1
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Castellano CM, Lacroix L, Mathis E, Prorok P, Hennion M, Lopez-Rubio JJ, Méchali M, Gomes A. The genetic landscape of origins of replication in P. falciparum. Nucleic Acids Res 2024; 52:660-676. [PMID: 38038269 PMCID: PMC10810204 DOI: 10.1093/nar/gkad1103] [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: 07/10/2023] [Revised: 10/18/2023] [Accepted: 11/01/2023] [Indexed: 12/02/2023] Open
Abstract
Various origin mapping approaches have enabled genome-wide identification of origins of replication (ORI) in model organisms, but only a few studies have focused on divergent organisms. By employing three complementary approaches we provide a high-resolution map of ORIs in Plasmodium falciparum, the deadliest human malaria parasite. We profiled the distribution of origin of recognition complex (ORC) binding sites by ChIP-seq of two PfORC subunits and mapped active ORIs using NFS and SNS-seq. We show that ORIs lack sequence specificity but are not randomly distributed, and group in clusters. Licensing is biased towards regions of higher GC content and associated with G-quadruplex forming sequences (G4FS). While strong transcription likely enhances firing, active origins are depleted from transcription start sites. Instead, most accumulate in transcriptionally active gene bodies. Single molecule analysis of nanopore reads containing multiple initiation events, which could have only come from individual nuclei, showed a relationship between the replication fork pace and the distance to the nearest origin. While some similarities were drawn with the canonic eukaryote model, the distribution of ORIs in P. falciparum is likely shaped by unique genomic features such as extreme AT-richness-a product of evolutionary pressure imposed by the parasitic lifestyle.
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Affiliation(s)
| | - Laurent Lacroix
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Paris, France
| | - Emilie Mathis
- LPHI, CNRS, Université de Montpellier, 34095 Montpellier, France
| | - Paulina Prorok
- Institute of Human Genetics, CNRS, 34396 Montpellier, France
| | - Magali Hennion
- Université Paris Cité, CNRS, Epigenetics and Cell Fate, F-75013 Paris, France
| | | | - Marcel Méchali
- Institute of Human Genetics, CNRS, 34396 Montpellier, France
| | - Ana Rita Gomes
- LPHI, CNRS, Université de Montpellier, 34095 Montpellier, France
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2
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Lu Y, Lee J, Li J, Allu SR, Wang J, Kim H, Bullaughey KL, Fisher SA, Nordgren CE, Rosario JG, Anderson SA, Ulyanova AV, Brem S, Chen HI, Wolf JA, Grady MS, Vinogradov SA, Kim J, Eberwine J. CHEX-seq detects single-cell genomic single-stranded DNA with catalytical potential. Nat Commun 2023; 14:7346. [PMID: 37963886 PMCID: PMC10645931 DOI: 10.1038/s41467-023-43158-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 11/02/2023] [Indexed: 11/16/2023] Open
Abstract
Genomic DNA (gDNA) undergoes structural interconversion between single- and double-stranded states during transcription, DNA repair and replication, which is critical for cellular homeostasis. We describe "CHEX-seq" which identifies the single-stranded DNA (ssDNA) in situ in individual cells. CHEX-seq uses 3'-terminal blocked, light-activatable probes to prime the copying of ssDNA into complementary DNA that is sequenced, thereby reporting the genome-wide single-stranded chromatin landscape. CHEX-seq is benchmarked in human K562 cells, and its utilities are demonstrated in cultures of mouse and human brain cells as well as immunostained spatially localized neurons in brain sections. The amount of ssDNA is dynamically regulated in response to perturbation. CHEX-seq also identifies single-stranded regions of mitochondrial DNA in single cells. Surprisingly, CHEX-seq identifies single-stranded loci in mouse and human gDNA that catalyze porphyrin metalation in vitro, suggesting a catalytic activity for genomic ssDNA. We posit that endogenous DNA enzymatic activity is a function of genomic ssDNA.
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Affiliation(s)
- Youtao Lu
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jaehee Lee
- Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jifen Li
- Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Srinivasa Rao Allu
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jinhui Wang
- Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - HyunBum Kim
- Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Kevin L Bullaughey
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Stephen A Fisher
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - C Erik Nordgren
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jean G Rosario
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Stewart A Anderson
- Department of Psychiatry, Children's Hospital of Philadelphia, ARC 517, 3615 Civic Center Blvd, Philadelphia, PA, 19104, USA
| | - Alexandra V Ulyanova
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Steven Brem
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - H Isaac Chen
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - John A Wolf
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - M Sean Grady
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Sergei A Vinogradov
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Junhyong Kim
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - James Eberwine
- Department of Systems Pharmacology and Translational Therapeutics Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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3
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Asaad W, Volos P, Maksimov D, Khavina E, Deviatkin A, Mityaeva O, Volchkov P. AAV genome modification for efficient AAV production. Heliyon 2023; 9:e15071. [PMID: 37095911 PMCID: PMC10121408 DOI: 10.1016/j.heliyon.2023.e15071] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/23/2023] [Accepted: 03/27/2023] [Indexed: 04/04/2023] Open
Abstract
The adeno-associated virus (AAV) is one of the most potent vectors in gene therapy. The experimental profile of this vector shows its efficiency and accepted safety, which explains its increased usage by scientists for the research and treatment of a wide range of diseases. These studies require using functional, pure, and high titers of vector particles. In fact, the current knowledge of AAV structure and genome helps improve the scalable production of AAV vectors. In this review, we summarize the latest studies on the optimization of scalable AAV production through modifying the AAV genome or biological processes inside the cell.
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4
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Jaksik R, Wheeler DA, Kimmel M. Detection and characterization of constitutive replication origins defined by DNA polymerase epsilon. BMC Biol 2023; 21:41. [PMID: 36829160 PMCID: PMC9960419 DOI: 10.1186/s12915-023-01527-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 01/24/2023] [Indexed: 02/26/2023] Open
Abstract
BACKGROUND Despite the process of DNA replication being mechanistically highly conserved, the location of origins of replication (ORI) may vary from one tissue to the next, or between rounds of replication in eukaryotes, suggesting flexibility in the choice of locations to initiate replication. Lists of human ORI therefore vary widely in number and location, and there are currently no methods available to compare them. Here, we propose a method of detection of ORI based on somatic mutation patterns generated by the mutator phenotype of damaged DNA polymerase epsilon (POLE). RESULTS We report the genome-wide localization of constitutive ORI in POLE-mutated human tumors using whole genome sequencing data. Mutations accumulated after many rounds of replication of unsynchronized dividing cell populations in tumors allow to identify constitutive origins, which we show are shared with high fidelity between individuals and tumor types. Using a Smith-Waterman-like dynamic programming approach, we compared replication origin positions obtained from multiple different methods. The comparison allowed us to define a consensus set of replication origins, identified consistently by multiple ORI detection methods. Many DNA features co-localized with the consensus set of ORI, including chromatin loop anchors, G-quadruplexes, S/MARs, and CpGs. Among all features, the H2A.Z histone exhibited the most significant association. CONCLUSIONS Our results show that mutation-based detection of replication origins is a viable approach to determining their location and associated sequence features.
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Affiliation(s)
- Roman Jaksik
- Department of Systems Biology and Engineering and Biotechnology Centre, Silesian University of Technology, Gliwice, Poland.
| | - David A. Wheeler
- grid.39382.330000 0001 2160 926XHuman Genome Sequencing Centre, Baylor College of Medicine, Houston, TX USA ,grid.240871.80000 0001 0224 711XPresent Address: Clinical Genomics Group, Department of Computational Biology, St Jude Children’s Research Hospital, Memphis, TN 38103 USA
| | - Marek Kimmel
- grid.6979.10000 0001 2335 3149Department of Systems Biology and Engineering and Biotechnology Centre, Silesian University of Technology, Gliwice, Poland ,grid.21940.3e0000 0004 1936 8278Department of Statistics, Rice University, Houston, TX USA ,grid.21940.3e0000 0004 1936 8278Department of Bioengineering, Rice University, Houston, TX USA
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5
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Shi J, Zhang X, Li J, Huang W, Wang Y, Wang Y, Qin J. MTA2 sensitizes gastric cancer cells to PARP inhibition by induction of DNA replication stress. Transl Oncol 2021; 14:101167. [PMID: 34280886 PMCID: PMC8313750 DOI: 10.1016/j.tranon.2021.101167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 12/24/2022] Open
Abstract
Poly (ADP-ribose) polymerase (PARP) inhibitor olaparib selectively kills cancer cells with BRCA-deficiency and is approved for BRCA-mutated breast, ovarian and pancreatic cancers by FDA. However, phase III study of olaparib failed to show a significant improvement in overall survival in patients with gastric cancer (GC). To discover an effective biomarker for GC patient-selection in olaparib treatment, we analyzed proteomic profiling of 12 GC cell lines. MTA2 was identified to confer sensitivity to olaparib by aggravating olaparib-induced replication stress in cancer cells. Mechanistically, we applied Cleavage Under Targets and Tagmentation assay to find that MTA2 proteins preferentially bind regions of replication origin-associated DNA sequences, which could be enhanced by olaparib treatment. Furthermore, MTA2 was validated here to render cancer cells susceptible to combination of olaparib with ATR inhibitor AZD6738. In general, our study identified MTA2 as a potential biomarker for olaparib sensitivity by aggravating olaparib-induced replication stress.
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Affiliation(s)
- Jinwen Shi
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing 102206, China
| | - Xiaofeng Zhang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing 102206, China
| | - Jin'e Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing 102206, China
| | - Wenwen Huang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou 510060, China
| | - Yini Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing 102206, China
| | - Yi Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing 102206, China
| | - Jun Qin
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing 102206, China.
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6
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Earley LF, Conatser LM, Lue VM, Dobbins AL, Li C, Hirsch ML, Samulski RJ. Adeno-Associated Virus Serotype-Specific Inverted Terminal Repeat Sequence Role in Vector Transgene Expression. Hum Gene Ther 2021; 31:151-162. [PMID: 31914802 DOI: 10.1089/hum.2019.274] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Adeno-associated viral vectors have been successfully used in laboratory and clinical settings for efficient gene delivery. In these vectors, 96% of the adeno-associated virus (AAV) genome is replaced with a gene cassette of interest, leaving only the 145 bp inverted terminal repeat (ITR) sequences. These cis-elements, primarily from AAV serotype 2, are required for genome rescue, replication, packaging, and vector persistence. Previous work from our lab and others have demonstrated that the AAV ITR2 sequence has inherent transcriptional activity, which may confound intended transgene expression in therapeutic applications. Currently, AAV capsids are extensively study for vector contribution; however, a comprehensive analysis of ITR promoter activity of various AAV serotypes has not been described to date. Here, the transcriptional activity of AAV ITRs from different serotypes (1-4, 6, and 7) was compared in numerous cell lines and a mouse model. Under the conditions used here, all ITRs tested were capable of promoting transgene expression both in vitro and in vivo. However, we observed three classes of AAV ITR expression in vitro. Class I ITRs (AAV2 and 3) generated the highest level, whereas class II (AAV 4) had intermediate levels, and class III (AAV1 and 6) had the lowest levels. These expression levels were consistent across multiple cell lines. Only ITR7 demonstrated cell-type dependent transcriptional activity. In vivo, all classes had promoter activity. Next-generation sequencing revealed multiple transcriptional start sites that originated from the ITR sequence, with most arising from within the Rep binding element. The collective results demonstrate that the serotype ITR sequence may have multiple levels of influence on transgene expression cassettes independent of promoter selection.
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Affiliation(s)
- Lauriel F Earley
- Gene Therapy Center, University of North Carolina, Chapel Hill, North Carolina
| | - Laura M Conatser
- Gene Therapy Center, University of North Carolina, Chapel Hill, North Carolina.,Department of Ophthalmology, University of North Carolina, Chapel Hill, North Carolina
| | - Victoria M Lue
- Gene Therapy Center, University of North Carolina, Chapel Hill, North Carolina.,Department of Ophthalmology, University of North Carolina, Chapel Hill, North Carolina
| | - Amanda L Dobbins
- Gene Therapy Center, University of North Carolina, Chapel Hill, North Carolina
| | - Chengwen Li
- Gene Therapy Center, University of North Carolina, Chapel Hill, North Carolina.,Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, North Carolina.,Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina
| | - Matthew L Hirsch
- Gene Therapy Center, University of North Carolina, Chapel Hill, North Carolina.,Department of Ophthalmology, University of North Carolina, Chapel Hill, North Carolina
| | - R Jude Samulski
- Gene Therapy Center, University of North Carolina, Chapel Hill, North Carolina.,Department of Pharmacology, University of North Carolina, Chapel Hill, North Carolina
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7
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Kumagai A, Dunphy WG. Binding of the Treslin-MTBP Complex to Specific Regions of the Human Genome Promotes the Initiation of DNA Replication. Cell Rep 2021; 32:108178. [PMID: 32966791 PMCID: PMC7523632 DOI: 10.1016/j.celrep.2020.108178] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 06/12/2020] [Accepted: 08/31/2020] [Indexed: 12/16/2022] Open
Abstract
The processes that control where higher eukaryotic cells initiate DNA replication throughout the genome are not understood clearly. In metazoans, the Treslin-MTBP complex mediates critical final steps in formation of the activated replicative helicase prior to initiation of replication. Here, we map the genome-wide distribution of the MTBP subunit of this complex in human cells. Our results indicate that MTBP binds to at least 30,000 sites in the genome. A majority of these sites reside in regions of open chromatin that contain transcriptional-regulatory elements (e.g., promoters, enhancers, and super-enhancers), which are known to be preferred areas for initiation of replication. Furthermore, many binding sites encompass two genomic features: a nucleosome-free DNA sequence (e.g., G-quadruplex DNA or AP-1 motif) and a nucleosome bearing histone marks characteristic of open chromatin, such as H3K4me2. Taken together, these findings indicate that Treslin-MTBP associates coordinately with multiple genomic signals to promote initiation of replication. Kumagai and Dunphy show that Treslin-MTBP, activator of the replicative helicase, binds to at least 30,000 sites in the human genome. Many sites contain a nucleosome with active chromatin marks and nucleosome-free DNA (G-quadruplex or AP-1 site). Thus, Treslin-MTBP associates with multiple genomic elements to promote initiation of DNA replication.
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Affiliation(s)
- Akiko Kumagai
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - William G Dunphy
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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8
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Akerman I, Kasaai B, Bazarova A, Sang PB, Peiffer I, Artufel M, Derelle R, Smith G, Rodriguez-Martinez M, Romano M, Kinet S, Tino P, Theillet C, Taylor N, Ballester B, Méchali M. A predictable conserved DNA base composition signature defines human core DNA replication origins. Nat Commun 2020; 11:4826. [PMID: 32958757 PMCID: PMC7506530 DOI: 10.1038/s41467-020-18527-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/18/2020] [Indexed: 02/06/2023] Open
Abstract
DNA replication initiates from multiple genomic locations called replication origins. In metazoa, DNA sequence elements involved in origin specification remain elusive. Here, we examine pluripotent, primary, differentiating, and immortalized human cells, and demonstrate that a class of origins, termed core origins, is shared by different cell types and host ~80% of all DNA replication initiation events in any cell population. We detect a shared G-rich DNA sequence signature that coincides with most core origins in both human and mouse genomes. Transcription and G-rich elements can independently associate with replication origin activity. Computational algorithms show that core origins can be predicted, based solely on DNA sequence patterns but not on consensus motifs. Our results demonstrate that, despite an attributed stochasticity, core origins are chosen from a limited pool of genomic regions. Immortalization through oncogenic gene expression, but not normal cellular differentiation, results in increased stochastic firing from heterochromatin and decreased origin density at TAD borders. In metazoan the DNA sequence elements characterizing origin specification are unknown. By generating and analysing 19 SNS-seq datasets from different human cell types, the authors reveal a class and features of Core origins of replication which can be predicted by an algorithm.
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Affiliation(s)
- Ildem Akerman
- Institute of Human Genetics, CNRS - University of Montpellier, Montpellier, France. .,Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK.
| | - Bahar Kasaai
- Institute of Human Genetics, CNRS - University of Montpellier, Montpellier, France
| | - Alina Bazarova
- Centre for Computational Biology (CCB), University of Birmingham, Birmingham, UK.,Institute for Biological Physics, University of Cologne, Cologne, Germany
| | - Pau Biak Sang
- Institute of Human Genetics, CNRS - University of Montpellier, Montpellier, France
| | - Isabelle Peiffer
- Institute of Human Genetics, CNRS - University of Montpellier, Montpellier, France
| | - Marie Artufel
- Aix-Marseille University, INSERM, TAGC, UMR S1090, Marseille, France
| | - Romain Derelle
- Life and Environmental Sciences (LES), University of Birmingham, Birmingham, UK
| | - Gabrielle Smith
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
| | | | - Manuela Romano
- Institut de Génétique Moléculaire de Montpellier (IGMM), University of Montpellier, CNRS, Montpellier, France
| | - Sandrina Kinet
- Institut de Génétique Moléculaire de Montpellier (IGMM), University of Montpellier, CNRS, Montpellier, France
| | - Peter Tino
- Centre for Computational Biology (CCB), University of Birmingham, Birmingham, UK
| | - Charles Theillet
- Institut de Recherche en Cancérologie de Montpellier (IRCM), Montpellier, France
| | - Naomi Taylor
- Institut de Génétique Moléculaire de Montpellier (IGMM), University of Montpellier, CNRS, Montpellier, France.,Pediatric Oncology Branch, NCI, CCR, NIH, Bethesda, MD, USA
| | - Benoit Ballester
- Aix-Marseille University, INSERM, TAGC, UMR S1090, Marseille, France
| | - Marcel Méchali
- Institute of Human Genetics, CNRS - University of Montpellier, Montpellier, France.
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9
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Yella VR, Vanaja A, Kulandaivelu U, Kumar A. Delving into Eukaryotic Origins of Replication Using DNA Structural Features. ACS OMEGA 2020; 5:13601-13611. [PMID: 32566825 PMCID: PMC7301376 DOI: 10.1021/acsomega.0c00441] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/15/2020] [Indexed: 05/18/2023]
Abstract
DNA replication in eukaryotes is an intricate process, which is precisely synchronized by a set of regulatory proteins, and the replication fork emanates from discrete sites on chromatin called origins of replication (Oris). These spots are considered as the gateway to chromosomal replication and are stereotyped by sequence motifs. The cognate sequences are noticeable in a small group of entire origin regions or totally absent across different metazoans. Alternatively, the use of DNA secondary structural features can provide additional information compared to the primary sequence. In this article, we report the trends in DNA sequence-based structural properties of origin sequences in nine eukaryotic systems representing different families of life. Biologically relevant DNA secondary structural properties, namely, stability, propeller twist, flexibility, and minor groove shape were studied in the sequences flanking replication start sites. Results indicate that Oris in yeasts show lower stability, more rigidity, and narrow minor groove preferences compared to genomic sequences surrounding them. Yeast Oris also show preference for A-tracts and the promoter element TATA box in the vicinity of replication start sites. On the contrary, Drosophila melanogaster, humans, and Arabidopsis thaliana do not have such features in their Oris, and instead, they show high preponderance of G-rich sequence motifs such as putative G-quadruplexes or i-motifs and CpG islands. Our extensive study applies the DNA structural feature computation to delve into origins of replication across organisms ranging from yeasts to mammals and including a plant. Insights from this study would be significant in understanding origin architecture and help in designing new algorithms for predicting DNA trans-acting factor recognition events.
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Affiliation(s)
- Venkata Rajesh Yella
- Department
of Biotechnology, Koneru Lakshmaiah Education
Foundation, Guntur 522502, Andhra Pradesh, India
| | - Akkinepally Vanaja
- Department
of Biotechnology, Koneru Lakshmaiah Education
Foundation, Guntur 522502, Andhra Pradesh, India
- KL
College of Pharmacy, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Guntur 522502, Andhra Pradesh, India
| | - Umasankar Kulandaivelu
- KL
College of Pharmacy, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Guntur 522502, Andhra Pradesh, India
| | - Aditya Kumar
- Department
of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028, Assam, India
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10
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Abstract
In all kingdoms of life, DNA is used to encode hereditary information. Propagation of the genetic material between generations requires timely and accurate duplication of DNA by semiconservative replication prior to cell division to ensure each daughter cell receives the full complement of chromosomes. DNA synthesis of daughter strands starts at discrete sites, termed replication origins, and proceeds in a bidirectional manner until all genomic DNA is replicated. Despite the fundamental nature of these events, organisms have evolved surprisingly divergent strategies that control replication onset. Here, we discuss commonalities and differences in replication origin organization and recognition in the three domains of life.
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Affiliation(s)
- Babatunde Ekundayo
- Quantitative Biology, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
| | - Franziska Bleichert
- Quantitative Biology, Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- * E-mail:
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11
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5-hydroxymethylcytosine Marks Mammalian Origins Acting as a Barrier to Replication. Sci Rep 2019; 9:11065. [PMID: 31363131 PMCID: PMC6667497 DOI: 10.1038/s41598-019-47528-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 07/15/2019] [Indexed: 01/07/2023] Open
Abstract
In most mammalian cells, DNA replication occurs once, and only once between cell divisions. Replication initiation is a highly regulated process with redundant mechanisms that prevent errant initiation events. In lower eukaryotes, replication is initiated from a defined consensus sequence, whereas a consensus sequence delineating mammalian origin of replication has not been identified. Here we show that 5-hydroxymethylcytosine (5hmC) is present at mammalian replication origins. Our data support the hypothesis that 5hmC has a role in cell cycle regulation. We show that 5hmC level is inversely proportional to proliferation; indeed, 5hmC negatively influences cell division by increasing the time a cell resides in G1. Our data suggest that 5hmC recruits replication-licensing factors, then is removed prior to or during origin firing. Later we propose that TET2, the enzyme catalyzing 5mC to 5hmC conversion, acts as barrier to rereplication. In a broader context, our results significantly advance the understating of 5hmC involvement in cell proliferation and disease states.
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12
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Prorok P, Artufel M, Aze A, Coulombe P, Peiffer I, Lacroix L, Guédin A, Mergny JL, Damaschke J, Schepers A, Cayrou C, Teulade-Fichou MP, Ballester B, Méchali M. Involvement of G-quadruplex regions in mammalian replication origin activity. Nat Commun 2019; 10:3274. [PMID: 31332171 PMCID: PMC6646384 DOI: 10.1038/s41467-019-11104-0] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 05/08/2019] [Indexed: 12/11/2022] Open
Abstract
Genome-wide studies of DNA replication origins revealed that origins preferentially associate with an Origin G-rich Repeated Element (OGRE), potentially forming G-quadruplexes (G4). Here, we functionally address their requirements for DNA replication initiation in a series of independent approaches. Deletion of the OGRE/G4 sequence strongly decreased the corresponding origin activity. Conversely, the insertion of an OGRE/G4 element created a new replication origin. This element also promoted replication of episomal EBV vectors lacking the viral origin, but not if the OGRE/G4 sequence was deleted. A potent G4 ligand, PhenDC3, stabilized G4s but did not alter the global origin activity. However, a set of new, G4-associated origins was created, whereas suppressed origins were largely G4-free. In vitro Xenopus laevis replication systems showed that OGRE/G4 sequences are involved in the activation of DNA replication, but not in the pre-replication complex formation. Altogether, these results converge to the functional importance of OGRE/G4 elements in DNA replication initiation.
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Affiliation(s)
- Paulina Prorok
- Institute of Human Genetics, CNRS-University of Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France
| | | | - Antoine Aze
- Institute of Human Genetics, CNRS-University of Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France
| | - Philippe Coulombe
- Institute of Human Genetics, CNRS-University of Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France
| | - Isabelle Peiffer
- Institute of Human Genetics, CNRS-University of Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France
| | - Laurent Lacroix
- Balasubramanian group, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK
| | - Aurore Guédin
- ARNA Laboratory, Université de Bordeaux, Inserm U1212, CNRS UMR5320, Institut Européen de Chimie Biologie (IECB), Pessac, 33607, France
| | - Jean-Louis Mergny
- ARNA Laboratory, Université de Bordeaux, Inserm U1212, CNRS UMR5320, Institut Européen de Chimie Biologie (IECB), Pessac, 33607, France.,Institut Curie, CNRS UMR9187, Inserm U1196, Universite Paris Saclay, Orsay, France
| | - Julia Damaschke
- Research Unit Gene Vectors, Helmholtz Zentrum München (GmbH), German Research Center for Environmental Health, Marchioninistraße 25, 81377, Munich, Germany
| | - Aloys Schepers
- Research Unit Gene Vectors, Helmholtz Zentrum München (GmbH), German Research Center for Environmental Health, Marchioninistraße 25, 81377, Munich, Germany.,Monoclonal Antibody Core Facility & Research Group, Institute for Diabetes and Obesity, Helmholtz Zentrum München, Ingolstädter Landstrasse, 85764, Neuherberg, Germany
| | - Christelle Cayrou
- Institute of Human Genetics, CNRS-University of Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France.,Centre de Recherche en Cancérologie de Marseille 27 Boulevard Lei Roure, 13273, Marseille, France
| | | | | | - Marcel Méchali
- Institute of Human Genetics, CNRS-University of Montpellier, 141 rue de la Cardonille, 34396, Montpellier, France.
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13
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Lyu X, Chastain M, Chai W. Genome-wide mapping and profiling of γH2AX binding hotspots in response to different replication stress inducers. BMC Genomics 2019; 20:579. [PMID: 31299901 PMCID: PMC6625122 DOI: 10.1186/s12864-019-5934-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 06/25/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Replication stress (RS) gives rise to DNA damage that threatens genome stability. RS can originate from different sources that stall replication by diverse mechanisms. However, the mechanism underlying how different types of RS contribute to genome instability is unclear, in part due to the poor understanding of the distribution and characteristics of damage sites induced by different RS mechanisms. RESULTS We use ChIP-seq to map γH2AX binding sites genome-wide caused by aphidicolin (APH), hydroxyurea (HU), and methyl methanesulfonate (MMS) treatments in human lymphocyte cells. Mapping of γH2AX ChIP-seq reveals that APH, HU, and MMS treatments induce non-random γH2AX chromatin binding at discrete regions, suggesting that there are γH2AX binding hotspots in the genome. Characterization of the distribution and sequence/epigenetic features of γH2AX binding sites reveals that the three treatments induce γH2AX binding at largely non-overlapping regions, suggesting that RS may cause damage at specific genomic loci in a manner dependent on the fork stalling mechanism. Nonetheless, γH2AX binding sites induced by the three treatments share common features including compact chromatin, coinciding with larger-than-average genes, and depletion of CpG islands and transcription start sites. Moreover, we observe significant enrichment of SINEs in γH2AX sites in all treatments, indicating that SINEs may be a common barrier for replication polymerases. CONCLUSIONS Our results identify the location and common features of genome instability hotspots induced by different types of RS, and help in deciphering the mechanisms underlying RS-induced genetic diseases and carcinogenesis.
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Affiliation(s)
- Xinxing Lyu
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
| | - Megan Chastain
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA
| | - Weihang Chai
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, Spokane, Washington, USA.
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14
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Kuehner JN, Bruggeman EC, Wen Z, Yao B. Epigenetic Regulations in Neuropsychiatric Disorders. Front Genet 2019; 10:268. [PMID: 31019524 PMCID: PMC6458251 DOI: 10.3389/fgene.2019.00268] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/11/2019] [Indexed: 12/14/2022] Open
Abstract
Precise genetic and epigenetic spatiotemporal regulation of gene expression is critical for proper brain development, function and circuitry formation in the mammalian central nervous system. Neuronal differentiation processes are tightly regulated by epigenetic mechanisms including DNA methylation, histone modifications, chromatin remodelers and non-coding RNAs. Dysregulation of any of these pathways is detrimental to normal neuronal development and functions, which can result in devastating neuropsychiatric disorders, such as depression, schizophrenia and autism spectrum disorders. In this review, we focus on the current understanding of epigenetic regulations in brain development and functions, as well as their implications in neuropsychiatric disorders.
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Affiliation(s)
- Janise N Kuehner
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
| | - Emily C Bruggeman
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
| | - Zhexing Wen
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States.,Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States
| | - Bing Yao
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
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15
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Pennings S, Revuelta A, McLaughlin KA, Abd Hadi NA, Petchreing P, Ottaviano R, Meehan RR. Dynamics and Mechanisms of DNA Methylation Reprogramming. EPIGENETICS AND REGENERATION 2019:19-45. [DOI: 10.1016/b978-0-12-814879-2.00002-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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16
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Fitz E, Wanka F, Seiboth B. The Promoter Toolbox for Recombinant Gene Expression in Trichoderma reesei. Front Bioeng Biotechnol 2018; 6:135. [PMID: 30364340 PMCID: PMC6193071 DOI: 10.3389/fbioe.2018.00135] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/12/2018] [Indexed: 01/05/2023] Open
Abstract
The ascomycete Trichoderma reesei is one of the main fungal producers of cellulases and xylanases based on its high production capacity. Its enzymes are applied in food, feed, and textile industry or in lignocellulose hydrolysis in biofuel and biorefinery industry. Over the last years, the demand to expand the molecular toolbox for T. reesei to facilitate genetic engineering and improve the production of heterologous proteins grew. An important instrument to modify the expression of key genes are promoters to initiate and control their transcription. To date, the most commonly used promoter for T. reesei is the strong inducible promoter of the main cellobiohydrolase cel7a. Beside this one, there is a number of alternative inducible promoters derived from other cellulase- and xylanase encoding genes and a few constitutive promoters. With the advances in genomics and transcriptomics the identification of new constitutive and tunable promoters with different expression strength was simplified. In this review, we will discuss new developments in the field of promoters and compare their advantages and disadvantages. Synthetic expression systems constitute a new option to control gene expression and build up complex gene circuits. Therefore, we will address common structural features of promoters and describe options for promoter engineering and synthetic design of promoters. The availability of well-characterized gene expression control tools is essential for the analysis of gene function, detection of bottlenecks in gene networks and yield increase for biotechnology applications.
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Affiliation(s)
- Elisabeth Fitz
- Research Division Biochemical Technology, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria.,Austrian Centre of Industrial Biotechnology (ACIB) GmbH, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
| | - Franziska Wanka
- Austrian Centre of Industrial Biotechnology (ACIB) GmbH, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
| | - Bernhard Seiboth
- Research Division Biochemical Technology, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria.,Austrian Centre of Industrial Biotechnology (ACIB) GmbH, Institute of Chemical, Environmental and Bioscience Engineering, TU Wien, Vienna, Austria
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17
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Manzo SG, Hartono SR, Sanz LA, Marinello J, De Biasi S, Cossarizza A, Capranico G, Chedin F. DNA Topoisomerase I differentially modulates R-loops across the human genome. Genome Biol 2018; 19:100. [PMID: 30060749 PMCID: PMC6066927 DOI: 10.1186/s13059-018-1478-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 07/10/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Co-transcriptional R-loops are abundant non-B DNA structures in mammalian genomes. DNA Topoisomerase I (Top1) is often thought to regulate R-loop formation owing to its ability to resolve both positive and negative supercoils. How Top1 regulates R-loop structures at a global level is unknown. RESULTS Here, we perform high-resolution strand-specific R-loop mapping in human cells depleted for Top1 and find that Top1 depletion results in both R-loop gains and losses at thousands of transcribed loci, delineating two distinct gene classes. R-loop gains are characteristic for long, highly transcribed, genes located in gene-poor regions anchored to Lamin B1 domains and in proximity to H3K9me3-marked heterochromatic patches. R-loop losses, by contrast, occur in gene-rich regions overlapping H3K27me3-marked active replication initiation regions. Interestingly, Top1 depletion coincides with a block of the cell cycle in G0/G1 phase and a trend towards replication delay. CONCLUSIONS Our findings reveal new properties of Top1 in regulating R-loop homeostasis in a context-dependent manner and suggest a potential role for Top1 in modulating the replication process via R-loop formation.
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Affiliation(s)
- Stefano G Manzo
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
- Present address: Division of Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Stella R Hartono
- Department of Molecular and Cellular Biology and Genome Center, University of California, Davis, USA
| | - Lionel A Sanz
- Department of Molecular and Cellular Biology and Genome Center, University of California, Davis, USA
| | - Jessica Marinello
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Sara De Biasi
- Department of Medical and Surgical Sciences for Children and Adults, University of Modena and Reggio Emilia, Modena, Italy
| | - Andrea Cossarizza
- Department of Medical and Surgical Sciences for Children and Adults, University of Modena and Reggio Emilia, Modena, Italy
| | - Giovanni Capranico
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.
| | - Frederic Chedin
- Department of Molecular and Cellular Biology and Genome Center, University of California, Davis, USA.
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18
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Chakraborty A, Viswanathan P. Methylation-Demethylation Dynamics: Implications of Changes in Acute Kidney Injury. Anal Cell Pathol (Amst) 2018. [DOI: https://doi.org/10.1155/2018/8764384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Over the years, the epigenetic landscape has grown increasingly complex. Until recently, methylation of DNA and histones was considered one of the most important epigenetic modifications. However, with the discovery of enzymes involved in the demethylation process, several exciting prospects have emerged that focus on the dynamic regulation of methylation and its crucial role in development and disease. An interplay of the methylation-demethylation machinery controls the process of gene expression. Since acute kidney injury (AKI), a major risk factor for chronic kidney disease and death, is characterised by aberrant expression of genes, understanding the dynamics of methylation and demethylation will provide new insights into the intricacies of the disease. Research on epigenetics in AKI has only made its mark in the recent years but has provided compelling evidence that implicates the involvement of methylation and demethylation changes in its pathophysiology. In this review, we explore the role of methylation and demethylation machinery in cellular epigenetic control and further discuss the contribution of methylomic changes and histone modifications to the pathophysiology of AKI.
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Affiliation(s)
- Anubhav Chakraborty
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Pragasam Viswanathan
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
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19
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El Fakih R, Komrokji R, Shaheen M, Almohareb F, Rasheed W, Hassanein M. Azacitidine Use for Myeloid Neoplasms. CLINICAL LYMPHOMA MYELOMA & LEUKEMIA 2018; 18:e147-e155. [DOI: 10.1016/j.clml.2018.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 01/23/2018] [Accepted: 02/02/2018] [Indexed: 01/08/2023]
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20
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Zhang R, Wu J, Ferrandon S, Glowacki KJ, Houghton JA. Targeting GLI by GANT61 involves mechanisms dependent on inhibition of both transcription and DNA licensing. Oncotarget 2018; 7:80190-80207. [PMID: 27863397 PMCID: PMC5348313 DOI: 10.18632/oncotarget.13376] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 11/07/2016] [Indexed: 12/31/2022] Open
Abstract
The GLI genes are transcription factors and in cancers are oncogenes, aberrantly and constitutively activated. GANT61, a specific GLI inhibitor, has induced extensive cytotoxicity in human models of colon cancer. The FOXM1 promoter was determined to be a transcriptional target of GLI1. In HT29 cells, inhibition of GLI1 binding at the GLI consensus sequence by GANT61 led to inhibited binding of Pol II, the pause-release factors DSIF, NELF and p-TEFb. The formation of R-loops (RNA:DNA hybrids, ssDNA), were reduced by GANT61 at the FOXM1 promoter. Pretreatment of HT29 cells with α-amanitin reduced GANT61-induced γH2AX foci. Co-localization of GLI1 and BrdU foci, inhibited by GANT61, indicated GLI1 and DNA replication to be linked. By co-immunoprecipitation and confocal microscopy, GLI1 co-localized with the DNA licensing factors ORC4, CDT1, and MCM2. Significant co-localization of GLI1 and ORC4 was inhibited by GANT61, and enrichment of ORC4 occurred at the GLI binding site in the FOXM1 promoter. CDT1 was found to be a transcription target of GLI1. Overexpression of CDT1 in HT29 and SW480 cells reduced GANT61-induced cell death, gH2AX foci, and cleavage of caspase-3. Data demonstrate involvement of transcription and of DNA replication licensing factors by non-transcriptional and transcriptional mechanisms in the GLI-dependent mechanism of action of GANT61.
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Affiliation(s)
- Ruowen Zhang
- Department of Oncology, Division of Drug Discovery, Southern Research, Birmingham, AL, USA
| | - Jiahui Wu
- Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Katie J Glowacki
- Department of Oncology, Division of Drug Discovery, Southern Research, Birmingham, AL, USA
| | - Janet A Houghton
- Department of Oncology, Division of Drug Discovery, Southern Research, Birmingham, AL, USA
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21
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Marques CA, McCulloch R. Conservation and Variation in Strategies for DNA Replication of Kinetoplastid Nuclear Genomes. Curr Genomics 2018; 19:98-109. [PMID: 29491738 PMCID: PMC5814967 DOI: 10.2174/1389202918666170815144627] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 03/19/2017] [Accepted: 04/11/2017] [Indexed: 12/21/2022] Open
Abstract
Introduction: Understanding how the nuclear genome of kinetoplastid parasites is replicated received experimental stimulus from sequencing of the Leishmania major, Trypanosoma brucei and Trypanosoma cruzi genomes around 10 years ago. Gene annotations suggested key players in DNA replication initiation could not be found in these organisms, despite considerable conservation amongst characterised eukaryotes. Initial studies that indicated trypanosomatids might possess an archaeal-like Origin Recognition Complex (ORC), composed of only a single factor termed ORC1/CDC6, have been supplanted by the more recent identification of an ORC in T. brucei. However, the constituent subunits of T. brucei ORC are highly diverged relative to other eukaryotic ORCs and the activity of the complex appears subject to novel, positive regulation. The availability of whole genome sequences has also allowed the deployment of genome-wide strategies to map DNA replication dynamics, to date in T. brucei and Leishmania. ORC1/CDC6 binding and function in T. brucei displays pronounced overlap with the unconventional organisation of gene expression in the genome. Moreover, mapping of sites of replication initiation suggests pronounced differences in replication dynamics in Leishmania relative to T. brucei. Conclusion: Here we discuss what implications these emerging data may have for parasite and eukaryotic biology of DNA replication.
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Affiliation(s)
- Catarina A Marques
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, Dow Street, University of Dundee, Dundee, DD1 5EH, UK
| | - Richard McCulloch
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, Sir Graeme Davis Building, 120 University Place, University of Glasgow, Glasgow, G12 8TA, UK
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22
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Chakraborty A, Viswanathan P. Methylation-Demethylation Dynamics: Implications of Changes in Acute Kidney Injury. Anal Cell Pathol (Amst) 2018; 2018:8764384. [PMID: 30073137 PMCID: PMC6057397 DOI: 10.1155/2018/8764384] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/05/2018] [Accepted: 06/14/2018] [Indexed: 02/05/2023] Open
Abstract
Over the years, the epigenetic landscape has grown increasingly complex. Until recently, methylation of DNA and histones was considered one of the most important epigenetic modifications. However, with the discovery of enzymes involved in the demethylation process, several exciting prospects have emerged that focus on the dynamic regulation of methylation and its crucial role in development and disease. An interplay of the methylation-demethylation machinery controls the process of gene expression. Since acute kidney injury (AKI), a major risk factor for chronic kidney disease and death, is characterised by aberrant expression of genes, understanding the dynamics of methylation and demethylation will provide new insights into the intricacies of the disease. Research on epigenetics in AKI has only made its mark in the recent years but has provided compelling evidence that implicates the involvement of methylation and demethylation changes in its pathophysiology. In this review, we explore the role of methylation and demethylation machinery in cellular epigenetic control and further discuss the contribution of methylomic changes and histone modifications to the pathophysiology of AKI.
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Affiliation(s)
- Anubhav Chakraborty
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Pragasam Viswanathan
- Renal Research Lab, Centre for Bio-Medical Research, School of Bio-Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
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23
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Abstract
The discovery of CpG islands (CGIs) and the study of their structure and properties run parallel to the development of molecular biology in the last two decades of the twentieth century and to the development of high-throughput genomic technologies at the turn of the millennium. First identified as discrete G + C-rich regions of unmethylated DNA in several vertebrates, CGIs were soon found to display additional distinctive chromatin features from the rest of the genome in terms of accessibility and of the epigenetic modifications of their histones. These features, together with their colocalization with promoters and with origins of DNA replication in mammals, highlighted their relevance in the regulation of genomic processes. Recent approaches have shown with unprecedented detail the dynamics and diversity of the epigenetic landscape of CGIs during normal development and under pathological conditions. Also, comparative analyses across species have started revealing how CGIs evolve and contribute to the evolution of the vertebrate genome.
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Affiliation(s)
- Francisco Antequera
- Instituto de Biología Funcional y Genómica, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca, Salamanca, Spain.
| | - Adrian Bird
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Michael Swann Building, Edinburgh, EH9 3BF, UK
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24
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Abstract
In this review, Prioleau and MacAlpine summarize recent advances in our understanding of how primary sequence, chromatin environment, and nuclear architecture contribute to the dynamic selection and activation of replication origins across diverse cell types and developmental stages. For more than three decades, investigators have sought to identify the precise locations where DNA replication initiates in mammalian genomes. The development of molecular and biochemical approaches to identify start sites of DNA replication (origins) based on the presence of defining and characteristic replication intermediates at specific loci led to the identification of only a handful of mammalian replication origins. The limited number of identified origins prevented a comprehensive and exhaustive search for conserved genomic features that were capable of specifying origins of DNA replication. More recently, the adaptation of origin-mapping assays to genome-wide approaches has led to the identification of tens of thousands of replication origins throughout mammalian genomes, providing an unprecedented opportunity to identify both genetic and epigenetic features that define and regulate their distribution and utilization. Here we summarize recent advances in our understanding of how primary sequence, chromatin environment, and nuclear architecture contribute to the dynamic selection and activation of replication origins across diverse cell types and developmental stages.
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Affiliation(s)
- Marie-Noëlle Prioleau
- Institut Jacques Monod, UMR7592, Centre National de la Recherche Scientifique, Universite Paris Diderot, Equipe Labellisee Association pour la Recherche sur le Cancer, Paris 75013, France
| | - David M MacAlpine
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710. USA
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25
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Rodríguez-Martínez M, Pinzón N, Ghommidh C, Beyne E, Seitz H, Cayrou C, Méchali M. The gastrula transition reorganizes replication-origin selection in Caenorhabditis elegans. Nat Struct Mol Biol 2017; 24:290-299. [PMID: 28112731 DOI: 10.1038/nsmb.3363] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/13/2016] [Indexed: 01/09/2023]
Abstract
Although some features underlying replication-origin activation in metazoan cells have been determined, little is known about their regulation during metazoan development. Using the nascent-strand purification method, here we identified replication origins throughout Caenorhabditis elegans embryonic development and found that the origin repertoire is thoroughly reorganized after gastrulation onset. During the pluripotent embryonic stages (pregastrula), potential cruciform structures and open chromatin are determining factors that establish replication origins. The observed enrichment of replication origins in transcription factor-binding sites and their presence in promoters of highly transcribed genes, particularly operons, suggest that transcriptional activity contributes to replication initiation before gastrulation. After the gastrula transition, when embryonic differentiation programs are set, new origins are selected at enhancers, close to CpG-island-like sequences, and at noncoding genes. Our findings suggest that origin selection coordinates replication initiation with transcriptional programs during metazoan development.
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Affiliation(s)
| | | | - Charles Ghommidh
- Agropolymer Engineering and Emerging Technologies, University of Montpellier, Montpellier, France
| | | | - Hervé Seitz
- Institute of Human Genetics, CNRS, Montpellier, France
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26
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Parker MW, Botchan MR, Berger JM. Mechanisms and regulation of DNA replication initiation in eukaryotes. Crit Rev Biochem Mol Biol 2017; 52:107-144. [PMID: 28094588 DOI: 10.1080/10409238.2016.1274717] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cellular DNA replication is initiated through the action of multiprotein complexes that recognize replication start sites in the chromosome (termed origins) and facilitate duplex DNA melting within these regions. In a typical cell cycle, initiation occurs only once per origin and each round of replication is tightly coupled to cell division. To avoid aberrant origin firing and re-replication, eukaryotes tightly regulate two events in the initiation process: loading of the replicative helicase, MCM2-7, onto chromatin by the origin recognition complex (ORC), and subsequent activation of the helicase by its incorporation into a complex known as the CMG. Recent work has begun to reveal the details of an orchestrated and sequential exchange of initiation factors on DNA that give rise to a replication-competent complex, the replisome. Here, we review the molecular mechanisms that underpin eukaryotic DNA replication initiation - from selecting replication start sites to replicative helicase loading and activation - and describe how these events are often distinctly regulated across different eukaryotic model organisms.
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Affiliation(s)
- Matthew W Parker
- a Department of Biophysics and Biophysical Chemistry , Johns Hopkins University School of Medicine , Baltimore , MD , USA
| | - Michael R Botchan
- b Department of Molecular and Cell Biology , University of California Berkeley , Berkeley , CA , USA
| | - James M Berger
- a Department of Biophysics and Biophysical Chemistry , Johns Hopkins University School of Medicine , Baltimore , MD , USA
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27
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Identification of Pif1 helicases with novel accessory domains in various amoebae. Mol Phylogenet Evol 2016; 103:64-74. [DOI: 10.1016/j.ympev.2016.07.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 06/06/2016] [Accepted: 07/12/2016] [Indexed: 11/19/2022]
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28
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Lombraña R, Álvarez A, Fernández-Justel JM, Almeida R, Poza-Carrión C, Gomes F, Calzada A, Requena JM, Gómez M. Transcriptionally Driven DNA Replication Program of the Human Parasite Leishmania major. Cell Rep 2016; 16:1774-1786. [PMID: 27477279 DOI: 10.1016/j.celrep.2016.07.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/26/2016] [Accepted: 07/01/2016] [Indexed: 01/04/2023] Open
Abstract
Faithful inheritance of eukaryotic genomes requires the orchestrated activation of multiple DNA replication origins (ORIs). Although origin firing is mechanistically conserved, how origins are specified and selected for activation varies across different model systems. Here, we provide a complete analysis of the nucleosomal landscape and replication program of the human parasite Leishmania major, building on a better evolutionary understanding of replication organization in Eukarya. We found that active transcription is a driving force for the nucleosomal organization of the L. major genome and that both the spatial and the temporal program of DNA replication can be explained as associated to RNA polymerase kinetics. This simple scenario likely provides flexibility and robustness to deal with the environmental changes that impose alterations in the genetic programs during parasitic life cycle stages. Our findings also suggest that coupling replication initiation to transcription elongation could be an ancient solution used by eukaryotic cells for origin maintenance.
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Affiliation(s)
- Rodrigo Lombraña
- Functional Organization of the Genome Group, Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Alba Álvarez
- Functional Organization of the Genome Group, Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - José Miguel Fernández-Justel
- Functional Organization of the Genome Group, Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Ricardo Almeida
- Functional Organization of the Genome Group, Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - César Poza-Carrión
- Functional Organization of the Genome Group, Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - Fábia Gomes
- Centro Nacional de Biotecnología (CSIC), Darwin 3, 28049 Madrid, Spain
| | - Arturo Calzada
- Centro Nacional de Biotecnología (CSIC), Darwin 3, 28049 Madrid, Spain
| | - José María Requena
- Functional Organization of the Genome Group, Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain
| | - María Gómez
- Functional Organization of the Genome Group, Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Nicolás Cabrera 1, 28049 Madrid, Spain.
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29
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Features of the interactions between the methyl-CpG motif and the arginine residues on the surface of MBD proteins. Struct Chem 2016. [DOI: 10.1007/s11224-016-0783-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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30
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Smith OK, Kim R, Fu H, Martin MM, Lin CM, Utani K, Zhang Y, Marks AB, Lalande M, Chamberlain S, Libbrecht MW, Bouhassira EE, Ryan MC, Noble WS, Aladjem MI. Distinct epigenetic features of differentiation-regulated replication origins. Epigenetics Chromatin 2016; 9:18. [PMID: 27168766 PMCID: PMC4862150 DOI: 10.1186/s13072-016-0067-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 04/25/2016] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Eukaryotic genome duplication starts at discrete sequences (replication origins) that coordinate cell cycle progression, ensure genomic stability and modulate gene expression. Origins share some sequence features, but their activity also responds to changes in transcription and cellular differentiation status. RESULTS To identify chromatin states and histone modifications that locally mark replication origins, we profiled origin distributions in eight human cell lines representing embryonic and differentiated cell types. Consistent with a role of chromatin structure in determining origin activity, we found that cancer and non-cancer cells of similar lineages exhibited highly similar replication origin distributions. Surprisingly, our study revealed that DNase hypersensitivity, which often correlates with early replication at large-scale chromatin domains, did not emerge as a strong local determinant of origin activity. Instead, we found that two distinct sets of chromatin modifications exhibited strong local associations with two discrete groups of replication origins. The first origin group consisted of about 40,000 regions that actively initiated replication in all cell types and preferentially colocalized with unmethylated CpGs and with the euchromatin markers, H3K4me3 and H3K9Ac. The second group included origins that were consistently active in cells of a single type or lineage and preferentially colocalized with the heterochromatin marker, H3K9me3. Shared origins replicated throughout the S-phase of the cell cycle, whereas cell-type-specific origins preferentially replicated during late S-phase. CONCLUSIONS These observations are in line with the hypothesis that differentiation-associated changes in chromatin and gene expression affect the activation of specific replication origins.
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Affiliation(s)
- Owen K. Smith
- />DNA Replication Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - RyanGuk Kim
- />In Silico Solutions, Falls Church, VA 22033 USA
| | - Haiqing Fu
- />DNA Replication Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Melvenia M. Martin
- />DNA Replication Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Chii Mei Lin
- />DNA Replication Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Koichi Utani
- />DNA Replication Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Ya Zhang
- />DNA Replication Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Anna B. Marks
- />DNA Replication Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
| | - Marc Lalande
- />Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06032 USA
| | - Stormy Chamberlain
- />Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06032 USA
| | - Maxwell W. Libbrecht
- />Department of Computer Science and Engineering, University of Washington, Seattle, WA 98195 USA
| | - Eric E. Bouhassira
- />Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461 USA
| | | | - William S. Noble
- />Department of Computer Science and Engineering, University of Washington, Seattle, WA 98195 USA
- />Department of Genome Sciences, University of Washington, Seattle, WA 98195 USA
| | - Mirit I. Aladjem
- />DNA Replication Group, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 USA
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31
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Hutchins JRA, Aze A, Coulombe P, Méchali M. Characteristics of Metazoan DNA Replication Origins. DNA REPLICATION, RECOMBINATION, AND REPAIR 2016. [PMCID: PMC7120227 DOI: 10.1007/978-4-431-55873-6_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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32
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Cayrou C, Ballester B, Peiffer I, Fenouil R, Coulombe P, Andrau JC, van Helden J, Méchali M. The chromatin environment shapes DNA replication origin organization and defines origin classes. Genome Res 2015; 25:1873-85. [PMID: 26560631 PMCID: PMC4665008 DOI: 10.1101/gr.192799.115] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Accepted: 10/14/2015] [Indexed: 12/22/2022]
Abstract
To unveil the still-elusive nature of metazoan replication origins, we identified them genome-wide and at unprecedented high-resolution in mouse ES cells. This allowed initiation sites (IS) and initiation zones (IZ) to be differentiated. We then characterized their genetic signatures and organization and integrated these data with 43 chromatin marks and factors. Our results reveal that replication origins can be grouped into three main classes with distinct organization, chromatin environment, and sequence motifs. Class 1 contains relatively isolated, low-efficiency origins that are poor in epigenetic marks and are enriched in an asymmetric AC repeat at the initiation site. Late origins are mainly found in this class. Class 2 origins are particularly rich in enhancer elements. Class 3 origins are the most efficient and are associated with open chromatin and polycomb protein-enriched regions. The presence of Origin G-rich Repeated elements (OGRE) potentially forming G-quadruplexes (G4) was confirmed at most origins. These coincide with nucleosome-depleted regions located upstream of the initiation sites, which are associated with a labile nucleosome containing H3K64ac. These data demonstrate that specific chromatin landscapes and combinations of specific signatures regulate origin localization. They explain the frequently observed links between DNA replication and transcription. They also emphasize the plasticity of metazoan replication origins and suggest that in multicellular eukaryotes, the combination of distinct genetic features and chromatin configurations act in synergy to define and adapt the origin profile.
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Affiliation(s)
| | - Benoit Ballester
- INSERM, U1090 TAGC, Marseille F-13288, France; Aix Marseille University, U1090 TAGC, Marseille F-13288, France
| | | | - Romain Fenouil
- Centre d'Immunologie de Marseille-Luminy (CIML), 13009 Marseille, France
| | | | | | - Jacques van Helden
- INSERM, U1090 TAGC, Marseille F-13288, France; Aix Marseille University, U1090 TAGC, Marseille F-13288, France
| | - Marcel Méchali
- Institute of Human Genetics, CNRS, 34396 Montpellier, France
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33
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Capturing snapshots of APE1 processing DNA damage. Nat Struct Mol Biol 2015; 22:924-31. [PMID: 26458045 PMCID: PMC4654669 DOI: 10.1038/nsmb.3105] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 09/06/2015] [Indexed: 12/22/2022]
Abstract
DNA apurinic-apyrimidinic (AP) sites are prevalent noncoding threats to genomic stability and are processed by AP endonuclease 1 (APE1). APE1 incises the AP-site phosphodiester backbone, generating a DNA-repair intermediate that is potentially cytotoxic. The molecular events of the incision reaction remain elusive, owing in part to limited structural information. We report multiple high-resolution human APE1-DNA structures that divulge new features of the APE1 reaction, including the metal-binding site, the nucleophile and the arginine clamps that mediate product release. We also report APE1-DNA structures with a T-G mismatch 5' to the AP site, representing a clustered lesion occurring in methylated CpG dinucleotides. These structures reveal that APE1 molds the T-G mismatch into a unique Watson-Crick-like geometry that distorts the active site, thus reducing incision. These snapshots provide mechanistic clarity for APE1 while affording a rational framework to manipulate biological responses to DNA damage.
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34
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El Fakih RO, Champlin R, Oran B. RETRACTED ARTICLE: 5-Azacitidine for treating acute myelogenous leukemia. Expert Opin Orphan Drugs 2015. [DOI: 10.1517/21678707.2015.1089168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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35
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Abstract
DNA replication begins with the assembly of pre-replication complexes (pre-RCs) at thousands of DNA replication origins during the G1 phase of the cell cycle. At the G1-S-phase transition, pre-RCs are converted into pre-initiation complexes, in which the replicative helicase is activated, leading to DNA unwinding and initiation of DNA synthesis. However, only a subset of origins are activated during any S phase. Recent insights into the mechanisms underlying this choice reveal how flexibility in origin usage and temporal activation are linked to chromosome structure and organization, cell growth and differentiation, and replication stress.
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36
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Tomic B, Kusic-Tisma J. HsOrc4-Dependent Dna Remodeling of the ori-β Dhfr Replicator. Cell Mol Biol Lett 2015; 20:549-61. [PMID: 26124052 DOI: 10.1515/cmble-2015-0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/18/2015] [Indexed: 11/15/2022] Open
Abstract
Replication of DNA in multicellular organisms initiates from origin of replication (ori) sequences, which significantly differ in length and complexity. One of the best characterized is hamster dihydrofolate reductase (DHFR), which contains the ori-β sequence with several functionally relevant domains, such as an AT-rich region, dinucleotide repeat element (DNR), sequence-induced bend DNA (BEND) and a RIP60 protein-binding site (RIP60). Prior to initiation, ori sequences are recognized by origin recognition complex (ORC), which is a hetero hexamer complex that serves as the landing pad for proteins of the pre-replication complex. The function of each ORC subunit is still unclear. In this study, we analyze the function of subunit 4 of the human ORC complex (HsOrc4) in interaction with a plasmid bearing the ori-β DHFR sequence. We show that the topologically closed DHFR ori-β replicator contains a bubble-like structure within its AT-rich region and that it is reversibly modified in the interaction with HsOrc4. The non-canonical structure of the AT-rich region in the topologically closed ori sequence is recognized and changed by HsOrc4 using the energy of supercoiled DNA. These findings could help to further elucidate DNA replication and its possible association with human genetic diseases.
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37
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38
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Bartholdy B, Mukhopadhyay R, Lajugie J, Aladjem MI, Bouhassira EE. Allele-specific analysis of DNA replication origins in mammalian cells. Nat Commun 2015; 6:7051. [PMID: 25987481 PMCID: PMC4479011 DOI: 10.1038/ncomms8051] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 03/26/2015] [Indexed: 01/01/2023] Open
Abstract
The mechanisms that control the location and timing of firing of replication origins are poorly understood. Using a novel functional genomic approach based on the analysis of SNPs and indels in phased human genomes, we observe that replication asynchrony is associated with small cumulative variations in the initiation efficiency of multiple origins between the chromosome homologues, rather than with the activation of dormant origins. Allele-specific measurements demonstrate that the presence of G-quadruplex-forming sequences does not correlate with the efficiency of initiation. Sequence analysis reveals that the origins are highly enriched in sequences with profoundly asymmetric G/C and A/T nucleotide distributions and are almost completely depleted of antiparallel triplex-forming sequences. We therefore propose that although G4-forming sequences are abundant in replication origins, an asymmetry in nucleotide distribution, which increases the propensity of origins to unwind and adopt non-B DNA structure, rather than the ability to form G4, is directly associated with origin activity.
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Affiliation(s)
- Boris Bartholdy
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
| | - Rituparna Mukhopadhyay
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
| | - Julien Lajugie
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
| | - Mirit I. Aladjem
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, 37 Convent Drive, Bethesda, Maryland 20892, USA
| | - Eric E. Bouhassira
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, USA
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39
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Urban JM, Foulk MS, Casella C, Gerbi SA. The hunt for origins of DNA replication in multicellular eukaryotes. F1000PRIME REPORTS 2015; 7:30. [PMID: 25926981 PMCID: PMC4371235 DOI: 10.12703/p7-30] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Origins of DNA replication (ORIs) occur at defined regions in the genome. Although DNA sequence defines the position of ORIs in budding yeast, the factors for ORI specification remain elusive in metazoa. Several methods have been used recently to map ORIs in metazoan genomes with the hope that features for ORI specification might emerge. These methods are reviewed here with analysis of their advantages and shortcomings. The various factors that may influence ORI selection for initiation of DNA replication are discussed.
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Affiliation(s)
- John M. Urban
- Division of Biology and Medicine, Department of Molecular Biology, Cell Biology and Biochemistry, Brown UniversitySidney Frank Hall, 185 Meeting Street, Providence, RI 02912USA
| | - Michael S. Foulk
- Division of Biology and Medicine, Department of Molecular Biology, Cell Biology and Biochemistry, Brown UniversitySidney Frank Hall, 185 Meeting Street, Providence, RI 02912USA
- Department of Biology, Mercyhurst University501 East 38th Street, Erie, PA 16546USA
| | - Cinzia Casella
- Division of Biology and Medicine, Department of Molecular Biology, Cell Biology and Biochemistry, Brown UniversitySidney Frank Hall, 185 Meeting Street, Providence, RI 02912USA
- Institute for Molecular Medicine, University of Southern DenmarkJB Winsloews Vej 25, 5000 Odense CDenmark
| | - Susan A. Gerbi
- Division of Biology and Medicine, Department of Molecular Biology, Cell Biology and Biochemistry, Brown UniversitySidney Frank Hall, 185 Meeting Street, Providence, RI 02912USA
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40
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Foulk MS, Urban JM, Casella C, Gerbi SA. Characterizing and controlling intrinsic biases of lambda exonuclease in nascent strand sequencing reveals phasing between nucleosomes and G-quadruplex motifs around a subset of human replication origins. Genome Res 2015; 25:725-35. [PMID: 25695952 PMCID: PMC4417120 DOI: 10.1101/gr.183848.114] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 02/18/2015] [Indexed: 01/02/2023]
Abstract
Nascent strand sequencing (NS-seq) is used to discover DNA replication origins genome-wide, allowing identification of features for their specification. NS-seq depends on the ability of lambda exonuclease (λ-exo) to efficiently digest parental DNA while leaving RNA-primer protected nascent strands intact. We used genomics and biochemical approaches to determine if λ-exo digests all parental DNA sequences equally. We report that λ-exo does not efficiently digest G-quadruplex (G4) structures in a plasmid. Moreover, λ-exo digestion of nonreplicating genomic DNA (LexoG0) enriches GC-rich DNA and G4 motifs genome-wide. We used LexoG0 data to control for nascent strand–independent λ-exo biases in NS-seq and validated this approach at the rDNA locus. The λ-exo–controlled NS-seq peaks are not GC-rich, and only 35.5% overlap with 6.8% of all G4s, suggesting that G4s are not general determinants for origin specification but may play a role for a subset. Interestingly, we observed a periodic spacing of G4 motifs and nucleosomes around the peak summits, suggesting that G4s may position nucleosomes at this subset of origins. Finally, we demonstrate that use of Na+ instead of K+ in the λ-exo digestion buffer reduced the effect of G4s on λ-exo digestion and discuss ways to increase both the sensitivity and specificity of NS-seq.
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Affiliation(s)
- Michael S Foulk
- Brown University Division of Biology and Medicine, Department of Molecular Biology, Cell Biology and Biochemistry, Providence, Rhode Island 02912, USA
| | - John M Urban
- Brown University Division of Biology and Medicine, Department of Molecular Biology, Cell Biology and Biochemistry, Providence, Rhode Island 02912, USA
| | - Cinzia Casella
- Brown University Division of Biology and Medicine, Department of Molecular Biology, Cell Biology and Biochemistry, Providence, Rhode Island 02912, USA
| | - Susan A Gerbi
- Brown University Division of Biology and Medicine, Department of Molecular Biology, Cell Biology and Biochemistry, Providence, Rhode Island 02912, USA
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41
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Flickinger RA. Possible role of H1 histone in replication timing. Dev Growth Differ 2014; 57:1-9. [PMID: 25495214 DOI: 10.1111/dgd.12190] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 11/03/2014] [Accepted: 11/04/2014] [Indexed: 01/02/2023]
Abstract
AT-rich repetitive DNA sequences become late replicating during cell differentiation. Replication timing is not correlated with LINE density in human cells (Ryba et al. 2010). However, short and properly spaced runs of oligo dA or dT present in nuclear matrix attachment regions (MARs) of the genome are good candidates for elements of AT-rich repetitive late replicating DNA. MAR attachment to the nuclear matrix is negatively regulated by chromatin binding of H1 histone, but this is counteracted by H1 phosphorylation, high mobility group proteins or, indirectly, core histone acetylation. Fewer MAR attachments correlates positively with longer average DNA loop size, longer replicons and an increase of late replicating DNA.
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Affiliation(s)
- Reed A Flickinger
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, 14260, New York, USA
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42
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Scala G, Affinito O, Miele G, Monticelli A, Cocozza S. Evidence for evolutionary and nonevolutionary forces shaping the distribution of human genetic variants near transcription start sites. PLoS One 2014; 9:e114432. [PMID: 25474578 PMCID: PMC4256220 DOI: 10.1371/journal.pone.0114432] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 11/09/2014] [Indexed: 11/19/2022] Open
Abstract
The regions surrounding transcription start sites (TSSs) of genes play a critical role in the regulation of gene expression. At the same time, current evidence indicates that these regions are particularly stressed by transcription-related mutagenic phenomena. In this work we performed a genome-wide analysis of the distribution of single nucleotide polymorphisms (SNPs) inside the 10 kb region flanking human TSSs by dividing SNPs into four classes according to their frequency (rare, two intermediate classes, and common). We found that, in this 10 kb region, the distribution of variants depends on their frequency and on their localization relative to the TSS. We found that the distribution of variants is generally different for TSSs located inside or outside of CpG islands. We found a significant relationship between the distribution of rare variants and nucleosome occupancy scores. Furthermore, our analysis suggests that evolutionary (purifying selection) and nonevolutionary (biased gene conversion) forces both play a role in determining the relative SNP frequency around TSSs. Finally, we analyzed the potential pathogenicity of each class of variant using the Combined Annotation Dependent Depletion score. In conclusion, this study provides a novel and detailed view of the distribution of genomic variants around TSSs, providing insight into the forces that instigate and maintain variability in such critical regions.
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Affiliation(s)
- Giovanni Scala
- Gruppo Interdipartimentale di Bioinformatica e Biologia Computazionale, Università degli Studi di Napoli “Federico II”, Naples, Italy
- Dipartimento di Fisica, Università degli Studi di Napoli “Federico II”, Naples, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Naples, Italy
- * E-mail:
| | - Ornella Affinito
- Gruppo Interdipartimentale di Bioinformatica e Biologia Computazionale, Università degli Studi di Napoli “Federico II”, Naples, Italy
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli “Federico II”, Naples, Italy
- Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS), CNR, Naples, Italy
| | - Gennaro Miele
- Gruppo Interdipartimentale di Bioinformatica e Biologia Computazionale, Università degli Studi di Napoli “Federico II”, Naples, Italy
- Dipartimento di Fisica, Università degli Studi di Napoli “Federico II”, Naples, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Naples, Italy
| | - Antonella Monticelli
- Gruppo Interdipartimentale di Bioinformatica e Biologia Computazionale, Università degli Studi di Napoli “Federico II”, Naples, Italy
- Istituto di Endocrinologia ed Oncologia Sperimentale (IEOS), CNR, Naples, Italy
| | - Sergio Cocozza
- Gruppo Interdipartimentale di Bioinformatica e Biologia Computazionale, Università degli Studi di Napoli “Federico II”, Naples, Italy
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli “Federico II”, Naples, Italy
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43
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Temporal and spatial regulation of eukaryotic DNA replication: From regulated initiation to genome-scale timing program. Semin Cell Dev Biol 2014; 30:110-20. [DOI: 10.1016/j.semcdb.2014.04.014] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 04/04/2014] [Indexed: 11/23/2022]
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44
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Mukhopadhyay R, Lajugie J, Fourel N, Selzer A, Schizas M, Bartholdy B, Mar J, Lin CM, Martin MM, Ryan M, Aladjem MI, Bouhassira EE. Allele-specific genome-wide profiling in human primary erythroblasts reveal replication program organization. PLoS Genet 2014; 10:e1004319. [PMID: 24787348 PMCID: PMC4006724 DOI: 10.1371/journal.pgen.1004319] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 03/10/2014] [Indexed: 11/19/2022] Open
Abstract
We have developed a new approach to characterize allele-specific timing of DNA replication genome-wide in human primary basophilic erythroblasts. We show that the two chromosome homologs replicate at the same time in about 88% of the genome and that large structural variants are preferentially associated with asynchronous replication. We identified about 600 megabase-sized asynchronously replicated domains in two tested individuals. The longest asynchronously replicated domains are enriched in imprinted genes suggesting that structural variants and parental imprinting are two causes of replication asynchrony in the human genome. Biased chromosome X inactivation in one of the two individuals tested was another source of detectable replication asynchrony. Analysis of high-resolution TimEX profiles revealed small variations termed timing ripples, which were undetected in previous, lower resolution analyses. Timing ripples reflect highly reproducible, variations of the timing of replication in the 100 kb-range that exist within the well-characterized megabase-sized replication timing domains. These ripples correspond to clusters of origins of replication that we detected using novel nascent strands DNA profiling methods. Analysis of the distribution of replication origins revealed dramatic differences in initiation of replication frequencies during S phase and a strong association, in both synchronous and asynchronous regions, between origins of replication and three genomic features: G-quadruplexes, CpG Islands and transcription start sites. The frequency of initiation in asynchronous regions was similar in the two homologs. Asynchronous regions were richer in origins of replication than synchronous regions. DNA replication in mammalian cells proceeds according to a distinct order. Genes that are expressed tend to replicate before genes that are not expressed. We report here that we have developed a method to measure the timing of replication of the maternal and paternal chromosomes separately. We found that the paternal and maternal chromosomes replicate at exactly the same time in the large majority of the genome and that the 12% of the genome that replicated asynchronously was enriched in imprinted genes and in structural variants. Previous experiments have shown that chromosomes could be divided into replication timing domains that are a few hundred thousand to a few megabases in size. We show here that these domains can be divided into sub-domains defined by ripples in the timing profile. These ripples corresponded to clusters of origins of replication. Finally, we show that the frequency of initiation in asynchronous regions was similar in the two homologs.
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Affiliation(s)
- Rituparna Mukhopadhyay
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Julien Lajugie
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Nicolas Fourel
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Ari Selzer
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Michael Schizas
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Boris Bartholdy
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Jessica Mar
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Chii Mei Lin
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Melvenia M. Martin
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Michael Ryan
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Mirit I. Aladjem
- Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Bethesda, Maryland, United States of America
| | - Eric E. Bouhassira
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
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45
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GC-rich DNA elements enable replication origin activity in the methylotrophic yeast Pichia pastoris. PLoS Genet 2014; 10:e1004169. [PMID: 24603708 PMCID: PMC3945215 DOI: 10.1371/journal.pgen.1004169] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 12/25/2013] [Indexed: 11/19/2022] Open
Abstract
The well-studied DNA replication origins of the model budding and fission yeasts are A/T-rich elements. However, unlike their yeast counterparts, both plant and metazoan origins are G/C-rich and are associated with transcription start sites. Here we show that an industrially important methylotrophic budding yeast, Pichia pastoris, simultaneously employs at least two types of replication origins--a G/C-rich type associated with transcription start sites and an A/T-rich type more reminiscent of typical budding and fission yeast origins. We used a suite of massively parallel sequencing tools to map and dissect P. pastoris origins comprehensively, to measure their replication dynamics, and to assay the global positioning of nucleosomes across the genome. Our results suggest that some functional overlap exists between promoter sequences and G/C-rich replication origins in P. pastoris and imply an evolutionary bifurcation of the modes of replication initiation.
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Sherstyuk VV, Shevchenko AI, Zakian SM. Epigenetic landscape for initiation of DNA replication. Chromosoma 2013; 123:183-99. [PMID: 24337246 DOI: 10.1007/s00412-013-0448-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 11/27/2013] [Accepted: 12/02/2013] [Indexed: 02/07/2023]
Abstract
The key genetic process of DNA replication is initiated at specific sites referred to as replication origins. In eukaryotes, origins of DNA replication are not specified by a defined nucleotide sequence. Recent studies have shown that the structural context and topology of DNA sequence, chromatin features, and its transcriptional activity play an important role in origin choice. During differentiation and development, significant changes in chromatin organization and transcription occur, influencing origin activity and choice. In the last few years, a number of different genome-wide studies have broadened the understanding of replication origin regulation. In this review, we discuss the epigenetic factors and mechanisms that modulate origin choice and firing.
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Affiliation(s)
- Vladimir V Sherstyuk
- Russian Academy of Sciences, Siberian Branch, Institute of Cytology and Genetics, pr. Akad. Lavrentieva 10, Novosibirsk, 630090, Russia
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Abstract
The onset of genomic DNA synthesis requires precise interactions of specialized initiator proteins with DNA at sites where the replication machinery can be loaded. These sites, defined as replication origins, are found at a few unique locations in all of the prokaryotic chromosomes examined so far. However, replication origins are dispersed among tens of thousands of loci in metazoan chromosomes, thereby raising questions regarding the role of specific nucleotide sequences and chromatin environment in origin selection and the mechanisms used by initiators to recognize replication origins. Close examination of bacterial and archaeal replication origins reveals an array of DNA sequence motifs that position individual initiator protein molecules and promote initiator oligomerization on origin DNA. Conversely, the need for specific recognition sequences in eukaryotic replication origins is relaxed. In fact, the primary rule for origin selection appears to be flexibility, a feature that is modulated either by structural elements or by epigenetic mechanisms at least partly linked to the organization of the genome for gene expression.
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Affiliation(s)
- Alan C Leonard
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, Florida 32901
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GC skew at the 5' and 3' ends of human genes links R-loop formation to epigenetic regulation and transcription termination. Genome Res 2013; 23:1590-600. [PMID: 23868195 PMCID: PMC3787257 DOI: 10.1101/gr.158436.113] [Citation(s) in RCA: 247] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Strand asymmetry in the distribution of guanines and cytosines, measured by GC skew, predisposes DNA sequences toward R-loop formation upon transcription. Previous work revealed that GC skew and R-loop formation associate with a core set of unmethylated CpG island (CGI) promoters in the human genome. Here, we show that GC skew can distinguish four classes of promoters, including three types of CGI promoters, each associated with unique epigenetic and gene ontology signatures. In particular, we identify a strong and a weak class of CGI promoters and show that these loci are enriched in distinct chromosomal territories reflecting the intrinsic strength of their protection against DNA methylation. Interestingly, we show that strong CGI promoters are depleted from the X chromosome while weak CGIs are enriched, a property consistent with the acquisition of DNA methylation during dosage compensation. Furthermore, we identify a third class of CGI promoters based on its unique GC skew profile and show that this gene set is enriched for Polycomb group targets. Lastly, we show that nearly 2000 genes harbor GC skew at their 3′ ends and that these genes are preferentially located in gene-dense regions and tend to be closely arranged. Genomic profiling of R-loops accordingly showed that a large proportion of genes with terminal GC skew form R-loops at their 3′ ends, consistent with a role for these structures in permitting efficient transcription termination. Altogether, we show that GC skew and R-loop formation offer significant insights into the epigenetic regulation, genomic organization, and function of human genes.
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Abstract
Although distinct chromatin types have been long known to replicate at different timepoints of S phase, fine replication control has only recently become considered as an epigenetic phenomenon. It is now clear that in course of differentiation significant changes in genome replication timing occur, and these changes are intimately linked with the changes in transcriptional activity and nuclear architecture. Temporally coordinate replication is organized spatially into discrete units having specific chromosomal organization and function. Even though the functional aspects of such tight control of replication timing remain to be explored, one can confidently consider the replication program as yet another fundamental feature characteristic of the given differentiation state. The present review touches upon the molecular mechanisms of spatial and temporal control of replication timing, involving individual replication origins as well as large chromatin domains.
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Evertts AG, Coller HA. Back to the origin: reconsidering replication, transcription, epigenetics, and cell cycle control. Genes Cancer 2013; 3:678-96. [PMID: 23634256 DOI: 10.1177/1947601912474891] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In bacteria, replication is a carefully orchestrated event that unfolds the same way for each bacterium and each cell division. The process of DNA replication in bacteria optimizes cell growth and coordinates high levels of simultaneous replication and transcription. In metazoans, the organization of replication is more enigmatic. The lack of a specific sequence that defines origins of replication has, until recently, severely limited our ability to define the organizing principles of DNA replication. This question is of particular importance as emerging data suggest that replication stress is an important contributor to inherited genetic damage and the genomic instability in tumors. We consider here the replication program in several different organisms including recent genome-wide analyses of replication origins in humans. We review recent studies on the role of cytosine methylation in replication origins, the role of transcriptional looping and gene gating in DNA replication, and the role of chromatin's 3-dimensional structure in DNA replication. We use these new findings to consider several questions surrounding DNA replication in metazoans: How are origins selected? What is the relationship between replication and transcription? How do checkpoints inhibit origin firing? Why are there early and late firing origins? We then discuss whether oncogenes promote cancer through a role in DNA replication and whether errors in DNA replication are important contributors to the genomic alterations and gene fusion events observed in cancer. We conclude with some important areas for future experimentation.
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