1
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Angel SO, Vanagas L, Alonso AM. Mechanisms of adaptation and evolution in Toxoplasma gondii. Mol Biochem Parasitol 2024; 258:111615. [PMID: 38354788 DOI: 10.1016/j.molbiopara.2024.111615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/28/2023] [Accepted: 02/06/2024] [Indexed: 02/16/2024]
Abstract
Toxoplasma has high host flexibility, infecting all nucleated cells of mammals and birds. This implies that during its infective process the parasite must constantly adapt to different environmental situations, which in turn leads to modifications in its metabolism, regulation of gene transcription, translation of mRNAs and stage specific factors. There are conserved pathways that support these adaptations, which we aim to elucidate in this review. We begin by exploring the widespread epigenetic mechanisms and transcription regulators, continue with the supportive role of Heat Shock Proteins (Hsp), the translation regulation, stress granules, and finish with the emergence of contingency genes in highly variable genomic domains, such as subtelomeres. Within epigenetics, the discovery of a new histone variant of the H2B family (H2B.Z), contributing to T. gondii virulence and differentiation, but also gene expression regulation and its association with the metabolic state of the parasite, is highlighted. Associated with the regulation of gene expression are transcription factors (TFs). An overview of the main findings on TF and development is presented. We also emphasize the role of Hsp90 and Tgj1 in T. gondii metabolic fitness and the regulation of protein translation. Translation regulation is also highlighted as a mechanism for adaptation to conditions encountered by the parasite as well as stress granules containing mRNA and proteins generated in the extracellular tachyzoite. Another important aspect in evolution and adaptability are the subtelomeres because of their high variability and gene duplication rate. Toxoplasma possess multigene families of membrane proteins and contingency genes that are associated with different metabolic stresses. Among them parasite differentiation and environmental stresses stand out, including those that lead tachyzoite to bradyzoite conversion. Finally, we are interested in positioning protozoa as valuable evolution models, focusing on research related to the Extended Evolutionary Synthesis, based on models recently generated, such as extracellular adaptation and ex vivo cyst recrudescence.
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Affiliation(s)
- Sergio O Angel
- Laboratorio de Parasitología Molecular, INTECH, CONICET-UNSAM, Av. Intendente Marino Km. 8.2, C.C 164, (B7130IIWA), Chascomús, Prov, Buenos Aires, Argentina.
| | - Laura Vanagas
- Laboratorio de Parasitología Molecular, INTECH, CONICET-UNSAM, Av. Intendente Marino Km. 8.2, C.C 164, (B7130IIWA), Chascomús, Prov, Buenos Aires, Argentina.
| | - Andres M Alonso
- Laboratorio de Parasitología Molecular, INTECH, CONICET-UNSAM, Av. Intendente Marino Km. 8.2, C.C 164, (B7130IIWA), Chascomús, Prov, Buenos Aires, Argentina.
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2
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Hu C, Zhu XT, He MH, Shao Y, Qin Z, Wu ZJ, Zhou JQ. Elimination of subtelomeric repeat sequences exerts little effect on telomere essential functions in Saccharomyces cerevisiae. eLife 2024; 12:RP91223. [PMID: 38656297 DOI: 10.7554/elife.91223] [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] [Indexed: 04/26/2024] Open
Abstract
Telomeres, which are chromosomal end structures, play a crucial role in maintaining genome stability and integrity in eukaryotes. In the baker's yeast Saccharomyces cerevisiae, the X- and Y'-elements are subtelomeric repetitive sequences found in all 32 and 17 telomeres, respectively. While the Y'-elements serve as a backup for telomere functions in cells lacking telomerase, the function of the X-elements remains unclear. This study utilized the S. cerevisiae strain SY12, which has three chromosomes and six telomeres, to investigate the role of X-elements (as well as Y'-elements) in telomere maintenance. Deletion of Y'-elements (SY12YΔ), X-elements (SY12XYΔ+Y), or both X- and Y'-elements (SY12XYΔ) did not impact the length of the terminal TG1-3 tracks or telomere silencing. However, inactivation of telomerase in SY12YΔ, SY12XYΔ+Y, and SY12XYΔ cells resulted in cellular senescence and the generation of survivors. These survivors either maintained their telomeres through homologous recombination-dependent TG1-3 track elongation or underwent microhomology-mediated intra-chromosomal end-to-end joining. Our findings indicate the non-essential role of subtelomeric X- and Y'-elements in telomere regulation in both telomerase-proficient and telomerase-null cells and suggest that these elements may represent remnants of S. cerevisiae genome evolution. Furthermore, strains with fewer or no subtelomeric elements exhibit more concise telomere structures and offer potential models for future studies in telomere biology.
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Affiliation(s)
- Can Hu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Xue-Ting Zhu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Ming-Hong He
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Yangyang Shao
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Zhongjun Qin
- Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Zhi-Jing Wu
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
- Key Laboratory of Systems Health Science of Zhejiang Province, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
| | - Jin-Qiu Zhou
- The State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
- Key Laboratory of Systems Health Science of Zhejiang Province, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
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3
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Li B. Unwrap RAP1's Mystery at Kinetoplastid Telomeres. Biomolecules 2024; 14:67. [PMID: 38254667 PMCID: PMC10813129 DOI: 10.3390/biom14010067] [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: 12/06/2023] [Revised: 12/27/2023] [Accepted: 12/27/2023] [Indexed: 01/24/2024] Open
Abstract
Although located at the chromosome end, telomeres are an essential chromosome component that helps maintain genome integrity and chromosome stability from protozoa to mammals. The role of telomere proteins in chromosome end protection is conserved, where they suppress various DNA damage response machineries and block nucleolytic degradation of the natural chromosome ends, although the detailed underlying mechanisms are not identical. In addition, the specialized telomere structure exerts a repressive epigenetic effect on expression of genes located at subtelomeres in a number of eukaryotic organisms. This so-called telomeric silencing also affects virulence of a number of microbial pathogens that undergo antigenic variation/phenotypic switching. Telomere proteins, particularly the RAP1 homologs, have been shown to be a key player for telomeric silencing. RAP1 homologs also suppress the expression of Telomere Repeat-containing RNA (TERRA), which is linked to their roles in telomere stability maintenance. The functions of RAP1s in suppressing telomere recombination are largely conserved from kinetoplastids to mammals. However, the underlying mechanisms of RAP1-mediated telomeric silencing have many species-specific features. In this review, I will focus on Trypanosoma brucei RAP1's functions in suppressing telomeric/subtelomeric DNA recombination and in the regulation of monoallelic expression of subtelomere-located major surface antigen genes. Common and unique mechanisms will be compared among RAP1 homologs, and their implications will be discussed.
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Affiliation(s)
- Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Arts and Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA;
- Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
- Center for RNA Science and Therapeutics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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4
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Dion C, Laberthonnière C, Magdinier F. [Epigenetics, principles and examples of applications]. Rev Med Interne 2023; 44:594-601. [PMID: 37438189 DOI: 10.1016/j.revmed.2023.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 06/20/2023] [Accepted: 06/20/2023] [Indexed: 07/14/2023]
Abstract
Since the discovery of DNA as the support of genetic information, the challenge for generations of life scientists was to understand the mechanisms underlying the process that translate the sequence of a gene to a phenotype. In the 1950s, the concept of epigenetics was defined by the British biologist Conrad H. Waddington as the study of "epigenesis" that governs the biological processes involved in the development of any organism. The term epigenetics, now best defined as "above the DNA sequence" reflects the gene-environment interactions by which genes determine traits. Since, its first description, studies underlying the mechanisms involved in these processes has led to an increasing understanding of the regulation all genome transactions such as transcription, replication, repair and the biological pathways coordinated by these mechanisms. We will discuss here the main principles regulating epigenetic processes, their roles in physiology, their evolution over the life time and their implications in medicine.
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Affiliation(s)
- C Dion
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, 13000 Marseille, France; MRC London Institute of Medical Sciences (LMS), London, United Kingdom; Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, United Kingdom
| | - C Laberthonnière
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, 13000 Marseille, France; Molecular Developmental Biology, Faculty of Science, Radboud University, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - F Magdinier
- Aix Marseille Univ, INSERM, Marseille Medical Genetics, 13000 Marseille, France.
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5
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Sanpedro-Luna JA, Vega-Alvarado L, Vázquez-Cruz C, Sánchez-Alonso P. Global Gene Expression of Post-Senescent Telomerase-Negative ter1Δ Strain of Ustilago maydis. J Fungi (Basel) 2023; 9:896. [PMID: 37755003 PMCID: PMC10532341 DOI: 10.3390/jof9090896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Revised: 08/15/2023] [Accepted: 08/16/2023] [Indexed: 09/28/2023] Open
Abstract
We analyzed the global expression patterns of telomerase-negative mutants from haploid cells of Ustilago maydis to identify the gene network required for cell survival in the absence of telomerase. Mutations in either of the telomerase core subunits (trt1 and ter1) of the dimorphic fungus U. maydis cause deficiencies in teliospore formation. We report the global transcriptome analysis of two ter1Δ survivor strains of U. maydis, revealing the deregulation of telomerase-deleted responses (TDR) genes, such as DNA-damage response, stress response, cell cycle, subtelomeric, and proximal telomere genes. Other differentially expressed genes (DEGs) found in the ter1Δ survivor strains were related to pathogenic lifestyle factors, plant-pathogen crosstalk, iron uptake, meiosis, and melanin synthesis. The two ter1Δ survivors were phenotypically comparable, yet DEGs were identified when comparing these strains. Our findings suggest that teliospore formation in U. maydis is controlled by key pathogenic lifestyle and meiosis genes.
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Affiliation(s)
- Juan Antonio Sanpedro-Luna
- Posgrado en Microbiología, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico;
| | - Leticia Vega-Alvarado
- Instituto de Ciencias Aplicadas y Tecnología, Universidad Nacional Autónoma de México, Ciudad de Mexico 04510, Mexico;
| | - Candelario Vázquez-Cruz
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico;
| | - Patricia Sánchez-Alonso
- Centro de Investigaciones en Ciencias Microbiológicas, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Puebla 72570, Mexico;
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6
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Cittadino GM, Andrews J, Purewal H, Estanislao Acuña Avila P, Arnone JT. Functional Clustering of Metabolically Related Genes Is Conserved across Dikarya. J Fungi (Basel) 2023; 9:jof9050523. [PMID: 37233234 DOI: 10.3390/jof9050523] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/08/2023] [Accepted: 04/27/2023] [Indexed: 05/27/2023] Open
Abstract
Transcriptional regulation is vital for organismal survival, with many layers and mechanisms collaborating to balance gene expression. One layer of this regulation is genome organization, specifically the clustering of functionally related, co-expressed genes along the chromosomes. Spatial organization allows for position effects to stabilize RNA expression and balance transcription, which can be advantageous for a number of reasons, including reductions in stochastic influences between the gene products. The organization of co-regulated gene families into functional clusters occurs extensively in Ascomycota fungi. However, this is less characterized within the related Basidiomycota fungi despite the many uses and applications for the species within this clade. This review will provide insight into the prevalence, purpose, and significance of the clustering of functionally related genes across Dikarya, including foundational studies from Ascomycetes and the current state of our understanding throughout representative Basidiomycete species.
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Affiliation(s)
- Gina M Cittadino
- Department of Biological and Environmental Sciences, Le Moyne College, Syracuse, NY 13214, USA
| | - Johnathan Andrews
- Department of Biological and Environmental Sciences, Le Moyne College, Syracuse, NY 13214, USA
| | - Harpreet Purewal
- Department of Biological and Environmental Sciences, Le Moyne College, Syracuse, NY 13214, USA
| | | | - James T Arnone
- Department of Biological and Environmental Sciences, Le Moyne College, Syracuse, NY 13214, USA
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7
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Lustig AJ. Investigating the origin of subtelomeric and centromeric AT-rich elements in Aspergillus flavus. PLoS One 2023; 18:e0279148. [PMID: 36758027 PMCID: PMC9910759 DOI: 10.1371/journal.pone.0279148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/30/2023] [Indexed: 02/10/2023] Open
Abstract
An in silico study of Aspergillus flavus genome stability uncovered significant variations in both coding and non-coding regions. The non-coding insertions uniformly consisted of AT-rich sequences that are evolutionarily maintained, albeit distributed at widely different sites in an array of A. flavus strains. A survey of ≥ 2kb AT-rich elements (AT ≥ 70%; ATEs) in non-centromeric regions uncovered two major categories of ATEs. The first category is composed of homologous insertions at ectopic, non-allelic sites that contain homology to transposable elements (TEs; Classes B, C, D, and E). Strains differed significantly in frequency, position, and TE type, but displayed a common enrichment in subtelomeric regions. The TEs were heavily mutated, with patterns consistent with the ancestral activity of repeat-induced point mutations (RIP). The second category consists of a conserved set of novel subtelomeric ATE repeats (Classes A, G, G, H, I and J) which lack discernible TEs and, unlike TEs, display a constant polarity relative to the telomere. Members of one of these classes are derivatives of a progenitor ATE that is predicted to have undergone extensive homologous recombination during evolution. A third category of ATEs consists of ~100 kb regions at each centromere. Centromeric ATEs and TE clusters within these centromeres display a high level of sequence identity between strains. These studies suggest that transposition and RIP are forces in the evolution of subtelomeric and centromeric structure and function.
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Affiliation(s)
- Arthur J. Lustig
- Department of Biochemistry and Molecular Biology, Tulane University Medical School, New Orleans, LA, United States of America
- * E-mail:
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8
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Zhang X, Zhang C, Zhou D, Zhang T, Chen X, Ren J, He C, Meng F, Zhou Q, Yang Q, Dai C, Lin G, Zeng S, Leng L. Telomeres cooperate in zygotic genome activation by affecting DUX4/ Dux transcription. iScience 2023; 26:106158. [PMID: 36843839 PMCID: PMC9950522 DOI: 10.1016/j.isci.2023.106158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/03/2022] [Accepted: 02/03/2023] [Indexed: 02/10/2023] Open
Abstract
Zygotic genome activation (ZGA) is initiated once the genome chromatin state is organized in the newly formed zygote. Telomeres are specialized chromatin structures at the ends of chromosomes and are reset during early embryogenesis, while the details and significance of telomere changes in preimplantation embryos remain unclear. We demonstrated that the telomere length was shortened in the minor ZGA stage and significantly elongated in the major ZGA stage of human and mouse embryos. Expression of the ZGA pioneer factor DUX4/Dux was negatively correlated with the telomere length. ATAC sequencing data revealed that the chromatin accessibility peaks on the DUX4 promoter region (i.e., the subtelomere of chromosome 4q) were transiently augmented in human minor ZGA. Reduction of telomeric heterochromatin H3K9me3 in the telomeric region also synergistically activated DUX4 expression with p53 in human embryonic stem cells. We propose herein that telomeres regulate the expression of DUX4/Dux through chromatin remodeling and are thereby involved in ZGA.
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Affiliation(s)
- Xiaorui Zhang
- Hospital of Hunan Guangxiu, Hunan Normal University, Hunan 410001, China,Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China,Department of Reproductive Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi 710061, China
| | - Changquan Zhang
- NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Di Zhou
- NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China
| | - Tianlei Zhang
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China
| | - Xueqin Chen
- NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Jinlin Ren
- Hospital of Hunan Guangxiu, Hunan Normal University, Hunan 410001, China
| | - Caixia He
- NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China
| | - Fei Meng
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China
| | - Qinwei Zhou
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China
| | - Qiaohui Yang
- NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Congling Dai
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China,NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China
| | - Ge Lin
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China,NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China,Corresponding author
| | - Sicong Zeng
- Hospital of Hunan Guangxiu, Hunan Normal University, Hunan 410001, China,Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China,Corresponding author
| | - Lizhi Leng
- Reproductive and Genetic Hospital of Citic-Xiangya, Hunan 410008, China,NHC Key Laboratory of Human Stem and Reproductive Engineering, School of Basic Medical Science, Central South University, Changsha, China,Hunan International Scientific and Technological Cooperation Base of Development and Carcinogenesis, Changsha, China,Corresponding author
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9
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Vinayagamurthy S, Bagri S, Mergny JL, Chowdhury S. Telomeres expand sphere of influence: emerging molecular impact of telomeres in non-telomeric functions. Trends Genet 2023; 39:59-73. [PMID: 36404192 PMCID: PMC7614491 DOI: 10.1016/j.tig.2022.10.002] [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: 06/05/2022] [Revised: 09/12/2022] [Accepted: 10/26/2022] [Indexed: 11/18/2022]
Abstract
Although the impact of telomeres on physiology stands well established, a question remains: how do telomeres impact cellular functions at a molecular level? This is because current understanding limits the influence of telomeres to adjacent subtelomeric regions despite the wide-ranging impact of telomeres. Emerging work in two distinct aspects offers opportunities to bridge this gap. First, telomere-binding factors were found with non-telomeric functions. Second, locally induced DNA secondary structures called G-quadruplexes are notably abundant in telomeres, and gene regulatory regions genome wide. Many telomeric factors bind to G-quadruplexes for non-telomeric functions. Here we discuss a more general model of how telomeres impact the non-telomeric genome - through factors that associate at telomeres and genome wide - and influence cell-intrinsic functions, particularly aging, cancer, and pluripotency.
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Affiliation(s)
- Soujanya Vinayagamurthy
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sulochana Bagri
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Jean-Louis Mergny
- Institute of Biophysics of the CAS, v.v.i. Královopolská 135, 612 65 Brno, Czech Republic; Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, INSERM, Institut Polytechnique de Paris, 91128 Palaiseau, France
| | - Shantanu Chowdhury
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India; GNR Knowledge Centre for Genome and Informatics, CSIR Institute of Genomics and Integrative Biology, New Delhi 110025, India.
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10
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Contreras SM, Zambrano Siri RT, Rivera EM, Cristaldi C, Kamenetzky L, Kim K, Clemente M, Ocampo J, Vanagas L, Angel SO. Architecture, Chromatin and Gene Organization of Toxoplasma gondii Subtelomeres. EPIGENOMES 2022; 6:29. [PMID: 36135316 PMCID: PMC9498087 DOI: 10.3390/epigenomes6030029] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/05/2022] [Accepted: 09/08/2022] [Indexed: 11/17/2022] Open
Abstract
Subtelomeres (ST) are chromosome regions that separate telomeres from euchromatin and play relevant roles in various biological processes of the cell. While their functions are conserved, ST structure and genetic compositions are unique to each species. This study aims to identify and characterize the subtelomeric regions of the 13 Toxoplasma gondii chromosomes of the Me49 strain. Here, STs were defined at chromosome ends based on poor gene density. The length of STs ranges from 8.1 to 232.4 kbp, with a gene density of 0.049 genes/kbp, lower than the Me49 genome (0.15 kbp). Chromatin organization showed that H3K9me3, H2A.X, and H3.3 are highly enriched near telomeres and the 5' end of silenced genes, decaying in intensity towards euchromatin. H3K4me3 and H2A.Z/H2B.Z are shown to be enriched in the 5' end of the ST genes. Satellite DNA was detected in almost all STs, mainly the sat350 family and a novel satellite named sat240. Beyond the STs, only short dispersed fragments of sat240 and sat350 were found. Within STs, there were 12 functional annotated genes, 59 with unknown functions (Hypothetical proteins), 15 from multigene FamB, and 13 from multigene family FamC. Some genes presented low interstrain synteny associated with the presence of satellite DNA. Orthologues of FamB and FamC were also detected in Neospora caninum and Hammondia hammondi. A re-analysis of previous transcriptomic data indicated that ST gene expression is strongly linked to the adaptation to different situations such as extracellular passage (evolve and resequencing study) and changes in metabolism (lack of acetyl-CoA cofactor). In conclusion, the ST region of the T. gondii chromosomes was defined, the STs genes were determined, and it was possible to associate them with high interstrain plasticity and a role in the adaptability of T. gondii to environmental changes.
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Affiliation(s)
- Susana M. Contreras
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús 7130, Argentina
| | - Romina T. Zambrano Siri
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres” (INGEBI-CONICET), Buenos Aires C1428ADN, Argentina
| | - Elías M. Rivera
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús 7130, Argentina
| | - Constanza Cristaldi
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús 7130, Argentina
| | - Laura Kamenetzky
- Laboratorio de Genómica y Bioinformática de Patógenos, iB3|Instituto de Biociencias, Biotecnología y Biología traslacional, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428EHA, Argentina
| | - Kami Kim
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33602, USA
| | - Marina Clemente
- Laboratorio de Molecular Farming y Vacunas, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús 7130, Argentina
| | - Josefina Ocampo
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr. Héctor N. Torres” (INGEBI-CONICET), Buenos Aires C1428ADN, Argentina
| | - Laura Vanagas
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús 7130, Argentina
| | - Sergio O. Angel
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Universidad Nacional de General San Martín (UNSAM), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Chascomús 7130, Argentina
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Jäger K, Mensch J, Grimmig ME, Neuner B, Gorzelniak K, Türkmen S, Demuth I, Hartmann A, Hartmann C, Wittig F, Sporbert A, Hermann A, Fuellen G, Möller S, Walter M. A conserved long-distance telomeric silencing mechanism suppresses mTOR signaling in aging human fibroblasts. SCIENCE ADVANCES 2022; 8:eabk2814. [PMID: 35977016 PMCID: PMC9385144 DOI: 10.1126/sciadv.abk2814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Telomeres are repetitive nucleotide sequences at the ends of each chromosome. It has been hypothesized that telomere attrition evolved as a tumor suppressor mechanism in large long-lived species. Long telomeres can silence genes millions of bases away through a looping mechanism called telomere position effect over long distances (TPE-OLD). The function of this silencing mechanism is unknown. We determined a set of 2322 genes with high positional conservation across replicatively aging species that includes known and candidate TPE-OLD genes that may mitigate potentially harmful effects of replicative aging. Notably, we identified PPP2R2C as a tumor suppressor gene, whose up-regulation by TPE-OLD in aged human fibroblasts leads to dephosphorylation of p70S6 kinase and mammalian target of rapamycin suppression. A mechanistic link between telomeres and a tumor suppressor mechanism supports the hypothesis that replicative aging fulfills a tumor suppressor function and motivates previously unknown antitumor and antiaging strategies.
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Affiliation(s)
- Kathrin Jäger
- Institute of Clinical Chemistry and Laboratory Medicine, Rostock University Medical Center, University of Rostock, Rostock, Germany
- Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany
| | - Juliane Mensch
- Institute of Clinical Chemistry and Laboratory Medicine, Rostock University Medical Center, University of Rostock, Rostock, Germany
- Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany
| | - Maria Elisabeth Grimmig
- Institute of Clinical Chemistry and Laboratory Medicine, Rostock University Medical Center, University of Rostock, Rostock, Germany
| | - Bruno Neuner
- Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Anesthesiology and Intensive Care Medicine, Berlin, Germany
| | - Kerstin Gorzelniak
- Unfallkrankenhaus Berlin, Institute of Laboratory Medicine, Berlin, Germany
| | - Seval Türkmen
- LNS Hematooncogenetics, National Center of Genetics Luxembourg, Dudelange, Luxemburg
- Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Medical Genetics and Human Genetics, Berlin, Germany
| | - Ilja Demuth
- Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Endocrinology and Metabolism, Berlin, Germany
- Berlin Institute of Health at Charité–Universitätsmedizin Berlin, BCRT - Berlin Institute of Health Center for Regenerative Therapies, Berlin, Germany
| | - Alexander Hartmann
- Institute of Clinical Chemistry and Laboratory Medicine, Rostock University Medical Center, University of Rostock, Rostock, Germany
| | - Christiane Hartmann
- Translational Neurodegeneration Section “Albrecht-Kossel”, Department of Neurology, Rostock University Medical Center, University of Rostock, 18147 Rostock, Germany
| | - Felix Wittig
- Institute of Pharmacology and Toxicology, Rostock University Medical Center, University of Rostock, Rostock, Germany
| | - Anje Sporbert
- Advanced Light Microscopy, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Andreas Hermann
- Translational Neurodegeneration Section “Albrecht-Kossel”, Department of Neurology, Rostock University Medical Center, University of Rostock, 18147 Rostock, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Rostock/Greifswald, Rostock, Germany
- Center for Transdisciplinary Neurosciences Rostock (CTNR), University Medical Center Rostock, Rostock, Germany
| | - Georg Fuellen
- Institute for Biostatistics and Informatics in Medicine and Ageing Research, Rostock University Medical Center, Rostock, Germany
| | - Steffen Möller
- Institute for Biostatistics and Informatics in Medicine and Ageing Research, Rostock University Medical Center, Rostock, Germany
| | - Michael Walter
- Institute of Clinical Chemistry and Laboratory Medicine, Rostock University Medical Center, University of Rostock, Rostock, Germany
- Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany
- Corresponding author.
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12
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Boldyreva LV, Andreyeva EN, Pindyurin AV. Position Effect Variegation: Role of the Local Chromatin Context in Gene Expression Regulation. Mol Biol 2022. [DOI: 10.1134/s0026893322030049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Sexual Dimorphism in Telomere Length in Childhood Autism. J Autism Dev Disord 2022; 53:2050-2061. [PMID: 35220523 DOI: 10.1007/s10803-022-05486-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2022] [Indexed: 10/19/2022]
Abstract
Autism spectrum disorders (ASD) are strikingly more prevalent in males, but the molecular mechanisms responsible for ASD sex-differential risk are poorly understood. Abnormally shorter telomeres have been associated with autism. Examination of relative telomere lengths (RTL) among non-syndromic male (N = 14) and female (N = 10) children with autism revealed that only autistic male children had significantly shorter RTL than typically-developing controls (N = 24) and paired siblings (N = 10). While average RTL of autistic girls did not differ significantly from controls, it was substantially longer than autistic boys. Our findings indicate a sexually-dimorphic pattern of RTL in childhood autism and could have important implications for RTL as a potential biomarker and the role/s of telomeres in the molecular mechanisms responsible for ASD sex-biased prevalence and etiology.
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14
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Dan J, Zhou Z, Wang F, Wang H, Guo R, Keefe DL, Liu L. Zscan4 Contributes to Telomere Maintenance in Telomerase-Deficient Late Generation Mouse ESCs and Human ALT Cancer Cells. Cells 2022; 11:cells11030456. [PMID: 35159266 PMCID: PMC8834411 DOI: 10.3390/cells11030456] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/24/2022] [Accepted: 01/25/2022] [Indexed: 02/06/2023] Open
Abstract
Proper telomere length is essential for indefinite self-renewal of embryonic stem (ES) cells and cancer cells. Telomerase-deficient late generation mouse ES cells and human ALT cancer cells are able to propagate for numerous passages, suggesting telomerase-independent mechanisms responding for telomere maintenance. However, the underlying mechanisms ensuring the telomere length maintenance are unclear. Here, using late generation telomerase KO (G4 Terc-/-) ESCs as a model, we show that Zscan4, highly upregulated in G4 Terc-/- ESCs, is responsible for the prolonged culture of these cells with stably short telomeres. Mechanistically, G4 Terc-/- ESCs showed reduced levels of DNA methylation and H3K9me3 at Zscan4 promoter and subtelomeres, which relieved the expression of Zscan4. Similarly, human ZSCAN4 was also derepressed by reduced H3K9me3 at its promoter in ALT U2 OS cells, and depletion of ZSCAN4 significantly shortened telomeres. Our results define a similar conserved pathway contributing to the telomere maintenance in telomerase-deficient late generation mESCs and human ALT U2OS cancer cells.
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Affiliation(s)
- Jiameng Dan
- State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China; (Z.Z.); (H.W.); (R.G.)
- State Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming, Yunnan 650500, China; Yunnan Key Laboratory of Primate Biomedical Research, Kunming, Yunnan 650500, China
- Correspondence: (J.D.); (L.L.)
| | - Zhongcheng Zhou
- State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China; (Z.Z.); (H.W.); (R.G.)
| | - Fang Wang
- Department of Obstetrics and Gynecology, New York University Langone Medical Center, New York, NY 10016, USA; (F.W.); (D.L.K.)
| | - Hua Wang
- State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China; (Z.Z.); (H.W.); (R.G.)
| | - Renpeng Guo
- State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China; (Z.Z.); (H.W.); (R.G.)
| | - David L. Keefe
- Department of Obstetrics and Gynecology, New York University Langone Medical Center, New York, NY 10016, USA; (F.W.); (D.L.K.)
| | - Lin Liu
- State Key Laboratory of Medicinal Chemical Biology, Department of Cell Biology and Genetics, College of Life Sciences, Nankai University, Tianjin 300071, China; (Z.Z.); (H.W.); (R.G.)
- Correspondence: (J.D.); (L.L.)
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15
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Kim HS. Genetic Interaction Between Site-Specific Epigenetic Marks and Roles of H4v in Transcription Termination in Trypanosoma brucei. Front Cell Dev Biol 2021; 9:744878. [PMID: 34722526 PMCID: PMC8551723 DOI: 10.3389/fcell.2021.744878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 09/15/2021] [Indexed: 11/13/2022] Open
Abstract
In Trypanosoma brucei, genes are assembled in polycistronic transcription units (PTUs). Boundaries of PTUs are designated transcription start sites and transcription termination sites (TTSs). Messenger RNAs are generated by trans-splicing and polyadenylation of precursor RNAs, and regulatory information in the 3' un-translated region (UTR), rather than promoter activity/sequence-specific transcription factors, controls mRNA levels. Given this peculiar genome structure, special strategies must be utilized to control transcription in T. brucei. TTSs are deposition sites for three non-essential chromatin factors-two of non-canonical histone variants (H3v and H4v) and a DNA modification (base J, which is a hydroxyl-glucosyl dT). This association generated the hypothesis that these three chromatin marks define a transcription termination site in T. brucei. Using a panel of null mutants lacking H3v, H4v, and base J, here I show that H4v is a major sign for transcription termination at TTSs. While having a secondary function at TTSs, H3v is important for monoallelic transcription of telomeric antigen genes. The simultaneous absence of both histone variants leads to proliferation and replication defects, which are exacerbated by the J absence, accompanied by accumulation of sub-G1 population. Thus, I propose that the coordinated actions of H3v, H4v, and J provide compensatory mechanisms for each other in chromatin organization, transcription, replication, and cell-cycle progression.
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Affiliation(s)
- Hee-Sook Kim
- Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States
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16
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Faria JRC. A nuclear enterprise: zooming in on nuclear organization and gene expression control in the African trypanosome. Parasitology 2021; 148:1237-1253. [PMID: 33407981 PMCID: PMC8311968 DOI: 10.1017/s0031182020002437] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 12/22/2020] [Accepted: 12/24/2020] [Indexed: 12/17/2022]
Abstract
African trypanosomes are early divergent protozoan parasites responsible for high mortality and morbidity as well as a great economic burden among the world's poorest populations. Trypanosomes undergo antigenic variation in their mammalian hosts, a highly sophisticated immune evasion mechanism. Their nuclear organization and mechanisms for gene expression control present several conventional features but also a number of striking differences to the mammalian counterparts. Some of these unorthodox characteristics, such as lack of controlled transcription initiation or enhancer sequences, render their monogenic antigen transcription, which is critical for successful antigenic variation, even more enigmatic. Recent technological developments have advanced our understanding of nuclear organization and gene expression control in trypanosomes, opening novel research avenues. This review is focused on Trypanosoma brucei nuclear organization and how it impacts gene expression, with an emphasis on antigen expression. It highlights several dedicated sub-nuclear bodies that compartmentalize specific functions, whilst outlining similarities and differences to more complex eukaryotes. Notably, understanding the mechanisms underpinning antigen as well as general gene expression control is of great importance, as it might help designing effective control strategies against these organisms.
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Affiliation(s)
- Joana R. C. Faria
- The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, DundeeDD1 5EH, UK
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17
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Li B, Zhao Y. Regulation of Antigenic Variation by Trypanosoma brucei Telomere Proteins Depends on Their Unique DNA Binding Activities. Pathogens 2021; 10:pathogens10080967. [PMID: 34451431 PMCID: PMC8402208 DOI: 10.3390/pathogens10080967] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 07/22/2021] [Accepted: 07/27/2021] [Indexed: 01/17/2023] Open
Abstract
Trypanosoma brucei causes human African trypanosomiasis and regularly switches its major surface antigen, Variant Surface Glycoprotein (VSG), to evade the host immune response. Such antigenic variation is a key pathogenesis mechanism that enables T. brucei to establish long-term infections. VSG is expressed exclusively from subtelomere loci in a strictly monoallelic manner, and DNA recombination is an important VSG switching pathway. The integrity of telomere and subtelomere structure, maintained by multiple telomere proteins, is essential for T. brucei viability and for regulating the monoallelic VSG expression and VSG switching. Here we will focus on T. brucei TRF and RAP1, two telomere proteins with unique nucleic acid binding activities, and summarize their functions in telomere integrity and stability, VSG switching, and monoallelic VSG expression. Targeting the unique features of TbTRF and TbRAP1′s nucleic acid binding activities to perturb the integrity of telomere structure and disrupt VSG monoallelic expression may serve as potential therapeutic strategy against T. brucei.
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Affiliation(s)
- Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
- Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
- Center for RNA Science and Therapeutics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
- Correspondence: (B.L.); (Y.Z.)
| | - Yanxiang Zhao
- Shenzhen Research Institute, The Hong Kong Polytechnic University, Shenzhen, China
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China
- Correspondence: (B.L.); (Y.Z.)
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18
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Saha A, Gaurav AK, Pandya UM, Afrin M, Sandhu R, Nanavaty V, Schnur B, Li B. TbTRF suppresses the TERRA level and regulates the cell cycle-dependent TERRA foci number with a TERRA binding activity in its C-terminal Myb domain. Nucleic Acids Res 2021; 49:5637-5653. [PMID: 34048580 PMCID: PMC8191777 DOI: 10.1093/nar/gkab401] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/05/2021] [Accepted: 04/29/2021] [Indexed: 02/07/2023] Open
Abstract
Telomere repeat-containing RNA (TERRA) has been identified in multiple organisms including Trypanosoma brucei, a protozoan parasite that causes human African trypanosomiasis. T. brucei regularly switches its major surface antigen, VSG, to evade the host immune response. VSG is expressed exclusively from subtelomeric expression sites, and we have shown that telomere proteins play important roles in the regulation of VSG silencing and switching. In this study, we identify several unique features of TERRA and telomere biology in T. brucei. First, the number of TERRA foci is cell cycle-regulated and influenced by TbTRF, the duplex telomere DNA binding factor in T. brucei. Second, TERRA is transcribed by RNA polymerase I mainly from a single telomere downstream of the active VSG. Third, TbTRF binds TERRA through its C-terminal Myb domain, which also has the duplex DNA binding activity, in a sequence-specific manner and suppresses the TERRA level without affecting its half-life. Finally, levels of the telomeric R-loop and telomere DNA damage were increased upon TbTRF depletion. Overexpression of an ectopic allele of RNase H1 that resolves the R-loop structure in TbTRF RNAi cells can partially suppress these phenotypes, revealing an underlying mechanism of how TbTRF helps maintain telomere integrity.
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Affiliation(s)
- Arpita Saha
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Amit Kumar Gaurav
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Unnati M Pandya
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Marjia Afrin
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Ranjodh Sandhu
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Vishal Nanavaty
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Brittny Schnur
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA.,Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.,Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.,Center for RNA Science and Therapeutics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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19
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Li B. Keeping Balance Between Genetic Stability and Plasticity at the Telomere and Subtelomere of Trypanosoma brucei. Front Cell Dev Biol 2021; 9:699639. [PMID: 34291053 PMCID: PMC8287324 DOI: 10.3389/fcell.2021.699639] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 06/08/2021] [Indexed: 12/13/2022] Open
Abstract
Telomeres, the nucleoprotein complexes at chromosome ends, are well-known for their essential roles in genome integrity and chromosome stability. Yet, telomeres and subtelomeres are frequently less stable than chromosome internal regions. Many subtelomeric genes are important for responding to environmental cues, and subtelomeric instability can facilitate organismal adaptation to extracellular changes, which is a common theme in a number of microbial pathogens. In this review, I will focus on the delicate and important balance between stability and plasticity at telomeres and subtelomeres of a kinetoplastid parasite, Trypanosoma brucei, which causes human African trypanosomiasis and undergoes antigenic variation to evade the host immune response. I will summarize the current understanding about T. brucei telomere protein complex, the telomeric transcript, and telomeric R-loops, focusing on their roles in maintaining telomere and subtelomere stability and integrity. The similarities and differences in functions and underlying mechanisms of T. brucei telomere factors will be compared with those in human and yeast cells.
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Affiliation(s)
- Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Sciences and Health Professions, Cleveland State University, Cleveland, OH, United States.,Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH, United States.,Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States.,Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, OH, United States
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20
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Black JA, Crouch K, Lemgruber L, Lapsley C, Dickens N, Tosi LRO, Mottram JC, McCulloch R. Trypanosoma brucei ATR Links DNA Damage Signaling during Antigenic Variation with Regulation of RNA Polymerase I-Transcribed Surface Antigens. Cell Rep 2021; 30:836-851.e5. [PMID: 31968257 PMCID: PMC6988115 DOI: 10.1016/j.celrep.2019.12.049] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 08/19/2019] [Accepted: 12/13/2019] [Indexed: 11/29/2022] Open
Abstract
Trypanosoma brucei evades mammalian immunity by using recombination to switch its surface-expressed variant surface glycoprotein (VSG), while ensuring that only one of many subtelomeric multigene VSG expression sites are transcribed at a time. DNA repair activities have been implicated in the catalysis of VSG switching by recombination, not transcriptional control. How VSG switching is signaled to guide the appropriate reaction or to integrate switching into parasite growth is unknown. Here, we show that the loss of ATR, a DNA damage-signaling protein kinase, is lethal, causing nuclear genome instability and increased VSG switching through VSG-localized damage. Furthermore, ATR loss leads to the increased transcription of silent VSG expression sites and expression of mixed VSGs on the cell surface, effects that are associated with the altered localization of RNA polymerase I and VEX1. This work shows that ATR acts in antigenic variation both through DNA damage signaling and surface antigen expression control. Loss of the repair protein kinase ATR in Trypanosoma brucei is lethal Loss of T. brucei ATR alters VSG coat expression needed for immune evasion Monoallelic RNA polymerase I VSG expression is undermined by ATR loss ATR loss leads to expression of subtelomeric VSGs, indicative of recombination
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Affiliation(s)
- Jennifer Ann Black
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow G12 8TA, UK; Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900 SP, Brazil
| | - Kathryn Crouch
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow G12 8TA, UK
| | - Leandro Lemgruber
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow G12 8TA, UK
| | - Craig Lapsley
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow G12 8TA, UK
| | - Nicholas Dickens
- Marine Science Lab, FAU Harbor Branch Oceanographic Institute, 5600 US 1 North, Fort Pierce, FL 34946, USA
| | - Luiz R O Tosi
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900 SP, Brazil
| | - Jeremy C Mottram
- Centre for Immunology and Infection, Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Richard McCulloch
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity, and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow G12 8TA, UK.
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21
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Zhang B, Liu L, Guo L, Guo S, Zhao X, Liu G, Li Q, Jiang L, Pan B, Nie J, Yang J. Telomere length mediates the association between polycyclic aromatic hydrocarbons exposure and abnormal glucose level among Chinese coke oven plant workers. CHEMOSPHERE 2021; 266:129111. [PMID: 33310362 DOI: 10.1016/j.chemosphere.2020.129111] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/20/2020] [Accepted: 11/22/2020] [Indexed: 06/12/2023]
Abstract
INTRODUCTION Diabetes is a chronic and complex disease determined by environmental and genetic factors. This study aimed to investigate the association between polycyclic aromatic hydrocarbons (PAHs) exposure and fasting blood glucose levels and telomere length among coke-oven plant workers, to explore potential role of telomere length (TL) in the association between PAHs exposure and abnormal glucose level. METHODS The cross-sectional survey was conducted in 2017. The high-performance liquid chromatography mass spectrometry (HPLC-MS) was used to detect 11 urine biomarkers of PAHs exposure. TL was measured using the Real-time quantitative polymerase chain reaction (RT-qPCR) method. Logistic regression model, the modified Poisson regression models, and mediation analysis were used to evaluate the associations between PAHs exposure, TL, and abnormal glucose. RESULTS The results showed that the urinary 1-hydroxypyrene (1-PYR) was positively related to abnormal glucose in a dose-dependent manner (Ptrend = 0.007), the prevalence ratio of abnormal glucose was 8% (95% CI: 1.01-1.16) higher in 3rd tertile of urinary 1-PYR levels. Urinary 1-PYR in the 2nd tertile and 3rd tertile were associated with a 53% (OR = 0.47, 95% CI: 0.28-0.79) and 59% (OR = 0.41, 95% CI: 0.23-0.76) higher risk of shortening TL. And there was a negatively association between 1-PYR and TL in a dose-dependent manner (Ptrend = 0.045). We observed that the association between 1-PYR and abnormal glucose was more significantly positive among participants with median TL level (Ptrend = 0.006). In addition, mediation analysis showed the TL could explain 11.7% of the effect of abnormal glucose related to PAHs exposure. CONCLUSIONS Our findings suggested the effect of abnormal glucose related to PAHs exposure was mediated by telomere length in coke oven plant workers.
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Affiliation(s)
- Bin Zhang
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China
| | - Lu Liu
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China
| | - Lan Guo
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China
| | - Shugang Guo
- Shanxi Provincial Center for Disease Control and Prevention, China
| | - Xinyu Zhao
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China
| | - Gaisheng Liu
- Center of Occupational Disease Prevention, Xishan Coal Electricity (Group) Co., Ltd., China
| | - Qiang Li
- Center of Occupational Disease Prevention, Xishan Coal Electricity (Group) Co., Ltd., China
| | - Liuquan Jiang
- Center of Occupational Disease Prevention, Xishan Coal Electricity (Group) Co., Ltd., China
| | - Baolong Pan
- General Hospital of Taiyuan Iron & Steel (Group) Co., Ltd., China
| | - Jisheng Nie
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China
| | - Jin Yang
- Department of Occupational Health, School of Public Health, Shanxi Medical University, China.
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Peron A, Catusi I, Recalcati MP, Calzari L, Larizza L, Vignoli A, Canevini MP. Ring Chromosome 20 Syndrome: Genetics, Clinical Characteristics, and Overlapping Phenotypes. Front Neurol 2020; 11:613035. [PMID: 33363513 PMCID: PMC7753021 DOI: 10.3389/fneur.2020.613035] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/09/2020] [Indexed: 12/15/2022] Open
Abstract
Ring chromosome 20 [r(20)] syndrome is a rare condition characterized by a non-supernumerary ring chromosome 20 replacing a normal chromosome 20. It is commonly seen in a mosaic state and is diagnosed by means of karyotyping. r(20) syndrome is characterized by a recognizable epileptic phenotype with typical EEG pattern, intellectual disability manifesting after seizure onset in otherwise normally developing children, and behavioral changes. Despite the distinctive phenotype, many patients still lack a diagnosis-especially in the genomic era-and the pathomechanisms of ring formation are poorly understood. In this review we address the genetic and clinical aspects of r(20) syndrome, and discuss differential diagnoses and overlapping phenotypes, providing the reader with useful tools for clinical and laboratory practice. We also discuss the current issues in understanding the mechanisms through which ring 20 chromosome causes the typical manifestations, and present unpublished data about methylation studies. Ultimately, we explore future perspectives of r(20) research. Our intended audience is clinical and laboratory geneticists, child and adult neurologists, and genetic counselors.
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Affiliation(s)
- Angela Peron
- Human Pathology and Medical Genetics, ASST Santi Paolo e Carlo, San Paolo Hospital, Milan, Italy.,Child Neuropsychiatry Unit - Epilepsy Center, Department of Health Sciences, ASST Santi Paolo e Carlo, San Paolo Hospital, Università Degli Studi di Milano, Milan, Italy.,Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Ilaria Catusi
- Laboratory of Cytogenetics and Molecular Genetics, Istituto Auxologico Italiano IRCCS-Istituto di Ricovero e Cura a Carattere Scientifico, Cusano Milanino, Milan, Italy
| | - Maria Paola Recalcati
- Laboratory of Cytogenetics and Molecular Genetics, Istituto Auxologico Italiano IRCCS-Istituto di Ricovero e Cura a Carattere Scientifico, Cusano Milanino, Milan, Italy
| | - Luciano Calzari
- Bioinformatics and Statistical Genomics Unit, Istituto Auxologico Italiano IRCCS-Istituto di Ricovero e Cura a Carattere Scientifico, Cusano Milanino, Milan, Italy
| | - Lidia Larizza
- Laboratory of Cytogenetics and Molecular Genetics, Istituto Auxologico Italiano IRCCS-Istituto di Ricovero e Cura a Carattere Scientifico, Cusano Milanino, Milan, Italy
| | - Aglaia Vignoli
- Child Neuropsychiatry Unit - Epilepsy Center, Department of Health Sciences, ASST Santi Paolo e Carlo, San Paolo Hospital, Università Degli Studi di Milano, Milan, Italy
| | - Maria Paola Canevini
- Child Neuropsychiatry Unit - Epilepsy Center, Department of Health Sciences, ASST Santi Paolo e Carlo, San Paolo Hospital, Università Degli Studi di Milano, Milan, Italy
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23
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Zhang T, Foreman R, Wollman R. Identifying chromatin features that regulate gene expression distribution. Sci Rep 2020; 10:20566. [PMID: 33239733 PMCID: PMC7688950 DOI: 10.1038/s41598-020-77638-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 11/10/2020] [Indexed: 12/17/2022] Open
Abstract
Gene expression variability, differences in the number of mRNA per cell across a population of cells, is ubiquitous across diverse organisms with broad impacts on cellular phenotypes. The role of chromatin in regulating average gene expression has been extensively studied. However, what aspects of the chromatin contribute to gene expression variability is still underexplored. Here we addressed this problem by leveraging chromatin diversity and using a systematic investigation of randomly integrated expression reporters to identify what aspects of chromatin microenvironment contribute to gene expression variability. Using DNA barcoding and split-pool decoding, we created a large library of isogenic reporter clones and identified reporter integration sites in a massive and parallel manner. By mapping our measurements of reporter expression at different genomic loci with multiple epigenetic profiles including the enrichment of transcription factors and the distance to different chromatin states, we identified new factors that impact the regulation of gene expression distributions.
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Affiliation(s)
- Thanutra Zhang
- Institute for Quantitative and Computational Biosciences, UCLA, Los Angeles, CA, USA
| | - Robert Foreman
- Institute for Quantitative and Computational Biosciences, UCLA, Los Angeles, CA, USA
| | - Roy Wollman
- Institute for Quantitative and Computational Biosciences, UCLA, Los Angeles, CA, USA.
- Departments of Integrative Biology and Physiology and Chemistry and Biochemistry, UCLA, Los Angeles, CA, USA.
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24
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Wang J, Veronezi GMB, Kang Y, Zagoskin M, O'Toole ET, Davis RE. Comprehensive Chromosome End Remodeling during Programmed DNA Elimination. Curr Biol 2020; 30:3397-3413.e4. [PMID: 32679104 PMCID: PMC7484210 DOI: 10.1016/j.cub.2020.06.058] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/09/2020] [Accepted: 06/16/2020] [Indexed: 01/14/2023]
Abstract
Germline and somatic genomes are in general the same in a multicellular organism. However, programmed DNA elimination leads to a reduced somatic genome compared to germline cells. Previous work on the parasitic nematode Ascaris demonstrated that programmed DNA elimination encompasses high-fidelity chromosomal breaks and loss of specific genome sequences including a major tandem repeat of 120 bp and ~1,000 germline-expressed genes. However, the precise chromosomal locations of these repeats, breaks regions, and eliminated genes remained unknown. We used PacBio long-read sequencing and chromosome conformation capture (Hi-C) to obtain fully assembled chromosomes of Ascaris germline and somatic genomes, enabling a complete chromosomal view of DNA elimination. We found that all 24 germline chromosomes undergo comprehensive chromosome end remodeling with DNA breaks in their subtelomeric regions and loss of distal sequences including the telomeres at both chromosome ends. All new Ascaris somatic chromosome ends are recapped by de novo telomere healing. We provide an ultrastructural analysis of Ascaris DNA elimination and show that eliminated DNA is incorporated into double membrane-bound structures, similar to micronuclei, during telophase of a DNA elimination mitosis. These micronuclei undergo dynamic changes including loss of active histone marks and localize to the cytoplasm following daughter nuclei formation and cytokinesis where they form autophagosomes. Comparative analysis of nematode chromosomes suggests that chromosome fusions occurred, forming Ascaris sex chromosomes that become independent chromosomes following DNA elimination breaks in somatic cells. These studies provide the first chromosomal view and define novel features and functions of metazoan programmed DNA elimination.
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Affiliation(s)
- Jianbin Wang
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA; RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA; Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA.
| | - Giovana M B Veronezi
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Yuanyuan Kang
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Maxim Zagoskin
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Eileen T O'Toole
- Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Richard E Davis
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045, USA; RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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25
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Yang B, Feng X, Li C. Microbial Cell Factory for Efficiently Synthesizing Plant Natural Products via Optimizing the Location and Adaptation of Pathway on Genome Scale. Front Bioeng Biotechnol 2020; 8:969. [PMID: 32923436 PMCID: PMC7457125 DOI: 10.3389/fbioe.2020.00969] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/27/2020] [Indexed: 01/03/2023] Open
Abstract
Plant natural products (PNPs) possess important pharmacological activities and are widely used in cosmetics, health care products, and as food additives. Currently, most PNPs are mainly extracted from cultivated plants, and the yield is limited by the long growth cycle, climate change and complex processing steps, which makes the process unsustainable. However, the complex structure of PNPs significantly reduces the efficiency of chemical synthesis. With the development of metabolic engineering and synthetic biology, heterologous biosynthesis of PNPs in microbial cell factories offers an attractive alternative. Based on the in-depth mining and analysis of genome and transcriptome data, the biosynthetic pathways of a number of natural products have been successfully elucidated, which lays the crucial foundation for heterologous production. However, there are several problems in the microbial synthesis of PNPs, including toxicity of intermediates, low enzyme activity, multiple auxotrophic dependence, and uncontrollable metabolic network. Although various metabolic engineering strategies have been developed to solve these problems, optimizing the location and adaptation of pathways on the whole-genome scale is an important strategy in microorganisms. From this perspective, this review introduces the application of CRISPR/Cas9 in editing PNPs biosynthesis pathways in model microorganisms, the influences of pathway location, and the approaches for optimizing the adaptation between metabolic pathways and chassis hosts for facilitating PNPs biosynthesis.
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Affiliation(s)
- Bo Yang
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Key Laboratory of Systems Bioengineering, Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Xudong Feng
- Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Chun Li
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Key Laboratory of Systems Bioengineering, Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Institute for Synthetic Biosystem/Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China.,Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China
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26
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Vinayagamurthy S, Ganguly A, Chowdhury S. Extra-telomeric impact of telomeres: Emerging molecular connections in pluripotency or stemness. J Biol Chem 2020; 295:10245-10254. [PMID: 32444498 DOI: 10.1074/jbc.rev119.009710] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 05/21/2020] [Indexed: 12/26/2022] Open
Abstract
Telomeres comprise specialized nucleic acid-protein complexes that help protect chromosome ends from DNA damage. Moreover, telomeres associate with subtelomeric regions through looping. This results in altered expression of subtelomeric genes. Recent observations further reveal telomere length-dependent gene regulation and epigenetic modifications at sites spread across the genome and distant from telomeres. This regulation is mediated through the telomere-binding protein telomeric repeat-binding factor 2 (TRF2). These observations suggest a role of telomeres in extra-telomeric functions. Most notably, telomeres have a broad impact on pluripotency and differentiation. For example, cardiomyocytes differentiate with higher efficacy from induced pluripotent stem cells having long telomeres, and differentiated cells obtained from human embryonic stem cells with relatively long telomeres have a longer lifespan. Here, we first highlight reports on these two seemingly distinct research areas: the extra-telomeric role of telomere-binding factors and the role of telomeres in pluripotency/stemness. On the basis of the observations reported in these studies, we draw attention to potential molecular connections between extra-telomeric biology and pluripotency. Finally, in the context of the nonlocal influence of telomeres on pluripotency and stemness, we discuss major opportunities for progress in molecular understanding of aging-related disorders and neurodegenerative diseases.
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Affiliation(s)
- Soujanya Vinayagamurthy
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR Institute of Genomics and Integrative Biology, New Delhi, India
| | - Akansha Ganguly
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi, India
| | - Shantanu Chowdhury
- Integrative and Functional Biology Unit, CSIR Institute of Genomics and Integrative Biology, New Delhi, India .,Academy of Scientific and Innovative Research (AcSIR), CSIR Institute of Genomics and Integrative Biology, New Delhi, India.,G.N.R. Knowledge Centre for Genome Informatics, CSIR Institute of Genomics and Integrative Biology, New Delhi, India
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27
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Zhang T, Pilko A, Wollman R. Loci specific epigenetic drug sensitivity. Nucleic Acids Res 2020; 48:4797-4810. [PMID: 32246716 PMCID: PMC7229858 DOI: 10.1093/nar/gkaa210] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 02/10/2020] [Accepted: 03/27/2020] [Indexed: 12/14/2022] Open
Abstract
Therapeutic targeting of epigenetic modulators offers a novel approach to the treatment of multiple diseases. The cellular consequences of chemical compounds that target epigenetic regulators (epi-drugs) are complex. Epi-drugs affect global cellular phenotypes and cause local changes to gene expression due to alteration of a gene chromatin environment. Despite increasing use in the clinic, the mechanisms responsible for cellular changes are unclear. Specifically, to what degree the effects are a result of cell-wide changes or disease related locus specific effects is unknown. Here we developed a platform to systematically and simultaneously investigate the sensitivity of epi-drugs at hundreds of genomic locations by combining DNA barcoding, unique split-pool encoding, and single cell expression measurements. Internal controls are used to isolate locus specific effects separately from any global consequences these drugs have. Using this platform we discovered wide-spread loci specific sensitivities to epi-drugs for three distinct epi-drugs that target histone deacetylase, DNA methylation and bromodomain proteins. By leveraging ENCODE data on chromatin modification, we identified features of chromatin environments that are most likely to be affected by epi-drugs. The measurements of loci specific epi-drugs sensitivities will pave the way to the development of targeted therapy for personalized medicine.
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Affiliation(s)
- Thanutra Zhang
- Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, CA, USA
| | - Anna Pilko
- Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, CA, USA
- Departments of Integrative Biology and Physiology and Chemistry and Biochemistry, University of California UCLA, CA, USA
| | - Roy Wollman
- Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, CA, USA
- Departments of Integrative Biology and Physiology and Chemistry and Biochemistry, University of California UCLA, CA, USA
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28
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Kwapisz M, Morillon A. Subtelomeric Transcription and its Regulation. J Mol Biol 2020; 432:4199-4219. [PMID: 32035903 PMCID: PMC7374410 DOI: 10.1016/j.jmb.2020.01.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 01/14/2020] [Accepted: 01/14/2020] [Indexed: 12/13/2022]
Abstract
The subtelomeres, highly heterogeneous repeated sequences neighboring telomeres, are transcribed into coding and noncoding RNAs in a variety of organisms. Telomereproximal subtelomeric regions produce non-coding transcripts i.e., ARRET, αARRET, subTERRA, and TERRA, which function in telomere maintenance. The role and molecular mechanisms of the majority of subtelomeric transcripts remain unknown. This review depicts the current knowledge and puts into perspective the results obtained in different models from yeasts to humans.
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Affiliation(s)
- Marta Kwapisz
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, France
| | - Antonin Morillon
- ncRNA, Epigenetic and Genome Fluidity, CNRS UMR 3244, Sorbonne Université, PSL University, Institut Curie, Centre de Recherche, 26 rue d'Ulm, 75248, Paris, France.
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29
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Abstract
Stress exposure can leave long-term footprints within the organism, like in telomeres (TLs), protective chromosome caps that shorten during cell replication and following exposure to stressors. Short TLs are considered to indicate lower fitness prospects, but why TLs shorten under stressful conditions is not understood. Glucocorticoid hormones (GCs) increase upon stress exposure and are thought to promote TL shortening by increasing oxidative damage. However, evidence that GCs are pro-oxidants and oxidative stress is causally linked to TL attrition is mixed . Based on new biochemical findings, we propose the metabolic telomere attrition hypothesis: during times of substantially increased energy demands, TLs are shortened as part of the transition into an organismal 'emergency state', which prioritizes immediate survival functions over processes with longer-term benefits. TL attrition during energy shortages could serve multiple roles including amplified signalling of cellular energy debt to re-direct critical resources to immediately important processes. This new view of TL shortening as a strategy to resolve major energetic trade-offs can improve our understanding of TL dynamics. We suggest that TLs are master regulators of cell homeostasis and propose future research avenues to understand the interactions between energy homeostasis, metabolic regulators and TL.
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Affiliation(s)
- Stefania Casagrande
- 1 Research Group Evolutionary Physiology, Max Planck Institute for Ornithology , 82319 Seewiesen , Germany
| | - Michaela Hau
- 1 Research Group Evolutionary Physiology, Max Planck Institute for Ornithology , 82319 Seewiesen , Germany.,2 Department of Biology, University of Konstanz , D-78457 Konstanz , Germany
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30
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Existence, Transition, and Propagation of Intermediate Silencing States in Ribosomal DNA. Mol Cell Biol 2019; 39:MCB.00146-19. [PMID: 31527077 DOI: 10.1128/mcb.00146-19] [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: 03/28/2019] [Accepted: 09/10/2019] [Indexed: 11/20/2022] Open
Abstract
The MET3 promoter (MET3pr) inserted into the silenced chromosome in budding yeast can overcome Sir2-dependent silencing upon induction and activate transcription in every single cell among a population. Despite the fact that MET3pr is turned on in all the cells, its activity still shows very high cell-to-cell variability. To understand the nature of such "gene expression noise," we followed the dynamics of the MET3pr-GFP expression inserted into ribosomal DNA (rDNA) using time-lapse microscopy. We found that the noisy "on" state is comprised of multiple substable states with discrete expression levels. These intermediate states stochastically transition between each other, with "up" transitions among different activated states occurring exclusively near the mitotic exit and "down" transitions occurring throughout the rest of the cell cycle. Such cell cycle dependence likely reflects the dynamic activity of the rDNA-specific RENT complex, as MET3pr-GFP expression in a telomeric locus does not have the same cell cycle dependence. The MET3pr-GFP expression in rDNA is highly correlated in mother and daughter cells after cell division, indicating that the silenced state in the mother cell is inherited in daughter cells. These states are disrupted by a brief repression and reset upon a second activation. Potential mechanisms behind these observations are further discussed.
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31
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Saha A, Nanavaty VP, Li B. Telomere and Subtelomere R-loops and Antigenic Variation in Trypanosomes. J Mol Biol 2019; 432:4167-4185. [PMID: 31682833 DOI: 10.1016/j.jmb.2019.10.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 10/02/2019] [Accepted: 10/21/2019] [Indexed: 12/12/2022]
Abstract
Trypanosoma brucei is a kinetoplastid parasite that causes African trypanosomiasis, which is fatal if left untreated. T. brucei regularly switches its major surface antigen, VSG, to evade the host immune responses. VSGs are exclusively expressed from subtelomeric expression sites (ESs) where VSG genes are flanked by upstream 70 bp repeats and downstream telomeric repeats. The telomere downstream of the active VSG is transcribed into a long-noncoding RNA (TERRA), which forms RNA:DNA hybrids (R-loops) with the telomeric DNA. At an elevated level, telomere R-loops cause more telomeric and subtelomeric double-strand breaks (DSBs) and increase VSG switching rate. In addition, stabilized R-loops are observed at the 70 bp repeats and immediately downstream of ES-linked VSGs in RNase H defective cells, which also have an increased amount of subtelomeric DSBs and more frequent VSG switching. Although subtelomere plasticity is expected to be beneficial to antigenic variation, severe defects in subtelomere integrity and stability increase cell lethality. Therefore, regulation of the telomere and 70 bp repeat R-loop levels is important for the balance between antigenic variation and cell fitness in T. brucei. In addition, the high level of the active ES transcription favors accumulation of R-loops at the telomere and 70 bp repeats, providing an intrinsic mechanism for local DSB formation, which is a strong inducer of VSG switching.
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Affiliation(s)
- Arpita Saha
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Vishal P Nanavaty
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, College of Science and Health Professions, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA; Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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32
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Sneaking Out for Happy Hour: Yeast-Based Approaches to Explore and Modulate Immune Response and Immune Evasion. Genes (Basel) 2019; 10:genes10090667. [PMID: 31480411 PMCID: PMC6770942 DOI: 10.3390/genes10090667] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 08/26/2019] [Accepted: 08/28/2019] [Indexed: 01/09/2023] Open
Abstract
Many pathogens (virus, bacteria, fungi, or parasites) have developed a wide variety of mechanisms to evade their host immune system. The budding yeast Saccharomyces cerevisiae has successfully been used to decipher some of these immune evasion strategies. This includes the cis-acting mechanism that limits the expression of the oncogenic Epstein–Barr virus (EBV)-encoded EBNA1 and thus of antigenic peptides derived from this essential but highly antigenic viral protein. Studies based on budding yeast have also revealed the molecular bases of epigenetic switching or recombination underlying the silencing of all except one members of extended families of genes that encode closely related and highly antigenic surface proteins. This mechanism is exploited by several parasites (that include pathogens such as Plasmodium, Trypanosoma, Candida, or Pneumocystis) to alternate their surface antigens, thereby evading the immune system. Yeast can itself be a pathogen, and pathogenic fungi such as Candida albicans, which is phylogenetically very close to S. cerevisiae, have developed stealthiness strategies that include changes in their cell wall composition, or epitope-masking, to control production or exposure of highly antigenic but essential polysaccharides in their cell wall. Finally, due to the high antigenicity of its cell wall, yeast has been opportunistically exploited to create adjuvants and vectors for vaccination.
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33
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Alnafakh RAA, Adishesh M, Button L, Saretzki G, Hapangama DK. Telomerase and Telomeres in Endometrial Cancer. Front Oncol 2019; 9:344. [PMID: 31157162 PMCID: PMC6533802 DOI: 10.3389/fonc.2019.00344] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/15/2019] [Indexed: 12/11/2022] Open
Abstract
Telomeres at the termini of human chromosomes are shortened with each round of cell division due to the “end replication problem” as well as oxidative stress. During carcinogenesis, cells acquire or retain mechanisms to maintain telomeres to avoid initiation of cellular senescence or apoptosis and halting cell division by critically short telomeres. The unique reverse transcriptase enzyme complex, telomerase, catalyzes the maintenance of telomeres but most human somatic cells do not have sufficient telomerase activity to prevent telomere shortening. Tissues with high and prolonged replicative potential demonstrate adequate cellular telomerase activity to prevent telomere erosion, and high telomerase activity appears to be a critical feature of most (80–90%) epithelial cancers, including endometrial cancer. Endometrial cancers regress in response to progesterone which is frequently used to treat advanced endometrial cancer. Endometrial telomerase is inhibited by progestogens and deciphering telomere and telomerase biology in endometrial cancer is therefore important, as targeting telomerase (a downstream target of progestogens) in endometrial cancer may provide novel and more effective therapeutic avenues. This review aims to examine the available evidence for the role and importance of telomere and telomerase biology in endometrial cancer.
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Affiliation(s)
- Rafah A A Alnafakh
- Liverpool Women's Hospital NHS Foundation Trust, Liverpool, United Kingdom.,Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Meera Adishesh
- Liverpool Women's Hospital NHS Foundation Trust, Liverpool, United Kingdom.,Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Lucy Button
- Liverpool Women's Hospital NHS Foundation Trust, Liverpool, United Kingdom.,Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Gabriele Saretzki
- The Ageing Biology Centre and Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Dharani K Hapangama
- Liverpool Women's Hospital NHS Foundation Trust, Liverpool, United Kingdom.,Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
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34
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Nguyen K, Broucqsault N, Chaix C, Roche S, Robin JD, Vovan C, Gerard L, Mégarbané A, Urtizberea JA, Bellance R, Barnérias C, David A, Eymard B, Fradin M, Manel V, Sacconi S, Tiffreau V, Zagnoli F, Cuisset JM, Salort-Campana E, Attarian S, Bernard R, Lévy N, Magdinier F. Deciphering the complexity of the 4q and 10q subtelomeres by molecular combing in healthy individuals and patients with facioscapulohumeral dystrophy. J Med Genet 2019; 56:590-601. [PMID: 31010831 DOI: 10.1136/jmedgenet-2018-105949] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/28/2019] [Accepted: 03/24/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Subtelomeres are variable regions between telomeres and chromosomal-specific regions. One of the most studied pathologies linked to subtelomeric imbalance is facioscapulohumeral dystrophy (FSHD). In most cases, this disease involves shortening of an array of D4Z4 macrosatellite elements at the 4q35 locus. The disease also segregates with a specific A-type haplotype containing a degenerated polyadenylation signal distal to the last repeat followed by a repetitive array of β-satellite elements. This classification applies to most patients with FSHD. A subset of patients called FSHD2 escapes this definition and carries a mutation in the SMCHD1 gene. We also recently described patients carrying a complex rearrangement consisting of a cis-duplication of the distal 4q35 locus identified by molecular combing. METHODS Using this high-resolution technology, we further investigated the organisation of the 4q35 region linked to the disease and the 10q26 locus presenting with 98% of homology in controls and patients. RESULTS Our analyses reveal a broad variability in size of the different elements composing these loci highlighting the complexity of these subtelomeres and the difficulty for genomic assembly. Out of the 1029 DNA samples analysed in our centre in the last 7 years, we also identified 54 cases clinically diagnosed with FSHD carrying complex genotypes. This includes mosaic patients, patients with deletions of the proximal 4q region and 23 cases with an atypical chromosome 10 pattern, infrequently found in the control population and never reported before. CONCLUSION Overall, this work underlines the complexity of these loci challenging the diagnosis and genetic counselling for this disease.
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Affiliation(s)
- Karine Nguyen
- Medical Genetics, Assistance Publique Hopitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, Marseille Medical Genetics U1251, Marseille, France
| | - Natacha Broucqsault
- Aix Marseille Univ, INSERM, MMG, Marseille Medical Genetics U1251, Marseille, France
| | - Charlene Chaix
- Medical Genetics, Assistance Publique Hopitaux de Marseille, Marseille, France
| | - Stephane Roche
- Aix Marseille Univ, INSERM, MMG, Marseille Medical Genetics U1251, Marseille, France
| | - Jérôme D Robin
- Aix Marseille Univ, INSERM, MMG, Marseille Medical Genetics U1251, Marseille, France
| | - Catherine Vovan
- Medical Genetics, Assistance Publique Hopitaux de Marseille, Marseille, France
| | - Laurene Gerard
- Medical Genetics, Assistance Publique Hopitaux de Marseille, Marseille, France
| | | | - Jon Andoni Urtizberea
- Pôle Soins de suite et réadaptation handicaps lourds et maladies rares neurologiques, Hôpital Marin, Assistance publique des hopitaux de Paris, Hendaye, France
| | - Remi Bellance
- Hopital Pierre Zobda-Quitman, Fort-de-France, France
| | - Christine Barnérias
- Service de Neurologie infantile, Université Paris Descartes, Sorbonne Paris Cité, Hôpital Necker-Enfants Malades, Assistance Publique-Hôpitaux de Paris, Paris, France.,Centre de Référence de Maladies Neuromusculaires Garches-Necker-Mondor-Hendaye (GNMH), Réseau National Français de la Filière Neuromusculaire (FILNEMUS), Paris, France
| | | | - Bruno Eymard
- Assistance Publique - Hopitaux de Paris, Paris, Île-de-France, France
| | - Melanie Fradin
- Service de Génétique Médicale, Centre De Référence Anomalies du Développement, CHU de Rennes, Rennes, France
| | - Véronique Manel
- Centre référent maladies neuromusculaires rares, Hospices Civils de Lyon, Hôpital Femme Mère Enfant, Bron, France
| | - Sabrina Sacconi
- Peripheral Nervous System, Muscle and ALS Department, Université Côte d'Azur, Nice, France.,Institute for Research on Cancer and Aging of Nice, Université Côte d'Azur, Faculty of Medicine, Nice, France
| | - Vincent Tiffreau
- Centre de Référence des Maladies Neuromusculaires, service de Médecine Physique et de Réadaptation, Centre hospitalier régionale de Lille, Lille, France
| | - Fabien Zagnoli
- Centre de Référence des Maladies Neuromusculaires, CHU Morvan, Brest, France
| | | | - Emmanuelle Salort-Campana
- Aix Marseille Univ, INSERM, MMG, Marseille Medical Genetics U1251, Marseille, France.,Centre de reference des maladies neuromusculaires, Assistance Publique Hopitaux de Marseille, Marseille, France
| | - Shahram Attarian
- Aix Marseille Univ, INSERM, MMG, Marseille Medical Genetics U1251, Marseille, France.,Centre de reference des maladies neuromusculaires, Assistance Publique Hopitaux de Marseille, Marseille, France
| | - Rafaëlle Bernard
- Medical Genetics, Assistance Publique Hopitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, Marseille Medical Genetics U1251, Marseille, France
| | - Nicolas Lévy
- Medical Genetics, Assistance Publique Hopitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, Marseille Medical Genetics U1251, Marseille, France
| | - Frederique Magdinier
- Aix Marseille Univ, INSERM, MMG, Marseille Medical Genetics U1251, Marseille, France
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35
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Cacchione S, Biroccio A, Rizzo A. Emerging roles of telomeric chromatin alterations in cancer. J Exp Clin Cancer Res 2019; 38:21. [PMID: 30654820 PMCID: PMC6337846 DOI: 10.1186/s13046-019-1030-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 01/07/2019] [Indexed: 12/26/2022] Open
Abstract
Telomeres, the nucleoprotein structures that cap the ends of eukaryotic chromosomes, play important and multiple roles in tumorigenesis. Functional telomeres need the establishment of a protective chromatin structure based on the interplay between the specific complex named shelterin and a tight nucleosomal organization. Telomere shortening in duplicating somatic cells leads eventually to the destabilization of the telomere capping structure and to the activation of a DNA damage response (DDR) signaling. The final outcome of this process is cell replicative senescence, which constitute a protective barrier against unlimited proliferation. Cells that can bypass senescence checkpoint continue to divide until a second replicative checkpoint, crisis, characterized by chromosome fusions and rearrangements leading to massive cell death by apoptosis. During crisis telomere dysfunctions can either inhibit cell replication or favor tumorigenesis by the accumulation of chromosomal rearrangements and neoplastic mutations. The acquirement of a telomere maintenance mechanism allows fixing the aberrant phenotype, and gives the neoplastic cell unlimited replicative potential, one of the main hallmarks of cancer.Despite the crucial role that telomeres play in cancer development, little is known about the epigenetic alterations of telomeric chromatin that affect telomere protection and are associated with tumorigenesis. Here we discuss the current knowledge on the role of telomeric chromatin in neoplastic transformation, with a particular focus on H3.3 mutations in alternative lengthening of telomeres (ALT) cancers and sirtuin deacetylases dysfunctions.
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Affiliation(s)
- Stefano Cacchione
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Roma, Piazzale Aldo Moro 5, 00185, Rome, Italy.
| | - Annamaria Biroccio
- Oncogenomic and Epigenetic Unit, IRCCS-Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144, Rome, Italy
| | - Angela Rizzo
- Oncogenomic and Epigenetic Unit, IRCCS-Regina Elena National Cancer Institute, Via Elio Chianesi 53, 00144, Rome, Italy.
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36
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Laberthonnière C, Magdinier F, Robin JD. Bring It to an End: Does Telomeres Size Matter? Cells 2019; 8:E30. [PMID: 30626097 PMCID: PMC6356554 DOI: 10.3390/cells8010030] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/01/2019] [Accepted: 01/04/2019] [Indexed: 12/22/2022] Open
Abstract
Telomeres are unique nucleoprotein structures. Found at the edge of each chromosome, their main purpose is to mask DNA ends from the DNA-repair machinery by formation of protective loops. Through life and cell divisions, telomeres shorten and bring cells closer to either cell proliferation crisis or senescence. Beyond this mitotic clock role attributed to the need for telomere to be maintained over a critical length, the very tip of our DNA has been shown to impact transcription by position effect. TPE and a long-reach counterpart, TPE-OLD, are mechanisms recently described in human biology. Still in infancy, the mechanism of action of these processes and their respective genome wide impact remain to be resolved. In this review, we will discuss recent findings on telomere dynamics, TPE, TPE-OLD, and lessons learnt from model organisms.
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Affiliation(s)
| | - Frédérique Magdinier
- Aix Marseille Univ, MMG, Marseille Medical Genetics U1251, 13385 Marseille, France.
| | - Jérôme D Robin
- Aix Marseille Univ, MMG, Marseille Medical Genetics U1251, 13385 Marseille, France.
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37
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Coluzzi E, Leone S, Sgura A. Oxidative Stress Induces Telomere Dysfunction and Senescence by Replication Fork Arrest. Cells 2019; 8:cells8010019. [PMID: 30609792 PMCID: PMC6356380 DOI: 10.3390/cells8010019] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 12/29/2018] [Indexed: 12/12/2022] Open
Abstract
Oxidative DNA damage, particularly 8-oxoguanine, represents the most frequent DNA damage in human cells, especially at the telomeric level. The presence of oxidative lesions in the DNA can hinder the replication fork and is able to activate the DNA damage response. In this study, we wanted to understand the mechanisms by which oxidative damage causes telomere dysfunction and senescence in human primary fibroblasts. After acute oxidative stress at telomeres, our data demonstrated a reduction in TRF1 and TRF2, which are involved in proper telomere replication and T-loop formation, respectively. Furthermore, we observed a higher level of γH2AX with respect to 53BP1 at telomeres, suggesting a telomeric replication fork stall rather than double-strand breaks. To confirm this finding, we studied the replication of telomeres by Chromosome Orientation-FISH (CO-FISH). The data obtained show an increase in unreplicated telomeres after hydrogen peroxide treatment, corroborating the idea that the presence of 8-oxoG can induce replication fork arrest at telomeres. Lastly, we analyzed the H3K9me3 histone mark after oxidative stress at telomeres, and our results showed an increase of this marker, most likely inducing the heterochromatinization of telomeres. These results suggest that 8-oxoG is fundamental in oxidative stress-induced telomeric damage, principally causing replication fork arrest.
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Affiliation(s)
- Elisa Coluzzi
- Department of Science, University of Rome "Roma TRE", Viale Guglielmo Marconi, 446, 00146 Rome, Italy.
| | - Stefano Leone
- Department of Science, University of Rome "Roma TRE", Viale Guglielmo Marconi, 446, 00146 Rome, Italy.
| | - Antonella Sgura
- Department of Science, University of Rome "Roma TRE", Viale Guglielmo Marconi, 446, 00146 Rome, Italy.
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38
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López-Fuentes E, Gutiérrez-Escobedo G, Timmermans B, Van Dijck P, De Las Peñas A, Castaño I. Candida glabrata's Genome Plasticity Confers a Unique Pattern of Expressed Cell Wall Proteins. J Fungi (Basel) 2018; 4:jof4020067. [PMID: 29874814 PMCID: PMC6023349 DOI: 10.3390/jof4020067] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 05/29/2018] [Accepted: 06/03/2018] [Indexed: 12/19/2022] Open
Abstract
Candida glabrata is the second most common cause of candidemia, and its ability to adhere to different host cell types, to microorganisms, and to medical devices are important virulence factors. Here, we consider three characteristics that confer extraordinary advantages to C. glabrata within the host. (1) C. glabrata has a large number of genes encoding for adhesins most of which are localized at subtelomeric regions. The number and sequence of these genes varies substantially depending on the strain, indicating that C. glabrata can tolerate high genomic plasticity; (2) The largest family of CWPs (cell wall proteins) is the EPA (epithelial adhesin) family of adhesins. Epa1 is the major adhesin and mediates adherence to epithelial, endothelial and immune cells. Several layers of regulation like subtelomeric silencing, cis-acting regulatory regions, activators, nutritional signaling, and stress conditions tightly regulate the expression of many adhesin-encoding genes in C. glabrata, while many others are not expressed. Importantly, there is a connection between acquired resistance to xenobiotics and increased adherence; (3) Other subfamilies of adhesins mediate adherence to Candida albicans, allowing C. glabrata to efficiently invade the oral epithelium and form robust biofilms. It is noteworthy that every C. glabrata strain analyzed presents a unique pattern of CWPs at the cell surface.
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Affiliation(s)
- Eunice López-Fuentes
- Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), División de Biología Molecular, Camino a la Presa San José 2055, San Luis Potosí, SLP 78216, Mexico.
| | - Guadalupe Gutiérrez-Escobedo
- Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), División de Biología Molecular, Camino a la Presa San José 2055, San Luis Potosí, SLP 78216, Mexico.
| | - Bea Timmermans
- KU Leuven, Laboratory of Molecular Cell Biology, Kasteelpark Arenberg 31 bus 2438, 3001 Leuven, Belgium.
- VIB-KU Leuven Center for Microbiology, 3001 Leuven, Belgium.
| | - Patrick Van Dijck
- KU Leuven, Laboratory of Molecular Cell Biology, Kasteelpark Arenberg 31 bus 2438, 3001 Leuven, Belgium.
- VIB-KU Leuven Center for Microbiology, 3001 Leuven, Belgium.
| | - Alejandro De Las Peñas
- Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), División de Biología Molecular, Camino a la Presa San José 2055, San Luis Potosí, SLP 78216, Mexico.
| | - Irene Castaño
- Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), División de Biología Molecular, Camino a la Presa San José 2055, San Luis Potosí, SLP 78216, Mexico.
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Qin L, Jiang X, Dong Z, Huang J, Chen X. Identification of two integration sites in favor of transgene expression in Trichoderma reesei. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:142. [PMID: 29796083 PMCID: PMC5956788 DOI: 10.1186/s13068-018-1139-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 05/02/2018] [Indexed: 05/28/2023]
Abstract
BACKGROUND The ascomycete fungus Trichoderma reesei was widely used as a biotechnological workhorse for production of cellulases and recombinant proteins due to its large capacity of protein secretion. Transgenesis by random integration of a gene of interest (GOI) into the genome of T. reesei can generate series of strains that express different levels of the indicated transgene. The insertion site of the GOI plays an important role in the ultimate production of the targeted proteins. However, so far no systematic studies have been made to identify transgene integration loci for optimal expression of the GOI in T. reesei. Currently, only the locus of exocellobiohydrolases I encoding gene (cbh1) is widely used as a promising integration site to lead to high expression level of the GOI. No additional sites associated with efficient gene expression have been characterized. RESULTS To search for gene integration sites that benefit for the secreted expression of GOI, the food-and-mouth disease virus 2A protein was applied for co-expression of an Aspergillus niger lipA gene and Discosoma sp. DsRed1 gene in T. reesei, by random integration of the expression cassette into the genome. We demonstrated that the fluorescent intensity of RFP (red fluorescent protein) inside of the cell was well correlated with the secreted lipase yields, based on which, we successfully developed a high-throughput screening method to screen strains with relatively higher secreted expression of the GOI (in this study, lipase). The copy number and the insertion sites of the transgene were investigated among the selected highly expressed strains. Eventually, in addition to cbh1 gene locus, two other genome insertion loci that efficiently facilitate gene expression in T. reesei were identified. CONCLUSIONS We have successfully developed a high-throughput screening method to screen strains with optimal expression of the indicated secreted proteins in T. reesei. Moreover, we identified two optimal genome loci for transgene expression, which could provide new approach to modulate gene expression levels while retaining the indicated promoter and culture conditions.
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Affiliation(s)
- Lina Qin
- National and Local Joint Engineering Research Center of Industrial Microbiology and Fermentation Technology, College of Life Sciences, Fujian Normal University, Qishan Campus, No.1 Keji Road, Shangjie, Minhou, Fuzhou, 350117 Fujian China
- Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, College of Life Sciences, Fujian Normal University, Fuzhou, 350117 Fujian China
| | - Xianzhang Jiang
- National and Local Joint Engineering Research Center of Industrial Microbiology and Fermentation Technology, College of Life Sciences, Fujian Normal University, Qishan Campus, No.1 Keji Road, Shangjie, Minhou, Fuzhou, 350117 Fujian China
| | - Zhiyang Dong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Jianzhong Huang
- National and Local Joint Engineering Research Center of Industrial Microbiology and Fermentation Technology, College of Life Sciences, Fujian Normal University, Qishan Campus, No.1 Keji Road, Shangjie, Minhou, Fuzhou, 350117 Fujian China
| | - Xiuzhen Chen
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101 China
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40
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Mason JMO, McEachern MJ. Chromosome ends as adaptive beginnings: the potential role of dysfunctional telomeres in subtelomeric evolvability. Curr Genet 2018; 64:997-1000. [PMID: 29589105 DOI: 10.1007/s00294-018-0822-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/05/2018] [Accepted: 03/07/2018] [Indexed: 10/17/2022]
Abstract
Telomeres serve as protective caps that help the cell differentiate between the naturally occurring ends of chromosomes and double-stranded breaks. When telomere capping function becomes compromised, chromosome ends are subjected to elevated rates of chromosome alterations. These effects can be particularly dramatic in the telomere-adjacent subtelomeric region. While the catastrophic impact of severe telomere dysfunction on genome stability has been well documented, the adaptive telomere failure hypothesis considers an alternative role telomere dysfunction may play in adaptive evolution. This hypothesis suggests that low levels of telomere failure, induced by certain environmental stresses, can lead to elevated subtelomeric recombination. Mutational loss, duplication, or modification of subtelomeric contingency genes could ultimately facilitate adaptation by generating novel mutants better able to survive environmental stress. In this perspective, we discuss recent work that examined mild telomere dysfunction and its role in altering the adaptive potential of subtelomeric genes.
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Affiliation(s)
- Jennifer M O Mason
- Department of Genetics, University of Georgia, Athens, GA, 30605, USA. .,Q2 Solutions, Morrisville, NC, 27560, USA.
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41
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Xie X, Shippen DE. DDM1 guards against telomere truncation in Arabidopsis. PLANT CELL REPORTS 2018; 37:501-513. [PMID: 29392401 PMCID: PMC5880217 DOI: 10.1007/s00299-017-2245-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 12/26/2017] [Indexed: 05/20/2023]
Abstract
Prolonged hypomethylation of DNA leads to telomere truncation correlated with increased telomere recombination, transposon mobilization and stem cell death. Epigenetic pathways, including DNA methylation, are crucial for telomere maintenance. Deficient in DNA Methylation 1 (DDM1) encodes a nucleosome remodeling protein, required to maintain DNA methylation in Arabidopsis thaliana. Plants lacking DDM1 can be self-propagated, but in the sixth generation (G6) hypomethylation leads to rampant transposon activation and infertility. Here we examine the role of DDM1 in telomere length homeostasis through a longitudinal study of successive generations of ddm1-2 mutants. We report that bulk telomere length remains within the wild-type range for the first five generations (G1-G5), and then precipitously drops in G6. While telomerase activity becomes more variable in later generation ddm1-2 mutants, there is no correlation between enzyme activity and telomere length. Plants lacking DDM1 also exhibit no dysregulation of several known telomere-associated transcripts, including TERRA. Instead, telomere shortening coincides with increased G-overhangs and extra-chromosomal circles, consistent with deletional recombination. Telomere shortening also correlates with transcriptional activation of retrotransposons, and a hypersensitive DNA damage response in root apical meristems. Since abiotic stresses, including DNA damage, stimulate homologous recombination, we hypothesize that telomere deletion in G6 ddm1-2 mutants is a by-product of elevated genome-wide recombination in response to transposon mobilization. Further, we speculate that telomere truncation may be beneficial in adverse environmental conditions by accelerating the elimination of stem cells with aberrant genomes.
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Affiliation(s)
- Xiaoyuan Xie
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843-2128, USA
| | - Dorothy E Shippen
- Department of Biochemistry and Biophysics, Texas A&M University, 2128 TAMU, College Station, TX, 77843-2128, USA.
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42
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Wang J, Gao S, Mostovoy Y, Kang Y, Zagoskin M, Sun Y, Zhang B, White LK, Easton A, Nutman TB, Kwok PY, Hu S, Nielsen MK, Davis RE. Comparative genome analysis of programmed DNA elimination in nematodes. Genome Res 2017; 27:2001-2014. [PMID: 29118011 PMCID: PMC5741062 DOI: 10.1101/gr.225730.117] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 10/12/2017] [Indexed: 12/20/2022]
Abstract
Programmed DNA elimination is a developmentally regulated process leading to the reproducible loss of specific genomic sequences. DNA elimination occurs in unicellular ciliates and a variety of metazoans, including invertebrates and vertebrates. In metazoa, DNA elimination typically occurs in somatic cells during early development, leaving the germline genome intact. Reference genomes for metazoa that undergo DNA elimination are not available. Here, we generated germline and somatic reference genome sequences of the DNA eliminating pig parasitic nematode Ascaris suum and the horse parasite Parascaris univalens. In addition, we carried out in-depth analyses of DNA elimination in the parasitic nematode of humans, Ascaris lumbricoides, and the parasitic nematode of dogs, Toxocara canis. Our analysis of nematode DNA elimination reveals that in all species, repetitive sequences (that differ among the genera) and germline-expressed genes (approximately 1000–2000 or 5%–10% of the genes) are eliminated. Thirty-five percent of these eliminated genes are conserved among these nematodes, defining a core set of eliminated genes that are preferentially expressed during spermatogenesis. Our analysis supports the view that DNA elimination in nematodes silences germline-expressed genes. Over half of the chromosome break sites are conserved between Ascaris and Parascaris, whereas only 10% are conserved in the more divergent T. canis. Analysis of the chromosomal breakage regions suggests a sequence-independent mechanism for DNA breakage followed by telomere healing, with the formation of more accessible chromatin in the break regions prior to DNA elimination. Our genome assemblies and annotations also provide comprehensive resources for analysis of DNA elimination, parasitology research, and comparative nematode genome and epigenome studies.
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Affiliation(s)
- Jianbin Wang
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Shenghan Gao
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA.,Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Yulia Mostovoy
- Cardiovascular Research Institute, UCSF School of Medicine, San Francisco, California 94158, USA
| | - Yuanyuan Kang
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Maxim Zagoskin
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Yongqiao Sun
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Bing Zhang
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Laura K White
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Alice Easton
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Thomas B Nutman
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Pui-Yan Kwok
- Cardiovascular Research Institute, UCSF School of Medicine, San Francisco, California 94158, USA
| | - Songnian Hu
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Martin K Nielsen
- Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546, USA
| | - Richard E Davis
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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Tashiro S, Nishihara Y, Kugou K, Ohta K, Kanoh J. Subtelomeres constitute a safeguard for gene expression and chromosome homeostasis. Nucleic Acids Res 2017; 45:10333-10349. [PMID: 28981863 PMCID: PMC5737222 DOI: 10.1093/nar/gkx780] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 08/28/2017] [Indexed: 12/19/2022] Open
Abstract
The subtelomere, a telomere-adjacent chromosomal domain, contains species-specific homologous DNA sequences, in addition to various genes. However, the functions of subtelomeres, particularly subtelomeric homologous (SH) sequences, remain elusive. Here, we report the first comprehensive analyses of the cellular functions of SH sequences in the fission yeast, Schizosaccharomyces pombe. Complete removal of SH sequences from the genome revealed that they are dispensable for mitosis, meiosis and telomere length control. However, when telomeres are lost, SH sequences prevent deleterious inter-chromosomal end fusion by facilitating intra-chromosomal circularization. Surprisingly, SH-deleted cells sometimes survive telomere loss through inter-chromosomal end fusions via homologous loci such as LTRs, accompanied by centromere inactivation of either chromosome. Moreover, SH sequences function as a buffer region against the spreading of subtelomeric heterochromatin into the neighboring gene-rich regions. Furthermore, we found a nucleosome-free region at the subtelomeric border, which may be a second barrier that blocks heterochromatin spreading into the subtelomere-adjacent euchromatin. Thus, our results demonstrate multiple defense functions of subtelomeres in chromosome homeostasis and gene expression.
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Affiliation(s)
- Sanki Tashiro
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yuki Nishihara
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kazuto Kugou
- Department of Life Sciences, University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Kunihiro Ohta
- Department of Life Sciences, University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Junko Kanoh
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
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44
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Nanavaty V, Sandhu R, Jehi SE, Pandya UM, Li B. Trypanosoma brucei RAP1 maintains telomere and subtelomere integrity by suppressing TERRA and telomeric RNA:DNA hybrids. Nucleic Acids Res 2017; 45:5785-5796. [PMID: 28334836 PMCID: PMC5449629 DOI: 10.1093/nar/gkx184] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/08/2017] [Indexed: 12/22/2022] Open
Abstract
Trypanosoma brucei causes human African trypanosomiasis and regularly switches its major surface antigen, VSG, thereby evading the host's immune response. VSGs are monoallelically expressed from subtelomeric expression sites (ESs), and VSG switching exploits subtelomere plasticity. However, subtelomere integrity is essential for T. brucei viability. The telomeric transcript, TERRA, was detected in T. brucei previously. We now show that the active ES-adjacent telomere is transcribed. We find that TbRAP1, a telomere protein essential for VSG silencing, suppresses VSG gene conversion-mediated switching. Importantly, TbRAP1 depletion increases the TERRA level, which appears to result from longer read-through into the telomere downstream of the active ES. Depletion of TbRAP1 also results in more telomeric RNA:DNA hybrids and more double strand breaks (DSBs) at telomeres and subtelomeres. In TbRAP1-depleted cells, expression of excessive TbRNaseH1, which cleaves the RNA strand of the RNA:DNA hybrid, brought telomeric RNA:DNA hybrids, telomeric/subtelomeric DSBs and VSG switching frequency back to WT levels. Therefore, TbRAP1-regulated appropriate levels of TERRA and telomeric RNA:DNA hybrid are fundamental to subtelomere/telomere integrity. Our study revealed for the first time an important role of a long, non-coding RNA in antigenic variation and demonstrated a link between telomeric silencing and subtelomere/telomere integrity through TbRAP1-regulated telomere transcription.
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Affiliation(s)
- Vishal Nanavaty
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Ranjodh Sandhu
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Sanaa E Jehi
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Unnati M Pandya
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA
| | - Bibo Li
- Center for Gene Regulation in Health and Disease, Department of Biological, Geological, and Environmental Sciences, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115, USA.,The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.,Department of Immunology, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.,Case Comprehensive Cancer Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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Steenstrup T, Kark JD, Verhulst S, Thinggaard M, Hjelmborg JVB, Dalgård C, Kyvik KO, Christiansen L, Mangino M, Spector TD, Petersen I, Kimura M, Benetos A, Labat C, Sinnreich R, Hwang SJ, Levy D, Hunt SC, Fitzpatrick AL, Chen W, Berenson GS, Barbieri M, Paolisso G, Gadalla SM, Savage SA, Christensen K, Yashin AI, Arbeev KG, Aviv A. Telomeres and the natural lifespan limit in humans. Aging (Albany NY) 2017; 9:1130-1142. [PMID: 28394764 PMCID: PMC5425118 DOI: 10.18632/aging.101216] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 03/23/2017] [Indexed: 02/04/2023]
Abstract
An ongoing debate in demography has focused on whether the human lifespan has a maximal natural limit. Taking a mechanistic perspective, and knowing that short telomeres are associated with diminished longevity, we examined whether telomere length dynamics during adult life could set a maximal natural lifespan limit. We define leukocyte telomere length of 5 kb as the 'telomeric brink', which denotes a high risk of imminent death. We show that a subset of adults may reach the telomeric brink within the current life expectancy and more so for a 100-year life expectancy. Thus, secular trends in life expectancy should confront a biological limit due to crossing the telomeric brink.
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Affiliation(s)
- Troels Steenstrup
- Epidemiology, Biostatistics and Biodemography, Institute of Public Health, University of Southern Denmark, Odense 5000, Denmark
| | - Jeremy D. Kark
- Epidemiology Unit, Hebrew University-Hadassah School of Public Health and Community Medicine, Jerusalem 91120, Israel
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Mikael Thinggaard
- Department of Clinical Genetics, Odense University Hospital, Odense 5220, Denmark
- Danish Aging Research Center, University of Southern Denmark, Odense 5000, Denmark
| | - Jacob V. B. Hjelmborg
- Epidemiology, Biostatistics and Biodemography, Institute of Public Health, University of Southern Denmark, Odense 5000, Denmark
- The Danish Twin Registry, University of Southern Denmark, Odense 5220, Denmark
| | - Christine Dalgård
- Department of Public Health, Environmental Medicine, University of Southern Denmark, 5000 Odense C, Denmark
| | - Kirsten Ohm Kyvik
- Department of Clinical Research, University of Southern Denmark and Odense Patient Data Explorative Network (OPEN), Odense University Hospital, Odense, Denmark
| | - Lene Christiansen
- Epidemiology, Biostatistics and Biodemography, Institute of Public Health, University of Southern Denmark, Odense 5000, Denmark
- Danish Aging Research Center, University of Southern Denmark, Odense 5000, Denmark
- The Danish Twin Registry, University of Southern Denmark, Odense 5220, Denmark
| | - Massimo Mangino
- Department of Twin Research and Genetic Epidemiology, King’s College London, London, UK
- NIHI Biomedical Research Center at Guy’s and St Thomas Foundation Trust, London SE1 9RT, UK
| | - Timothy D. Spector
- Department of Twin Research and Genetic Epidemiology, King’s College London, London, UK
| | - Inge Petersen
- Epidemiology, Biostatistics and Biodemography, Institute of Public Health, University of Southern Denmark, Odense 5000, Denmark
| | - Masayuki Kimura
- Center of Human Development and Aging, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA
| | - Athanase Benetos
- Department of Geriatrics, University Hospital of Nancy, F54500, France
- INSERM, U1116, Vandoeuvre-les-Nancy, F54500, France
- Université de Lorraine, Nancy, F54000, France
| | - Carlos Labat
- INSERM, U1116, Vandoeuvre-les-Nancy, F54500, France
- Université de Lorraine, Nancy, F54000, France
| | - Ronit Sinnreich
- Epidemiology Unit, Hebrew University-Hadassah School of Public Health and Community Medicine, Jerusalem 91120, Israel
| | - Shih-Jen Hwang
- Population Sciences Branch of the National Heart, Lung and Blood Institute, Bethesda, MD and the Framingham Heart Study, Framingham, MA 01702, USA
| | - Daniel Levy
- Population Sciences Branch of the National Heart, Lung and Blood Institute, Bethesda, MD and the Framingham Heart Study, Framingham, MA 01702, USA
| | - Steven C. Hunt
- Cardiovascular Genetics Division, Department of Medicine, Cornell University, Ithaca, NY 14850 USA
| | | | - Wei Chen
- Center for Cardiovascular Health, Tulane University, New Orleans, LA 07118, USA
| | - Gerald S. Berenson
- Center for Cardiovascular Health, Tulane University, New Orleans, LA 07118, USA
| | - Michelangela Barbieri
- Department of Medical, Surgery, Neurologic, Metabolic and Aging Science, University of Campania “Luigi Vanvtelli” 80138 Naples, Italy
| | - Giuseppe Paolisso
- Department of Medical, Surgery, Neurologic, Metabolic and Aging Science, University of Campania “Luigi Vanvtelli” 80138 Naples, Italy
| | - Shahinaz M. Gadalla
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20890, USA
| | - Sharon A. Savage
- Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD 20890, USA
| | - Kaare Christensen
- Department of Clinical Genetics, Odense University Hospital, Odense 5220, Denmark
- Danish Aging Research Center, University of Southern Denmark, Odense 5000, Denmark
- The Danish Twin Registry, University of Southern Denmark, Odense 5220, Denmark
| | - Anatoliy I. Yashin
- Biodemography of Aging Research Unit, Social Science Research Institute, Duke University, Durham, NC 27708, USA
| | - Konstantin G. Arbeev
- Biodemography of Aging Research Unit, Social Science Research Institute, Duke University, Durham, NC 27708, USA
| | - Abraham Aviv
- Center of Human Development and Aging, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, NJ 07103, USA
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Robin JD, Magdinier F. Physiological and Pathological Aging Affects Chromatin Dynamics, Structure and Function at the Nuclear Edge. Front Genet 2016; 7:153. [PMID: 27602048 PMCID: PMC4993774 DOI: 10.3389/fgene.2016.00153] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2016] [Accepted: 08/08/2016] [Indexed: 01/29/2023] Open
Abstract
Lamins are intermediate filaments that form a complex meshwork at the inner nuclear membrane. Mammalian cells express two types of Lamins, Lamins A/C and Lamins B, encoded by three different genes, LMNA, LMNB1, and LMNB2. Mutations in the LMNA gene are associated with a group of phenotypically diverse diseases referred to as laminopathies. Lamins interact with a large number of binding partners including proteins of the nuclear envelope but also chromatin-associated factors. Lamins not only constitute a scaffold for nuclear shape, rigidity and resistance to stress but also contribute to the organization of chromatin and chromosomal domains. We will discuss here the impact of A-type Lamins loss on alterations of chromatin organization and formation of chromatin domains and how disorganization of the lamina contributes to the patho-physiology of premature aging syndromes.
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Affiliation(s)
- Jérôme D Robin
- IRCAN, CNRS UMR 7284/INSERM U1081, Faculté de Médecine Nice, France
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Geronimo CL, Zakian VA. Getting it done at the ends: Pif1 family DNA helicases and telomeres. DNA Repair (Amst) 2016; 44:151-158. [PMID: 27233114 DOI: 10.1016/j.dnarep.2016.05.021] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
It is widely appreciated that the ends of linear DNA molecules cannot be fully replicated by the conventional replication apparatus. Less well known is that semi-conservative replication of telomeric DNA also presents problems for DNA replication. These problems likely arise from the atypical chromatin structure of telomeres, the GC-richness of telomeric DNA that makes it prone to forming DNA secondary structures, and from RNA-DNA hybrids, formed by transcripts of one or both DNA strands. Given the different aspects of telomeres that complicate their replication, it is not surprising that multiple DNA helicases promote replication of telomeric DNA. This review focuses on one such class of DNA helicases, the Pif1 family of 5'-3' DNA helicases. In budding and fission yeasts, Pif1 family helicases impact both telomerase-mediated and semi-conservative replication of telomeric DNA as well as recombination-mediated telomere lengthening.
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Affiliation(s)
- Carly L Geronimo
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544 USA
| | - Virginia A Zakian
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544 USA.
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Chen X, Zhang J. The Genomic Landscape of Position Effects on Protein Expression Level and Noise in Yeast. Cell Syst 2016; 2:347-54. [PMID: 27185547 DOI: 10.1016/j.cels.2016.03.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 02/17/2016] [Accepted: 03/28/2016] [Indexed: 10/21/2022]
Abstract
Position effect, the influence of the chromosomal location of a gene on its activity, is a fundamental property of the genome. By placing a GFP gene cassette at 482 different locations across all chromosomes in budding yeast, we quantified the position effects on protein expression level and noise at the genomic scale. The position effects are significant, altering the mean protein expression level by up to 15 times and expression noise by up to 20 times. DNA replication timing, 3D chromosomal conformation, and several histone modifications are major covariates of position effects. Essential genes are enriched in genomic regions with inherently low expression noise, supporting the hypothesis that chromosomal clustering of essential genes results from selection against their expressional stochasticity. Position effects exhibit significant interactions with promoters. Together, our results suggest that position effects have shaped the evolution of chromosome organization and should inform future genome engineering efforts.
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Affiliation(s)
- Xiaoshu Chen
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jianzhi Zhang
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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49
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Telomere Length Maintenance and Cardio-Metabolic Disease Prevention Through Exercise Training. Sports Med 2016; 46:1213-37. [DOI: 10.1007/s40279-016-0482-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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50
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Procházková Schrumpfová P, Schořová Š, Fajkus J. Telomere- and Telomerase-Associated Proteins and Their Functions in the Plant Cell. FRONTIERS IN PLANT SCIENCE 2016; 7:851. [PMID: 27446102 PMCID: PMC4924339 DOI: 10.3389/fpls.2016.00851] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 05/31/2016] [Indexed: 05/20/2023]
Abstract
Telomeres, as physical ends of linear chromosomes, are targets of a number of specific proteins, including primarily telomerase reverse transcriptase. Access of proteins to the telomere may be affected by a number of diverse factors, e.g., protein interaction partners, local DNA or chromatin structures, subcellular localization/trafficking, or simply protein modification. Knowledge of composition of the functional nucleoprotein complex of plant telomeres is only fragmentary. Moreover, the plant telomeric repeat binding proteins that were characterized recently appear to also be involved in non-telomeric processes, e.g., ribosome biogenesis. This interesting finding was not totally unexpected since non-telomeric functions of yeast or animal telomeric proteins, as well as of telomerase subunits, have been reported for almost a decade. Here we summarize known facts about the architecture of plant telomeres and compare them with the well-described composition of telomeres in other organisms.
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Affiliation(s)
- Petra Procházková Schrumpfová
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityBrno, Czech Republic
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityBrno, Czech Republic
- *Correspondence: Petra Procházková Schrumpfová,
| | - Šárka Schořová
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityBrno, Czech Republic
| | - Jiří Fajkus
- Mendel Centre for Plant Genomics and Proteomics, Central European Institute of Technology, Masaryk UniversityBrno, Czech Republic
- Laboratory of Functional Genomics and Proteomics, National Centre for Biomolecular Research, Faculty of Science, Masaryk UniversityBrno, Czech Republic
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i.Brno, Czech Republic
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