1
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Wu Z, Gu X, Zha L, Yang Q, Zhou Y, Zeng Z. Structural and functional insights into yeast Tbf1 as an atypical telomeric repeat-binding factor. Structure 2024:S0969-2126(24)00128-X. [PMID: 38677290 DOI: 10.1016/j.str.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/14/2024] [Accepted: 04/02/2024] [Indexed: 04/29/2024]
Abstract
Telomeric repeat-binding factor 1 (Tbf1) has a similar architecture as the TRF family of telomeric proteins and plays important roles in both telomere homeostasis and ribosome regulation. However, the molecular basis of why Tbf1 has such different functions compared to other TRFs remains unclear. Here, we present the crystal structures of the TRF homology (TRFH) and Myb-L domains from Schizosaccharomyces pombe Tbf1 (spTbf1). TRFH-mediated homodimerization is essential for spTbf1 stability. Importantly, spTbf1TRFH lacks the conserved docking motif for interactions with telomeric proteins, explaining why spTbf1 does not participate in the assembly of the shelterin complex. Finally, structural and biochemical analyses demonstrate that TRFH and Myb-L domains as well as the loop region of spTbf1 coordinate to recognize S. pombe telomeric double-stranded DNA. Overall, our findings provide structural and functional insights into how fungi Tbf1 acts as an atypical telomeric repeat-binding factor, which helps to understand the evolution of TRFH-containing telomeric proteins.
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Affiliation(s)
- Zhenfang Wu
- 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.
| | - Xin Gu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Lin Zha
- 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
| | - Qingqiu Yang
- Department of Hematology, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Yuanze Zhou
- Department of Hematology, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China.
| | - Zhixiong Zeng
- Hunan Provincial Key Laboratory of the TCM Agricultural Biogenomics, Changsha Medical University, Changsha 410219, China.
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2
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Li J, Lin K, Zhang S, Wu J, Fang Y, Wang Y. Genome-Wide Analysis of Myeloblastosis-Related Genes in Brassica napus L. and Positive Modulation of Osmotic Tolerance by BnMRD107. FRONTIERS IN PLANT SCIENCE 2021; 12:678202. [PMID: 34220898 PMCID: PMC8248502 DOI: 10.3389/fpls.2021.678202] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 04/30/2021] [Indexed: 06/01/2023]
Abstract
Myeloblastosis (MYB)-related transcription factors comprise a large subfamily of the MYB family. They play significant roles in plant development and in stress responses. However, MYB-related proteins have not been comprehensively investigated in rapeseed (Brassica napus L.). In the present study, a genome-wide analysis of MYB-related transcription factors was performed in rapeseed. We identified 251 Brassica napus MYB (BnMYB)-related members, which were divided phylogenetically into five clades. Evolutionary analysis suggested that whole genome duplication and segmental duplication events have played a significant role in the expansion of BnMYB-related gene family. Selective pressure of BnMYB-related genes was estimated using the Ka/Ks ratio, which indicated that BnMYB-related genes underwent strong purifying selection during evolution. In silico analysis showed that various development-associated, phytohormone-responsive, and stress-related cis-acting regulatory elements were enriched in the promoter regions of BnMYB-related genes. Furthermore, MYB-related genes with tissue or organ-specific, stress-responsive expression patterns were identified in B. napus based on temporospatial and abiotic stress expression profiles. Among the stress-responsive MYB-related genes, BnMRD107 was strongly induced by drought stress, and was therefore selected for functional study. Rapeseed seedlings overexpressing BnMRD107 showed improved resistance to osmotic stress. Our findings not only lay a foundation for further functional characterization of BnMYB-related genes, but also provide valuable clues to determine candidate genes for future genetic improvement of B. napus.
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Affiliation(s)
- Jian Li
- Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Yangzhou University, Yangzhou, China
| | - Keyun Lin
- Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Yangzhou University, Yangzhou, China
| | - Shuai Zhang
- Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Yangzhou University, Yangzhou, China
| | - Jian Wu
- Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Yujie Fang
- Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Youping Wang
- Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, China
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3
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Lee I, Kim H, Ko YJ, Lee W. NMR Characterization of the DNA-binding Domain of Arabidopsis thalianaTelomere Repeat Factor. B KOREAN CHEM SOC 2016. [DOI: 10.1002/bkcs.10708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Inhwan Lee
- Department of Biochemistry, College of Life Science and Biotechnology; Yonsei University; Seoul 120-749 Korea
| | - Heeyoun Kim
- Department of Biochemistry, College of Life Science and Biotechnology; Yonsei University; Seoul 120-749 Korea
| | - Yoon-Joo Ko
- National Center for Inter-University Research Facilities; Seoul National University; Seoul 151-747 Korea
| | - Weontae Lee
- Department of Biochemistry, College of Life Science and Biotechnology; Yonsei University; Seoul 120-749 Korea
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4
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Nelson ADL, Forsythe ES, Gan X, Tsiantis M, Beilstein MA. Extending the model of Arabidopsis telomere length and composition across Brassicaceae. Chromosome Res 2015; 22:153-66. [PMID: 24846723 DOI: 10.1007/s10577-014-9423-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Telomeres are repetitive TG-rich DNA elements essential for maintaining the stability of genomes and replicative capacity of cells in almost all eukaryotes. Most of what is known about telomeres in plants comes from the angiosperm Arabidopsis thaliana, which has become an important comparative model for telomere biology. Arabidopsis tolerates numerous insults to its genome, many of which are catastrophic or lethal in other eukaryotic systems such as yeast and vertebrates. Despite the importance of Arabidopsis in establishing a model for the structure and regulation of plant telomeres, only a handful of studies have used this information to assay components of telomeres from across land plants, or even among the closest relatives of Arabidopsis in the plant family Brassicaceae. Here, we determined how well Arabidopsis represents Brassicaceae by comparing multiple aspects of telomere biology in species that represent major clades in the family tree. Specifically, we determined the telomeric repeat sequence, measured bulk telomere length, and analyzed variation in telomere length on syntenic chromosome arms. In addition, we used a phylogenetic approach to infer the evolutionary history of putative telomere-binding proteins, CTC1, STN1, TEN1 (CST), telomere repeat-binding factor like (TRFL), and single Myb histone (SMH). Our analyses revealed conservation of the telomeric DNA repeat sequence, but considerable variation in telomere length among the sampled species, even in comparisons of syntenic chromosome arms. We also found that the single-stranded and double-stranded telomeric DNA-binding complexes CST and TRFL, respectively, differ in their pattern of gene duplication and loss. The TRFL and SMH gene families have undergone numerous duplication events, and these duplicate copies are often retained in the genome. In contrast, CST components occur as single-copy genes in all sampled genomes, even in species that experienced recent whole genome duplication events. Taken together, our results place the Arabidopsis model in the context of other species in Brassicaceae, making the family the best characterized plant group in regard to telomere architecture.
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Affiliation(s)
- Andrew D L Nelson
- School of Plant Sciences, University of Arizona, Tucson, AZ, 85721, USA
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5
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Yun JH, Lee WK, Kim H, Kim E, Cheong C, Cho MH, Lee W. Solution structure of telomere binding domain of AtTRB2 derived from Arabidopsis thaliana. Biochem Biophys Res Commun 2014; 452:436-42. [DOI: 10.1016/j.bbrc.2014.08.095] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 08/19/2014] [Indexed: 10/24/2022]
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6
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Kaplan-Levy RN, Quon T, O'Brien M, Sappl PG, Smyth DR. Functional domains of the PETAL LOSS protein, a trihelix transcription factor that represses regional growth in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 79:477-91. [PMID: 24889508 DOI: 10.1111/tpj.12574] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 05/25/2014] [Accepted: 05/27/2014] [Indexed: 05/11/2023]
Abstract
PETAL LOSS (PTL) is a trihelix transcription factor that represses growth, especially between sepal primordia. As one of 30 trihelix proteins in Arabidopsis, it falls in the GT2 clade with duplicated trihelix DNA-binding domains and a long α-helical central domain. PTL orthologs occur in all angiosperm genomes examined except grasses, and sequence comparisons reveal that there are two further short conserved domains at each end. GT2 itself carries two nuclear localization sequences, but PTL has an additional nuclear localization sequence (NLS). We show that PTL can act as a transcriptional activator in yeast and in planta, with the latter tested by two different functional assays. Specific deletions revealed that the activation region is C-terminal. Site-directed mutagenesis of the DNA-binding domains has shown that a conserved tryptophan and two downstream acidic amino acids in the second trihelix, predicted to promote folding, are each required for PTL function. Also, three basic residues in the third helix, near the DNA interaction sites, support its function. PTL was found to dimerize in yeast. This was confirmed and extended by jointly expressing differentially tagged forms of PTL in a transient expression system in Nicotiana benthamiana leaves. Cytoplasmic PTL (with mutant NLS sequences) was carried into the nucleus upon binding with nuclear-localized PTL, providing each partner carried intact central domains. As this 90-amino acid domain is conserved in most trihelix family members, it seems likely that they all function in dimeric form.
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Affiliation(s)
- Ruth N Kaplan-Levy
- School of Biological Sciences, Monash University, Melbourne, 3800, Vic., Australia
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7
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Lopato S, Borisjuk N, Langridge P, Hrmova M. Endosperm transfer cell-specific genes and proteins: structure, function and applications in biotechnology. FRONTIERS IN PLANT SCIENCE 2014; 5:64. [PMID: 24578704 PMCID: PMC3936200 DOI: 10.3389/fpls.2014.00064] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 02/07/2014] [Indexed: 05/21/2023]
Abstract
Endosperm transfer cells (ETC) are one of four main types of cells in endosperm. A characteristic feature of ETC is the presence of cell wall in-growths that create an enlarged plasma membrane surface area. This specialized cell structure is important for the specific function of ETC, which is to transfer nutrients from maternal vascular tissue to endosperm. ETC-specific genes are of particular interest to plant biotechnologists, who use genetic engineering to improve grain quality and yield characteristics of important field crops. The success of molecular biology-based approaches to manipulating ETC function is dependent on a thorough understanding of the functions of ETC-specific genes and ETC-specific promoters. The aim of this review is to summarize the existing data on structure and function of ETC-specific genes and their products. Potential applications of ETC-specific genes, and in particular their promoters for biotechnology will be discussed.
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Affiliation(s)
- Sergiy Lopato
- *Correspondence: Sergiy Lopato, Australian Centre for Plant Functional Genomics, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia e-mail:
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8
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Kaas Q, Craik DJ. NMR of plant proteins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 71:1-34. [PMID: 23611313 DOI: 10.1016/j.pnmrs.2013.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 01/21/2013] [Indexed: 06/02/2023]
Affiliation(s)
- Quentin Kaas
- The University of Queensland, Institute for Molecular Bioscience, Brisbane, Queensland 4072, Australia
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9
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Giraud-Panis MJ, Pisano S, Benarroch-Popivker D, Pei B, Le Du MH, Gilson E. One identity or more for telomeres? Front Oncol 2013; 3:48. [PMID: 23509004 PMCID: PMC3598436 DOI: 10.3389/fonc.2013.00048] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Accepted: 02/23/2013] [Indexed: 12/19/2022] Open
Abstract
A major issue in telomere research is to understand how the integrity of chromosome ends is controlled. The fact that different types of nucleoprotein complexes have been described at the telomeres of different organisms raises the question of whether they have in common a structural identity that explains their role in chromosome protection. We will review here how telomeric nucleoprotein complexes are structured, comparing different organisms and trying to link these structures to telomere biology. It emerges that telomeres are formed by a complex and specific network of interactions between DNA, RNA, and proteins. The fact that these interactions and associated activities are reinforcing each other might help to guarantee the robustness of telomeric functions across the cell cycle and in the event of cellular perturbations. We will also discuss the recent notion that telomeres have evolved specific systems to overcome the DNA topological stress generated during their replication and transcription. This will lead to revisit the way we envisage the functioning of telomeric complexes since the regulation of topology is central to DNA stability, replication, recombination, and transcription as well as to chromosome higher-order organization.
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Affiliation(s)
- Marie-Josèphe Giraud-Panis
- Faculté de Médecine de Nice, Université de Nice-Sophia Antipolis, Institute for Research on Cancer and Aging Nice, UMR 7284 CNRS, U1081 INSERM Nice, France
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10
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Lee WK, Yun JH, Lee W, Cho MH. DNA-binding domain of AtTRB2 reveals unique features of a single Myb histone protein family that binds to both Arabidopsis- and human-type telomeric DNA sequences. MOLECULAR PLANT 2012; 5:1406-1408. [PMID: 22859734 DOI: 10.1093/mp/sss063] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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11
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Crystal structure of the Klebsiella pneumoniae NFeoB/FeoC complex and roles of FeoC in regulation of Fe2+ transport by the bacterial Feo system. J Bacteriol 2012; 194:6518-26. [PMID: 23024345 DOI: 10.1128/jb.01228-12] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Feo is a transport system commonly used by bacteria to acquire environmental Fe(2+). It consists of three proteins: FeoA, FeoB, and FeoC. FeoB is a large protein with a cytosolic N-terminal domain (NFeoB) that contains a regulatory G protein domain and a helical S domain. The C-terminal region of FeoB is a transmembrane domain that likely acts as the Fe(2+) permease. NFeoB has been shown to form a trimer pore that may function as an Fe(2+) gate. FeoC is a small winged-helix protein that possesses four conserved cysteine residues with a consensus sequence that likely provides binding sites for the [Fe-S] cluster. Therefore, FeoC is presumed to be an [Fe-S] cluster-dependent regulator that directly controls transcription of the feo operon. Despite the apparent significance of the Feo system, however, the function of FeoC has not been experimentally demonstrated. Here, we show that Klebsiella pneumoniae FeoC (KpFeoC) forms a tight complex with the intracellular N-terminal domain of FeoB (KpNFeoB). The crystal structure of the complex reveals that KpFeoC binds to KpNFeoB between the switch II region of the G protein domain and the effector S domain and that the long KpFeoC W1 loop lies above the KpNFeoB nucleotide-binding site. These interactions suggest that KpFeoC modulates the guanine nucleotide-mediated signal transduction process. Moreover, we showed that binding of KpFeoC disrupts pore formation by interfering with KpNFeoB trimerization. These results provide strong evidence suggesting that KpFeoC plays a crucial role in regulating Fe(2+) transport in Klebsiella pneumonia in addition to the presumed gene regulator role.
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12
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Qin S, Zhou HX. Structural models of protein-DNA complexes based on interface prediction and docking. Curr Protein Pept Sci 2012; 12:531-9. [PMID: 21787304 DOI: 10.2174/138920311796957694] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 04/01/2011] [Accepted: 05/04/2011] [Indexed: 11/22/2022]
Abstract
Protein-DNA interactions are the physical basis of gene expression and DNA modification. Structural models that reveal these interactions are essential for their understanding. As only a limited number of structures for protein-DNA complexes have been determined by experimental methods, computation methods provide a potential way to fill the need. We have developed the DISPLAR method to predict DNA binding sites on proteins. Predicted binding sites have been used to assist the building of structural models by docking, either by guiding the docking or by selecting near-native candidates from the docked poses. Here we applied the DISPLAR method to predict the DNA binding sites for 20 DNA-binding proteins, which have had their DNA binding sites characterized by NMR chemical shift perturbation. For two of these proteins, the structures of their complexes with DNA have also been determined. With the help of the DISPLAR predictions, we built structural models for these two complexes. Evaluations of both the DNA binding sites for 20 proteins and the structural models of the two protein-DNA complexes against experimental results demonstrate the significant promise of our model-building approach.
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Affiliation(s)
- Sanbo Qin
- Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306, USA
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13
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Wei SY, Lou YC, Tsai JY, Ho MR, Chou CC, Rajasekaran M, Hsu HM, Tai JH, Hsiao CD, Chen C. Structure of the Trichomonas vaginalis Myb3 DNA-binding domain bound to a promoter sequence reveals a unique C-terminal β-hairpin conformation. Nucleic Acids Res 2011; 40:449-60. [PMID: 21908401 PMCID: PMC3245928 DOI: 10.1093/nar/gkr707] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Trichomonas vaginalis Myb3 transcription factor (tvMyb3) recognizes the MRE-1 promoter sequence and regulates ap65-1 gene, which encodes a hydrogenosomal malic enzyme that may play a role in the cytoadherence of the parasite. Here, we identified tvMyb353–180 as the essential fragment for DNA recognition and report the crystal structure of tvMyb353–180 bound to MRE-1 DNA. The N-terminal fragment adopts the classical conformation of an Myb DNA-binding domain, with the third helices of R2 and R3 motifs intercalating in the major groove of DNA. The C-terminal extension forms a β-hairpin followed by a flexible tail, which is stabilized by several interactions with the R3 motif and is not observed in other Myb proteins. Interestingly, this unique C-terminal fragment does not stably connect with DNA in the complex structure but is involved in DNA binding, as demonstrated by NMR chemical shift perturbation, 1H-15N heteronuclear-nuclear Overhauser effect and intermolecular paramagnetic relaxation enhancement. Site-directed mutagenesis also revealed that this C-terminal fragment is crucial for DNA binding, especially the residue Arg153 and the fragment K170KRK173. We provide a structural basis for MRE-1 DNA recognition and suggest a possible post-translational regulation of tvMyb3 protein.
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Affiliation(s)
- Shu-Yi Wei
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan, ROC
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14
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Giraud-Panis MJ, Pisano S, Poulet A, Le Du MH, Gilson E. Structural identity of telomeric complexes. FEBS Lett 2010; 584:3785-99. [PMID: 20696167 DOI: 10.1016/j.febslet.2010.08.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 08/02/2010] [Accepted: 08/02/2010] [Indexed: 02/01/2023]
Abstract
A major issue in telomere research is to understand how the integrity of chromosome ends is controlled. Although several nucleoprotein complexes have been described at the telomeres of different organisms, it is still unclear how they confer a structural identity to chromosome ends in order to mask them from DNA repair and to ensure their proper replication. In this review, we describe how telomeric nucleoprotein complexes are structured, comparing different organisms and trying to link these structures to telomere biology. It emerges that telomeres are formed by a complex and specific network of interactions between DNA, RNA and proteins. The fact that these interactions and associated activities are reinforcing each other might help to guaranty the robustness of telomeric functions across the cell cycle and in the event of cellular perturbations. We propose that telomeric nucleoprotein complexes orient cell fate through dynamic transitions in their structures and their organization.
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Affiliation(s)
- Marie-Josèphe Giraud-Panis
- University de Nice, Laboratory of Biology and Pathology of Genomes, UMR 6267 CNRS U998 INSERM, Faculté de Médecine, Nice, France
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15
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Watson JM, Riha K. Comparative biology of telomeres: where plants stand. FEBS Lett 2010; 584:3752-9. [PMID: 20580356 PMCID: PMC3767043 DOI: 10.1016/j.febslet.2010.06.017] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 06/11/2010] [Accepted: 06/14/2010] [Indexed: 01/02/2023]
Abstract
Telomeres are essential structures at the ends of eukaryotic chromosomes. Work on their structure and function began almost 70 years ago in plants and flies, continued through the Nobel Prize winning work on yeast and ciliates, and goes on today in many model and non-model organisms. The basic molecular mechanisms of telomeres are highly conserved throughout evolution, and our current understanding of how telomeres function is a conglomeration of insights gained from many different species. This review will compare the current knowledge of telomeres in plants with other organisms, with special focus on the functional length of telomeric DNA, the search for TRF homologs, the family of POT1 proteins, and the recent discovery of members of the CST complex.
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Affiliation(s)
- J Matthew Watson
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna, Austria
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16
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Single-Myb-histone proteins from Arabidopsis thaliana: a quantitative study of telomere-binding specificity and kinetics. Biochem J 2009; 419:221-8, 2 p following 228. [DOI: 10.1042/bj20082195] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Proteins that bind telomeric DNA modulate the structure of chromosome ends and control telomere function and maintenance. It has been shown that AtTRB (Arabidopsis thaliana telomere-repeat-binding factor) proteins from the SMH (single-Myb-histone) family selectively bind double-stranded telomeric DNA and interact with the telomeric protein AtPOT1b (A. thaliana protection of telomeres 1b), which is involved in telomere capping. In the present study, we performed the first quantitative DNA-binding study of this plant-specific family of proteins. Interactions of full-length proteins AtTRB1 and AtTRB3 with telomeric DNA were analysed by electrophoretic mobility-shift assay, fluorescence anisotropy and surface plasmon resonance to reveal their binding stoichiometry and kinetics. Kinetic analyses at different salt conditions enabled us to estimate the electrostatic component of binding and explain different affinities of the two proteins to telomeric DNA. On the basis of available data, a putative model explaining the binding stoichiometry and the protein arrangement on telomeric DNA is presented.
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17
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Ko S, Yu EY, Shin J, Yoo HH, Tanaka T, Kim WT, Cho HS, Lee W, Chung IK. Solution Structure of the DNA Binding Domain of Rice Telomere Binding Protein RTBP1,. Biochemistry 2009; 48:827-38. [DOI: 10.1021/bi801270g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sunggeon Ko
- Departments of Biochemistry and Biology, Protein Network Research Center, Yonsei University, Seoul 120-749, Korea, and Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Eun Young Yu
- Departments of Biochemistry and Biology, Protein Network Research Center, Yonsei University, Seoul 120-749, Korea, and Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Joon Shin
- Departments of Biochemistry and Biology, Protein Network Research Center, Yonsei University, Seoul 120-749, Korea, and Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Hyun Hee Yoo
- Departments of Biochemistry and Biology, Protein Network Research Center, Yonsei University, Seoul 120-749, Korea, and Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Toshiyuki Tanaka
- Departments of Biochemistry and Biology, Protein Network Research Center, Yonsei University, Seoul 120-749, Korea, and Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Woo Taek Kim
- Departments of Biochemistry and Biology, Protein Network Research Center, Yonsei University, Seoul 120-749, Korea, and Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Hyun-Soo Cho
- Departments of Biochemistry and Biology, Protein Network Research Center, Yonsei University, Seoul 120-749, Korea, and Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Weontae Lee
- Departments of Biochemistry and Biology, Protein Network Research Center, Yonsei University, Seoul 120-749, Korea, and Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - In Kwon Chung
- Departments of Biochemistry and Biology, Protein Network Research Center, Yonsei University, Seoul 120-749, Korea, and Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
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18
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Shakirov EV, Salzberg SL, Alam M, Shippen DE. Analysis of Carica papaya Telomeres and Telomere-Associated Proteins: Insights into the Evolution of Telomere Maintenance in Brassicales. TROPICAL PLANT BIOLOGY 2008; 1:202-215. [PMID: 20664721 PMCID: PMC2909770 DOI: 10.1007/s12042-008-9018-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Telomeres are terminal regions of linear eukaryotic chromosomes that are critical for genome stability and continued cell proliferation. The draft assembly of the papaya genome provides an opportunity to analyze and compare the evolution of telomeric DNA sequence composition and telomere maintenance machinery in this and other organisms of the Brassicales Order, which includes Arabidopsis. Here we investigate telomere size and sequence variation at papaya chromosome ends. As with most other plant species, papaya telomeres consist of TTTAGGG repeats. However, in contrast to members of the closely related Brassicaceae family, telomeres in papaya are ~10-fold longer. Sequence analysis reveals that many centromereproximal telomere repeats in papaya harbor nucleotide substitutions and insertions of Gs and Ts. In contrast, we found very few N-to-C substitutions, and even fewer instances of nucleotide deletion, suggesting that a six-nucleotide telomere repeat is not well tolerated. The papaya genome encodes single-copy sequence homologues of several genes involved in telomere maintenance and chromosome end protection, including the Telomerase Reverse Transcriptase (TERT) and Protection Of Telomeres (POT1). Notably, unlike Arabidopsis, which encodes six Telomere Repeat binding Factor-like (TRFL) proteins that bind double-stranded telomere DNA, papaya appears to encode only two such proteins. Thus, the more streamlined genome of papaya will provide an excellent resource for comparative and functional analysis of telomeres in plants.
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Affiliation(s)
- E. V. Shakirov
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843-2128, USA
| | - S. L. Salzberg
- Center for Bioinformatics and Computational Biology, and Department of Computer Science, University of Maryland, 3125 Biomolecular Sciences Bldg, College Park, MD 20742, USA
| | - M. Alam
- Advanced Studies in Genomics, Proteomics and Bioinformatics, and Department of Microbiology, University of Hawaii, Honolulu, HI 96822, USA
| | - D. E. Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX 77843-2128, USA,
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19
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Agudelo-Romero P, Carbonell P, de la Iglesia F, Carrera J, Rodrigo G, Jaramillo A, Pérez-Amador MA, Elena SF. Changes in the gene expression profile of Arabidopsis thaliana after infection with Tobacco etch virus. Virol J 2008; 5:92. [PMID: 18684336 PMCID: PMC2518140 DOI: 10.1186/1743-422x-5-92] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Accepted: 08/07/2008] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Tobacco etch potyvirus (TEV) has been extensively used as model system for the study of positive-sense RNA virus infecting plants. TEV ability to infect Arabidopsis thaliana varies among ecotypes. In this study, changes in gene expression of A. thaliana ecotype Ler infected with TEV have been explored using long-oligonucleotide arrays. A. thaliana Ler is a susceptible host that allows systemic movement, although the viral load is low and syndrome induced ranges from asymptomatic to mild. Gene expression profiles were monitored in whole plants 21 days post-inoculation (dpi). Microarrays contained 26,173 protein-coding genes and 87 miRNAs. RESULTS Expression analysis identified 1727 genes that displayed significant and consistent changes in expression levels either up or down, in infected plants. Identified TEV-responsive genes encode a diverse array of functional categories that include responses to biotic (such as the systemic acquired resistance pathway and hypersensitive responses) and abiotic stresses (droughtness, salinity, temperature, and wounding). The expression of many different transcription factors was also significantly affected, including members of the R2R3-MYB family and ABA-inducible TFs. In concordance with several other plant and animal viruses, the expression of heat-shock proteins (HSP) was also increased. Finally, we have associated functional GO categories with KEGG biochemical pathways, and found that many of the altered biological functions are controlled by changes in basal metabolism. CONCLUSION TEV infection significantly impacts a wide array of cellular processes, in particular, stress-response pathways, including the systemic acquired resistance and hypersensitive responses. However, many of the observed alterations may represent a global response to viral infection rather than being specific of TEV.
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Affiliation(s)
- Patricia Agudelo-Romero
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022, València, Spain
| | - Pablo Carbonell
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022, València, Spain
| | - Francisca de la Iglesia
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022, València, Spain
| | - Javier Carrera
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022, València, Spain
| | - Guillermo Rodrigo
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022, València, Spain
| | - Alfonso Jaramillo
- Laboratoire de Biochimie, École Polytechnique, 91128, Palaiseau, France
| | - Miguel A Pérez-Amador
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022, València, Spain
| | - Santiago F Elena
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022, València, Spain
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20
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Guerler A, Knapp EW. Novel protein folds and their nonsequential structural analogs. Protein Sci 2008; 17:1374-82. [PMID: 18583523 DOI: 10.1110/ps.035469.108] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Newly determined protein structures are classified to belong to a new fold, if the structures are sufficiently dissimilar from all other so far known protein structures. To analyze structural similarities of proteins, structure alignment tools are used. We demonstrate that the usage of nonsequential structure alignment tools, which neglect the polypeptide chain connectivity, can yield structure alignments with significant similarities between proteins of known three-dimensional structure and newly determined protein structures that possess a new fold. The recently introduced protein structure alignment tool, GANGSTA, is specialized to perform nonsequential alignments with proper assignment of the secondary structure types by focusing on helices and strands only. In the new version, GANGSTA+, the underlying algorithms were completely redesigned, yielding enhanced quality of structure alignments, offering alignment against a larger database of protein structures, and being more efficient. We applied DaliLite, TM-align, and GANGSTA+ on three protein crystal structures considered to be novel folds. Applying GANGSTA+ to these novel folds, we find proteins in the ASTRAL40 database, which possess significant structural similarities, albeit the alignments are nonsequential and in some cases involve secondary structure elements aligned in reverse orientation. A web server is available at http://agknapp.chemie.fu-berlin.de/gplus for pairwise alignment, visualization, and database comparison.
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Affiliation(s)
- Aysam Guerler
- Department of Chemistry and Biochemistry, Freie Universität Berlin, 14195 Berlin, Germany
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21
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Mozgová I, Schrumpfová PP, Hofr C, Fajkus J. Functional characterization of domains in AtTRB1, a putative telomere-binding protein in Arabidopsis thaliana. PHYTOCHEMISTRY 2008; 69:1814-9. [PMID: 18479720 DOI: 10.1016/j.phytochem.2008.04.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2008] [Revised: 03/24/2008] [Accepted: 04/01/2008] [Indexed: 05/24/2023]
Abstract
Telomeres are nucleoprotein structures ensuring the stability of eukaryotic chromosome ends. Two protein families, TRFL (TFL-Like) and SMH (Single-Myb-Histone), containing a specific telobox motif in their Myb domain, have been identified as potential candidates involved in a functional nucleoprotein structure analogous to human "shelterin" at plant telomeres. We analyze the DNA-protein interaction of the full-length and truncated variants of AtTRB1, a SMH-family member with a typical structure: N-terminal Myb domain, central H1/5 domain and C-terminal coiled-coil. We show that preferential interaction of AtTRB1 with double-stranded telomeric DNA is mediated by the Myb domain, while the H1/5 domain is involved in non-specific DNA-protein interaction and in the multimerization of AtTRB1.
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Affiliation(s)
- Iva Mozgová
- Department of Functional Genomics and Proteomics, Institute of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5, CZ-62500 Brno, Czech Republic
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22
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Identification and characterization of three telomere repeat-binding factors in rice. Biochem Biophys Res Commun 2008; 372:85-90. [PMID: 18477473 DOI: 10.1016/j.bbrc.2008.04.181] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 04/29/2008] [Indexed: 12/16/2022]
Abstract
Telomeres consist of nucleoprotein complexes that protect chromosome end structures. Here, we describe three OsTRBF genes, encoding telomere repeat-binding factors of the single Myb histone family in rice. The predicted proteins contain a Myb DNA-binding motif and a linker histone H1/H5 domain in the N-terminal and central regions, respectively. The OsTRBF transcripts were constitutively detected in rice plants grown under greenhouse conditions. Gel retardation assays showed that these OsTRBF proteins bind specifically to the plant double-stranded telomeric sequence, TTTAGGG, with markedly different binding affinities as judged by their respective dissociation constants. Yeast two-hybrid and in vitro pull-down assays indicated that both OsTRBF1 and OsTRBF2 interact with one another to form homo- and hetero-complexes, while OsTRBF3 appeared to act as a monomer. Our results suggest that OsTRBFs play combinatory roles in the function and structure of telomeres in rice.
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23
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Ko S, Jun SH, Bae H, Byun JS, Han W, Park H, Yang SW, Park SY, Jeon YH, Cheong C, Kim WT, Lee W, Cho HS. Structure of the DNA-binding domain of NgTRF1 reveals unique features of plant telomere-binding proteins. Nucleic Acids Res 2008; 36:2739-55. [PMID: 18367475 PMCID: PMC2377444 DOI: 10.1093/nar/gkn030] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2007] [Revised: 01/17/2008] [Accepted: 01/18/2008] [Indexed: 02/04/2023] Open
Abstract
Telomeres are protein-DNA elements that are located at the ends of linear eukaryotic chromosomes. In concert with various telomere-binding proteins, they play an essential role in genome stability. We determined the structure of the DNA-binding domain of NgTRF1, a double-stranded telomere-binding protein of tobacco, using multidimensional NMR spectroscopy and X-ray crystallography. The DNA-binding domain of NgTRF1 contained the Myb-like domain and C-terminal Myb-extension that is characteristic of plant double-stranded telomere-binding proteins. It encompassed amino acids 561-681 (NgTRF1(561-681)), and was composed of 4 alpha-helices. We also determined the structure of NgTRF1(561-681) bound to plant telomeric DNA. We identified several amino acid residues that interacted directly with DNA, and confirmed their role in the binding of NgTRF1 to telomere using site-directed mutagenesis. Based on a structural comparison of the DNA-binding domains of NgTRF1 and human TRF1 (hTRF1), NgTRF1 has both common and unique DNA-binding properties. Interaction of Myb-like domain with telomeric sequences is almost identical in NgTRF1(561-681) with the DNA-binding domain of hTRF1. The interaction of Arg-638 with the telomeric DNA, which is unique in NgTRF1(561-681), may provide the structural explanation for the specificity of NgTRF1 to the plant telomere sequences, (TTTAGGG)(n).
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Affiliation(s)
- Sunggeon Ko
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Sung-Hoon Jun
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Hansol Bae
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Jung-Sue Byun
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Woong Han
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Heeyoung Park
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Seong Wook Yang
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Sam-Yong Park
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Young Ho Jeon
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Chaejoon Cheong
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Woo Taek Kim
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Weontae Lee
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
| | - Hyun-Soo Cho
- Department of Biochemistry, Department of Biology, Protein Network Research Center, College of Life Sciences and Biotechnology, Yonsei University, Seoul 120-749, Korea, Protein Design Laboratory, Yokohama City University, Suehiro 1-7-29, Tsurumi-ku, Yokohama 230-0045, Japan and Magnetic Resonance Team, Korea Basic Science Institute (KBSI), Ochang, Chungbuk 363-883, Korea
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24
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Zellinger B, Riha K. Composition of plant telomeres. ACTA ACUST UNITED AC 2007; 1769:399-409. [PMID: 17383025 DOI: 10.1016/j.bbaexp.2007.02.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Revised: 02/01/2007] [Accepted: 02/09/2007] [Indexed: 12/15/2022]
Abstract
Telomeres are essential elements of eukaryotic chromosomes that differentiate native chromosome ends from deleterious DNA double-strand breaks (DSBs). This is achieved by assembling chromosome termini in elaborate high-order nucleoprotein structures that in most organisms encompass telomeric DNA, specific telomere-associated proteins as well as general chromatin and DNA repair factors. Although the individual components of telomeric chromatin are evolutionary highly conserved, cross species comparisons have revealed a remarkable flexibility in their utilization at telomeres. This review outlines the strategies used for chromosome end protection and maintenance in mammals, yeast and flies and discusses current progress in deciphering telomere structure in plants.
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Affiliation(s)
- Barbara Zellinger
- Gregor Mendel Institute of Plant Molecular Biology, Austrian Academy of Sciences, Dr. Bohrgasse 3, A-1030 Vienna, Austria
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25
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Hwang MG, Cho MH. Arabidopsis thaliana telomeric DNA-binding protein 1 is required for telomere length homeostasis and its Myb-extension domain stabilizes plant telomeric DNA binding. Nucleic Acids Res 2007; 35:1333-42. [PMID: 17272298 PMCID: PMC1851659 DOI: 10.1093/nar/gkm043] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Telomeres are specific protein–DNA complexes that protect the ends of eukaryotic chromosomes from fusion and degradation and are maintained by a specialized mechanism exerted by telomerase and telomere-binding proteins (TBPs), which are evolutionarily conserved. AtTBP1 is an Arabidopsis thaliana protein that binds plant telomeric DNA in vitro. Here, we demonstrated that lack of AtTBP1 results in a deregulation of telomere length control, with mutant telomeres expanding steadily by the fourth generation. DNA-binding studies with mutant AtTBP1 proteins showed that the Myb-extension domain of AtTBP1 is required for binding to plant telomeric DNA. Our results suggest that AtTBP1 is involved in the telomere length mechanism in A. thaliana and that the Myb-extension domain of AtTBP1 may stabilize plant telomeric DNA binding.
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Affiliation(s)
| | - Myeon Haeng Cho
- *To whom correspondence should be addressed. Tel: +82 2 2123 4460; Fax: +82 2 312 5657;
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