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Makova KD, Pickett BD, Harris RS, Hartley GA, Cechova M, Pal K, Nurk S, Yoo D, Li Q, Hebbar P, McGrath BC, Antonacci F, Aubel M, Biddanda A, Borchers M, Bomberg E, Bouffard GG, Brooks SY, Carbone L, Carrel L, Carroll A, Chang PC, Chin CS, Cook DE, Craig SJ, de Gennaro L, Diekhans M, Dutra A, Garcia GH, Grady PG, Green RE, Haddad D, Hallast P, Harvey WT, Hickey G, Hillis DA, Hoyt SJ, Jeong H, Kamali K, Kosakovsky Pond SL, LaPolice TM, Lee C, Lewis AP, Loh YHE, Masterson P, McCoy RC, Medvedev P, Miga KH, Munson KM, Pak E, Paten B, Pinto BJ, Potapova T, Rhie A, Rocha JL, Ryabov F, Ryder OA, Sacco S, Shafin K, Shepelev VA, Slon V, Solar SJ, Storer JM, Sudmant PH, Sweetalana, Sweeten A, Tassia MG, Thibaud-Nissen F, Ventura M, Wilson MA, Young AC, Zeng H, Zhang X, Szpiech ZA, Huber CD, Gerton JL, Yi SV, Schatz MC, Alexandrov IA, Koren S, O’Neill RJ, Eichler E, Phillippy AM. The Complete Sequence and Comparative Analysis of Ape Sex Chromosomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.30.569198. [PMID: 38077089 PMCID: PMC10705393 DOI: 10.1101/2023.11.30.569198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
Apes possess two sex chromosomes-the male-specific Y and the X shared by males and females. The Y chromosome is crucial for male reproduction, with deletions linked to infertility. The X chromosome carries genes vital for reproduction and cognition. Variation in mating patterns and brain function among great apes suggests corresponding differences in their sex chromosome structure and evolution. However, due to their highly repetitive nature and incomplete reference assemblies, ape sex chromosomes have been challenging to study. Here, using the state-of-the-art experimental and computational methods developed for the telomere-to-telomere (T2T) human genome, we produced gapless, complete assemblies of the X and Y chromosomes for five great apes (chimpanzee, bonobo, gorilla, Bornean and Sumatran orangutans) and a lesser ape, the siamang gibbon. These assemblies completely resolved ampliconic, palindromic, and satellite sequences, including the entire centromeres, allowing us to untangle the intricacies of ape sex chromosome evolution. We found that, compared to the X, ape Y chromosomes vary greatly in size and have low alignability and high levels of structural rearrangements. This divergence on the Y arises from the accumulation of lineage-specific ampliconic regions and palindromes (which are shared more broadly among species on the X) and from the abundance of transposable elements and satellites (which have a lower representation on the X). Our analysis of Y chromosome genes revealed lineage-specific expansions of multi-copy gene families and signatures of purifying selection. In summary, the Y exhibits dynamic evolution, while the X is more stable. Finally, mapping short-read sequencing data from >100 great ape individuals revealed the patterns of diversity and selection on their sex chromosomes, demonstrating the utility of these reference assemblies for studies of great ape evolution. These complete sex chromosome assemblies are expected to further inform conservation genetics of nonhuman apes, all of which are endangered species.
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Affiliation(s)
| | - Brandon D. Pickett
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | | | | | - Monika Cechova
- University of California Santa Cruz, Santa Cruz, CA, USA
| | - Karol Pal
- Penn State University, University Park, PA, USA
| | - Sergey Nurk
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - DongAhn Yoo
- University of Washington School of Medicine, Seattle, WA, USA
| | - Qiuhui Li
- Johns Hopkins University, Baltimore, MD, USA
| | - Prajna Hebbar
- University of California Santa Cruz, Santa Cruz, CA, USA
| | | | | | | | | | | | - Erich Bomberg
- University of Münster, Münster, Germany
- MPI for Developmental Biology, Tübingen, Germany
| | - Gerard G. Bouffard
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Shelise Y. Brooks
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Lucia Carbone
- Oregon Health & Science University, Portland, OR, USA
- Oregon National Primate Research Center, Hillsboro, OR, USA
| | - Laura Carrel
- Penn State University School of Medicine, Hershey, PA, USA
| | | | | | - Chen-Shan Chin
- Foundation of Biological Data Sciences, Belmont, CA, USA
| | | | | | | | - Mark Diekhans
- University of California Santa Cruz, Santa Cruz, CA, USA
| | - Amalia Dutra
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Gage H. Garcia
- University of Washington School of Medicine, Seattle, WA, USA
| | | | | | - Diana Haddad
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Pille Hallast
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | | | - Glenn Hickey
- University of California Santa Cruz, Santa Cruz, CA, USA
| | - David A. Hillis
- University of California Santa Barbara, Santa Barbara, CA, USA
| | | | - Hyeonsoo Jeong
- University of Washington School of Medicine, Seattle, WA, USA
| | | | | | | | - Charles Lee
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | | | | | - Patrick Masterson
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | | | | | - Karen H. Miga
- University of California Santa Cruz, Santa Cruz, CA, USA
| | | | - Evgenia Pak
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Benedict Paten
- University of California Santa Cruz, Santa Cruz, CA, USA
| | | | | | - Arang Rhie
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Fedor Ryabov
- Masters Program in National Research University Higher School of Economics, Moscow, Russia
| | | | - Samuel Sacco
- University of California Santa Cruz, Santa Cruz, CA, USA
| | | | | | | | - Steven J. Solar
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | | | | | - Sweetalana
- Penn State University, University Park, PA, USA
| | - Alex Sweeten
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Johns Hopkins University, Baltimore, MD, USA
| | | | - Françoise Thibaud-Nissen
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | | | | | - Alice C. Young
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Xinru Zhang
- Penn State University, University Park, PA, USA
| | | | | | | | - Soojin V. Yi
- University of California Santa Barbara, Santa Barbara, CA, USA
| | | | | | - Sergey Koren
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Evan Eichler
- University of Washington School of Medicine, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Adam M. Phillippy
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
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2
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Novo CL. A Tale of Two States: Pluripotency Regulation of Telomeres. Front Cell Dev Biol 2021; 9:703466. [PMID: 34307383 PMCID: PMC8300013 DOI: 10.3389/fcell.2021.703466] [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: 04/30/2021] [Accepted: 06/08/2021] [Indexed: 01/01/2023] Open
Abstract
Inside the nucleus, chromatin is functionally organized and maintained as a complex three-dimensional network of structures with different accessibility such as compartments, lamina associated domains, and membraneless bodies. Chromatin is epigenetically and transcriptionally regulated by an intricate and dynamic interplay of molecular processes to ensure genome stability. Phase separation, a process that involves the spontaneous organization of a solution into separate phases, has been proposed as a mechanism for the timely coordination of several cellular processes, including replication, transcription and DNA repair. Telomeres, the repetitive structures at the end of chromosomes, are epigenetically maintained in a repressed heterochromatic state that prevents their recognition as double-strand breaks (DSB), avoiding DNA damage repair and ensuring cell proliferation. In pluripotent embryonic stem cells, telomeres adopt a non-canonical, relaxed epigenetic state, which is characterized by a low density of histone methylation and expression of telomere non-coding transcripts (TERRA). Intriguingly, this telomere non-canonical conformation is usually associated with chromosome instability and aneuploidy in somatic cells, raising the question of how genome stability is maintained in a pluripotent background. In this review, we will explore how emerging technological and conceptual developments in 3D genome architecture can provide novel mechanistic perspectives for the pluripotent epigenetic paradox at telomeres. In particular, as RNA drives the formation of LLPS, we will consider how pluripotency-associated high levels of TERRA could drive and coordinate phase separation of several nuclear processes to ensure genome stability. These conceptual advances will provide a better understanding of telomere regulation and genome stability within the highly dynamic pluripotent background.
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Affiliation(s)
- Clara Lopes Novo
- The Francis Crick Institute, London, United Kingdom
- Imperial College London, London, United Kingdom
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3
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Vohhodina J, Goehring LJ, Liu B, Kong Q, Botchkarev VV, Huynh M, Liu Z, Abderazzaq FO, Clark AP, Ficarro SB, Marto JA, Hatchi E, Livingston DM. BRCA1 binds TERRA RNA and suppresses R-Loop-based telomeric DNA damage. Nat Commun 2021; 12:3542. [PMID: 34112789 PMCID: PMC8192922 DOI: 10.1038/s41467-021-23716-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 05/11/2021] [Indexed: 12/13/2022] Open
Abstract
R-loop structures act as modulators of physiological processes such as transcription termination, gene regulation, and DNA repair. However, they can cause transcription-replication conflicts and give rise to genomic instability, particularly at telomeres, which are prone to forming DNA secondary structures. Here, we demonstrate that BRCA1 binds TERRA RNA, directly and physically via its N-terminal nuclear localization sequence, as well as telomere-specific shelterin proteins in an R-loop-, and a cell cycle-dependent manner. R-loop-driven BRCA1 binding to CpG-rich TERRA promoters represses TERRA transcription, prevents TERRA R-loop-associated damage, and promotes its repair, likely in association with SETX and XRN2. BRCA1 depletion upregulates TERRA expression, leading to overly abundant TERRA R-loops, telomeric replication stress, and signs of telomeric aberrancy. Moreover, BRCA1 mutations within the TERRA-binding region lead to an excess of TERRA-associated R-loops and telomeric abnormalities. Thus, normal BRCA1/TERRA binding suppresses telomere-centered genome instability. BRCA1-mediated resolution of R-loops has previously been described. Here the authors reveal a functional association of BRCA1 with TERRA RNA at telomeres, which develops in an R-loop-, and a cell cycle-dependent manner.
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Affiliation(s)
- Jekaterina Vohhodina
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA. .,Department of Genetics, Harvard Medical School, Boston, MA, USA.
| | - Liana J Goehring
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Ben Liu
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Qing Kong
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Vladimir V Botchkarev
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Mai Huynh
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Zhiqi Liu
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Fieda O Abderazzaq
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Allison P Clark
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Scott B Ficarro
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jarrod A Marto
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Elodie Hatchi
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.,Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - David M Livingston
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA. .,Department of Genetics, Harvard Medical School, Boston, MA, USA.
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4
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Ahmad SF, Singchat W, Jehangir M, Suntronpong A, Panthum T, Malaivijitnond S, Srikulnath K. Dark Matter of Primate Genomes: Satellite DNA Repeats and Their Evolutionary Dynamics. Cells 2020; 9:E2714. [PMID: 33352976 PMCID: PMC7767330 DOI: 10.3390/cells9122714] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/12/2022] Open
Abstract
A substantial portion of the primate genome is composed of non-coding regions, so-called "dark matter", which includes an abundance of tandemly repeated sequences called satellite DNA. Collectively known as the satellitome, this genomic component offers exciting evolutionary insights into aspects of primate genome biology that raise new questions and challenge existing paradigms. A complete human reference genome was recently reported with telomere-to-telomere human X chromosome assembly that resolved hundreds of dark regions, encompassing a 3.1 Mb centromeric satellite array that had not been identified previously. With the recent exponential increase in the availability of primate genomes, and the development of modern genomic and bioinformatics tools, extensive growth in our knowledge concerning the structure, function, and evolution of satellite elements is expected. The current state of knowledge on this topic is summarized, highlighting various types of primate-specific satellite repeats to compare their proportions across diverse lineages. Inter- and intraspecific variation of satellite repeats in the primate genome are reviewed. The functional significance of these sequences is discussed by describing how the transcriptional activity of satellite repeats can affect gene expression during different cellular processes. Sex-linked satellites are outlined, together with their respective genomic organization. Mechanisms are proposed whereby satellite repeats might have emerged as novel sequences during different evolutionary phases. Finally, the main challenges that hinder the detection of satellite DNA are outlined and an overview of the latest methodologies to address technological limitations is presented.
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Affiliation(s)
- Syed Farhan Ahmad
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (A.S.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
| | - Worapong Singchat
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (A.S.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
| | - Maryam Jehangir
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (A.S.); (T.P.)
- Department of Structural and Functional Biology, Institute of Bioscience at Botucatu, São Paulo State University (UNESP), Botucatu, São Paulo 18618-689, Brazil
| | - Aorarat Suntronpong
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (A.S.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
| | - Thitipong Panthum
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (A.S.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
| | - Suchinda Malaivijitnond
- National Primate Research Center of Thailand, Chulalongkorn University, Saraburi 18110, Thailand;
- Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Kornsorn Srikulnath
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (A.S.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900, Thailand
- National Primate Research Center of Thailand, Chulalongkorn University, Saraburi 18110, Thailand;
- Center of Excellence on Agricultural Biotechnology (AG-BIO/PERDO-CHE), Bangkok 10900, Thailand
- Omics Center for Agriculture, Bioresources, Food and Health, Kasetsart University (OmiKU), Bangkok 10900, Thailand
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5
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Cechova M, Harris RS, Tomaszkiewicz M, Arbeithuber B, Chiaromonte F, Makova KD. High Satellite Repeat Turnover in Great Apes Studied with Short- and Long-Read Technologies. Mol Biol Evol 2019; 36:2415-2431. [PMID: 31273383 PMCID: PMC6805231 DOI: 10.1093/molbev/msz156] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 12/23/2022] Open
Abstract
Satellite repeats are a structural component of centromeres and telomeres, and in some instances, their divergence is known to drive speciation. Due to their highly repetitive nature, satellite sequences have been understudied and underrepresented in genome assemblies. To investigate their turnover in great apes, we studied satellite repeats of unit sizes up to 50 bp in human, chimpanzee, bonobo, gorilla, and Sumatran and Bornean orangutans, using unassembled short and long sequencing reads. The density of satellite repeats, as identified from accurate short reads (Illumina), varied greatly among great ape genomes. These were dominated by a handful of abundant repeated motifs, frequently shared among species, which formed two groups: 1) the (AATGG)n repeat (critical for heat shock response) and its derivatives; and 2) subtelomeric 32-mers involved in telomeric metabolism. Using the densities of abundant repeats, individuals could be classified into species. However, clustering did not reproduce the accepted species phylogeny, suggesting rapid repeat evolution. Several abundant repeats were enriched in males versus females; using Y chromosome assemblies or Fluorescent In Situ Hybridization, we validated their location on the Y. Finally, applying a novel computational tool, we identified many satellite repeats completely embedded within long Oxford Nanopore and Pacific Biosciences reads. Such repeats were up to 59 kb in length and consisted of perfect repeats interspersed with other similar sequences. Our results based on sequencing reads generated with three different technologies provide the first detailed characterization of great ape satellite repeats, and open new avenues for exploring their functions.
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Affiliation(s)
- Monika Cechova
- Department of Biology, Pennsylvania State University, University Park, PA
| | - Robert S Harris
- Department of Biology, Pennsylvania State University, University Park, PA
| | | | | | - Francesca Chiaromonte
- Department of Statistics, Pennsylvania State University, University Park, PA
- EMbeDS, Sant’Anna School of Advanced Studies, Pisa, Italy
- Center for Medical Genomics, Penn State, University Park, PA
| | - Kateryna D Makova
- Department of Biology, Pennsylvania State University, University Park, PA
- Center for Medical Genomics, Penn State, University Park, PA
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6
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SAMMSON fosters cancer cell fitness by concertedly enhancing mitochondrial and cytosolic translation. Nat Struct Mol Biol 2018; 25:1035-1046. [PMID: 30374086 PMCID: PMC6223542 DOI: 10.1038/s41594-018-0143-4] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 09/12/2018] [Indexed: 01/09/2023]
Abstract
Synchronization of mitochondrial and cytoplasmic translation rates is critical for the maintenance of cellular fitness, with cancer cells being especially vulnerable to translational uncoupling. Although alterations of cytosolic protein synthesis are common in human cancer, compensating mechanisms in mitochondrial translation remain elusive. Here we show that the malignant long non-coding RNA (lncRNA) SAMMSON promotes a balanced increase in ribosomal RNA (rRNA) maturation and protein synthesis in the cytosol and mitochondria by modulating the localization of CARF, an RNA-binding protein that sequesters the exo-ribonuclease XRN2 in the nucleoplasm, which under normal circumstances limits nucleolar rRNA maturation. SAMMSON interferes with XRN2 binding to CARF in the nucleus by favoring the formation of an aberrant cytoplasmic RNA-protein complex containing CARF and p32, a mitochondrial protein required for the processing of the mitochondrial rRNAs. These data highlight how a single oncogenic lncRNA can simultaneously modulate RNA-protein complex formation in two distinct cellular compartments to promote cell growth.
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7
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Piqueret-Stephan L, Ricoul M, Hempel WM, Sabatier L. Replication Timing of Human Telomeres is Conserved during Immortalization and Influenced by Respective Subtelomeres. Sci Rep 2016; 6:32510. [PMID: 27587191 PMCID: PMC5009427 DOI: 10.1038/srep32510] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 08/05/2016] [Indexed: 12/16/2022] Open
Abstract
Telomeres are specific structures that protect chromosome ends and act as a biological clock, preventing normal cells from replicating indefinitely. Mammalian telomeres are replicated throughout S-phase in a predetermined order. However, the mechanism of this regulation is still unknown. We wished to investigate this phenomenon under physiological conditions in a changing environment, such as the immortalization process to better understand the mechanism for its control. We thus examined the timing of human telomere replication in normal and SV40 immortalized cells, which are cytogenetically very similar to cancer cells. We found that the timing of telomere replication was globally conserved under different conditions during the immortalization process. The timing of telomere replication was conserved despite changes in telomere length due to endogenous telomerase reactivation, in duplicated homologous chromosomes, and in rearranged chromosomes. Importantly, translocated telomeres, possessing their initial subtelomere, retained the replication timing of their homolog, independently of the proportion of the translocated arm, even when the remaining flanking DNA is restricted to its subtelomere, the closest chromosome-specific sequences (inferior to 500 kb). Our observations support the notion that subtelomere regions strongly influence the replication timing of the associated telomere.
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Affiliation(s)
- Laure Piqueret-Stephan
- PROCyTOX Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Fontenay-aux-Roses and Université Paris-Saclay, France
| | - Michelle Ricoul
- PROCyTOX Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Fontenay-aux-Roses and Université Paris-Saclay, France
| | - William M Hempel
- PROCyTOX Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Fontenay-aux-Roses and Université Paris-Saclay, France
| | - Laure Sabatier
- PROCyTOX Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Fontenay-aux-Roses and Université Paris-Saclay, France
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8
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Cenci G, Ciapponi L, Marzullo M, Raffa GD, Morciano P, Raimondo D, Burla R, Saggio I, Gatti M. The Analysis of Pendolino (peo) Mutants Reveals Differences in the Fusigenic Potential among Drosophila Telomeres. PLoS Genet 2015; 11:e1005260. [PMID: 26110638 PMCID: PMC4481407 DOI: 10.1371/journal.pgen.1005260] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 05/04/2015] [Indexed: 01/08/2023] Open
Abstract
Drosophila telomeres are sequence-independent structures that are maintained by transposition to chromosome ends of three specialized retroelements (HeT-A, TART and TAHRE; collectively designated as HTT) rather than telomerase activity. Fly telomeres are protected by the terminin complex (HOAP-HipHop-Moi-Ver) that localizes and functions exclusively at telomeres and by non-terminin proteins that do not serve telomere-specific functions. Although all Drosophila telomeres terminate with HTT arrays and are capped by terminin, they differ in the type of subtelomeric chromatin; the Y, XR, and 4L HTT are juxtaposed to constitutive heterochromatin, while the XL, 2L, 2R, 3L and 3R HTT are linked to the TAS repetitive sequences; the 4R HTT is associated with a chromatin that has features common to both euchromatin and heterochromatin. Here we show that mutations in pendolino (peo) cause telomeric fusions (TFs). The analysis of several peo mutant combinations showed that these TFs preferentially involve the Y, XR and 4th chromosome telomeres, a TF pattern never observed in the other 10 telomere-capping mutants so far characterized. peo encodes a non-terminin protein homologous to the E2 variant ubiquitin-conjugating enzymes. The Peo protein directly interacts with the terminin components, but peo mutations do not affect telomeric localization of HOAP, Moi, Ver and HP1a, suggesting that the peo-dependent telomere fusion phenotype is not due to loss of terminin from chromosome ends. peo mutants are also defective in DNA replication and PCNA recruitment. However, our results suggest that general defects in DNA replication are unable to induce TFs in Drosophila cells. We thus hypothesize that DNA replication in Peo-depleted cells results in specific fusigenic lesions concentrated in heterochromatin-associated telomeres. Alternatively, it is possible that Peo plays a dual function being independently required for DNA replication and telomere capping. Telomeres are specialized structures that protect chromosome ends from incomplete replication, degradation and end-to-end fusion. Abnormalities in telomere structure or maintenance can promote a variety of human diseases including premature aging and cancer. Although all human telomeres contain the same DNA sequences, they differ from each other in the subtelomeric regions or subtelomeres. Recent work has shown that human subtelomeres control telomere replication and that abnormalities in these structures can lead to localized chromosome instability and disease. However, the relationships between subtelomeres and telomeres are currently poorly understood. Here, we have addressed this problem using the fruit fly Drosophila melanogaster as model system. Drosophila subtelomers are very different from each other as they contain different types of chromatin. We have found that mutations in a gene we called pendolino (peo) cause telomeric fusions (TFs) and that these fusions preferentially involve the telomeres associated with a tightly packed form of chromatin called heterochromatin. Interestingly, none of the 10 mutants with TFs so far described in Drosophila shows the pattern of TFs observed in peo mutants. Thus, our data provide the first demonstration that subtelomeres can affect telomere fusion. We believe that these results will stimulate further studies on the role of subtelomeres in the maintenance of genome stability.
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Affiliation(s)
- Giovanni Cenci
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Laura Ciapponi
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Marta Marzullo
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Grazia D. Raffa
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Patrizia Morciano
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | | | - Romina Burla
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Isabella Saggio
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
- IBPM CNR, Sapienza—Università di Roma, Roma, Italy
| | - Maurizio Gatti
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
- IBPM CNR, Sapienza—Università di Roma, Roma, Italy
- * E-mail:
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9
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Burla R, Carcuro M, Raffa GD, Galati A, Raimondo D, Rizzo A, La Torre M, Micheli E, Ciapponi L, Cenci G, Cundari E, Musio A, Biroccio A, Cacchione S, Gatti M, Saggio I. AKTIP/Ft1, a New Shelterin-Interacting Factor Required for Telomere Maintenance. PLoS Genet 2015; 11:e1005167. [PMID: 26110528 PMCID: PMC4481533 DOI: 10.1371/journal.pgen.1005167] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 03/23/2015] [Indexed: 12/18/2022] Open
Abstract
Telomeres are nucleoprotein complexes that protect the ends of linear chromosomes from incomplete replication, degradation and detection as DNA breaks. Mammalian telomeres are protected by shelterin, a multiprotein complex that binds the TTAGGG telomeric repeats and recruits a series of additional factors that are essential for telomere function. Although many shelterin-associated proteins have been so far identified, the inventory of shelterin-interacting factors required for telomere maintenance is still largely incomplete. Here, we characterize AKTIP/Ft1 (human AKTIP and mouse Ft1 are orthologous), a novel mammalian shelterin-bound factor identified on the basis of its homology with the Drosophila telomere protein Pendolino. AKTIP/Ft1 shares homology with the E2 variant ubiquitin-conjugating (UEV) enzymes and has been previously implicated in the control of apoptosis and in vesicle trafficking. RNAi-mediated depletion of AKTIP results in formation of telomere dysfunction foci (TIFs). Consistent with these results, AKTIP interacts with telomeric DNA and binds the shelterin components TRF1 and TRF2 both in vivo and in vitro. Analysis of AKTIP- depleted human primary fibroblasts showed that they are defective in PCNA recruiting and arrest in the S phase due to the activation of the intra S checkpoint. Accordingly, AKTIP physically interacts with PCNA and the RPA70 DNA replication factor. Ft1-depleted p53-/- MEFs did not arrest in the S phase but displayed significant increases in multiple telomeric signals (MTS) and sister telomere associations (STAs), two hallmarks of defective telomere replication. In addition, we found an epistatic relation for MST formation between Ft1 and TRF1, which has been previously shown to be required for replication fork progression through telomeric DNA. Ch-IP experiments further suggested that in AKTIP-depleted cells undergoing the S phase, TRF1 is less tightly bound to telomeric DNA than in controls. Thus, our results collectively suggest that AKTIP/Ft1 works in concert with TRF1 to facilitate telomeric DNA replication.
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Affiliation(s)
- Romina Burla
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Mariateresa Carcuro
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Grazia D. Raffa
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Alessandra Galati
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | | | - Angela Rizzo
- Istituto Nazionale Tumori Regina Elena, Rome, Italy
| | - Mattia La Torre
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Emanuela Micheli
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Laura Ciapponi
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Giovanni Cenci
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Enrico Cundari
- Istituto di Biologia e Patologia Molecolari del CNR, Sapienza—Università di Roma, Roma, Italy
| | - Antonio Musio
- Istituto di Ricerca Genetica e Biomedica del CNR, Pisa, and Istituto Toscano Tumori, Firenze, Italy
| | | | - Stefano Cacchione
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
| | - Maurizio Gatti
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
- Istituto di Biologia e Patologia Molecolari del CNR, Sapienza—Università di Roma, Roma, Italy
- * E-mail: (MG); (IS)
| | - Isabella Saggio
- Dipartimento di Biologia e Biotecnologie, Sapienza—Università di Roma, Roma, Italy
- Istituto Pasteur Fondazione Cenci Bolognetti, Sapienza—Università di Roma, Roma, Italy
- Istituto di Biologia e Patologia Molecolari del CNR, Sapienza—Università di Roma, Roma, Italy
- * E-mail: (MG); (IS)
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10
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Recombinogenic telomeres in diploid Sorex granarius (Soricidae, Eulipotyphla) fibroblast cells. Mol Cell Biol 2014; 34:2786-99. [PMID: 24842907 DOI: 10.1128/mcb.01697-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The telomere structure in the Iberian shrew Sorex granarius is characterized by unique, striking features, with short arms of acrocentric chromosomes carrying extremely long telomeres (up to 300 kb) with interspersed ribosomal DNA (rDNA) repeat blocks. In this work, we investigated the telomere physiology of S. granarius fibroblast cells and found that telomere repeats are transcribed on both strands and that there is no telomere-dependent senescence mechanism. Although telomerase activity is detectable throughout cell culture and appears to act on both short and long telomeres, we also discovered that signatures of a recombinogenic activity are omnipresent, including telomere-sister chromatid exchanges, formation of alternative lengthening of telomeres (ALT)-associated PML-like bodies, production of telomere circles, and a high frequency of telomeres carrying marks of a DNA damage response. Our results suggest that recombination participates in the maintenance of the very long telomeres in normal S. granarius fibroblasts. We discuss the possible interplay between the interspersed telomere and rDNA repeats in the stabilization of the very long telomeres in this organism.
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