1
|
Teplitz GM, Pasquier E, Bonnell E, De Laurentiis E, Bartle L, Lucier JF, Sholes S, Greider CW, Wellinger RJ. A mechanism for telomere-specific telomere length regulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.12.598646. [PMID: 38915611 PMCID: PMC11195199 DOI: 10.1101/2024.06.12.598646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Telomeric DNA, composed of short, direct repeats, is of crucial importance for chromosome stability. Due to intrinsic problems with replicating this DNA, the repeat tracts shorten at each cell division. Once repeat tracts become critically short, a telomeric stress signal induces cellular senescence and division arrest, which eventually may lead to devastating age-related degenerative diseases associated with dysfunctional telomers. Conversely, maintenance of telomere length by telomerase upregulation is a hallmark of cancer. Therefore, telomere length is a critical determinant of telomere function. How telomere length is established and molecular mechanisms for telomere-specific length regulation remained unknown. Here we show that subtelomeric chromatin is a determinant for how telomere equilibrium set-length is established in cis. The results demonstrate that telomerase recruitment mediated by the telomere-associated Sir4 protein is modulated on chromosome 3L in a telomere-specific way. Increased Sir4 abundance on subtelomeric heterochromatin of this specific telomere leads to telomere lengthening of only that telomere in cis, but not at other telomeres. Therefore, this work describes a mechanism for a how telomere-specific repeat tract length can be established. Further, our results will force the evaluation of telomere length away from a generalized view to a more telomere-specific consideration.
Collapse
Affiliation(s)
- Gabriela M. Teplitz
- Department of Microbiology and Infectiology, Faculty of Medicine and Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | - Emeline Pasquier
- Department of Microbiology and Infectiology, Faculty of Medicine and Sciences, Université de Sherbrooke, Sherbrooke, Canada
- Current Address: CNRS-UMR9019, Gustave Roussy Institute, Villejuif, France
| | - Erin Bonnell
- Department of Microbiology and Infectiology, Faculty of Medicine and Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | - Evelina De Laurentiis
- Department of Microbiology and Infectiology, Faculty of Medicine and Sciences, Université de Sherbrooke, Sherbrooke, Canada
| | - Louise Bartle
- Department of Microbiology and Infectiology, Faculty of Medicine and Sciences, Université de Sherbrooke, Sherbrooke, Canada
- Current Address: School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, Australia
| | - Jean-François Lucier
- Department of Biology, Faculty of Sciences, Université de Sherbrooke, Sherbrooke Canada
| | - Samantha Sholes
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA
- Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University School of Medicine, Baltimore, USA
- Current Address: Merck & Co., 770 Sumneytown Pike, West Point, USA
| | - Carol W. Greider
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, USA
- Department of Molecular Cell and Developmental Biology, University of California, Santa Cruz, USA
| | - Raymund J. Wellinger
- Department of Microbiology and Infectiology, Faculty of Medicine and Sciences, Université de Sherbrooke, Sherbrooke, Canada
| |
Collapse
|
2
|
Roy S, Adhikary H, D’Amours D. The SMC5/6 complex: folding chromosomes back into shape when genomes take a break. Nucleic Acids Res 2024; 52:2112-2129. [PMID: 38375830 PMCID: PMC10954462 DOI: 10.1093/nar/gkae103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/28/2024] [Accepted: 02/01/2024] [Indexed: 02/21/2024] Open
Abstract
High-level folding of chromatin is a key determinant of the shape and functional state of chromosomes. During cell division, structural maintenance of chromosome (SMC) complexes such as condensin and cohesin ensure large-scale folding of chromatin into visible chromosomes. In contrast, the SMC5/6 complex plays more local and context-specific roles in the structural organization of interphase chromosomes with important implications for health and disease. Recent advances in single-molecule biophysics and cryo-electron microscopy revealed key insights into the architecture of the SMC5/6 complex and how interactions connecting the complex to chromatin components give rise to its unique repertoire of interphase functions. In this review, we provide an integrative view of the features that differentiates the SMC5/6 complex from other SMC enzymes and how these enable dramatic reorganization of DNA folding in space during DNA repair reactions and other genome transactions. Finally, we explore the mechanistic basis for the dynamic targeting of the SMC5/6 complex to damaged chromatin and its crucial role in human health.
Collapse
Affiliation(s)
- Shamayita Roy
- Ottawa Institute of Systems Biology, Department of Cellular and Molecular Medicine, University of Ottawa, Roger Guindon Hall, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
| | - Hemanta Adhikary
- Ottawa Institute of Systems Biology, Department of Cellular and Molecular Medicine, University of Ottawa, Roger Guindon Hall, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
| | - Damien D’Amours
- Ottawa Institute of Systems Biology, Department of Cellular and Molecular Medicine, University of Ottawa, Roger Guindon Hall, 451 Smyth Rd, Ottawa, ON K1H 8M5, Canada
| |
Collapse
|
3
|
O’Brien MP, Pryzhkova MV, Lake EMR, Mandino F, Shen X, Karnik R, Atkins A, Xu MJ, Ji W, Konstantino M, Brueckner M, Ment LR, Khokha MK, Jordan PW. SMC5 Plays Independent Roles in Congenital Heart Disease and Neurodevelopmental Disability. Int J Mol Sci 2023; 25:430. [PMID: 38203602 PMCID: PMC10779392 DOI: 10.3390/ijms25010430] [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: 11/30/2023] [Revised: 12/19/2023] [Accepted: 12/20/2023] [Indexed: 01/12/2024] Open
Abstract
Up to 50% of patients with severe congenital heart disease (CHD) develop life-altering neurodevelopmental disability (NDD). It has been presumed that NDD arises in CHD cases because of hypoxia before, during, or after cardiac surgery. Recent studies detected an enrichment in de novo mutations in CHD and NDD, as well as significant overlap between CHD and NDD candidate genes. However, there is limited evidence demonstrating that genes causing CHD can produce NDD independent of hypoxia. A patient with hypoplastic left heart syndrome and gross motor delay presented with a de novo mutation in SMC5. Modeling mutation of smc5 in Xenopus tropicalis embryos resulted in reduced heart size, decreased brain length, and disrupted pax6 patterning. To evaluate the cardiac development, we induced the conditional knockout (cKO) of Smc5 in mouse cardiomyocytes, which led to the depletion of mature cardiomyocytes and abnormal contractility. To test a role for Smc5 specifically in the brain, we induced cKO in the mouse central nervous system, which resulted in decreased brain volume, and diminished connectivity between areas related to motor function but did not affect vascular or brain ventricular volume. We propose that genetic factors, rather than hypoxia alone, can contribute when NDD and CHD cases occur concurrently.
Collapse
Affiliation(s)
- Matthew P. O’Brien
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Marina V. Pryzhkova
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD 21205, USA
- Department of Biochemistry and Molecular Biology, Uniformed Services, University of the Health Sciences, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA
| | - Evelyn M. R. Lake
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Francesca Mandino
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Xilin Shen
- Department of Radiology and Biomedical Imaging, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Ruchika Karnik
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Alisa Atkins
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD 21205, USA
| | - Michelle J. Xu
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD 21205, USA
| | - Weizhen Ji
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
- Pediatric Genomics Discovery Program, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Monica Konstantino
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
- Pediatric Genomics Discovery Program, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Martina Brueckner
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Laura R. Ment
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
- Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Mustafa K. Khokha
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
- Pediatric Genomics Discovery Program, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
- Department of Genetics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, USA
| | - Philip W. Jordan
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD 21205, USA
- Department of Biochemistry and Molecular Biology, Uniformed Services, University of the Health Sciences, 4301 Jones Bridge Rd, Bethesda, MD 20814, USA
| |
Collapse
|
4
|
Manzato C, Larini L, Oss Pegorar C, Dello Stritto MR, Jurikova K, Jantsch V, Cusanelli E. TERRA expression is regulated by the telomere-binding proteins POT-1 and POT-2 in Caenorhabditis elegans. Nucleic Acids Res 2023; 51:10681-10699. [PMID: 37713629 PMCID: PMC10602879 DOI: 10.1093/nar/gkad742] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/23/2023] [Accepted: 08/31/2023] [Indexed: 09/17/2023] Open
Abstract
Several aspects of telomere biology are regulated by the telomeric repeat-containing RNA TERRA. While TERRA expression is conserved through evolution, species-specific mechanisms regulate its biogenesis and function. Here we report on the expression of TERRA in Caenorhabditis elegans. We show that C. elegans TERRA is regulated by the telomere-binding proteins POT-1 and POT-2 which repress TERRA in a telomere-specific manner. C. elegans TERRA transcripts are heterogeneous in length and form discrete nuclear foci, as detected by RNA FISH, in both postmitotic and germline cells; a fraction of TERRA foci localizes to telomeres. Interestingly, in germ cells, TERRA is expressed in all stages of meiotic prophase I, and it increases during pachytene, a stage in meiosis when homologous recombination is ongoing. We used the MS2-GFP system to study the spatiotemporal dynamics of single-telomere TERRA molecules. Single particle tracking revealed different types of motilities, suggesting complex dynamics of TERRA transcripts. Finally, we unveiled distinctive features of C. elegans TERRA, which is regulated by telomere shortening in a telomere-specific manner, and it is upregulated in the telomerase-deficient trt-1; pot-2 double mutant prior to activation of the alternative lengthening mechanism ALT. Interestingly, in these worms TERRA displays distinct dynamics with a higher fraction of fast-moving particles.
Collapse
Affiliation(s)
- Caterina Manzato
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, 38123, Trento, Italy
| | - Luca Larini
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, 38123, Trento, Italy
| | - Claudio Oss Pegorar
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, 38123, Trento, Italy
| | - Maria Rosaria Dello Stritto
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter 1030, Vienna, Austria
| | - Katarina Jurikova
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, 38123, Trento, Italy
- Department of Genetics, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Mlynská dolina 84215, Bratislava, Slovakia
| | - Verena Jantsch
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter 1030, Vienna, Austria
| | - Emilio Cusanelli
- Laboratory of Cell Biology and Molecular Genetics, Department CIBIO, University of Trento, 38123, Trento, Italy
| |
Collapse
|
5
|
Sosa Ponce ML, Remedios MH, Moradi-Fard S, Cobb JA, Zaremberg V. SIR telomere silencing depends on nuclear envelope lipids and modulates sensitivity to a lysolipid. J Cell Biol 2023; 222:e202206061. [PMID: 37042812 PMCID: PMC10103788 DOI: 10.1083/jcb.202206061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 11/29/2022] [Accepted: 03/24/2023] [Indexed: 04/13/2023] Open
Abstract
The nuclear envelope (NE) is important in maintaining genome organization. The role of lipids in communication between the NE and telomere regulation was investigated, including how changes in lipid composition impact gene expression and overall nuclear architecture. Yeast was treated with the non-metabolizable lysophosphatidylcholine analog edelfosine, known to accumulate at the perinuclear ER. Edelfosine induced NE deformation and disrupted telomere clustering but not anchoring. Additionally, the association of Sir4 at telomeres decreased. RNA-seq analysis showed altered expression of Sir-dependent genes located at sub-telomeric (0-10 kb) regions, consistent with Sir4 dispersion. Transcriptomic analysis revealed that two lipid metabolic circuits were activated in response to edelfosine, one mediated by the membrane sensing transcription factors, Spt23/Mga2, and the other by a transcriptional repressor, Opi1. Activation of these transcriptional programs resulted in higher levels of unsaturated fatty acids and the formation of nuclear lipid droplets. Interestingly, cells lacking Sir proteins displayed resistance to unsaturated-fatty acids and edelfosine, and this phenotype was connected to Rap1.
Collapse
Affiliation(s)
| | | | - Sarah Moradi-Fard
- Departments of Biochemistry and Molecular Biology and Oncology, Cumming School of Medicine, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Calgary, Canada
| | - Jennifer A. Cobb
- Departments of Biochemistry and Molecular Biology and Oncology, Cumming School of Medicine, Robson DNA Science Centre, Arnie Charbonneau Cancer Institute, Calgary, Canada
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, Canada
| | - Vanina Zaremberg
- Department of Biological Sciences, University of Calgary, Calgary, Canada
| |
Collapse
|
6
|
Zeinoun B, Teixeira MT, Barascu A. TERRA and Telomere Maintenance in the Yeast Saccharomyces cerevisiae. Genes (Basel) 2023; 14:genes14030618. [PMID: 36980890 PMCID: PMC10048448 DOI: 10.3390/genes14030618] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 02/24/2023] [Accepted: 02/26/2023] [Indexed: 03/06/2023] Open
Abstract
Telomeres are structures made of DNA, proteins and RNA found at the ends of eukaryotic linear chromosomes. These dynamic nucleoprotein structures protect chromosomal tips from end-to-end fusions, degradation, activation of damage checkpoints and erroneous DNA repair events. Telomeres were thought to be transcriptionally silent regions because of their constitutive heterochromatin signature until telomeric long non-coding RNAs (LncRNAs) were discovered. One of them, TERRA (TElomeric Repeat-containing RNA), starts in the subtelomeric regions towards the chromosome ends from different telomeres and has been extensively studied in many evolutionarily distant eukaryotes. Changes in TERRA’s expression can lead to telomeric dysfunction, interfere with the replicative machinery and impact telomere length. TERRA also co-localizes in vivo with telomerase, and can form RNA:DNA hybrid structures called R-loops, which have been implicated in the onset of senescence and the alternative lengthening of telomere (ALT) pathway. Yet, the molecular mechanisms involving TERRA, as well as its function, remain elusive. Here, we review the current knowledge of TERRA transcription, structure, expression, regulation and its multiple telomeric and extra-telomeric functions in the budding yeast Saccharomyces cerevisiae.
Collapse
|
7
|
Xu F, Song H, Xiao Q, Wei Q, Pang X, Gao Y, Tan G. Type-III interferon stimulated gene TRIM31 mutation in an HBV patient blocks its ability in promoting HBx degradation. Virus Res 2022; 308:198650. [PMID: 34863820 DOI: 10.1016/j.virusres.2021.198650] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 11/29/2021] [Accepted: 11/29/2021] [Indexed: 10/19/2022]
Abstract
TRIM5γ, together with TRIM31, has been shown to promote HBx ubiquitination and degradation. This study aimed to explore whether a patient with HCC (hepatic cell carcinoma) having a small nucleotide inserted into the TRIM31 gene, which made a shorter transcript stop at 768 bp, would result in blocking the activity of TRIM31 in promoting HBx degradation. Besides, this study aimed to determine the binding region of the TRIM31-TRIM5γ-HBx complex. HBV (Hepatitis B virus) infection was reported to induce type-III IFN but not type-I or type-II IFNs, here TRIM31 was found to be a type III rather than a type I stimulated gene, which was indispensable in inhibiting the hepatitis B virus replication by the interferon families. Thus, this study further identified the critical role of TRIM31 in the host-hepatitis B virus interaction.
Collapse
Affiliation(s)
- Fengchao Xu
- Department of Immunology, Institute of Translational Medicine, the First Hospital of Jilin University, Changchun, Jilin 130061, China
| | - Hongxiao Song
- Department of Immunology, Institute of Translational Medicine, the First Hospital of Jilin University, Changchun, Jilin 130061, China
| | - Qingfei Xiao
- Department of Nephrology, the First Hospital of Jilin University, Changchun, 130031, Jilin, China
| | - Qi Wei
- Department of Anesthesia, the First Hospital, Jilin University, Changchun, 130021, Jilin, China
| | - Xiaoli Pang
- Department of Pediatric Gastroenterology, the First Hospital, Jilin University, Changchun 130021, Jilin, China
| | - Yanli Gao
- Department of Pediatrics, the First Hospital, Jilin University, Changchun 130021, Jilin, China.
| | - Guangyun Tan
- Department of Immunology, Institute of Translational Medicine, the First Hospital of Jilin University, Changchun, Jilin 130061, China.
| |
Collapse
|
8
|
Ptak C, Saik NO, Premashankar A, Lapetina DL, Aitchison JD, Montpetit B, Wozniak RW. Phosphorylation-dependent mitotic SUMOylation drives nuclear envelope-chromatin interactions. J Cell Biol 2021; 220:212843. [PMID: 34787675 PMCID: PMC8641411 DOI: 10.1083/jcb.202103036] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 07/30/2021] [Accepted: 09/22/2021] [Indexed: 12/15/2022] Open
Abstract
In eukaryotes, chromatin binding to the inner nuclear membrane (INM) and nuclear pore complexes (NPCs) contributes to spatial organization of the genome and epigenetic programs important for gene expression. In mitosis, chromatin–nuclear envelope (NE) interactions are lost and then formed again as sister chromosomes segregate to postmitotic nuclei. Investigating these processes in S. cerevisiae, we identified temporally and spatially controlled phosphorylation-dependent SUMOylation events that positively regulate postmetaphase chromatin association with the NE. Our work establishes a phosphorylation-mediated targeting mechanism of the SUMO ligase Siz2 to the INM during mitosis, where Siz2 binds to and SUMOylates the VAP protein Scs2. The recruitment of Siz2 through Scs2 is further responsible for a wave of SUMOylation along the INM that supports the assembly and anchorage of subtelomeric chromatin at the INM and localization of an active gene (INO1) to NPCs during the later stages of mitosis and into G1-phase.
Collapse
Affiliation(s)
- Christopher Ptak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Natasha O Saik
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | | | - Diego L Lapetina
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | | | - Ben Montpetit
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada.,Department of Viticulture and Enology, University of California Davis, Davis, CA
| | - Richard W Wozniak
- Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
9
|
Moradi‐Fard S, Mojumdar A, Chan M, Harkness TA, Cobb JA. Smc5/6 in the rDNA modulates lifespan independently of Fob1. Aging Cell 2021; 20:e13373. [PMID: 33979898 PMCID: PMC8208791 DOI: 10.1111/acel.13373] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/18/2021] [Accepted: 04/08/2021] [Indexed: 12/28/2022] Open
Abstract
The ribosomal DNA (rDNA) in Saccharomycescerevisiae is in one tandem repeat array on Chromosome XII. Two regions within each repetitive element, called intergenic spacer 1 (IGS1) and IGS2, are important for organizing the rDNA within the nucleolus. The Smc5/6 complex localizes to IGS1 and IGS2. We show that Smc5/6 has a function in the rDNA beyond its role in homologous recombination (HR) at the replication fork barrier (RFB) located in IGS1. Fob1 is required for optimal binding of Smc5/6 at IGS1 whereas the canonical silencing factor Sir2 is required for its optimal binding at IGS2, independently of Fob1. Through interdependent interactions, Smc5/6 stabilizes Sir2 and Cohibin at both IGS and its recovery at IGS2 is important for nucleolar compaction and transcriptional silencing, which in turn supports rDNA stability and lifespan.
Collapse
Affiliation(s)
- Sarah Moradi‐Fard
- Departments of Biochemistry & Molecular Biology and Oncology Robson DNA Science Centre Arnie Charbonneau Cancer Institute Cumming School of Medicine University of Calgary Calgary AB Canada
| | - Aditya Mojumdar
- Departments of Biochemistry & Molecular Biology and Oncology Robson DNA Science Centre Arnie Charbonneau Cancer Institute Cumming School of Medicine University of Calgary Calgary AB Canada
| | - Megan Chan
- Departments of Biochemistry & Molecular Biology and Oncology Robson DNA Science Centre Arnie Charbonneau Cancer Institute Cumming School of Medicine University of Calgary Calgary AB Canada
| | - Troy A.A. Harkness
- Department of Biochemistry, Microbiology and Immunology University of Saskatchewan Saskatoon SK Canada
| | - Jennifer A. Cobb
- Departments of Biochemistry & Molecular Biology and Oncology Robson DNA Science Centre Arnie Charbonneau Cancer Institute Cumming School of Medicine University of Calgary Calgary AB Canada
| |
Collapse
|
10
|
Dupont L, Bloor S, Williamson JC, Cuesta SM, Shah R, Teixeira-Silva A, Naamati A, Greenwood EJD, Sarafianos SG, Matheson NJ, Lehner PJ. The SMC5/6 complex compacts and silences unintegrated HIV-1 DNA and is antagonized by Vpr. Cell Host Microbe 2021; 29:792-805.e6. [PMID: 33811831 PMCID: PMC8118623 DOI: 10.1016/j.chom.2021.03.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/31/2020] [Accepted: 02/26/2021] [Indexed: 12/16/2022]
Abstract
Silencing of nuclear DNA is an essential feature of innate immune responses to invading pathogens. Early in infection, unintegrated lentiviral cDNA accumulates in the nucleus yet remains poorly expressed. In HIV-1-like lentiviruses, the Vpr accessory protein enhances unintegrated viral DNA expression, suggesting Vpr antagonizes cellular restriction. We previously showed how Vpr remodels the host proteome, identifying multiple cellular targets. We now screen these using a targeted CRISPR-Cas9 library and identify SMC5-SMC6 complex localization factor 2 (SLF2) as the Vpr target responsible for silencing unintegrated HIV-1. SLF2 recruits the SMC5/6 complex to unintegrated lentiviruses, and depletion of SLF2, or the SMC5/6 complex, increases viral expression. ATAC-seq demonstrates that Vpr-mediated SLF2 depletion increases chromatin accessibility of unintegrated virus, suggesting that the SMC5/6 complex compacts viral chromatin to silence gene expression. This work implicates the SMC5/6 complex in nuclear immunosurveillance of extrachromosomal DNA and defines its targeting by Vpr as an evolutionarily conserved antagonism.
Collapse
Affiliation(s)
- Liane Dupont
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK
| | - Stuart Bloor
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK
| | - James C Williamson
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK
| | | | - Raven Shah
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Ana Teixeira-Silva
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK
| | - Adi Naamati
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK
| | - Edward J D Greenwood
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK
| | - Stefan G Sarafianos
- Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA 30322, USA
| | - Nicholas J Matheson
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK
| | - Paul J Lehner
- Cambridge Institute for Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0AW, UK.
| |
Collapse
|
11
|
Nuclear Periphery and Telomere Maintenance: TERRA Joins the Stage. Trends Genet 2021; 37:608-611. [PMID: 33663806 DOI: 10.1016/j.tig.2021.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 11/21/2022]
Abstract
Long noncoding (lnc)RNAs derived from telomeres, the ends of linear eukaryotic chromosomes, help to maintain telomere length and stability by multiple means, including regulation of telomerase activity and recombination-based telomere maintenance. New findings in yeast promote a model in which telomere attachment to the nuclear envelope regulates telomere transcription and maintenance.
Collapse
|
12
|
Atkins A, Xu MJ, Li M, Rogers NP, Pryzhkova MV, Jordan PW. SMC5/6 is required for replication fork stability and faithful chromosome segregation during neurogenesis. eLife 2020; 9:e61171. [PMID: 33200984 PMCID: PMC7723410 DOI: 10.7554/elife.61171] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 11/16/2020] [Indexed: 12/21/2022] Open
Abstract
Mutations of SMC5/6 components cause developmental defects, including primary microcephaly. To model neurodevelopmental defects, we engineered a mouse wherein Smc5 is conditionally knocked out (cKO) in the developing neocortex. Smc5 cKO mice exhibited neurodevelopmental defects due to neural progenitor cell (NPC) apoptosis, which led to reduction in cortical layer neurons. Smc5 cKO NPCs formed DNA bridges during mitosis and underwent chromosome missegregation. SMC5/6 depletion triggers a CHEK2-p53 DNA damage response, as concomitant deletion of the Trp53 tumor suppressor or Chek2 DNA damage checkpoint kinase rescued Smc5 cKO neurodevelopmental defects. Further assessment using Smc5 cKO and auxin-inducible degron systems demonstrated that absence of SMC5/6 leads to DNA replication stress at late-replicating regions such as pericentromeric heterochromatin. In summary, SMC5/6 is important for completion of DNA replication prior to entering mitosis, which ensures accurate chromosome segregation. Thus, SMC5/6 functions are critical in highly proliferative stem cells during organism development.
Collapse
Affiliation(s)
- Alisa Atkins
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
| | - Michelle J Xu
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
| | - Maggie Li
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
| | - Nathaniel P Rogers
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
| | - Marina V Pryzhkova
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
| | - Philip W Jordan
- Biochemistry and Molecular Biology Department, Johns Hopkins University Bloomberg School of Public HealthBaltimoreUnited States
| |
Collapse
|
13
|
Hagee D, Abu Hardan A, Botero J, Arnone JT. Genomic clustering within functionally related gene families in Ascomycota fungi. Comput Struct Biotechnol J 2020; 18:3267-3277. [PMID: 33209211 PMCID: PMC7653285 DOI: 10.1016/j.csbj.2020.10.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/15/2020] [Accepted: 10/17/2020] [Indexed: 12/17/2022] Open
Abstract
Multiple mechanisms collaborate for proper regulation of gene expression. One layer of this regulation is through the clustering of functionally related genes at discrete loci throughout the genome. This phenomenon occurs extensively throughout Ascomycota fungi and is an organizing principle for many gene families whose proteins participate in diverse molecular functions throughout the cell. Members of this phylum include organisms that serve as model systems and those of interest medically, pharmaceutically, and for industrial and biotechnological applications. In this review, we discuss the prevalence of functional clustering through a broad range of organisms within the phylum. Position effects on transcription, genomic locations of clusters, transcriptional regulation of clusters, and selective pressures contributing to the formation and maintenance of clusters are addressed, as are common methods to identify and characterize clusters.
Collapse
Affiliation(s)
- Danielle Hagee
- Department of Biology, William Paterson University, Wayne, NJ 07470, USA
| | - Ahmad Abu Hardan
- Department of Biology, William Paterson University, Wayne, NJ 07470, USA
| | - Juan Botero
- Department of Biology, William Paterson University, Wayne, NJ 07470, USA
| | - James T. Arnone
- Department of Biology, William Paterson University, Wayne, NJ 07470, USA
| |
Collapse
|
14
|
Lalonde M, Chartrand P. TERRA, a Multifaceted Regulator of Telomerase Activity at Telomeres. J Mol Biol 2020; 432:4232-4243. [PMID: 32084415 DOI: 10.1016/j.jmb.2020.02.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/06/2020] [Accepted: 02/10/2020] [Indexed: 02/07/2023]
Abstract
In eukaryotes, telomeres are repetitive sequences at the end of chromosomes, which are maintained in a constitutive heterochromatin state. It is now known that telomeres can be actively transcribed, leading to the production of a telomeric repeat-containing noncoding RNA called TERRA. Due to its sequence complementarity to the telomerase template, it was suggested early on that TERRA could be an inhibitor of telomerase. Since then, TERRA has been shown to be involved in heterochromatin formation at telomeres, to invade telomeric dsDNA and form R-loops, and even to promote telomerase recruitment at short telomeres. All these functions depend on the diverse capacities of this lncRNA to bind various cofactors, act as a scaffold, and promote higher-order complexes in cells. In this review, it will be highlighted as to how these properties of TERRA work together to regulate telomerase activity at telomeres.
Collapse
Affiliation(s)
- Maxime Lalonde
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Quebec, Canada
| | - Pascal Chartrand
- Department of Biochemistry and Molecular Medicine, Université de Montréal, Quebec, Canada.
| |
Collapse
|
15
|
Abstract
Smc5 and Smc6, together with the kleisin Nse4, form the heart of the enigmatic and poorly understood Smc5/6 complex, which is frequently viewed as a cousin of cohesin and condensin with functions in DNA repair. As novel functions for cohesin and condensin complexes in the organization of long-range chromatin architecture have recently emerged, new unsuspected roles for Smc5/6 have also surfaced. Here, I aim to provide a comprehensive overview of our current knowledge of the Smc5/6 complex, including its long-established function in genome stability, its multiple roles in DNA repair, and its recently discovered connection to the transcription inhibition of hepatitis B virus genomes. In addition, I summarize new research that is beginning to tease out the molecular details of Smc5/6 structure and function, knowledge that will illuminate the nuclear activities of Smc5/6 in the stability and dynamics of eukaryotic genomes.
Collapse
Affiliation(s)
- Luis Aragón
- Cell Cycle Group, MRC London Institute of Medical Sciences, Hammersmith Hospital Campus, London W12 0NN, United Kingdom;
| |
Collapse
|
16
|
Ravi M, Ramanathan S, Krishna K. Factors, mechanisms and implications of chromatin condensation and chromosomal structural maintenance through the cell cycle. J Cell Physiol 2019; 235:758-775. [PMID: 31264212 DOI: 10.1002/jcp.29038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 06/12/2019] [Indexed: 12/16/2022]
Abstract
A series of well-orchestrated events help in the chromatin condensation and the formation of chromosomes. Apart from the formation of chromosomes, maintenance of their structure is important, especially for the cell division. The structural maintenance of chromosome (SMC) proteins, the non-SMC proteins and the SMC complexes are critical for the maintenance of chromosome structure. While condensins have roles for the DNA compaction, organization, and segregation, the cohesin functions in a cyclic manner through the cell cycle, as a "cohesin cycle." Specific mechanisms maintain the architecture of the centromere, the kinetochore and the telomeres which are in tandem with the cell cycle checkpoints. The presence of chromosomal territories and compactness differences through the length of the chromosomes might have implications on selective susceptibility of specific chromosomes for induced genotoxicity.
Collapse
Affiliation(s)
- Maddaly Ravi
- Department of Human Genetics, Faculty of Biomedical Sciences, Technology and Research, Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai, India
| | - Srishti Ramanathan
- Department of Human Genetics, Faculty of Biomedical Sciences, Technology and Research, Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai, India
| | - Krupa Krishna
- Department of Human Genetics, Faculty of Biomedical Sciences, Technology and Research, Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai, India
| |
Collapse
|
17
|
DNA replication stress and its impact on chromosome segregation and tumorigenesis. Semin Cancer Biol 2018; 55:61-69. [PMID: 29692334 DOI: 10.1016/j.semcancer.2018.04.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 01/11/2023]
Abstract
Genome instability and cell cycle dysregulation are commonly associated with cancer. DNA replication stress driven by oncogene activation during tumorigenesis is now well established as a source of genome instability. Replication stress generates DNA damage not only during S phase, but also in the subsequent mitosis, where it impacts adversely on chromosome segregation. Some regions of the genome seem particularly sensitive to replication stress-induced instability; most notably, chromosome fragile sites. In this article, we review some of the important issues that have emerged in recent years concerning DNA replication stress and fragile site expression, as well as how chromosome instability is minimized by a family of ring-shaped protein complexes known as SMC proteins. Understanding how replication stress impacts on S phase and mitosis in cancer should provide opportunities for the development of novel and tumour-specific treatments.
Collapse
|
18
|
Avogaro L, Querido E, Dalachi M, Jantsch MF, Chartrand P, Cusanelli E. Live-cell imaging reveals the dynamics and function of single-telomere TERRA molecules in cancer cells. RNA Biol 2018; 15:787-796. [PMID: 29658398 PMCID: PMC6152429 DOI: 10.1080/15476286.2018.1456300] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Telomeres cap the ends of eukaryotic chromosomes, protecting them from degradation and erroneous recombination events which may lead to genome instability. Telomeres are transcribed giving rise to telomeric repeat-containing RNAs, called TERRA. The TERRA long noncoding RNAs have been proposed to play important roles in telomere biology, including heterochromatin formation and telomere length homeostasis. While TERRA RNAs are predominantly nuclear and localize at telomeres, little is known about the dynamics and function of TERRA molecules expressed from individual telomeres. Herein, we developed an assay to image endogenous TERRA molecules expressed from a single telomere in living human cancer cells. We show that single-telomere TERRA can be detected as TERRA RNA single particles which freely diffuse within the nucleus. Furthermore, TERRA molecules aggregate forming TERRA clusters. Three-dimensional size distribution and single particle tracking analyses revealed distinct sizes and dynamics for TERRA RNA single particles and clusters. Simultaneous time lapse confocal imaging of TERRA particles and telomeres showed that TERRA clusters transiently co-localize with telomeres. Finally, we used chemically modified antisense oligonucleotides to deplete TERRA molecules expressed from a single telomere. Single-telomere TERRA depletion resulted in increased DNA damage at telomeres and elsewhere in the genome. These results suggest that single-telomere TERRA transcripts participate in the maintenance of genomic integrity in human cancer cells.
Collapse
Affiliation(s)
- Laura Avogaro
- a Centre for Integrative Biology (CIBIO), University of Trento , Trento , Italy
| | - Emmanuelle Querido
- b Department of Biochemistry and Molecular Medicine , Université de Montréal , QC , Canada
| | - Myriam Dalachi
- b Department of Biochemistry and Molecular Medicine , Université de Montréal , QC , Canada
| | - Michael F Jantsch
- c Centre of Anatomy and Cell Biology, Medical University of Vienna , Vienna , Austria
| | - Pascal Chartrand
- b Department of Biochemistry and Molecular Medicine , Université de Montréal , QC , Canada
| | - Emilio Cusanelli
- a Centre for Integrative Biology (CIBIO), University of Trento , Trento , Italy
| |
Collapse
|
19
|
Induction and relocalization of telomeric repeat-containing RNAs during diauxic shift in budding yeast. Curr Genet 2018; 64:1117-1127. [PMID: 29569051 DOI: 10.1007/s00294-018-0829-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/09/2018] [Accepted: 03/20/2018] [Indexed: 02/03/2023]
Abstract
Telomeres are maintained in a heterochromatic state that represses transcription of subtelomeric genes, a phenomenon known as telomere position effect. Nevertheless, telomeric DNA is actively transcribed, leading to the synthesis of telomeric repeat-containing noncoding RNA or TERRA. This nuclear noncoding RNA has been proposed to play important roles at telomeres, regulating their silencing, capping, repair and elongation by telomerase. In the budding yeast Saccharomyces cerevisiae, TERRA accumulation is repressed by telomeric silencing and the Rat1 exonuclease. On the other hand, telomere shortening promotes expression of TERRA. So far, little is known about the biological processes that induce TERRA expression in yeast. Understanding the dynamics of TERRA expression and localization is essential to define its function in telomere biology. Here, we aim to study the dynamics of TERRA expression during yeast cell growth. Using live-cell imaging, RNA-FISH and quantitative RT-PCR, we show that TERRA expression is induced as yeast cells undergo diauxic shift, a lag phase during which yeast cells switch their metabolism from anaerobic fermentation to oxidative respiration. This induction is transient as TERRA levels decrease during post-diauxic shift. The increased expression of TERRA is not due to the shortening of telomeres or increased stability of this transcript. Surprisingly, this induction is coincident with a cytoplasmic accumulation of TERRA molecules. Our results suggest that TERRA transcripts may play extranuclear functions with important implications in telomere biology and add a novel layer of complexity in the interplay between telomere biology, metabolism and stress response.
Collapse
|
20
|
Lafuente-Barquero J, Luke-Glaser S, Graf M, Silva S, Gómez-González B, Lockhart A, Lisby M, Aguilera A, Luke B. The Smc5/6 complex regulates the yeast Mph1 helicase at RNA-DNA hybrid-mediated DNA damage. PLoS Genet 2017; 13:e1007136. [PMID: 29281624 PMCID: PMC5760084 DOI: 10.1371/journal.pgen.1007136] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 01/09/2018] [Accepted: 11/28/2017] [Indexed: 01/08/2023] Open
Abstract
RNA-DNA hybrids are naturally occurring obstacles that must be overcome by the DNA replication machinery. In the absence of RNase H enzymes, RNA-DNA hybrids accumulate, resulting in replication stress, DNA damage and compromised genomic integrity. We demonstrate that Mph1, the yeast homolog of Fanconi anemia protein M (FANCM), is required for cell viability in the absence of RNase H enzymes. The integrity of the Mph1 helicase domain is crucial to prevent the accumulation of RNA-DNA hybrids and RNA-DNA hybrid-dependent DNA damage, as determined by Rad52 foci. Mph1 forms foci when RNA-DNA hybrids accumulate, e.g. in RNase H or THO-complex mutants and at short telomeres. Mph1, however is a double-edged sword, whose action at hybrids must be regulated by the Smc5/6 complex. This is underlined by the observation that simultaneous inactivation of RNase H2 and Smc5/6 results in Mph1-dependent synthetic lethality, which is likely due to an accumulation of toxic recombination intermediates. The data presented here support a model, where Mph1’s helicase activity plays a crucial role in responding to persistent RNA-DNA hybrids. DNA damage can either occur exogenously through DNA damaging agents such as UV light and exposure to chemotherapeutics, or endogenously via metabolic, cellular processes. The RNA product of transcription, for example, can engage in the formation of RNA-DNA hybrids. Such RNA-DNA hybrids can impede replication fork progression and cause genomic instability, a hallmark of cancer. The misregulation of RNA-DNA hybrids has also been implicated in several neurological disorders. Recently, it has become evident that RNA-DNA hybrids may also have beneficial roles and therefore, these structures have to be tightly controlled. We found that Mph1 (mutator phenotype 1), the budding yeast homolog of Fanconi Anemia protein M, counteracts the accumulation of RNA-DNA hybrids. The inactivation of MPH1 results in a severe growth defect when combined with mutations in the well-characterized RNase H enzymes, that degrade the RNA moiety of an RNA-DNA hybrid. Based on the data presented here, we propose a model, where Mph1 itself has to be kept in check by the SMC (structural maintenance of chromosome) 5/6 complex at replication forks stalled by RNA-DNA hybrids. Mph1 acts as a double-edged sword, as both its deletion and the inability to control its helicase activity cause DNA damage and growth arrest when RNA-DNA hybrids accumulate.
Collapse
Affiliation(s)
- Juan Lafuente-Barquero
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Avda. Americo Vespucio 24, Seville, Spain
| | - Sarah Luke-Glaser
- Institute of Molecular Biology (IMB), Mainz, Germany
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Marco Graf
- Institute of Molecular Biology (IMB), Mainz, Germany
| | - Sonia Silva
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Avda. Americo Vespucio 24, Seville, Spain
- Department of Biology, University of Copenhagen, Ole Maaloeesvej 5, Copenhagen N, Denmark
| | - Belén Gómez-González
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Avda. Americo Vespucio 24, Seville, Spain
| | | | - Michael Lisby
- Department of Biology, University of Copenhagen, Ole Maaloeesvej 5, Copenhagen N, Denmark
| | - Andrés Aguilera
- Andalusian Center for Molecular Biology and Regenerative Medicine-CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Avda. Americo Vespucio 24, Seville, Spain
- * E-mail: (BL); (AA)
| | - Brian Luke
- Institute of Molecular Biology (IMB), Mainz, Germany
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
- Institute of Neurobiology and Developmental Biology, JGU Mainz, Mainz, Germany
- * E-mail: (BL); (AA)
| |
Collapse
|
21
|
Steinbrecher D, Jebaraj BMC, Schneider C, Edelmann J, Cymbalista F, Leblond V, Delmer A, Ibach S, Tausch E, Scheffold A, Bloehdorn J, Hallek M, Dreger P, Döhner H, Stilgenbauer S. Telomere length in poor-risk chronic lymphocytic leukemia: associations with disease characteristics and outcome. Leuk Lymphoma 2017; 59:1614-1623. [PMID: 29063805 DOI: 10.1080/10428194.2017.1390236] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Telomere length in chronic lymphocytic leukemia (CLL) is described as an independent prognostic factor based largely on previously untreated patients from chemotherapy based trials. Here, we studied telomere length associations in high-risk, relapsed/refractory CLL treated with alemtuzumab in the CLL2O study (n = 110) of German and French CLL study groups. Telomere length (median 3.28 kb, range 2.52-7.24 kb) was relatively short, since 84.4% of patients had 17p- which is generally associated with short telomeres. Median telomere length was used for dichotomization into short and long telomere subgroups. Telomere length was associated with s-TK (p = .025) and TP53 mutations (p = .050) in untreated patients, while no association with clinical/biological characteristics was observed in relapsed/refractory CLL. Short telomeres had significant association with shorter PFS (p = .018) only in refractory CLL. Presence of short telomeres, loss of genes maintaining genomic integrity (SMC5) and increased incidence of chromothripsis, indicated the prevalence of genomic instability in this high-risk cohort (clinicaltrials.gov: NCT01392079).
Collapse
Affiliation(s)
| | | | - Christof Schneider
- a Department of Internal Medicine III , University of Ulm , Ulm , Germany
| | - Jennifer Edelmann
- b Barts Cancer Institute, Queen Mary University of London , London , UK
| | | | - Véronique Leblond
- d Service d'Hématologie , Hôpital Pitié-Salpêtrière , Paris , France
| | - Alain Delmer
- e Service d'Hématologie Clinique , CHU de Reims , Reims , France
| | - Stefan Ibach
- f WiSP Wissenschaftliche Service Pharma GmbH , Langenfeld , Germany
| | - Eugen Tausch
- a Department of Internal Medicine III , University of Ulm , Ulm , Germany
| | - Annika Scheffold
- a Department of Internal Medicine III , University of Ulm , Ulm , Germany
| | - Johannes Bloehdorn
- a Department of Internal Medicine III , University of Ulm , Ulm , Germany
| | - Michael Hallek
- g Internal Medicine I , University Cologne , Cologne , Germany
| | - Peter Dreger
- h Internal Medicine V , University of Heidelberg , Heidelberg , Germany
| | - Hartmut Döhner
- a Department of Internal Medicine III , University of Ulm , Ulm , Germany
| | | |
Collapse
|
22
|
Alternative Lengthening of Telomeres Mediated by Mitotic DNA Synthesis Engages Break-Induced Replication Processes. Mol Cell Biol 2017; 37:MCB.00226-17. [PMID: 28760773 DOI: 10.1128/mcb.00226-17] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 07/20/2017] [Indexed: 01/05/2023] Open
Abstract
Alternative lengthening of telomeres (ALT) is a telomerase-independent telomere maintenance mechanism that occurs in a subset of cancers. By analyzing telomerase-positive cells and their human TERC knockout-derived ALT human cell lines, we show that ALT cells harbor more fragile telomeres representing telomere replication problems. ALT-associated replication defects trigger mitotic DNA synthesis (MiDAS) at telomeres in a RAD52-dependent, but RAD51-independent, manner. Telomeric MiDAS is a conservative DNA synthesis process, potentially mediated by break-induced replication, similar to type II ALT survivors in Saccharomyces cerevisiae Replication stresses induced by ectopic oncogenic expression of cyclin E, G-quadruplexes, or R-loop formation facilitate the ALT pathway and lead to telomere clustering, a hallmark of ALT cancers. The TIMELESS/TIPIN complex suppresses telomere clustering and telomeric MiDAS, whereas the SMC5/6 complex promotes them. In summary, ALT cells exhibit more telomere replication defects that result in persistent DNA damage responses at telomeres, leading to the engagement of telomeric MiDAS (spontaneous mitotic telomere synthesis) that is triggered by DNA replication stress, a potential driver of genomic duplications in cancer.
Collapse
|
23
|
Jalal D, Chalissery J, Hassan AH. Genome maintenance in Saccharomyces cerevisiae: the role of SUMO and SUMO-targeted ubiquitin ligases. Nucleic Acids Res 2017; 45:2242-2261. [PMID: 28115630 PMCID: PMC5389695 DOI: 10.1093/nar/gkw1369] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 01/02/2017] [Indexed: 01/08/2023] Open
Abstract
The genome of the cell is often exposed to DNA damaging agents and therefore requires an intricate well-regulated DNA damage response (DDR) to overcome its deleterious effects. The DDR needs proper regulation for its timely activation, repression, as well as appropriate choice of repair pathway. Studies in Saccharomyces cerevisiae have advanced our understanding of the DNA damage response, as well as the mechanisms the cell employs to maintain genome stability and how these mechanisms are regulated. Eukaryotic cells utilize post-translational modifications as a means for fine-tuning protein functions. Ubiquitylation and SUMOylation involve the attachment of small protein molecules onto proteins to modulate function or protein–protein interactions. SUMO in particular, was shown to act as a molecular glue when DNA damage occurs, facilitating the assembly of large protein complexes in repair foci. In other instances, SUMOylation alters a protein's biochemical activities, and interactions. SUMO-targeted ubiquitin ligases (STUbLs) are enzymes that target SUMOylated proteins for ubiquitylation and subsequent degradation, providing a function for the SUMO modification in the regulation and disassembly of repair complexes. Here, we discuss the major contributions of SUMO and STUbLs in the regulation of DNA damage repair pathways as well as in the maintenance of critical regions of the genome, namely rDNA regions, telomeres and the 2 μm circle in budding yeast.
Collapse
Affiliation(s)
- Deena Jalal
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al-Ain, UAE
| | - Jisha Chalissery
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al-Ain, UAE
| | - Ahmed H Hassan
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al-Ain, UAE
| |
Collapse
|