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Smirnov E, Molínová P, Chmúrčiaková N, Vacík T, Cmarko D. Non-canonical DNA structures in the human ribosomal DNA. Histochem Cell Biol 2023; 160:499-515. [PMID: 37750997 DOI: 10.1007/s00418-023-02233-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2023] [Indexed: 09/27/2023]
Abstract
Non-canonical structures (NCS) refer to the various forms of DNA that differ from the B-conformation described by Watson and Crick. It has been found that these structures are usual components of the genome, actively participating in its essential functions. The present review is focused on the nine kinds of NCS appearing or likely to appear in human ribosomal DNA (rDNA): supercoiling structures, R-loops, G-quadruplexes, i-motifs, DNA triplexes, cruciform structures, DNA bubbles, and A and Z DNA conformations. We discuss the conditions of their generation, including their sequence specificity, distribution within the locus, dynamics, and beneficial and detrimental role in the cell.
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Affiliation(s)
- Evgeny Smirnov
- Laboratory of Cell Biology, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 00, Prague, Czech Republic.
| | - Pavla Molínová
- Laboratory of Cell Biology, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 00, Prague, Czech Republic
| | - Nikola Chmúrčiaková
- Laboratory of Cell Biology, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 00, Prague, Czech Republic
| | - Tomáš Vacík
- Laboratory of Cell Biology, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 00, Prague, Czech Republic
| | - Dušan Cmarko
- Laboratory of Cell Biology, Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 00, Prague, Czech Republic
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2
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Esnault C, Magat T, Zine El Aabidine A, Garcia-Oliver E, Cucchiarini A, Bouchouika S, Lleres D, Goerke L, Luo Y, Verga D, Lacroix L, Feil R, Spicuglia S, Mergny JL, Andrau JC. G4access identifies G-quadruplexes and their associations with open chromatin and imprinting control regions. Nat Genet 2023; 55:1359-1369. [PMID: 37400615 DOI: 10.1038/s41588-023-01437-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 05/31/2023] [Indexed: 07/05/2023]
Abstract
Metazoan promoters are enriched in secondary DNA structure-forming motifs, such as G-quadruplexes (G4s). Here we describe 'G4access', an approach to isolate and sequence G4s associated with open chromatin via nuclease digestion. G4access is antibody- and crosslinking-independent and enriches for computationally predicted G4s (pG4s), most of which are confirmed in vitro. Using G4access in human and mouse cells, we identify cell-type-specific G4 enrichment correlated with nucleosome exclusion and promoter transcription. G4access allows measurement of variations in G4 repertoire usage following G4 ligand treatment, HDAC and G4 helicases inhibitors. Applying G4access to cells from reciprocal hybrid mouse crosses suggests a role for G4s in the control of active imprinting regions. Consistently, we also observed that G4access peaks are unmethylated, while methylation at pG4s correlates with nucleosome repositioning on DNA. Overall, our study provides a new tool for studying G4s in cellular dynamics and highlights their association with open chromatin, transcription and their antagonism to DNA methylation.
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Affiliation(s)
- Cyril Esnault
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Talha Magat
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Amal Zine El Aabidine
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Encar Garcia-Oliver
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Anne Cucchiarini
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, Inserm, Institut Polytechnique de Paris, Palaiseau, France
| | - Soumya Bouchouika
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - David Lleres
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Lutz Goerke
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Yu Luo
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, Inserm, Institut Polytechnique de Paris, Palaiseau, France
- Université Paris-Saclay, Institut Curie, Orsay, France
| | - Daniela Verga
- Université Paris-Saclay, Institut Curie, Orsay, France
| | - Laurent Lacroix
- Institut de Biologie de l'École Normale Supérieure, ENS, CNRS UMR8197, Inserm U1024, Paris, France
| | - Robert Feil
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France
| | - Salvatore Spicuglia
- Aix-Marseille University, INSERM, TAGC, UMR 1090, Marseille, France
- Equipe Labellisée Ligue Contre le Cancer, Marseille, France
| | - Jean-Louis Mergny
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, Inserm, Institut Polytechnique de Paris, Palaiseau, France
| | - Jean-Christophe Andrau
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS-UMR 5535, Montpellier, France.
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3
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Ajoge HO, Renner TM, Bélanger K, Greig M, Dankar S, Kohio HP, Coleman MD, Ndashimye E, Arts EJ, Langlois MA, Barr SD. Antiretroviral APOBEC3 cytidine deaminases alter HIV-1 provirus integration site profiles. Nat Commun 2023; 14:16. [PMID: 36627271 PMCID: PMC9832166 DOI: 10.1038/s41467-022-35379-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 11/30/2022] [Indexed: 01/12/2023] Open
Abstract
APOBEC3 (A3) proteins are host-encoded deoxycytidine deaminases that provide an innate immune barrier to retroviral infection, notably against HIV-1. Low levels of deamination are believed to contribute to the genetic evolution of HIV-1, while intense catalytic activity of these proteins can induce catastrophic hypermutation in proviral DNA leading to near-total HIV-1 restriction. So far, little is known about how A3 cytosine deaminases might impact HIV-1 proviral DNA integration sites in human chromosomal DNA. Using a deep sequencing approach, we analyze the influence of catalytic active and inactive APOBEC3F and APOBEC3G on HIV-1 integration site selections. Here we show that DNA editing is detected at the extremities of the long terminal repeat regions of the virus. Both catalytic active and non-catalytic A3 mutants decrease insertions into gene coding sequences and increase integration sites into SINE elements, oncogenes and transcription-silencing non-B DNA features. Our data implicates A3 as a host factor influencing HIV-1 integration site selection and also promotes what appears to be a more latent expression profile.
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Affiliation(s)
- Hannah O Ajoge
- Western University, Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, London, ON, Canada
| | - Tyler M Renner
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Kasandra Bélanger
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Matthew Greig
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Samar Dankar
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Hinissan P Kohio
- Western University, Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, London, ON, Canada
| | - Macon D Coleman
- Western University, Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, London, ON, Canada
| | - Emmanuel Ndashimye
- Western University, Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, London, ON, Canada
| | - Eric J Arts
- Western University, Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, London, ON, Canada
| | - Marc-André Langlois
- Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada. .,Ottawa Center for Infection, Immunity and Inflammation (CI3), Ottawa, ON, Canada.
| | - Stephen D Barr
- Western University, Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, London, ON, Canada.
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4
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Kouzine F, Wojtowicz D, Przytycka TM, Levens D. Detection of Z-DNA Structures in Supercoiled Genome. Methods Mol Biol 2023; 2651:179-193. [PMID: 36892768 PMCID: PMC10512777 DOI: 10.1007/978-1-0716-3084-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
Z-DNAs are nucleic acid secondary structures that form within a special pattern of nucleotides and are promoted by DNA supercoiling. Through Z-DNA formation, DNA encodes information by dynamic changes in its secondary structure. A growing body of evidence indicates that Z-DNA formation can play a role in gene regulation; it can affect chromatin architecture and demonstrates its association with genomic instability, genetic diseases, and genome evolution. Many functional roles of Z-DNA are yet to be discovered highlighting the need for techniques to detect genome-wide folding of DNA into this structure. Here, we describe an approach to convert linear genome into supercoiled genome sponsoring Z-DNA formation. Applying permanganate-based methodology and high-throughput sequencing to supercoiled genome allows genome-wide detection of single-stranded DNA. Single-stranded DNA is characteristic of the junctions between the classical B-form of DNA and Z-DNA. Consequently, analysis of single-stranded DNA map provides snapshots of the Z-DNA conformation over the whole genome.
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Affiliation(s)
- Fedor Kouzine
- Laboratory of Pathology, NCI/NIH, Bethesda, MD, USA.
| | | | | | - David Levens
- Laboratory of Pathology, NCI/NIH, Bethesda, MD, USA
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5
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Ajoge HO, Kohio HP, Paparisto E, Coleman MD, Wong K, Tom SK, Bain KL, Berry CC, Arts EJ, Barr SD. G-Quadruplex DNA and Other Non-Canonical B-Form DNA Motifs Influence Productive and Latent HIV-1 Integration and Reactivation Potential. Viruses 2022; 14:v14112494. [PMID: 36423103 PMCID: PMC9692945 DOI: 10.3390/v14112494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/04/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
The integration of the HIV-1 genome into the host genome is an essential step in the life cycle of the virus and it plays a critical role in the expression, long-term persistence, and reactivation of HIV expression. To better understand the local genomic environment surrounding HIV-1 proviruses, we assessed the influence of non-canonical B-form DNA (non-B DNA) on the HIV-1 integration site selection. We showed that productively and latently infected cells exhibit different integration site biases towards non-B DNA motifs. We identified a correlation between the integration sites of the latent proviruses and non-B DNA features known to potently influence gene expression (e.g., cruciform, guanine-quadruplex (G4), triplex, and Z-DNA). The reactivation potential of latent proviruses with latency reversal agents also correlated with their proximity to specific non-B DNA motifs. The perturbation of G4 structures in vitro using G4 structure-destabilizing or -stabilizing ligands resulted in a significant reduction in integration within 100 base pairs of G4 motifs. The stabilization of G4 structures increased the integration within 300-500 base pairs from G4 motifs, increased integration near transcription start sites, and increased the proportion of latently infected cells. Moreover, we showed that host lens epithelium-derived growth factor (LEDGF)/p75 and cleavage and polyadenylation specificity factor 6 (CPSF6) influenced the distribution of integration sites near several non-B DNA motifs, especially G4 DNA. Our findings identify non-B DNA motifs as important factors that influence productive and latent HIV-1 integration and the reactivation potential of latent proviruses.
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Affiliation(s)
- Hannah O. Ajoge
- Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, Western University, Dental Sciences Building Room 3007, London, ON N6A 5C1, Canada
| | - Hinissan P. Kohio
- Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, Western University, Dental Sciences Building Room 3007, London, ON N6A 5C1, Canada
| | - Ermela Paparisto
- Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, Western University, Dental Sciences Building Room 3007, London, ON N6A 5C1, Canada
| | - Macon D. Coleman
- Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, Western University, Dental Sciences Building Room 3007, London, ON N6A 5C1, Canada
| | - Kemen Wong
- Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, Western University, Dental Sciences Building Room 3007, London, ON N6A 5C1, Canada
| | - Sean K. Tom
- Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, Western University, Dental Sciences Building Room 3007, London, ON N6A 5C1, Canada
| | - Katie L. Bain
- Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, Western University, Dental Sciences Building Room 3007, London, ON N6A 5C1, Canada
| | - Charles C. Berry
- Department of Family Medicine and Public Health, University of California San Diego, La Jolla, CA 92093, USA
| | - Eric J. Arts
- Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, Western University, Dental Sciences Building Room 3007, London, ON N6A 5C1, Canada
| | - Stephen D. Barr
- Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, Western University, Dental Sciences Building Room 3007, London, ON N6A 5C1, Canada
- Correspondence:
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6
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Mellor C, Perez C, Sale JE. Creation and resolution of non-B-DNA structural impediments during replication. Crit Rev Biochem Mol Biol 2022; 57:412-442. [PMID: 36170051 PMCID: PMC7613824 DOI: 10.1080/10409238.2022.2121803] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 08/02/2022] [Accepted: 08/25/2022] [Indexed: 01/27/2023]
Abstract
During replication, folding of the DNA template into non-B-form secondary structures provides one of the most abundant impediments to the smooth progression of the replisome. The core replisome collaborates with multiple accessory factors to ensure timely and accurate duplication of the genome and epigenome. Here, we discuss the forces that drive non-B structure formation and the evidence that secondary structures are a significant and frequent source of replication stress that must be actively countered. Taking advantage of recent advances in the molecular and structural biology of the yeast and human replisomes, we examine how structures form and how they may be sensed and resolved during replication.
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Affiliation(s)
- Christopher Mellor
- Division of Protein & Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Consuelo Perez
- Division of Protein & Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Julian E Sale
- Division of Protein & Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK
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7
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Jeffery D, Lochhead M, Almouzni G. CENP-A: A Histone H3 Variant with Key Roles in Centromere Architecture in Healthy and Diseased States. Results Probl Cell Differ 2022; 70:221-261. [PMID: 36348109 DOI: 10.1007/978-3-031-06573-6_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Centromeres are key architectural components of chromosomes. Here, we examine their construction, maintenance, and functionality. Focusing on the mammalian centromere- specific histone H3 variant, CENP-A, we highlight its coevolution with both centromeric DNA and its chaperone, HJURP. We then consider CENP-A de novo deposition and the importance of centromeric DNA recently uncovered with the added value from new ultra-long-read sequencing. We next review how to ensure the maintenance of CENP-A at the centromere throughout the cell cycle. Finally, we discuss the impact of disrupting CENP-A regulation on cancer and cell fate.
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Affiliation(s)
- Daniel Jeffery
- Equipe Labellisée Ligue contre le Cancer, Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics Unit, UMR3664, Paris, France
| | - Marina Lochhead
- Equipe Labellisée Ligue contre le Cancer, Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics Unit, UMR3664, Paris, France
| | - Geneviève Almouzni
- Equipe Labellisée Ligue contre le Cancer, Institut Curie, PSL Research University, CNRS, Sorbonne Université, Nuclear Dynamics Unit, UMR3664, Paris, France.
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8
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Pandya N, Bhagwat SR, Kumar A. Regulatory role of Non-canonical DNA Polymorphisms in human genome and their relevance in Cancer. Biochim Biophys Acta Rev Cancer 2021; 1876:188594. [PMID: 34303788 DOI: 10.1016/j.bbcan.2021.188594] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 07/19/2021] [Accepted: 07/19/2021] [Indexed: 12/17/2022]
Abstract
DNA has the ability to form polymorphic structures like canonical duplex DNA and non-canonical triplex DNA, Cruciform, Z-DNA, G-quadruplex (G4), i-motifs, and hairpin structures. The alteration in the form of DNA polymorphism in the response to environmental changes influences the gene expression. Non-canonical structures are engaged in various biological functions, including chromatin epigenetic and gene expression regulation via transcription and translation, as well as DNA repair and recombination. The presence of non-canonical structures in the regulatory region of the gene alters the gene expression and affects the cellular machinery. Formation of non-canonical structure in the regulatory site of cancer-related genes either inhibits or dysregulate the gene function and promote tumour formation. In the current article, we review the influence of non-canonical structure on the regulatory mechanisms in human genome. Moreover, we have also discussed the relevance of non-canonical structures in cancer and provided information on the drugs used for their treatment by targeting these structures.
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Affiliation(s)
- Nirali Pandya
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Sonali R Bhagwat
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore 453552, India.
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9
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Felipe C, Shin J, Kolomeisky AB. DNA Looping and DNA Conformational Fluctuations Can Accelerate Protein Target Search. J Phys Chem B 2021; 125:1727-1734. [PMID: 33570939 DOI: 10.1021/acs.jpcb.0c09599] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Protein searching and binding to specific sites on DNA is a fundamentally important process that marks the beginning of all major cellular transformations. While the dynamics of protein-DNA interactions in in vitro settings is well investigated, the situation is much more complex for in vivo conditions because the DNA molecules in live cells are packed into chromosomal structures where they are undergoing strong dynamic and conformational fluctuations. In this work, we present a theoretical investigation on the role of DNA looping and DNA conformational fluctuations in the protein target search. It is based on a discrete-state stochastic analysis that allows for explicit calculations of dynamic properties, which is also supplemented by Monte Carlo computer simulations. It is found that for stronger nonspecific interactions between DNA and proteins the search occurs faster on the DNA looped conformation in comparison with the unlooped conformation, and the fastest search is observed when the loop is formed near the target site. It is also shown that DNA fluctuations between the looped and unlooped conformations influence the search dynamics, and this depends on the magnitude of conformational transition rates and on which conformation is more energetically stable. Physical-chemical arguments explaining these observations are presented. Our theoretical study suggests that the geometry and conformational changes in DNA are additional factors that might efficiently control the gene regulation processes.
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Affiliation(s)
- Cayke Felipe
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States.,Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States
| | - Jaeoh Shin
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States.,Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Anatoly B Kolomeisky
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States.,Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, United States.,Department of Chemistry, Rice University, Houston, Texas 77005, United States.,Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
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10
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Kumar M, Kaushik M, Kukreti S. Interaction of a photosensitizer methylene blue with various structural forms (cruciform, bulge duplex and hairpin) of designed DNA sequences. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 242:118716. [PMID: 32731146 DOI: 10.1016/j.saa.2020.118716] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/03/2020] [Accepted: 07/04/2020] [Indexed: 06/11/2023]
Abstract
Functionally important, local structural transitions in DNA generate various alternative conformations. Cruciform is one of such alternative DNA structures, usually targeted in genomes by various proteins. Symmetry elements in sequence as inverted repeats are the key factor for cruciform formation, facilitated by the presence of the AT-rich regions. Here, we used biophysical and biochemical techniques such as Gel electrophoresis, Circular dichroism (CD), and UV-thermal melting analysis to explore the structural status of the designed DNA sequences, which had potential to form cruciform structures under physiological conditions. The gel electrophoresis analysis revealed that the designed 53-mer DNA oligonucleotide sequence CR forms an intermolecular bulge duplex with flanking ends, while another sequence CRC adopts an intramolecular hairpin structure with flanking ends. Their equimolar complex (CRCRC) bestowed much-retarded migration due to the formation of a quite intriguing cruciform structure. CD studies confirmed that all the alternative structures (cruciform, bulge duplex, and hairpin with flanking ends) exhibit characteristics of B-DNA type conformation. A triphasic UV-thermal melting curve displayed by the complex formed by the equimolar ratio (CRCRC) is also suggestive of the formation of the cruciform structure. The interaction studies of CR, CRC, and their equimolar complex (1:1) with a photosensitizer methylene blue (MB) indicated that MB could not stabilize the discrete structures formed by CR and CRC sequences, however, the cruciform structure showed a quite significant increment in the melting temperature. Such studies facilitate our understanding of various secondary structures possibly present inside the cell and their interactions with drug/dye molecules.
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Affiliation(s)
- Mohan Kumar
- Department of Chemistry, University of Delhi, Delhi, India; Department of Chemistry, Shri Varshney College, Aligarh, Uttar Pradesh, India
| | - Mahima Kaushik
- Nano-bioconjugate Chemistry Lab, Cluster Innovation Centre, University of Delhi, Delhi, India
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11
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Kouzine F, Wojtowicz D, Yamane A, Casellas R, Przytycka TM, Levens DL. In Vivo Chemical Probing for G-Quadruplex Formation. Methods Mol Biol 2020; 2035:369-382. [PMID: 31444763 DOI: 10.1007/978-1-4939-9666-7_23] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
While DNA inside the cells is predominantly canonical right-handed double helix, guanine-rich DNAs have potential to fold into four-stranded structures that contain stacks of G-quartets (G4 DNA quadruplex). Genome sequencing has revealed G4 sequences tend to localize at the gene control regions, especially in the promoters of oncogenes. A growing body of evidence indicates that G4 DNA quadruplexes might have important regulatory roles in genome function, highlighting the need for techniques to detect genome-wide folding of DNA into this structure. Potassium permanganate in vivo treatment of cells results in oxidizing of nucleotides in single-stranded DNA regions that accompany G4 DNA quadruplexes formation, providing an excellent probe for the conformational state of DNA inside the living cells. Here, we describe a permanganate-based methodology to detect G4 DNA quadruplex, genome-wide. This methodology combined with high-throughput sequencing provides a snapshot of the DNA conformation over the whole genome in vivo.
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Affiliation(s)
- Fedor Kouzine
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA
| | - Damian Wojtowicz
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA
| | - Arito Yamane
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA
| | - Rafael Casellas
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA
| | - Teresa M Przytycka
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA
| | - David L Levens
- Laboratory of Pathology, National Cancer Institute, National Institutes of Health (USA), Bethesda, MD, USA.
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12
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The Rich World of p53 DNA Binding Targets: The Role of DNA Structure. Int J Mol Sci 2019; 20:ijms20225605. [PMID: 31717504 PMCID: PMC6888028 DOI: 10.3390/ijms20225605] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 10/29/2019] [Accepted: 11/08/2019] [Indexed: 12/14/2022] Open
Abstract
The tumor suppressor functions of p53 and its roles in regulating the cell cycle, apoptosis, senescence, and metabolism are accomplished mainly by its interactions with DNA. p53 works as a transcription factor for a significant number of genes. Most p53 target genes contain so-called p53 response elements in their promoters, consisting of 20 bp long canonical consensus sequences. Compared to other transcription factors, which usually bind to one concrete and clearly defined DNA target, the p53 consensus sequence is not strict, but contains two repeats of a 5′RRRCWWGYYY3′ sequence; therefore it varies remarkably among target genes. Moreover, p53 binds also to DNA fragments that at least partially and often completely lack this consensus sequence. p53 also binds with high affinity to a variety of non-B DNA structures including Holliday junctions, cruciform structures, quadruplex DNA, triplex DNA, DNA loops, bulged DNA, and hemicatenane DNA. In this review, we summarize information of the interactions of p53 with various DNA targets and discuss the functional consequences of the rich world of p53 DNA binding targets for its complex regulatory functions.
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13
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Bartas M, Bažantová P, Brázda V, Liao JC, Červeň J, Pečinka P. Identification of Distinct Amino Acid Composition of Human Cruciform Binding Proteins. Mol Biol 2019. [DOI: 10.1134/s0026893319010023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Miura O, Ogake T, Yoneyama H, Kikuchi Y, Ohyama T. A strong structural correlation between short inverted repeat sequences and the polyadenylation signal in yeast and nucleosome exclusion by these inverted repeats. Curr Genet 2018; 65:575-590. [PMID: 30498953 PMCID: PMC6420913 DOI: 10.1007/s00294-018-0907-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/14/2018] [Accepted: 11/15/2018] [Indexed: 11/22/2022]
Abstract
DNA sequences that read the same from 5′ to 3′ in either strand are called inverted repeat sequences or simply IRs. They are found throughout a wide variety of genomes, from prokaryotes to eukaryotes. Despite extensive research, their in vivo functions, if any, remain unclear. Using Saccharomyces cerevisiae, we performed genome-wide analyses for the distribution, occurrence frequency, sequence characteristics and relevance to chromatin structure, for the IRs that reportedly have a cruciform-forming potential. Here, we provide the first comprehensive map of these IRs in the S. cerevisiae genome. The statistically significant enrichment of the IRs was found in the close vicinity of the DNA positions corresponding to polyadenylation [poly(A)] sites and ~ 30 to ~ 60 bp downstream of start codon-coding sites (referred to as ‘start codons’). In the former, ApT- or TpA-rich IRs and A-tract- or T-tract-rich IRs are enriched, while in the latter, different IRs are enriched. Furthermore, we found a strong structural correlation between the former IRs and the poly(A) signal. In the chromatin formed on the gene end regions, the majority of the IRs causes low nucleosome occupancy. The IRs in the region ~ 30 to ~ 60 bp downstream of start codons are located in the + 1 nucleosomes. In contrast, fewer IRs are present in the adjacent region downstream of start codons. The current study suggests that the IRs play similar roles in Escherichia coli and S. cerevisiae to regulate or complete transcription at the RNA level.
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Affiliation(s)
- Osamu Miura
- Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Toshihiro Ogake
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Hiroki Yoneyama
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Yo Kikuchi
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Takashi Ohyama
- Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan. .,Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
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15
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Brázda V, Červeň J, Bartas M, Mikysková N, Coufal J, Pečinka P. The Amino Acid Composition of Quadruplex Binding Proteins Reveals a Shared Motif and Predicts New Potential Quadruplex Interactors. Molecules 2018; 23:E2341. [PMID: 30216987 PMCID: PMC6225207 DOI: 10.3390/molecules23092341] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 09/09/2018] [Accepted: 09/12/2018] [Indexed: 12/27/2022] Open
Abstract
The importance of local DNA structures in the regulation of basic cellular processes is an emerging field of research. Amongst local non-B DNA structures, G-quadruplexes are perhaps the most well-characterized to date, and their presence has been demonstrated in many genomes, including that of humans. G-quadruplexes are selectively bound by many regulatory proteins. In this paper, we have analyzed the amino acid composition of all seventy-seven described G-quadruplex binding proteins of Homo sapiens. Our comparison with amino acid frequencies in all human proteins and specific protein subsets (e.g., all nucleic acid binding) revealed unique features of quadruplex binding proteins, with prominent enrichment for glycine (G) and arginine (R). Cluster analysis with bootstrap resampling shows similarities and differences in amino acid composition of particular quadruplex binding proteins. Interestingly, we found that all characterized G-quadruplex binding proteins share a 20 amino acid long motif/domain (RGRGR GRGGG SGGSG GRGRG) which is similar to the previously described RG-rich domain (RRGDG RRRGG GGRGQ GGRGR GGGFKG) of the FRM1 G-quadruplex binding protein. Based on this protein fingerprint, we have predicted a new set of potential G-quadruplex binding proteins sharing this interesting domain rich in glycine and arginine residues.
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Affiliation(s)
- Václav Brázda
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 135, 612 65 Brno, Czech Republic.
| | - Jiří Červeň
- Department of Biology and Ecology/Institute of Environmental Technologies, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic.
| | - Martin Bartas
- Department of Biology and Ecology/Institute of Environmental Technologies, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic.
| | - Nikol Mikysková
- Department of Biology and Ecology/Institute of Environmental Technologies, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic.
| | - Jan Coufal
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 135, 612 65 Brno, Czech Republic.
| | - Petr Pečinka
- Department of Biology and Ecology/Institute of Environmental Technologies, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic.
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16
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Miura O, Ogake T, Ohyama T. Requirement or exclusion of inverted repeat sequences with cruciform-forming potential in Escherichia coli revealed by genome-wide analyses. Curr Genet 2018; 64:945-958. [PMID: 29484452 PMCID: PMC6060812 DOI: 10.1007/s00294-018-0815-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 02/16/2018] [Accepted: 02/19/2018] [Indexed: 12/31/2022]
Abstract
Inverted repeat (IR) sequences are DNA sequences that read the same from 5' to 3' in each strand. Some IRs can form cruciforms under the stress of negative supercoiling, and these IRs are widely found in genomes. However, their biological significance remains unclear. The aim of the current study is to explore this issue further. We constructed the first Escherichia coli genome-wide comprehensive map of IRs with cruciform-forming potential. Based on the map, we performed detailed and quantitative analyses. Here, we report that IRs with cruciform-forming potential are statistically enriched in the following five regions: the adjacent regions downstream of the stop codon-coding sites (referred to as the stop codons), on and around the positions corresponding to mRNA ends (referred to as the gene ends), ~ 20 to ~45 bp upstream of the start codon-coding sites (referred to as the start codons) within the 5'-UTR (untranslated region), ~ 25 to ~ 60 bp downstream of the start codons, and promoter regions. For the adjacent regions downstream of the stop codons and on and around the gene ends, most of the IRs with a repeat unit length of ≥ 8 bp and a spacer size of ≤ 8 bp were parts of the intrinsic terminators, regardless of the location, and presumably used for Rho-independent transcription termination. In contrast, fewer IRs were present in the small region preceding the start codons. In E. coli, IRs with cruciform-forming potential are actively placed or excluded in the regulatory regions for the initiation and termination of transcription and translation, indicating their deep involvement or influence in these processes.
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Affiliation(s)
- Osamu Miura
- Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Toshihiro Ogake
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Takashi Ohyama
- Department of Biology, Faculty of Education and Integrated Arts and Sciences, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
- Major in Integrative Bioscience and Biomedical Engineering, Graduate School of Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
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17
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Anas M, Sharma R, Dhamodharan V, Pradeepkumar PI, Manhas A, Srivastava K, Ahmed S, Kumar N. Investigating Pharmacological Targeting of G-Quadruplexes in the Human Malaria Parasite. Biochemistry 2017; 56:6691-6699. [DOI: 10.1021/acs.biochem.7b00964] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Mohammad Anas
- Parasitology
Division, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India
| | - Richa Sharma
- Parasitology
Division, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India
| | - V. Dhamodharan
- Department
of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra, India
| | - P. I. Pradeepkumar
- Department
of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, Maharashtra, India
| | - Ashan Manhas
- Parasitology
Division, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India
| | - Kumkum Srivastava
- Parasitology
Division, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India
- Academy of Scientific and Innovative Research (AcSIR), Delhi, India
| | - Shakil Ahmed
- Molecular
and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India
- Academy of Scientific and Innovative Research (AcSIR), Delhi, India
| | - Niti Kumar
- Parasitology
Division, CSIR-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India
- Academy of Scientific and Innovative Research (AcSIR), Delhi, India
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18
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Bagshaw AT. Functional Mechanisms of Microsatellite DNA in Eukaryotic Genomes. Genome Biol Evol 2017; 9:2428-2443. [PMID: 28957459 PMCID: PMC5622345 DOI: 10.1093/gbe/evx164] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/23/2017] [Indexed: 02/06/2023] Open
Abstract
Microsatellite repeat DNA is best known for its length mutability, which is implicated in several neurological diseases and cancers, and often exploited as a genetic marker. Less well-known is the body of work exploring the widespread and surprisingly diverse functional roles of microsatellites. Recently, emerging evidence includes the finding that normal microsatellite polymorphism contributes substantially to the heritability of human gene expression on a genome-wide scale, calling attention to the task of elucidating the mechanisms involved. At present, these are underexplored, but several themes have emerged. I review evidence demonstrating roles for microsatellites in modulation of transcription factor binding, spacing between promoter elements, enhancers, cytosine methylation, alternative splicing, mRNA stability, selection of transcription start and termination sites, unusual structural conformations, nucleosome positioning and modification, higher order chromatin structure, noncoding RNA, and meiotic recombination hot spots.
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19
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Permanganate/S1 Nuclease Footprinting Reveals Non-B DNA Structures with Regulatory Potential across a Mammalian Genome. Cell Syst 2017; 4:344-356.e7. [PMID: 28237796 DOI: 10.1016/j.cels.2017.01.013] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 09/06/2016] [Accepted: 01/13/2017] [Indexed: 12/11/2022]
Abstract
DNA in cells is predominantly B-form double helix. Though certain DNA sequences in vitro may fold into other structures, such as triplex, left-handed Z form, or quadruplex DNA, the stability and prevalence of these structures in vivo are not known. Here, using computational analysis of sequence motifs, RNA polymerase II binding data, and genome-wide potassium permanganate-dependent nuclease footprinting data, we map thousands of putative non-B DNA sites at high resolution in mouse B cells. Computational analysis associates these non-B DNAs with particular structures and indicates that they form at locations compatible with an involvement in gene regulation. Further analyses support the notion that non-B DNA structure formation influences the occupancy and positioning of nucleosomes in chromatin. These results suggest that non-B DNAs contribute to the control of a variety of critical cellular and organismal processes.
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20
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Brázda V, Coufal J. Recognition of Local DNA Structures by p53 Protein. Int J Mol Sci 2017; 18:ijms18020375. [PMID: 28208646 PMCID: PMC5343910 DOI: 10.3390/ijms18020375] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 02/03/2017] [Indexed: 02/06/2023] Open
Abstract
p53 plays critical roles in regulating cell cycle, apoptosis, senescence and metabolism and is commonly mutated in human cancer. These roles are achieved by interaction with other proteins, but particularly by interaction with DNA. As a transcription factor, p53 is well known to bind consensus target sequences in linear B-DNA. Recent findings indicate that p53 binds with higher affinity to target sequences that form cruciform DNA structure. Moreover, p53 binds very tightly to non-B DNA structures and local DNA structures are increasingly recognized to influence the activity of wild-type and mutant p53. Apart from cruciform structures, p53 binds to quadruplex DNA, triplex DNA, DNA loops, bulged DNA and hemicatenane DNA. In this review, we describe local DNA structures and summarize information about interactions of p53 with these structural DNA motifs. These recent data provide important insights into the complexity of the p53 pathway and the functional consequences of wild-type and mutant p53 activation in normal and tumor cells.
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Affiliation(s)
- Václav Brázda
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 135, 612 65 Brno, Czech Republic.
| | - Jan Coufal
- Institute of Biophysics, Academy of Sciences of the Czech Republic v.v.i., Královopolská 135, 612 65 Brno, Czech Republic.
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21
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Molin WT, Wright AA, Lawton-Rauh A, Saski CA. The unique genomic landscape surrounding the EPSPS gene in glyphosate resistant Amaranthus palmeri: a repetitive path to resistance. BMC Genomics 2017; 18:91. [PMID: 28095770 PMCID: PMC5240378 DOI: 10.1186/s12864-016-3336-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 11/23/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The expanding number and global distributions of herbicide resistant weedy species threaten food, fuel, fiber and bioproduct sustainability and agroecosystem longevity. Amongst the most competitive weeds, Amaranthus palmeri S. Wats has rapidly evolved resistance to glyphosate primarily through massive amplification and insertion of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene across the genome. Increased EPSPS gene copy numbers results in higher titers of the EPSPS enzyme, the target of glyphosate, and confers resistance to glyphosate treatment. To understand the genomic unit and mechanism of EPSPS gene copy number proliferation, we developed and used a bacterial artificial chromosome (BAC) library from a highly resistant biotype to sequence the local genomic landscape flanking the EPSPS gene. RESULTS By sequencing overlapping BACs, a 297 kb sequence was generated, hereafter referred to as the "EPSPS cassette." This region included several putative genes, dense clusters of tandem and inverted repeats, putative helitron and autonomous replication sequences, and regulatory elements. Whole genome shotgun sequencing (WGS) of two biotypes exhibiting high and no resistance to glyphosate was performed to compare genomic representation across the EPSPS cassette. Mapping of sequences for both biotypes to the reference EPSPS cassette revealed significant differences in upstream and downstream sequences relative to EPSPS with regard to both repetitive units and coding content between these biotypes. The differences in sequence may have resulted from a compounded-building mechanism such as repetitive transpositional events. The association of putative helitron sequences with the cassette suggests a possible amplification and distribution mechanism. Flow cytometry revealed that the EPSPS cassette added measurable genomic content. CONCLUSIONS The adoption of glyphosate resistant cropping systems in major crops such as corn, soybean, cotton and canola coupled with excessive use of glyphosate herbicide has led to evolved glyphosate resistance in several important weeds. In Amaranthus palmeri, the amplification of the EPSPS cassette, characterized by a complex array of repetitive elements and putative helitron sequences, suggests an adaptive structural genomic mechanism that drives amplification and distribution around the genome. The added genomic content not found in glyphosate sensitive plants may be driving evolution through genome expansion.
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Affiliation(s)
- William T Molin
- United States Department of Agriculture, Crop Production Systems Research Unit, Stoneville, MS, USA.
| | - Alice A Wright
- United States Department of Agriculture, Crop Production Systems Research Unit, Stoneville, MS, USA
| | - Amy Lawton-Rauh
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC, USA
| | - Christopher A Saski
- Institute of Translational Genomics, Genomics and Computational Biology Lab, Clemson University, Clemson, SC, USA.
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22
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Effects of Replication and Transcription on DNA Structure-Related Genetic Instability. Genes (Basel) 2017; 8:genes8010017. [PMID: 28067787 PMCID: PMC5295012 DOI: 10.3390/genes8010017] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 12/21/2016] [Accepted: 12/26/2016] [Indexed: 12/20/2022] Open
Abstract
Many repetitive sequences in the human genome can adopt conformations that differ from the canonical B-DNA double helix (i.e., non-B DNA), and can impact important biological processes such as DNA replication, transcription, recombination, telomere maintenance, viral integration, transposome activation, DNA damage and repair. Thus, non-B DNA-forming sequences have been implicated in genetic instability and disease development. In this article, we discuss the interactions of non-B DNA with the replication and/or transcription machinery, particularly in disease states (e.g., tumors) that can lead to an abnormal cellular environment, and how such interactions may alter DNA replication and transcription, leading to potential conflicts at non-B DNA regions, and eventually result in genetic stability and human disease.
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23
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Brázda V, Kolomazník J, Lýsek J, Hároníková L, Coufal J, Št'astný J. Palindrome analyser - A new web-based server for predicting and evaluating inverted repeats in nucleotide sequences. Biochem Biophys Res Commun 2016; 478:1739-45. [PMID: 27603574 DOI: 10.1016/j.bbrc.2016.09.015] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 09/02/2016] [Indexed: 10/21/2022]
Abstract
DNA cruciform structures play an important role in the regulation of natural processes including gene replication and expression, as well as nucleosome structure and recombination. They have also been implicated in the evolution and development of diseases such as cancer and neurodegenerative disorders. Cruciform structures are formed by inverted repeats, and their stability is enhanced by DNA supercoiling and protein binding. They have received broad attention because of their important roles in biology. Computational approaches to study inverted repeats have allowed detailed analysis of genomes. However, currently there are no easily accessible and user-friendly tools that can analyse inverted repeats, especially among long nucleotide sequences. We have developed a web-based server, Palindrome analyser, which is a user-friendly application for analysing inverted repeats in various DNA (or RNA) sequences including genome sequences and oligonucleotides. It allows users to search and retrieve desired gene/nucleotide sequence entries from the NCBI databases, and provides data on length, sequence, locations and energy required for cruciform formation. Palindrome analyser also features an interactive graphical data representation of the distribution of the inverted repeats, with options for sorting according to the length of inverted repeat, length of loop, and number of mismatches. Palindrome analyser can be accessed at http://bioinformatics.ibp.cz.
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Affiliation(s)
- Václav Brázda
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65, Brno, Czech Republic.
| | - Jan Kolomazník
- Mendel University in Brno, Zemědělská 1, 613 00, Brno, Czech Republic
| | - Jiří Lýsek
- Mendel University in Brno, Zemědělská 1, 613 00, Brno, Czech Republic
| | - Lucia Hároníková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65, Brno, Czech Republic
| | - Jan Coufal
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65, Brno, Czech Republic
| | - Jiří Št'astný
- Mendel University in Brno, Zemědělská 1, 613 00, Brno, Czech Republic
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24
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Wang G, Zhao J, Vasquez KM. Detection of cis- and trans-acting Factors in DNA Structure-Induced Genetic Instability Using In silico and Cellular Approaches. Front Genet 2016; 7:135. [PMID: 27532010 PMCID: PMC4969553 DOI: 10.3389/fgene.2016.00135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 07/15/2016] [Indexed: 11/13/2022] Open
Abstract
Sequences that can adopt alternative DNA structures (i.e., non-B DNA) are very abundant in mammalian genomes, and recent studies have revealed many important biological functions of non-B DNA structures in chromatin remodeling, DNA replication, transcription, and genetic instability. Here, we provide results from an in silico web-based search engine coupled with cell-based experiments to characterize the roles of non-B DNA conformations in genetic instability in eukaryotes. The purpose of this article is to illustrate strategies that can be used to identify and interrogate the biological roles of non-B DNA structures, particularly on genetic instability. We have included unpublished data using a short H-DNA-forming sequence from the human c-MYC promoter region as an example, and identified two different mechanisms of H-DNA-induced genetic instability in yeast and mammalian cells: a DNA replication-related model of mutagenesis; and a replication-independent cleavage model. Further, we identified candidate proteins involved in H-DNA-induced genetic instability by using a yeast genetic screen. A combination of in silico and cellular methods, as described here, should provide further insight into the contributions of non-B DNA structures in biological functions, genetic evolution, and disease development.
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Affiliation(s)
- Guliang Wang
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute Austin, TX, USA
| | - Junhua Zhao
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute Austin, TX, USA
| | - Karen M Vasquez
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Pediatric Research Institute Austin, TX, USA
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25
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Brázda V, Hároníková L, Liao JCC, Fridrichová H, Jagelská EB. Strong preference of BRCA1 protein to topologically constrained non-B DNA structures. BMC Mol Biol 2016; 17:14. [PMID: 27277344 PMCID: PMC4898351 DOI: 10.1186/s12867-016-0068-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 05/30/2016] [Indexed: 11/30/2022] Open
Abstract
Background The breast and ovarian cancer susceptibility gene BRCA1 encodes a multifunctional tumor suppressor protein BRCA1, which is involved in regulating cellular processes such as cell cycle, transcription, DNA repair, DNA damage response and chromatin remodeling. BRCA1 protein, located primarily in cell nuclei, interacts with multiple proteins and various DNA targets. It has been demonstrated that BRCA1 protein binds to damaged DNA and plays a role in the transcriptional regulation of downstream target genes. As a key protein in the repair of DNA double-strand breaks, the BRCA1-DNA binding properties, however, have not been reported in detail. Results In this study, we provided detailed analyses of BRCA1 protein (DNA-binding domain, amino acid residues 444–1057) binding to topologically constrained non-B DNA structures (e.g. cruciform, triplex and quadruplex). Using electrophoretic retardation assay, atomic force microscopy and DNA binding competition assay, we showed the greatest preference of the BRCA1 DNA-binding domain to cruciform structure, followed by DNA quadruplex, with the weakest affinity to double stranded B-DNA and single stranded DNA. While preference of the BRCA1 protein to cruciform structures has been reported previously, our observations demonstrated for the first time a preferential binding of the BRCA1 protein also to triplex and quadruplex DNAs, including its visualization by atomic force microscopy. Conclusions Our discovery highlights a direct BRCA1 protein interaction with DNA. When compared to double stranded DNA, such a strong preference of the BRCA1 protein to cruciform and quadruplex structures suggests its importance in biology and may thus shed insight into the role of these interactions in cell regulation and maintenance. Electronic supplementary material The online version of this article (doi:10.1186/s12867-016-0068-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Václav Brázda
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic.
| | - Lucia Hároníková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Jack C C Liao
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic.,School of Medicine, University of Queensland, Brisbane, 4006, Australia
| | - Helena Fridrichová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
| | - Eva B Jagelská
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65, Brno, Czech Republic
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26
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Abstract
DNA mismatch repair is a conserved antimutagenic pathway that maintains genomic stability through rectification of DNA replication errors and attenuation of chromosomal rearrangements. Paradoxically, mutagenic action of mismatch repair has been implicated as a cause of triplet repeat expansions that cause neurological diseases such as Huntington disease and myotonic dystrophy. This mutagenic process requires the mismatch recognition factor MutSβ and the MutLα (and/or possibly MutLγ) endonuclease, and is thought to be triggered by the transient formation of unusual DNA structures within the expanded triplet repeat element. This review summarizes the current knowledge of DNA mismatch repair involvement in triplet repeat expansion, which encompasses in vitro biochemical findings, cellular studies, and various in vivo transgenic animal model experiments. We present current mechanistic hypotheses regarding mismatch repair protein function in mediating triplet repeat expansions and discuss potential therapeutic approaches targeting the mismatch repair pathway.
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Affiliation(s)
- Ravi R Iyer
- Teva Branded Pharmaceutical Products R&D, Inc., West Chester, Pennsylvania 19380;
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27
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Li D, Lv B, Zhang H, Lee JY, Li T. Positive supercoiling affiliated with nucleosome formation repairs non-B DNA structures. Chem Commun (Camb) 2014; 50:10641-4. [PMID: 25075997 DOI: 10.1039/c4cc04789c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
It is demonstrated that positive supercoiling affiliated with nucleosome formation can act as the driving force to repair the G-quadruplex, cruciform as well as a stable non-B DNA structure caused by peptide nucleic acid.
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Affiliation(s)
- Dawei Li
- The Southern Modern Forestry Collaborative Innovation Center, Nanjing Forestry University, 159 Longpan Road, Nanjing, 210037, China
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Bansal M, Kumar A, Yella VR. Role of DNA sequence based structural features of promoters in transcription initiation and gene expression. Curr Opin Struct Biol 2014; 25:77-85. [PMID: 24503515 DOI: 10.1016/j.sbi.2014.01.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 01/07/2014] [Indexed: 11/18/2022]
Abstract
Regulatory information for transcription initiation is present in a stretch of genomic DNA, called the promoter region that is located upstream of the transcription start site (TSS) of the gene. The promoter region interacts with different transcription factors and RNA polymerase to initiate transcription and contains short stretches of transcription factor binding sites (TFBSs), as well as structurally unique elements. Recent experimental and computational analyses of promoter sequences show that they often have non-B-DNA structural motifs, as well as some conserved structural properties, such as stability, bendability, nucleosome positioning preference and curvature, across a class of organisms. Here, we briefly describe these structural features, the differences observed in various organisms and their possible role in regulation of gene expression.
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Affiliation(s)
- Manju Bansal
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
| | - Aditya Kumar
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
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Huang Y, Mrázek J. Assessing diversity of DNA structure-related sequence features in prokaryotic genomes. DNA Res 2014; 21:285-97. [PMID: 24408877 PMCID: PMC4060949 DOI: 10.1093/dnares/dst057] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Prokaryotic genomes are diverse in terms of their nucleotide and oligonucleotide composition as well as presence of various sequence features that can affect physical properties of the DNA molecule. We present a survey of local sequence patterns which have a potential to promote non-canonical DNA conformations (i.e. different from standard B-DNA double helix) and interpret the results in terms of relationships with organisms' habitats, phylogenetic classifications, and other characteristics. Our present work differs from earlier similar surveys not only by investigating a wider range of sequence patterns in a large number of genomes but also by using a more realistic null model to assess significant deviations. Our results show that simple sequence repeats and Z-DNA-promoting patterns are generally suppressed in prokaryotic genomes, whereas palindromes and inverted repeats are over-represented. Representation of patterns that promote Z-DNA and intrinsic DNA curvature increases with increasing optimal growth temperature (OGT), and decreases with increasing oxygen requirement. Additionally, representations of close direct repeats, palindromes and inverted repeats exhibit clear negative trends with increasing OGT. The observed relationships with environmental characteristics, particularly OGT, suggest possible evolutionary scenarios of structural adaptation of DNA to particular environmental niches.
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Affiliation(s)
- Yongjie Huang
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Jan Mrázek
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA Department of Microbiology, University of Georgia, Athens, GA 30602, USA
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Karam M, Thenoz M, Capraro V, Robin JP, Pinatel C, Lancon A, Galia P, Sibon D, Thomas X, Ducastelle-Lepretre S, Nicolini F, El-Hamri M, Chelghoun Y, Wattel E, Mortreux F. Chromatin redistribution of the DEK oncoprotein represses hTERT transcription in leukemias. Neoplasia 2014; 16:21-30. [PMID: 24563617 PMCID: PMC3927101 DOI: 10.1593/neo.131658] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 12/16/2013] [Accepted: 12/19/2013] [Indexed: 12/30/2022]
Abstract
Although numerous factors have been found to modulate hTERT transcription, the mechanism of its repression in certain leukemias remains unknown. We show here that DEK represses hTERT transcription through its enrichment on the hTERT promoter in cells from chronic and acute myeloid leukemias, chronic lymphocytic leukemia, but not acute lymphocytic leukemias where hTERT is overexpressed. We isolated DEK from the hTERT promoter incubated with nuclear extracts derived from fresh acute myelogenous leukemia (AML) cells and from cells expressing Tax, an hTERT repressor encoded by the human T cell leukemia virus type 1. In addition to the recruitment of DEK, the displacement of two potent known hTERT transactivators from the hTERT promoter characterized both AML cells and Tax-expressing cells. Reporter and chromatin immunoprecipitation assays permitted to map the region that supports the repressive effect of DEK on hTERT transcription, which was proportionate to the level of DEK-promoter association but not with the level of DEK expression. Besides hTERT repression, this context of chromatin redistribution of DEK was found to govern about 40% of overall transcriptional modifications, including those of cancer-prone genes. In conclusion, DEK emerges as an hTERT repressor shared by various leukemia subtypes and seems involved in the deregulation of numerous genes associated with leukemogenesis.
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Affiliation(s)
- Maroun Karam
- Université de Lyon 1, Centre National pour la Recherche Scientifique UMR5239, Oncovirologie et Biothérapies, Centre Léon Bérard, Lyon Cedex, France
| | - Morgan Thenoz
- Université de Lyon 1, Centre National pour la Recherche Scientifique UMR5239, Oncovirologie et Biothérapies, Centre Léon Bérard, Lyon Cedex, France
| | - Valérie Capraro
- Université de Lyon 1, Centre National pour la Recherche Scientifique UMR5239, Oncovirologie et Biothérapies, Centre Léon Bérard, Lyon Cedex, France
| | - Jean-Philippe Robin
- Université de Lyon 1, Centre National pour la Recherche Scientifique UMR5239, Oncovirologie et Biothérapies, Centre Léon Bérard, Lyon Cedex, France
| | - Christiane Pinatel
- Université de Lyon 1, Centre National pour la Recherche Scientifique UMR5239, Oncovirologie et Biothérapies, Centre Léon Bérard, Lyon Cedex, France
| | - Agnès Lancon
- Université de Lyon 1, Centre National pour la Recherche Scientifique UMR5239, Oncovirologie et Biothérapies, Centre Léon Bérard, Lyon Cedex, France
| | - Perrine Galia
- Université de Lyon 1, Centre National pour la Recherche Scientifique UMR5239, Oncovirologie et Biothérapies, Centre Léon Bérard, Lyon Cedex, France
| | - David Sibon
- Université de Lyon 1, Centre National pour la Recherche Scientifique UMR5239, Oncovirologie et Biothérapies, Centre Léon Bérard, Lyon Cedex, France
- Service d'Hématologie Adultes, Hôpital Necker-Enfants Malades, Paris, France
| | - Xavier Thomas
- Service d'Hématologie, Pavillon Marcel Bérard, Centre Hospitalier Lyon-Sud 165, Pierre Bénite Cedex, France
| | - Sophie Ducastelle-Lepretre
- Service d'Hématologie, Pavillon Marcel Bérard, Centre Hospitalier Lyon-Sud 165, Pierre Bénite Cedex, France
| | - Franck Nicolini
- Service d'Hématologie, Pavillon Marcel Bérard, Centre Hospitalier Lyon-Sud 165, Pierre Bénite Cedex, France
| | - Mohamed El-Hamri
- Service d'Hématologie, Pavillon Marcel Bérard, Centre Hospitalier Lyon-Sud 165, Pierre Bénite Cedex, France
| | - Youcef Chelghoun
- Service d'Hématologie, Pavillon Marcel Bérard, Centre Hospitalier Lyon-Sud 165, Pierre Bénite Cedex, France
| | - Eric Wattel
- Université de Lyon 1, Centre National pour la Recherche Scientifique UMR5239, Oncovirologie et Biothérapies, Centre Léon Bérard, Lyon Cedex, France
- Service d'Hématologie, Pavillon Marcel Bérard, Centre Hospitalier Lyon-Sud 165, Pierre Bénite Cedex, France
| | - Franck Mortreux
- Université de Lyon 1, Centre National pour la Recherche Scientifique UMR5239, Oncovirologie et Biothérapies, Centre Léon Bérard, Lyon Cedex, France
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Munari FM, Revers LF, Cardone JM, Immich BF, Moura DJ, Guecheva TN, Bonatto D, Laurino JP, Saffi J, Brendel M, Henriques JAP. Sak1 kinase interacts with Pso2 nuclease in response to DNA damage induced by interstrand crosslink-inducing agents in Saccharomyces cerevisiae. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2013; 130:241-53. [PMID: 24362320 DOI: 10.1016/j.jphotobiol.2013.11.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 11/20/2013] [Accepted: 11/27/2013] [Indexed: 11/29/2022]
Abstract
By isolating putative binding partners through the two-hybrid system (THS) we further extended the characterization of the specific interstrand cross-link (ICL) repair gene PSO2 of Saccharomyces cerevisiae. Nine fusion protein products were isolated for Pso2p using THS, among them the Sak1 kinase, which interacted with the C-terminal β-CASP domain of Pso2p. Comparison of mutagen-sensitivity phenotypes of pso2Δ, sak1Δ and pso2Δsak1Δ disruptants revealed that SAK1 is necessary for complete WT-like repair. The epistatic interaction of both mutant alleles suggests that Sak1p and Pso2p act in the same pathway of controlling sensitivity to DNA-damaging agents. We also observed that Pso2p is phosphorylated by Sak1 kinase in vitro and co-immunoprecipitates with Sak1p after 8-MOP+UVA treatment. Survival data after treatment of pso2Δ, yku70Δ and yku70Δpso2Δ with nitrogen mustard, PSO2 and SAK1 with YKU70 or DNL4 single-, double- and triple mutants with 8-MOP+UVA indicated that ICL repair is independent of YKu70p and DNL4p in S. cerevisiae. Furthermore, a non-epistatic interaction was observed between MRE11, PSO2 and SAK1 genes after ICL induction, indicating that their encoded proteins act on the same substrate, but in distinct repair pathways. In contrast, an epistatic interaction was observed for PSO2 and RAD52, PSO2 and RAD50, PSO2 and XRS2 genes in 8-MOP+UVA treated exponentially growing cells.
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Affiliation(s)
- Fernanda M Munari
- Biotechnology Center, Federal University of Rio Grande do Sul (UFRGS), 91507-970 Porto Alegre, RS, Brazil
| | - Luis F Revers
- Biotechnology Center, Federal University of Rio Grande do Sul (UFRGS), 91507-970 Porto Alegre, RS, Brazil
| | - Jacqueline M Cardone
- Biotechnology Center, Federal University of Rio Grande do Sul (UFRGS), 91507-970 Porto Alegre, RS, Brazil
| | - Bruna F Immich
- Biotechnology Center, Federal University of Rio Grande do Sul (UFRGS), 91507-970 Porto Alegre, RS, Brazil; Federal University of Health Sciences of Porto Alegre (UFCSPA), 90050-170 Porto Alegre, RS, Brazil
| | - Dinara J Moura
- Federal University of Health Sciences of Porto Alegre (UFCSPA), 90050-170 Porto Alegre, RS, Brazil
| | - Temenouga N Guecheva
- Biotechnology Center, Federal University of Rio Grande do Sul (UFRGS), 91507-970 Porto Alegre, RS, Brazil; Department of Biophysics, Federal University of Rio Grande do Sul (UFRGS), 91507-970 Porto Alegre, RS, Brazil
| | - Diego Bonatto
- Biotechnology Center, Federal University of Rio Grande do Sul (UFRGS), 91507-970 Porto Alegre, RS, Brazil
| | - Jomar P Laurino
- Biotechnology Institute, University of Caxias do Sul (UCS), 95070-560 Caxias do Sul, RS, Brazil
| | - Jenifer Saffi
- Federal University of Health Sciences of Porto Alegre (UFCSPA), 90050-170 Porto Alegre, RS, Brazil
| | - Martin Brendel
- Department of Biological Sciences, State University of Santa Cruz (UESC), 45662-900 Ilhéus, BA, Brazil
| | - João A P Henriques
- Biotechnology Center, Federal University of Rio Grande do Sul (UFRGS), 91507-970 Porto Alegre, RS, Brazil; Department of Biophysics, Federal University of Rio Grande do Sul (UFRGS), 91507-970 Porto Alegre, RS, Brazil; Biotechnology Institute, University of Caxias do Sul (UCS), 95070-560 Caxias do Sul, RS, Brazil.
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Belotserkovskii BP, Mirkin SM, Hanawalt PC. DNA sequences that interfere with transcription: implications for genome function and stability. Chem Rev 2013; 113:8620-37. [PMID: 23972098 DOI: 10.1021/cr400078y] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Bansal A, Prasad M, Roy K, Kukreti S. A short GC-rich palindrome of human mannose receptor gene coding region displays a conformational switch. Biopolymers 2012; 97:950-62. [PMID: 22987586 DOI: 10.1002/bip.22111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Conformational switching in DNA is fundamental to biological processes. The structural status of a palindromic GC-rich dodecamer DNA sequence, integral part of human MRC2 coding region, and a related sequence of opposite polarity from human FDX1 gene were characterized and compared. UV-melting, circular dichroism, and gel electrophoresis experiments demonstrated the formation of intermolecular structures. Although stability and molecularity of both the oligomeric structures were found to be almost identical, their secondary structures differed remarkably as A1 MRC2 sequence showed A-like and B-like DNA conformation, whereas the A2 FDX1 sequence exhibited only the A-like signatures. The study is relevant for understanding structural polymorphism at genomic locations depending on DNA sequence and solution environment.
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Affiliation(s)
- Aparna Bansal
- Nucleic Acids Research Laboratory, Department of Chemistry, University of Delhi (North Campus), Delhi 110007, India
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Abstract
In addition to the canonical double helix, DNA can fold into various other inter- and intramolecular secondary structures. Although many such structures were long thought to be in vitro artefacts, bioinformatics demonstrates that DNA sequences capable of forming these structures are conserved throughout evolution, suggesting the existence of non-B-form DNA in vivo. In addition, genes whose products promote formation or resolution of these structures are found in diverse organisms, and a growing body of work suggests that the resolution of DNA secondary structures is critical for genome integrity. This Review focuses on emerging evidence relating to the characteristics of G-quadruplex structures and the possible influence of such structures on genomic stability and cellular processes, such as transcription.
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Preferential binding of IFI16 protein to cruciform structure and superhelical DNA. Biochem Biophys Res Commun 2012; 422:716-20. [PMID: 22618232 DOI: 10.1016/j.bbrc.2012.05.065] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 05/12/2012] [Indexed: 01/01/2023]
Abstract
Interferon (IFN)-inducible HIN-200 proteins play an important role in transcriptional regulation linked to cell cycle control, inflammation, autoimmunity and differentiation. IFI16 has been identified as a target of IFNα and γ and is a member of the HIN-200 protein family. Expression level of IFI16 is often decreased in breast cancers, implicating its role as a tumor suppressor. As a potent transcription factor, IFI16 possesses a transcriptional regulatory region, a PYD/DAPIN/PAAD region which associates with IFN response, DNA-binding domains and binding regions for tumor suppressor proteins BRCA1 and p53. It is also reported that IFI16 protein is capable of binding p53 and cMYC gene promoters. Here, we demonstrate that IFI16 protein binds strongly to negatively superhelical plasmid DNA at a native superhelix density, as evidenced by electrophoretic retardation of supercoiled (sc) DNA in agarose gels. Binding of IFI16 to supercoiled DNA results in the appearance of one or more retarded DNA bands on the gels. After removal of IFI16, the original mobility of the scDNA is recovered. By contrast, IFI16 protein binds very weakly to the same DNA in linear state. Using short oligonucleotide targets, we also detect a strong preference for IFI16 binding to cruciform DNA structure compared to linear DNA topology. Hence, this novel DNA-binding property of IFI16 protein to scDNA and cruciform structures may play critical roles in its tumor suppressor function.
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36
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Deniz O, Flores O, Battistini F, Pérez A, Soler-López M, Orozco M. Physical properties of naked DNA influence nucleosome positioning and correlate with transcription start and termination sites in yeast. BMC Genomics 2011; 12:489. [PMID: 21981773 PMCID: PMC3224377 DOI: 10.1186/1471-2164-12-489] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 10/07/2011] [Indexed: 01/13/2023] Open
Abstract
Background In eukaryotic organisms, DNA is packaged into chromatin structure, where most of DNA is wrapped into nucleosomes. DNA compaction and nucleosome positioning have clear functional implications, since they modulate the accessibility of genomic regions to regulatory proteins. Despite the intensive research effort focused in this area, the rules defining nucleosome positioning and the location of DNA regulatory regions still remain elusive. Results Naked (histone-free) and nucleosomal DNA from yeast were digested by microccocal nuclease (MNase) and sequenced genome-wide. MNase cutting preferences were determined for both naked and nucleosomal DNAs. Integration of their sequencing profiles with DNA conformational descriptors derived from atomistic molecular dynamic simulations enabled us to extract the physical properties of DNA on a genomic scale and to correlate them with chromatin structure and gene regulation. The local structure of DNA around regulatory regions was found to be unusually flexible and to display a unique pattern of nucleosome positioning. Ab initio physical descriptors derived from molecular dynamics were used to develop a computational method that accurately predicts nucleosome enriched and depleted regions. Conclusions Our experimental and computational analyses jointly demonstrate a clear correlation between sequence-dependent physical properties of naked DNA and regulatory signals in the chromatin structure. These results demonstrate that nucleosome positioning around TSS (Transcription Start Site) and TTS (Transcription Termination Site) (at least in yeast) is strongly dependent on DNA physical properties, which can define a basal regulatory mechanism of gene expression.
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Affiliation(s)
- Ozgen Deniz
- Institute for Research in Biomedicine and Barcelona Supercomputing Center Joint Research Program on Computational Biology, Baldiri i Reixac 10, Barcelona 08028, Spain
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Brázda V, Laister RC, Jagelská EB, Arrowsmith C. Cruciform structures are a common DNA feature important for regulating biological processes. BMC Mol Biol 2011; 12:33. [PMID: 21816114 PMCID: PMC3176155 DOI: 10.1186/1471-2199-12-33] [Citation(s) in RCA: 174] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 08/05/2011] [Indexed: 04/10/2023] Open
Abstract
DNA cruciforms play an important role in the regulation of natural processes involving DNA. These structures are formed by inverted repeats, and their stability is enhanced by DNA supercoiling. Cruciform structures are fundamentally important for a wide range of biological processes, including replication, regulation of gene expression, nucleosome structure and recombination. They also have been implicated in the evolution and development of diseases including cancer, Werner's syndrome and others. Cruciform structures are targets for many architectural and regulatory proteins, such as histones H1 and H5, topoisomerase IIβ, HMG proteins, HU, p53, the proto-oncogene protein DEK and others. A number of DNA-binding proteins, such as the HMGB-box family members, Rad54, BRCA1 protein, as well as PARP-1 polymerase, possess weak sequence specific DNA binding yet bind preferentially to cruciform structures. Some of these proteins are, in fact, capable of inducing the formation of cruciform structures upon DNA binding. In this article, we review the protein families that are involved in interacting with and regulating cruciform structures, including (a) the junction-resolving enzymes, (b) DNA repair proteins and transcription factors, (c) proteins involved in replication and (d) chromatin-associated proteins. The prevalence of cruciform structures and their roles in protein interactions, epigenetic regulation and the maintenance of cell homeostasis are also discussed.
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Affiliation(s)
- Václav Brázda
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v,v,i,, Královopolská 135, Brno, 612 65, Czech Republic.
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Middendorf SM, Diebler H. Metal Ion Induced Conformational Changes of Double-Stranded Polynucleotides: Poly (dG-m5dC) and Poly (dA-dT). ACTA ACUST UNITED AC 2010. [DOI: 10.1002/bbpc.19961000516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Molecular dynamics of DNA and nucleosomes in solution studied by fast-scanning atomic force microscopy. Ultramicroscopy 2010; 110:682-8. [DOI: 10.1016/j.ultramic.2010.02.032] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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40
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Selective binding of tumor suppressor p53 protein to topologically constrained DNA: Modulation by intercalative drugs. Biochem Biophys Res Commun 2010; 393:894-9. [DOI: 10.1016/j.bbrc.2010.02.120] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2010] [Accepted: 02/18/2010] [Indexed: 11/17/2022]
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Jagelská EB, Pivonková H, Fojta M, Brázda V. The potential of the cruciform structure formation as an important factor influencing p53 sequence-specific binding to natural DNA targets. Biochem Biophys Res Commun 2010; 391:1409-14. [PMID: 20026061 DOI: 10.1016/j.bbrc.2009.12.076] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 12/11/2009] [Indexed: 11/29/2022]
Abstract
p53 is one of the most important tumor suppressors which responds to DNA damage by binding to DNA and regulating the transcription of genes involved in cell cycle arrest, apoptosis, or senescence. As it was shown previously, p53 binding to DNA is strongly influenced by DNA topology. DNA supercoiling is fundamentally important for a wide range of biological processes including DNA transcription, replication, recombination, control of gene expression and genome organization. In this study, we investigated the cruciform structures formation of various inverted repeats in p53-responsive sequences from p21, RGC, mdm2 and GADD45 promoters under negative superhelical stress, and analyzed the effects of these DNA topology changes on p53-DNA binding. We demonstrated using three different methods (gel retardation analyses, ELISA and magnetic immunoprecipitation assay) that the p53 protein binds preferentially to negatively supercoiled plasmid DNAs with p53-responsive sequence presented as a cruciform structure. Not only the appearance of the cruciform structures within naked supercoiled DNA, but also the potential of the binding sites for adopting the non-B structures can contribute to a more favorable p53-DNA complex.
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Affiliation(s)
- Eva B Jagelská
- Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Královopolská 135, 612 65 Brno, Czech Republic
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42
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Brázda V, Jagelská EB, Liao JC, Arrowsmith CH. The Central Region of BRCA1 Binds Preferentially to Supercoiled DNA. J Biomol Struct Dyn 2009; 27:97-104. [DOI: 10.1080/07391102.2009.10507299] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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43
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Lavelle C. Forces and torques in the nucleus: chromatin under mechanical constraints. Biochem Cell Biol 2009; 87:307-22. [PMID: 19234543 DOI: 10.1139/o08-123] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Genomic DNA in eukaryotic cells is organized in discrete chromosome territories, each consisting of a single huge hierarchically supercoiled nucleosomal fiber. Through dynamic changes in structure, resulting from chemical modifications and mechanical constraints imposed by numerous factors in vivo, chromatin plays a critical role in the regulation of DNA metabolism processes, including replication and transcription. Indeed, DNA-translocating enzymes, such as polymerases, produce physical constraints that chromatin has to overcome. Recent techniques, in particular single-molecule micromanipulation, have allowed precise quantization of forces and torques at work in the nucleus and have greatly improved our understanding of chromatin behavior under physiological mechanical constraints. These new biophysical approaches should enable us to build realistic mechanistic models and progressively specify the ad hoc and hazy "because of chromatin structure" argument often used to interpret experimental studies of biological function in the context of chromatin.
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DNA topology influences p53 sequence-specific DNA binding through structural transitions within the target sites. Biochem J 2008; 412:57-63. [PMID: 18271758 DOI: 10.1042/bj20071648] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The tumour suppressor protein p53 is one of the most important factors regulating cell proliferation, differentiation and programmed cell death in response to a variety of cellular stress signals. P53 is a nuclear phosphoprotein and its biochemical function is closely associated with its ability to bind DNA in a sequence-specific manner and operate as a transcription factor. Using a competition assay, we investigated the effect of DNA topology on the DNA binding of human wild-type p53 protein. We prepared sets of topoisomers of plasmid DNA with and without p53 target sequences, differing in their internal symmetry. Binding of p53 to DNA increased with increasing negative superhelix density (-sigma). At -sigma < or = 0.03, the relative effect of DNA supercoiling on protein-DNA binding was similar for DNA containing both symmetrical and non-symmetrical target sites. On the other hand, at higher -sigma, target sites with a perfect inverted repeat sequence exhibited a more significant enhancement of p53 binding as a result of increasing levels of negative DNA supercoiling. For -sigma = 0.07, an approx. 3-fold additional increase in binding was observed for a symmetrical target site compared with a non-symmetrical target site. The p53 target sequences possessing the inverted repeat symmetry were shown to form a cruciform structure in sufficiently negative supercoiled DNA. We show that formation of cruciforms in DNA topoisomers at -sigma > or = 0.05 correlates with the extra enhancement of p53-DNA binding.
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45
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The functional response of upstream DNA to dynamic supercoiling in vivo. Nat Struct Mol Biol 2008; 15:146-54. [PMID: 18193062 DOI: 10.1038/nsmb.1372] [Citation(s) in RCA: 226] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 11/09/2007] [Indexed: 11/08/2022]
Abstract
Because RNA polymerase is a powerful motor, transmission of transcription-generated forces might directly alter DNA structure, chromatin or gene activity in mammalian cells. Here we show that transcription-generated supercoils streaming dynamically from active promoters have considerable consequences for DNA structure and function in cells. Using a tamoxifen-activatable Cre recombinase to excise a test segment of chromatin positioned between divergently transcribed metallothionein-IIa promoters, we found the degree of dynamic supercoiling to increase as transcription intensified, and it was very sensitive to the specific arrangement of promoters and cis elements. Using psoralen as an in vivo probe confirmed that, during transcription, sufficient supercoiling is produced to enable transitions to conformations other than B-DNA in elements such as the human MYC far upstream element (FUSE), which in turn recruit structure-sensitive regulatory proteins, such as FUSE Binding Protein (FBP) and FBP-Interacting Repressor (FIR). These results indicate that mechanical stresses, constrained by architectural features of DNA and chromatin, may broadly contribute to gene regulation.
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Ragazzon PA, Garbett NC, Chaires JB. Competition dialysis: a method for the study of structural selective nucleic acid binding. Methods 2007; 42:173-82. [PMID: 17472899 DOI: 10.1016/j.ymeth.2006.09.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Revised: 09/20/2006] [Accepted: 09/21/2006] [Indexed: 01/01/2023] Open
Abstract
Competition dialysis is a powerful new tool for the discovery of ligands that bind to nucleic acids with structural- or sequence-selectivity. The method is based on firm thermodynamic principles and is simple to implement. In the competition dialysis experiment, an array of nucleic acid structures and sequences is dialyzed against a common test ligand solution. After equilibration, the amount of ligand bound to each structure or sequence is determined by absorbance or fluorescence measurements. Since all structures and sequences are in equilibrium with the same free ligand concentration, the amount bound is directly proportional to the ligand binding affinity. Competition dialysis thus provides a direct and quantitative measure of selectivity, and unambiguously identifies which of the samples within the array are preferred by a particular ligand. We describe here the third generation implementation of the method, in which competition dialysis was adapted for use in a 96-well plate format. In this format, we have been able to greatly expand the array of nucleic acid structures studied, and now can routinely study the interactions of a ligand of interest with 46 different structures and sequences.
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Affiliation(s)
- Patricia A Ragazzon
- James Graham Brown Cancer Center, University of Louisville, 529 S. Jackson St., Louisville, KY 40202, USA
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Mrázek J, Guo X, Shah A. Simple sequence repeats in prokaryotic genomes. Proc Natl Acad Sci U S A 2007; 104:8472-7. [PMID: 17485665 PMCID: PMC1895974 DOI: 10.1073/pnas.0702412104] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Indexed: 11/18/2022] Open
Abstract
Simple sequence repeats (SSRs) in DNA sequences are composed of tandem iterations of short oligonucleotides and may have functional and/or structural properties that distinguish them from general DNA sequences. They are variable in length because of slip-strand mutations and may also affect local structure of the DNA molecule or the encoded proteins. Long SSRs (LSSRs) are common in eukaryotes but rare in most prokaryotes. In pathogens, SSRs can enhance antigenic variance of the pathogen population in a strategy that counteracts the host immune response. We analyze representations of SSRs in >300 prokaryotic genomes and report significant differences among different prokaryotes as well as among different types of SSRs. LSSRs composed of short oligonucleotides (1-4 bp length, designated LSSR(1-4)) are often found in host-adapted pathogens with reduced genomes that are not known to readily survive in a natural environment outside the host. In contrast, LSSRs composed of longer oligonucleotides (5-11 bp length, designated LSSR(5-11)) are found mostly in nonpathogens and opportunistic pathogens with large genomes. Comparisons among SSRs of different lengths suggest that LSSR(1-4) are likely maintained by selection. This is consistent with the established role of some LSSR(1-4) in enhancing antigenic variance. By contrast, abundance of LSSR(5-11) in some genomes may reflect the SSRs' general tendency to expand rather than their specific role in the organisms' physiology. Differences among genomes in terms of SSR representations and their possible interpretations are discussed.
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Affiliation(s)
- Jan Mrázek
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA.
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Wong B, Chen S, Kwon JA, Rich A. Characterization of Z-DNA as a nucleosome-boundary element in yeast Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 2007; 104:2229-34. [PMID: 17284586 PMCID: PMC1892989 DOI: 10.1073/pnas.0611447104] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this article, the effect of a d(CG) DNA dinucleotide repeat sequence on RNA polymerase II transcription is examined in yeast Saccharomyces cerevisiae. Our previous report shows that a d(CG)n dinucleotide repeat sequence located proximally upstream of the TATA box enhances transcription from a minimal CYC1 promoter in a manner that depends on its surrounding negative supercoiling. Here, we demonstrate that the d(CG)9 repeat sequence stimulates gene activity by forming a Z-DNA secondary structure. Furthermore, the extent of transcriptional enhancement by Z-DNA is promoter-specific and determined by its separation distance relative to the TATA box. The stimulatory effect exerted by promoter proximal Z-DNA is not affected by helical phasing relative to the TATA box, suggesting that Z-DNA effects transcription without interacting with the general transcription machinery by looping-out the intervening DNA. A nucleosome-scanning assay reveals that the d(CG)9 repeat sequence in the Z conformation blocks nucleosome formation, and it is found in the linker DNA with two flanking nucleosomes. This result suggests that Z-DNA formation proximally upstream of a promoter is sufficient to demarcate the boundaries of its neighboring nucleosomes, which produces transcriptionally favorable locations for the TATA box near the nucleosomal DNA-entry site and at dyad positions on the nucleosome. These findings suggest that Z-DNA formation in chromatin is a part of the "genomic code" for nucleosome positioning in vivo.
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Affiliation(s)
- Ben Wong
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Shuai Chen
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
| | - Jin-Ah Kwon
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139
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Ma C, Zhang J, Durrin LK, Lv J, Zhu D, Han X, Sun Y. The BCL2 major breakpoint region (mbr) regulates gene expression. Oncogene 2006; 26:2649-57. [PMID: 17057736 DOI: 10.1038/sj.onc.1210069] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BCL2 expression is finely tuned by a variety of environmental and endogenous stimuli and regulated at both transcriptional and post-transcriptional levels. Our previous investigations demonstrated that the BCL2 major breakpoint region (mbr) in the 3'-UTR upregulates reporter gene expression, which implies that this region possessed intrinsic regulatory function. However, the effect of the mbr on BCL2 expression, and the underlying regulatory mechanisms, remain to be elucidated. To assess the direct effect of the mbr on the transcriptional activity of the BCL2 gene, we employed targeted homologous recombination to establish a mbr(+)/mbr(-) heterozygous Nalm-6 cell line and then compared the transcriptional activity and apoptotic effect on transcription between the wild type and targeted alleles. We found that deletion of the mbr significantly decreased the transcriptional activity of the corresponding allele in the mbr(+)/mbr(-) cell. The BCL2 allele deleted of the mbr had a slower response to apoptotic stimuli than did the wild type allele. The regulatory function of the mbr was mediated through SATB1. Overexpression of SATB1 increased BCL2 expression, while knockdown of SATB1 with RNAi decreased BCL2 expression. Our results clearly indicated that the mbr could positively regulate BCL2 gene expression and this regulatory function was closely related to SATB1.
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Affiliation(s)
- C Ma
- Key Laboratory of Human Functional Genomics of Jiangsu Province, Nanjing Medical University, Nanjing, PR China
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Zhang J, Ma C, Han X, Durrin LK, Sun Y. The bcl-2 major breakpoint region (mbr) possesses transcriptional regulatory function. Gene 2006; 379:127-31. [PMID: 16777355 DOI: 10.1016/j.gene.2006.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Accepted: 05/01/2006] [Indexed: 11/29/2022]
Abstract
The bcl-2 major breakpoint region (mbr), located within the 3'-UTR of the bcl-2 gene, is the site of the most common chromosomal translocation, t(14;18) (q32;q21), which occurs in follicular lymphoma. The mbr forms a triplex DNA structure under physiological conditions and the transcription factor special AT-rich sequence-binding protein 1 (SATB1) binds immediately downstream of the mbr. These observations raise the possibility that the mbr may be involved in regulation of bcl-2 gene expression. We investigated the role of the bcl-2 mbr on reporter gene activity and the relevance of SATB1 to this function in a variety of cell lines. We found that the mbr up-regulated reporter gene expression. Deletion of the 37-bp AT-rich SATB1 binding site abolished the bcl-2 mbr regulation of reporter gene expression. Overexpression of SATB1 enhanced bcl-2 mbr up-regulation of the reporter gene activity. Our data strongly demonstrated that the bcl-2 mbr possessed regulatory function that was related to SATB1.
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Affiliation(s)
- Jingjing Zhang
- Key Laboratory of Human Functional Genomics of Jiangsu Province, PR China
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