12 and (TGTAGG)6 inserts were incorporated into a positioned nucleosome in the core promoter region, and did not affect the reporter gene expression. In contrast, the insertion of (CGG)12, (TTAGGG)6, (A)34 or (CG)8 induced lacZ expression by 10-20 fold. Nucleosome mapping analyses revealed that the inserts that induced the reporter gene expression prevented nucleosome formation, and created an NDR upstream of the TATA boxes. Thus, our results demonstrated that NDR formation dictated by DNA sequences is sufficient for transcriptional activation from the core promoter in vivo.
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Affiliation(s)
- Yuichi Ichikawa
- Graduate School of Advanced Science and Engineering/RISE, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8640, Japan; Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
| | - Nobuyuki Morohashi
- Program in Chemistry and Life Science, School of Science and Engineering, Department of Chemistry, Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo 191-8506, Japan
| | - Nobuyuki Tomita
- Program in Chemistry and Life Science, School of Science and Engineering, Department of Chemistry, Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo 191-8506, Japan
| | - Aaron P Mitchell
- Department of Biological Sciences, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, PA 15213, USA
| | - Hitoshi Kurumizaka
- Graduate School of Advanced Science and Engineering/RISE, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8640, Japan
| | - Mitsuhiro Shimizu
- Program in Chemistry and Life Science, School of Science and Engineering, Department of Chemistry, Graduate School of Science and Engineering, Meisei University, 2-1-1 Hodokubo, Hino, Tokyo 191-8506, Japan.
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15
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Ichikawa Y, Nishimura Y, Kurumizaka H, Shimizu M. Nucleosome organization and chromatin dynamics in telomeres. Biomol Concepts 2016; 6:67-75. [PMID: 25720088 DOI: 10.1515/bmc-2014-0035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 12/01/2014] [Indexed: 11/15/2022] Open
Abstract
Telomeres are DNA-protein complexes located at the ends of linear eukaryotic chromosomes, and are essential for chromosome stability and maintenance. In most organisms, telomeres consist of tandemly repeated sequences of guanine-clusters. In higher eukaryotes, most of the telomeric repeat regions are tightly packaged into nucleosomes, even though telomeric repeats act as nucleosome-disfavoring sequences. Although telomeres were considered to be condensed heterochromatin structures, recent studies revealed that the chromatin structures in telomeres are actually dynamic. The dynamic properties of telomeric chromatin are considered to be important for the structural changes between the euchromatic and heterochromatic states during the cell cycle and in cellular differentiation. We propose that the nucleosome-disfavoring property of telomeric repeats is a crucial determinant for the lability of telomeric nucleosomes, and provides a platform for chromatin dynamics in telomeres. Furthermore, we discuss the influences of telomeric components on the nucleosome organization and chromatin dynamics in telomeres.
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16
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Wang J, Cohen AL, Letian A, Tadeo X, Moresco JJ, Liu J, Yates JR, Qiao F, Jia S. The proper connection between shelterin components is required for telomeric heterochromatin assembly. Genes Dev 2016; 30:827-39. [PMID: 26988418 PMCID: PMC4826398 DOI: 10.1101/gad.266718.115] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 02/24/2016] [Indexed: 12/31/2022]
Abstract
Telomeric regions contain prominent sites of heterochromatin, which is associated with unique histone modification profiles such as the methylation of histone H3 at Lys9 (H3K9me). In fission yeast, the conserved telomeric shelterin complex recruits the histone H3K9 methyltransferase complex CLRC to establish subtelomeric heterochromatin. Although many shelterin mutations affect subtelomeric heterochromatin assembly, the mechanism remains elusive due to the diverse functions of shelterin. Through affinity purification, we found that shelterin directly associates with CLRC through the Ccq1 subunit. Surprisingly, mutations that disrupt interactions between shelterin subunits compromise subtelomeric heterochromatin without affecting CLRC interaction with shelterin component Pot1, located at chromosome ends. We further discovered that telomeric repeats are refractory to heterochromatin spreading and that artificial restoration of shelterin connections or increased heterochromatin spreading rescued heterochromatin defects in these shelterin mutants. Thus, subtelomeric heterochromatin assembly requires both the recruitment of CLRC by shelterin to chromosome ends and the proper connection of shelterin components, which allows CLRC to skip telomeric repeats to internal regions.
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Affiliation(s)
- Jiyong Wang
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Allison L Cohen
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Anudari Letian
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Xavier Tadeo
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - James J Moresco
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Jinqiang Liu
- Department of Biological Chemistry, University of California at Irvine, Irvine, California 92697, USA
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Feng Qiao
- Department of Biological Chemistry, University of California at Irvine, Irvine, California 92697, USA
| | - Songtao Jia
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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17
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Udugama M, M Chang FT, Chan FL, Tang MC, Pickett HA, R McGhie JD, Mayne L, Collas P, Mann JR, Wong LH. Histone variant H3.3 provides the heterochromatic H3 lysine 9 tri-methylation mark at telomeres. Nucleic Acids Res 2015; 43:10227-37. [PMID: 26304540 PMCID: PMC4666390 DOI: 10.1093/nar/gkv847] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 08/11/2015] [Indexed: 11/15/2022] Open
Abstract
In addition to being a hallmark at active genes, histone variant H3.3 is deposited by ATRX at repressive chromatin regions, including the telomeres. It is unclear how H3.3 promotes heterochromatin assembly. We show that H3.3 is targeted for K9 trimethylation to establish a heterochromatic state enriched in trimethylated H3.3K9 at telomeres. In H3f3a−/− and H3f3b−/− mouse embryonic stem cells (ESCs), H3.3 deficiency results in reduced levels of H3K9me3, H4K20me3 and ATRX at telomeres. The H3f3b−/− cells show increased levels of telomeric damage and sister chromatid exchange (t-SCE) activity when telomeres are compromised by treatment with a G-quadruplex (G4) DNA binding ligand or by ASF1 depletion. Overexpression of wild-type H3.3 (but not a H3.3K9 mutant) in H3f3b−/− cells increases H3K9 trimethylation level at telomeres and represses t-SCE activity induced by a G4 ligand. This study demonstrates the importance of H3.3K9 trimethylation in heterochromatin formation at telomeres. It provides insights into H3.3 function in maintaining integrity of mammalian constitutive heterochromatin, adding to its role in mediating transcription memory in the genome.
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Affiliation(s)
- Maheshi Udugama
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Fiona T M Chang
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - F Lyn Chan
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Michelle C Tang
- Department of Zoology, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Hilda A Pickett
- Telomere Length Regulation Group, Children's Medical Research Institute, University of Sydney, Westmead, New South Wales, Australia
| | - James D R McGhie
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Lynne Mayne
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Philippe Collas
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, and Norwegian Center for Stem Cell Research, University of Oslo, 0317 Oslo, Norway
| | - Jeffrey R Mann
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Lee H Wong
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
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18
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Galati A, Micheli E, Alicata C, Ingegnere T, Cicconi A, Pusch MC, Giraud-Panis MJ, Gilson E, Cacchione S. TRF1 and TRF2 binding to telomeres is modulated by nucleosomal organization. Nucleic Acids Res 2015; 43:5824-37. [PMID: 25999344 PMCID: PMC4499135 DOI: 10.1093/nar/gkv507] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 05/04/2015] [Indexed: 01/22/2023] Open
Abstract
The ends of eukaryotic chromosomes need to be protected from the activation of a DNA damage response that leads the cell to replicative senescence or apoptosis. In mammals, protection is accomplished by a six-factor complex named shelterin, which organizes the terminal TTAGGG repeats in a still ill-defined structure, the telomere. The stable interaction of shelterin with telomeres mainly depends on the binding of two of its components, TRF1 and TRF2, to double-stranded telomeric repeats. Tethering of TRF proteins to telomeres occurs in a chromatin environment characterized by a very compact nucleosomal organization. In this work we show that binding of TRF1 and TRF2 to telomeric sequences is modulated by the histone octamer. By means of in vitro models, we found that TRF2 binding is strongly hampered by the presence of telomeric nucleosomes, whereas TRF1 binds efficiently to telomeric DNA in a nucleosomal context and is able to remodel telomeric nucleosomal arrays. Our results indicate that the different behavior of TRF proteins partly depends on the interaction with histone tails of their divergent N-terminal domains. We propose that the interplay between the histone octamer and TRF proteins plays a role in the steps leading to telomere deprotection.
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Affiliation(s)
- Alessandra Galati
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, 00185 Rome, Italy Institute Pasteur-Fondazione Cenci-Bolognetti, Sapienza University of Rome, 00185 Rome, Italy
| | - Emanuela Micheli
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, 00185 Rome, Italy Institute Pasteur-Fondazione Cenci-Bolognetti, Sapienza University of Rome, 00185 Rome, Italy
| | - Claudia Alicata
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, 00185 Rome, Italy
| | - Tiziano Ingegnere
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, 00185 Rome, Italy
| | - Alessandro Cicconi
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, 00185 Rome, Italy Institute Pasteur-Fondazione Cenci-Bolognetti, Sapienza University of Rome, 00185 Rome, Italy
| | | | - Marie-Josèphe Giraud-Panis
- Institute for Research on Cancer and Aging, Nice (IRCAN) CNRS UMR 7284/INSERM U1081, University of Nice Sophia Antipolis, 06107 Nice, France
| | - Eric Gilson
- Institute for Research on Cancer and Aging, Nice (IRCAN) CNRS UMR 7284/INSERM U1081, University of Nice Sophia Antipolis, 06107 Nice, France Department of Medical Genetics, Hospital, CHU of Nice, 06202 Nice, France
| | - Stefano Cacchione
- Department of Biology and Biotechnology 'Charles Darwin', Sapienza University of Rome, 00185 Rome, Italy Institute Pasteur-Fondazione Cenci-Bolognetti, Sapienza University of Rome, 00185 Rome, Italy
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19
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Yamagishi J, Wakaguri H, Yokoyama N, Yamashita R, Suzuki Y, Xuan X, Igarashi I. The Babesia bovis gene and promoter model: an update from full-length EST analysis. BMC Genomics 2014; 15:678. [PMID: 25124460 PMCID: PMC4148916 DOI: 10.1186/1471-2164-15-678] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 07/08/2014] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Babesia bovis is an apicomplexan parasite that causes babesiosis in infected cattle. Genomes of pathogens contain promising information that can facilitate the development of methods for controlling infections. Although the genome of B. bovis is publically available, annotated gene models are not highly reliable prior to experimental validation. Therefore, we validated a preproposed gene model of B. bovis and extended the associated annotations on the basis of experimentally obtained full-length expressed sequence tags (ESTs). RESULTS From in vitro cultured merozoites, 12,286 clones harboring full-length cDNAs were sequenced from both ends using the Sanger method, and 6,787 full-length cDNAs were assembled. These were then clustered, and a nonredundant referential data set of 2,115 full-length cDNA sequences was constructed. The comparison of the preproposed gene model with our data set identified 310 identical genes, 342 almost identical genes, 1,054 genes with potential structural inconsistencies, and 409 novel genes. The median length of 5' untranslated regions (UTRs) was 152 nt. Subsequently, we identified 4,086 transcription start sites (TSSs) and 2,023 transcriptionally active regions (TARs) by examining 5' ESTs. We identified ATGGGG and CCCCAT sites as consensus motifs in TARs that were distributed around -50 bp from TSSs. In addition, we found ACACA, TGTGT, and TATAT sites, which were distributed periodically around TSSs in cycles of approximately 150 bp. Moreover, related periodical distributions were not observed in mammalian promoter regions. CONCLUSIONS The observations in this study indicate the utility of integrated bioinformatics and experimental data for improving genome annotations. In particular, full-length cDNAs with one-base resolution for TSSs enabled the identification of consensus motifs in promoter sequences and demonstrated clear distributions of identified motifs. These observations allowed the illustration of a model promoter composition, which supports the differences in transcriptional regulation frameworks between apicomplexan parasites and mammals.
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Affiliation(s)
- Junya Yamagishi
- />Tohoku Medical Megabank Organization, Tohoku University, 6-3-09, aza Aoba, Sendai, Miyagi 980-8579 Japan
- />National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho west 2-13, Obihiro, Hokkaido 080-8555 Japan
| | - Hiroyuki Wakaguri
- />Department of Medical Genome Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan
| | - Naoaki Yokoyama
- />National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho west 2-13, Obihiro, Hokkaido 080-8555 Japan
| | - Riu Yamashita
- />Tohoku Medical Megabank Organization, Tohoku University, 6-3-09, aza Aoba, Sendai, Miyagi 980-8579 Japan
| | - Yutaka Suzuki
- />Department of Medical Genome Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562 Japan
| | - Xuenan Xuan
- />National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho west 2-13, Obihiro, Hokkaido 080-8555 Japan
| | - Ikuo Igarashi
- />National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho west 2-13, Obihiro, Hokkaido 080-8555 Japan
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