1
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Prevo B, Earnshaw WC. DNA packaging by molecular motors: from bacteriophage to human chromosomes. Nat Rev Genet 2024:10.1038/s41576-024-00740-y. [PMID: 38886215 DOI: 10.1038/s41576-024-00740-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2024] [Indexed: 06/20/2024]
Abstract
Dense packaging of genomic DNA is crucial for organismal survival, as DNA length always far exceeds the dimensions of the cells that contain it. Organisms, therefore, use sophisticated machineries to package their genomes. These systems range across kingdoms from a single ultra-powerful rotary motor that spools the DNA into a bacteriophage head, to hundreds of thousands of relatively weak molecular motors that coordinate the compaction of mitotic chromosomes in eukaryotic cells. Recent technological advances, such as DNA proximity-based sequencing approaches, polymer modelling and in vitro reconstitution of DNA loop extrusion, have shed light on the biological mechanisms driving DNA organization in different systems. Here, we discuss DNA packaging in bacteriophage, bacteria and eukaryotic cells, which, despite their extreme variation in size, structure and genomic content, all rely on the action of molecular motors to package their genomes.
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Affiliation(s)
- Bram Prevo
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK.
| | - William C Earnshaw
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK.
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2
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Janissen R, Barth R, Polinder M, van der Torre J, Dekker C. Single-molecule visualization of twin-supercoiled domains generated during transcription. Nucleic Acids Res 2024; 52:1677-1687. [PMID: 38084930 PMCID: PMC10899792 DOI: 10.1093/nar/gkad1181] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/13/2023] [Accepted: 11/30/2023] [Indexed: 02/29/2024] Open
Abstract
Transcription-coupled supercoiling of DNA is a key factor in chromosome compaction and the regulation of genetic processes in all domains of life. It has become common knowledge that, during transcription, the DNA-dependent RNA polymerase (RNAP) induces positive supercoiling ahead of it (downstream) and negative supercoils in its wake (upstream), as rotation of RNAP around the DNA axis upon tracking its helical groove gets constrained due to drag on its RNA transcript. Here, we experimentally validate this so-called twin-supercoiled-domain model with in vitro real-time visualization at the single-molecule scale. Upon binding to the promoter site on a supercoiled DNA molecule, RNAP merges all DNA supercoils into one large pinned plectoneme with RNAP residing at its apex. Transcription by RNAP in real time demonstrates that up- and downstream supercoils are generated simultaneously and in equal portions, in agreement with the twin-supercoiled-domain model. Experiments carried out in the presence of RNases A and H, revealed that an additional viscous drag of the RNA transcript is not necessary for the RNAP to induce supercoils. The latter results contrast the current consensus and simulations on the origin of the twin-supercoiled domains, pointing at an additional mechanistic cause underlying supercoil generation by RNAP in transcription.
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Affiliation(s)
- Richard Janissen
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, South-Holland 2629HZ, The Netherlands
| | - Roman Barth
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, South-Holland 2629HZ, The Netherlands
| | - Minco Polinder
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, South-Holland 2629HZ, The Netherlands
| | - Jaco van der Torre
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, South-Holland 2629HZ, The Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, Delft, South-Holland 2629HZ, The Netherlands
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3
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Kolbeck PJ, Tišma M, Analikwu BT, Vanderlinden W, Dekker C, Lipfert J. Supercoiling-dependent DNA binding: quantitative modeling and applications to bulk and single-molecule experiments. Nucleic Acids Res 2024; 52:59-72. [PMID: 38000393 PMCID: PMC10783501 DOI: 10.1093/nar/gkad1055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 10/02/2023] [Accepted: 10/27/2023] [Indexed: 11/26/2023] Open
Abstract
DNA stores our genetic information and is ubiquitous in applications, where it interacts with binding partners ranging from small molecules to large macromolecular complexes. Binding is modulated by mechanical strains in the molecule and can change local DNA structure. Frequently, DNA occurs in closed topological forms where topology and supercoiling add a global constraint to the interplay of binding-induced deformations and strain-modulated binding. Here, we present a quantitative model with a straight-forward numerical implementation of how the global constraints introduced by DNA topology modulate binding. We focus on fluorescent intercalators, which unwind DNA and enable direct quantification via fluorescence detection. Our model correctly describes bulk experiments using plasmids with different starting topologies, different intercalators, and over a broad range of intercalator and DNA concentrations. We demonstrate and quantitatively model supercoiling-dependent binding in a single-molecule assay, where we directly observe the different intercalator densities going from supercoiled to nicked DNA. The single-molecule assay provides direct access to binding kinetics and DNA supercoil dynamics. Our model has broad implications for the detection and quantification of DNA, including the use of psoralen for UV-induced DNA crosslinking to quantify torsional tension in vivo, and for the modulation of DNA binding in cellular contexts.
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Affiliation(s)
- Pauline J Kolbeck
- Department of Physics and Center for NanoScience, LMU Munich, Amalienstrasse 54, 80799 Munich, Germany
- Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Miloš Tišma
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Brian T Analikwu
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Willem Vanderlinden
- Department of Physics and Center for NanoScience, LMU Munich, Amalienstrasse 54, 80799 Munich, Germany
- Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Jan Lipfert
- Department of Physics and Center for NanoScience, LMU Munich, Amalienstrasse 54, 80799 Munich, Germany
- Soft Condensed Matter and Biophysics, Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
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4
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Das S, Forrest J, Kuzminov A. Synthetic lethal mutants in Escherichia coli define pathways necessary for survival with RNase H deficiency. J Bacteriol 2023; 205:e0028023. [PMID: 37819120 PMCID: PMC10601623 DOI: 10.1128/jb.00280-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 09/09/2023] [Indexed: 10/13/2023] Open
Abstract
Ribonucleotides frequently contaminate DNA and, if not removed, cause genomic instability. Consequently, all organisms are equipped with RNase H enzymes to remove RNA-DNA hybrids (RDHs). Escherichia coli lacking RNase HI (rnhA) and RNase HII (rnhB) enzymes, the ∆rnhA ∆rnhB double mutant, accumulates RDHs in its DNA. These RDHs can convert into RNA-containing DNA lesions (R-lesions) of unclear nature that compromise genomic stability. The ∆rnhAB double mutant has severe phenotypes, like growth inhibition, replication stress, sensitivity to ultraviolet radiation, SOS induction, increased chromosomal fragmentation, and defects in nucleoid organization. In this study, we found that RNase HI deficiency also alters wild-type levels of DNA supercoiling. Despite these severe chromosomal complications, ∆rnhAB double mutant survives, suggesting that dedicated pathways operate to avoid or repair R-lesions. To identify these pathways, we systematically searched for mutants synthetic lethal (colethal) with the rnhAB defect using an unbiased color screen and a candidate gene approach. We identified both novel and previously reported rnhAB-colethal and -coinhibited mutants, characterized them, and sorted them into avoidance or repair pathways. These mutants operate in various parts of nucleic acid metabolism, including replication fork progression, R-loop prevention and removal, nucleoid organization, tRNA modification, recombinational repair, and chromosome-dimer resolution, demonstrating the pleiotropic nature of RNase H deficiency. IMPORTANCE Ribonucleotides (rNs) are structurally very similar to deoxyribonucleotides. Consequently, rN contamination of DNA is common and pervasive across all domains of life. Failure to remove rNs from DNA has severe consequences, and all organisms are equipped with RNase H enzymes to remove RNA-DNA hybrids. RNase H deficiency leads to complications in bacteria, yeast, and mouse, and diseases like progressive external ophthalmoplegia (mitochondrial defects in RNASEH1) and Aicardi-Goutières syndrome (defects in RNASEH2) in humans. Escherichia coli ∆rnhAB mutant, deficient in RNases H, has severe chromosomal complications. Despite substantial problems, nearly half of the mutant population survives. We have identified novel and previously confirmed pathways in various parts of nucleic acid metabolism that ensure survival with RNase H deficiency.
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Affiliation(s)
- Sneha Das
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Jonathan Forrest
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Andrei Kuzminov
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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5
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Elanany MA, Osman EEA, Gedawy EM, Abou-Seri SM. Design and synthesis of novel cytotoxic fluoroquinolone analogs through topoisomerase inhibition, cell cycle arrest, and apoptosis. Sci Rep 2023; 13:4144. [PMID: 36914702 PMCID: PMC10011602 DOI: 10.1038/s41598-023-30885-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 03/02/2023] [Indexed: 03/16/2023] Open
Abstract
To exploit the advantageous properties of approved drugs to hasten anticancer drug discovery, we designed and synthesized a series of fluoroquinolone (FQ) analogs via functionalization of the acid hydrazides of moxifloxacin, ofloxacin, and ciprofloxacin. Under the NCI-60 Human Tumor Cell Line Screening Assay, (IIIf) was the most potent among moxifloxacin derivatives, whereas (VIb) was the only ofloxacin derivative with significant effects and ciprofloxacin derivatives were devoid of activity. (IIIf) and (VIb) were further selected for five-dose evaluation, where they showed potent growth inhibition with a mean GI50 of 1.78 and 1.45 µM, respectively. (VIb) elicited a more potent effect reaching sub-micromolar level on many cell lines, including MDA-MB-468 and MCF-7 breast cancer cell lines (GI50 = 0.41 and 0.42 µM, respectively), NSCLC cell line HOP-92 (GI50 = 0.50 µM) and CNS cell lines SNB-19 and U-251 (GI50 = 0.51 and 0.61 µM, respectively). (IIIf) and (VIb) arrested MCF-7 cells at G1/S and G1, respectively, and induced apoptosis mainly through the intrinsic pathway as shown by the increased ratio of Bax/Bcl-2 and caspase-9 with a lesser activation of the extrinsic pathway through caspase-8. Both compounds inhibited topoisomerase (Topo) with preferential activity on type II over type I and (VIb) was marginally more potent than (IIIf). Docking study suggests that (IIIf) and (VIb) bind differently to Topo II compared to etoposide. (IIIf) and (VIb) possess high potential for oral absorption, low CNS permeability and low binding to plasma proteins as suggested by in silico ADME calculations. Collectively, (IIIf) and (VIb) represent excellent lead molecules for the development of cytotoxic agents from quinolone scaffolds.
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Affiliation(s)
- Mohamed A Elanany
- Department of Pharmaceutical Chemistry, School of Pharmacy and Pharmaceutical Industries, Badr University in Cairo (BUC), Badr City, 11829, Cairo, Egypt.
| | - Essam Eldin A Osman
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt
| | - Ehab Mohamed Gedawy
- Department of Pharmaceutical Chemistry, School of Pharmacy and Pharmaceutical Industries, Badr University in Cairo (BUC), Badr City, 11829, Cairo, Egypt.,Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt
| | - Sahar M Abou-Seri
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt.
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6
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Li D, Chen X, Yan R, Jiang Z, Zhou B, Lv B. G-quadruplex-containing oligodeoxynucleotides as DNA topoisomerase I inhibitors. Int J Biol Macromol 2022; 223:281-289. [PMID: 36356864 DOI: 10.1016/j.ijbiomac.2022.11.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/24/2022] [Accepted: 11/01/2022] [Indexed: 11/09/2022]
Abstract
DNA topoisomerase I was found to be highly abundant in fast-proliferating tumor cells and is a potential target for anticancer therapy. A series of G-quadruplex-containing oligodeoxynucleotides (ODNs) were designed and used as inhibitors of DNA topoisomerase I. It was demonstrated that ODNs with G-quadruplexes can efficiently inhibit the supercoiled DNA relaxation reaction catalyzed by DNA topoisomerase I. Compared with the other conformations, the parallel propeller-type G-quadruplex was the most efficient DNA topoisomerase I inhibitor. Further studies revealed that integrating G-quadruplexes with duplexes to form quadruplex-duplex hybrids could significantly improve the inhibition efficiency. In addition, a circular ODN that consists of a G-quadruplex motif and DNA topoisomerase I binding site was synthesized and used as a DNA topoisomerase I inhibitor. The results showed that the particularly designed circular ODN displayed high inhibitory efficiency on the activity of DNA topoisomerase I with an IC50 value of 54.8 nM. Moreover, the circular ODN exhibited excellent thermal stability and nuclease resistance. Considering the low cytotoxicity of DNA-based biopharmaceuticals, the design strategy and results reported in this study may shed new light on nucleic acid-based DNA topoisomerase I inhibitor construction for potential anticancer drugs.
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Affiliation(s)
- Dawei Li
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of State Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China.
| | - Xiyu Chen
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of State Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Rumeng Yan
- Jiangsu Key Laboratory for Biofunctional Molecules, College of Life Science and Chemistry, Jiangsu Second Normal University, Nanjing 210013, China
| | - Zeshan Jiang
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of State Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Bing Zhou
- Co-Innovation Center for Sustainable Forestry in Southern China, Key Laboratory of State Forestry and Grassland Administration on Subtropical Forest Biodiversity Conservation, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, China
| | - Bei Lv
- Jiangsu Key Laboratory for Biofunctional Molecules, College of Life Science and Chemistry, Jiangsu Second Normal University, Nanjing 210013, China.
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7
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Naughton C, Huidobro C, Catacchio CR, Buckle A, Grimes GR, Nozawa RS, Purgato S, Rocchi M, Gilbert N. Human centromere repositioning activates transcription and opens chromatin fibre structure. Nat Commun 2022; 13:5609. [PMID: 36153345 PMCID: PMC9509383 DOI: 10.1038/s41467-022-33426-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 09/14/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractHuman centromeres appear as constrictions on mitotic chromosomes and form a platform for kinetochore assembly in mitosis. Biophysical experiments led to a suggestion that repetitive DNA at centromeric regions form a compact scaffold necessary for function, but this was revised when neocentromeres were discovered on non-repetitive DNA. To test whether centromeres have a special chromatin structure we have analysed the architecture of a neocentromere. Centromere repositioning is accompanied by RNA polymerase II recruitment and active transcription to form a decompacted, negatively supercoiled domain enriched in ‘open’ chromatin fibres. In contrast, centromerisation causes a spreading of repressive epigenetic marks to surrounding regions, delimited by H3K27me3 polycomb boundaries and divergent genes. This flanking domain is transcriptionally silent and partially remodelled to form ‘compact’ chromatin, similar to satellite-containing DNA sequences, and exhibits genomic instability. We suggest transcription disrupts chromatin to provide a foundation for kinetochore formation whilst compact pericentromeric heterochromatin generates mechanical rigidity.
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8
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A comprehensive review on acridone based derivatives as future anti-cancer agents and their structure activity relationships. Eur J Med Chem 2022; 239:114527. [PMID: 35717872 DOI: 10.1016/j.ejmech.2022.114527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 05/27/2022] [Accepted: 06/07/2022] [Indexed: 11/03/2022]
Abstract
The development of drug resistance and severe side-effects has reduced the clinical efficacy of the existing anti-cancer drugs available in the market. Thus, there is always a constant need to develop newer anti-cancer drugs with minimal adverse effects. Researchers all over the world have been focusing on various alternative strategies to discover novel, potent, and target specific molecules for cancer therapy. In this direction, several heterocyclic compounds are being explored but amongst them one promising heterocycle is acridone which has attracted the attention of medicinal chemists and gained huge biological importance as acridones are found to act on different therapeutically proven molecular targets, overcome ABC transporters mediated drug resistance and DNA intercalation in cancer cells. Some of these acridone derivatives have reached clinical studies as these heterocycles have shown huge potential in cancer therapeutics and imaging. Here, the authors have attempted to compile and make some recommendations of acridone based derivatives concerning their cancer biological targets and in vitro-cytotoxicity based on drug design and novelty to increase their therapeutic potential. This review also provides some important insights on the design, receptor targeting and future directions for the development of acridones as possible clinically effective anti-cancer agents.
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9
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Krajewski WA. Histone Modifications, Internucleosome Dynamics, and DNA Stresses: How They Cooperate to “Functionalize” Nucleosomes. Front Genet 2022; 13:873398. [PMID: 35571051 PMCID: PMC9096104 DOI: 10.3389/fgene.2022.873398] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 03/28/2022] [Indexed: 12/25/2022] Open
Abstract
Tight packaging of DNA in chromatin severely constrains DNA accessibility and dynamics. In contrast, nucleosomes in active chromatin state are highly flexible, can exchange their histones, and are virtually “transparent” to RNA polymerases, which transcribe through gene bodies at rates comparable to that of naked DNA. Defining mechanisms that revert nucleosome repression, in addition to their value for basic science, is of key importance for the diagnosis and treatment of genetic diseases. Chromatin activity is largely regulated by histone posttranslational modifications, ranging from small chemical groups up to the yet understudied “bulky” ubiquitylation and sumoylation. However, it is to be revealed how histone marks are “translated” to permissive or repressive changes in nucleosomes: it is a general opinion that histone modifications act primarily as “signals” for recruiting the regulatory proteins or as a “neutralizer” of electrostatic shielding of histone tails. Here, we would like to discuss recent evidence suggesting that histone ubiquitylation, in a DNA stress–dependent manner, can directly regulate the dynamics of the nucleosome and their primary structure and can promote nucleosome decomposition to hexasome particles or additionally stabilize nucleosomes against unwrapping. In addition, nucleosome repression/ derepression studies are usually performed with single mononucleosomes as a model. We would like to review and discuss recent findings showing that internucleosomal interactions could strongly modulate the dynamics and rearrangements of nucleosomes. Our hypothesis is that bulky histone modifications, nucleosome inherent dynamics, internucleosome interactions, and DNA torsions could act in cooperation to orchestrate the formation of different dynamic states of arrayed nucleosomes and thus promote chromatin functionality and diversify epigenetic programming methods.
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10
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Abstract
In mammalian cells, genomic DNA is packaged with histone proteins and condensed into chromatin. To gain access to the DNA, chromatin remodelling is required that is enhanced through histone post-translational modifications, which subsequently stimulate processes including DNA repair and transcription. Histone acetylation is one of the most well understood modifications and is controlled by histone acetyltransferases (HATs) and histone deacetylases (HDACs). These enzymes play critical roles in normal cellular functioning, and the dysregulation of HDAC expression in particular has been linked with the development of a number of different cancer types. Conversely, tumour cell killing following radiotherapy is triggered through DNA damage and HDACs can help co-ordinate the cellular DNA damage response which promotes radioresistance. Consequently, HDAC inhibitors have been investigated as potential radiosensitizers in vitro and in vivo to improve the efficacy or radiotherapy in specific tumour types. In this review, we provide an up-to-date summary of HDACs and their cellular functions, including in DNA damage repair. We also review evidence demonstrating that HDAC inhibitors can effectively enhance tumour radiosensitisation, and which therefore show potential for translation into the clinic for cancer patient benefit.
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11
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Wan B, Yu J. Two-phase dynamics of DNA supercoiling based on DNA polymer physics. Biophys J 2022; 121:658-669. [PMID: 35016860 PMCID: PMC8873955 DOI: 10.1016/j.bpj.2022.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 10/11/2021] [Accepted: 01/05/2022] [Indexed: 11/28/2022] Open
Abstract
DNA supercoils are generated in genome regulation processes such as transcription and replication and provide mechanical feedback to such processes. Under tension, a DNA supercoil can present a coexistence state of plectonemic and stretched phases. Experiments have revealed the dynamic behaviors of plectonemes, e.g., diffusion, nucleation, and hopping. To represent these dynamics with conformational changes, we demonstrated first the fast dynamics on the DNA to reach torque equilibrium within the plectonemic and stretched phases, and then identified the two-phase boundaries as collective slow variables to describe the essential dynamics. According to the timescale separation demonstrated here, we developed a two-phase model on the dynamics of DNA supercoiling, which can capture physiologically relevant events across timescales of several orders of magnitudes. In this model, we systematically characterized the slow dynamics between the two phases and compared the numerical results with those from the DNA polymer physics-based worm-like chain model. The supercoiling dynamics, including the nucleation, diffusion, and hopping of plectonemes, have been well represented and reproduced, using the two-phase dynamic model, at trivial computational costs. Our current developments, therefore, can be implemented to explore multiscale physical mechanisms of the DNA supercoiling-dependent physiological processes.
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Affiliation(s)
- Biao Wan
- Complex Systems Division, Beijing Computational Science Research Center, Beijing, China.
| | - Jin Yu
- Department of Physics and Astronomy, Department of Chemistry, NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, California.
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12
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Tripathi S, Brahmachari S, Onuchic JN, Levine H. DNA supercoiling-mediated collective behavior of co-transcribing RNA polymerases. Nucleic Acids Res 2021; 50:1269-1279. [PMID: 34951454 PMCID: PMC8860607 DOI: 10.1093/nar/gkab1252] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 12/02/2021] [Accepted: 12/06/2021] [Indexed: 11/14/2022] Open
Abstract
Multiple RNA polymerases (RNAPs) transcribing a gene have been known to exhibit collective group behavior, causing the transcription elongation rate to increase with the rate of transcription initiation. Such behavior has long been believed to be driven by a physical interaction or ‘push’ between closely spaced RNAPs. However, recent studies have posited that RNAPs separated by longer distances may cooperate by modifying the DNA segment under transcription. Here, we present a theoretical model incorporating the mechanical coupling between RNAP translocation and the DNA torsional response. Using stochastic simulations, we demonstrate DNA supercoiling-mediated long-range cooperation between co-transcribing RNAPs. We find that inhibiting transcription initiation can slow down the already recruited RNAPs, in agreement with recent experimental observations, and predict that the average transcription elongation rate varies non-monotonically with the rate of transcription initiation. We further show that while RNAPs transcribing neighboring genes oriented in tandem can cooperate, those transcribing genes in divergent or convergent orientations can act antagonistically, and that such behavior holds over a large range of intergenic separations. Our model makes testable predictions, revealing how the mechanical interplay between RNAPs and the DNA they transcribe can govern transcriptional dynamics.
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Affiliation(s)
- Shubham Tripathi
- PhD Program in Systems, Synthetic, and Physical Biology, Rice University, Houston, TX, USA.,Center for Theoretical Biological Physics & Department of Physics, Northeastern University, Boston, MA, USA
| | | | - José N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, TX, USA.,Department of Physics and Astronomy, Department of Chemistry, & Department of Biosciences, Rice University, Houston, TX, USA
| | - Herbert Levine
- Center for Theoretical Biological Physics & Department of Physics, Northeastern University, Boston, MA, USA
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13
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Villain P, da Cunha V, Villain E, Forterre P, Oberto J, Catchpole R, Basta T. The hyperthermophilic archaeon Thermococcus kodakarensis is resistant to pervasive negative supercoiling activity of DNA gyrase. Nucleic Acids Res 2021; 49:12332-12347. [PMID: 34755863 PMCID: PMC8643681 DOI: 10.1093/nar/gkab869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/10/2021] [Accepted: 11/02/2021] [Indexed: 01/15/2023] Open
Abstract
In all cells, DNA topoisomerases dynamically regulate DNA supercoiling allowing essential DNA processes such as transcription and replication to occur. How this complex system emerged in the course of evolution is poorly understood. Intriguingly, a single horizontal gene transfer event led to the successful establishment of bacterial gyrase in Archaea, but its emergent function remains a mystery. To better understand the challenges associated with the establishment of pervasive negative supercoiling activity, we expressed the gyrase of the bacterium Thermotoga maritima in a naïve archaeon Thermococcus kodakarensis which naturally has positively supercoiled DNA. We found that the gyrase was catalytically active in T. kodakarensis leading to strong negative supercoiling of plasmid DNA which was stably maintained over at least eighty generations. An increased sensitivity of gyrase-expressing T. kodakarensis to ciprofloxacin suggested that gyrase also modulated chromosomal topology. Accordingly, global transcriptome analyses revealed large scale gene expression deregulation and identified a subset of genes responding to the negative supercoiling activity of gyrase. Surprisingly, the artificially introduced dominant negative supercoiling activity did not have a measurable effect on T. kodakarensis growth rate. Our data suggest that gyrase can become established in Thermococcales archaea without critically interfering with DNA transaction processes.
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Affiliation(s)
- Paul Villain
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Violette da Cunha
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | | | - Patrick Forterre
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.,Archaeal Virology Unit, Institut Pasteur, Paris, France
| | - Jacques Oberto
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Ryan Catchpole
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Tamara Basta
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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14
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TOP2B's contributions to transcription. Biochem Soc Trans 2021; 49:2483-2493. [PMID: 34747992 DOI: 10.1042/bst20200454] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/07/2021] [Accepted: 10/11/2021] [Indexed: 12/23/2022]
Abstract
Transcription is regulated and mediated by multiprotein complexes in a chromatin context. Transcription causes changes in DNA topology which is modulated by DNA topoisomerases, enzymes that catalyse changes in DNA topology via transient breaking and re-joining of one or both strands of the phosphodiester backbone. Mammals have six DNA topoisomerases, this review focuses on one, DNA topoisomerase II beta (TOP2B). In the absence of TOP2B transcription of many developmentally regulated genes is altered. Long genes seem particularly susceptible to the lack of TOP2B. Biochemical studies of the role of TOP2B in transcription regulated by ligands such as nuclear hormones, growth factors and insulin has revealed PARP1 associated with TOP2B and also PRKDC, XRCC5 and XRCC6. Analysis of publicly available databases of protein interactions confirms these interactions and illustrates interactions with other key transcriptional regulators including TRIM28. TOP2B has been shown to interact with proteins involved in chromosome organisation including CTCF and RAD21. Comparison of publicly available Chip-seq datasets reveals the location at which these proteins interact with genes. The availability of resources such as large datasets of protein-protein interactions, e.g. BioGrid and IntAct and protein-DNA interactions such as Chip-seq in GEO enables scientists to extend models and propose new hypotheses.
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15
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Duprey A, Groisman EA. The regulation of DNA supercoiling across evolution. Protein Sci 2021; 30:2042-2056. [PMID: 34398513 PMCID: PMC8442966 DOI: 10.1002/pro.4171] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/04/2021] [Accepted: 08/04/2021] [Indexed: 11/11/2022]
Abstract
DNA supercoiling controls a variety of cellular processes, including transcription, recombination, chromosome replication, and segregation, across all domains of life. As a physical property, DNA supercoiling alters the double helix structure by under- or over-winding it. Intriguingly, the evolution of DNA supercoiling reveals both similarities and differences in its properties and regulation across the three domains of life. Whereas all organisms exhibit local, constrained DNA supercoiling, only bacteria and archaea exhibit unconstrained global supercoiling. DNA supercoiling emerges naturally from certain cellular processes and can also be changed by enzymes called topoisomerases. While structurally and mechanistically distinct, topoisomerases that dissipate excessive supercoils exist in all domains of life. By contrast, topoisomerases that introduce positive or negative supercoils exist only in bacteria and archaea. The abundance of topoisomerases is also transcriptionally and post-transcriptionally regulated in domain-specific ways. Nucleoid-associated proteins, metabolites, and physicochemical factors influence DNA supercoiling by acting on the DNA itself or by impacting the activity of topoisomerases. Overall, the unique strategies that organisms have evolved to regulate DNA supercoiling hold significant therapeutic potential, such as bactericidal agents that target bacteria-specific processes or anticancer drugs that hinder abnormal DNA replication by acting on eukaryotic topoisomerases specialized in this process. The investigation of DNA supercoiling therefore reveals general principles, conserved mechanisms, and kingdom-specific variations relevant to a wide range of biological questions.
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Affiliation(s)
- Alexandre Duprey
- Department of Microbial PathogenesisYale School of MedicineNew HavenConnecticutUSA
| | - Eduardo A. Groisman
- Department of Microbial PathogenesisYale School of MedicineNew HavenConnecticutUSA
- Yale Microbial Sciences InstituteWest HavenConnecticutUSA
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16
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Neguembor MV, Martin L, Castells-García Á, Gómez-García PA, Vicario C, Carnevali D, AlHaj Abed J, Granados A, Sebastian-Perez R, Sottile F, Solon J, Wu CT, Lakadamyali M, Cosma MP. Transcription-mediated supercoiling regulates genome folding and loop formation. Mol Cell 2021; 81:3065-3081.e12. [PMID: 34297911 PMCID: PMC9482096 DOI: 10.1016/j.molcel.2021.06.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 03/27/2021] [Accepted: 06/08/2021] [Indexed: 12/21/2022]
Abstract
The chromatin fiber folds into loops, but the mechanisms controlling loop extrusion are still poorly understood. Using super-resolution microscopy, we visualize that loops in intact nuclei are formed by a scaffold of cohesin complexes from which the DNA protrudes. RNA polymerase II decorates the top of the loops and is physically segregated from cohesin. Augmented looping upon increased loading of cohesin on chromosomes causes disruption of Lamin at the nuclear rim and chromatin blending, a homogeneous distribution of chromatin within the nucleus. Altering supercoiling via either transcription or topoisomerase inhibition counteracts chromatin blending, increases chromatin condensation, disrupts loop formation, and leads to altered cohesin distribution and mobility on chromatin. Overall, negative supercoiling generated by transcription is an important regulator of loop formation in vivo.
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Affiliation(s)
- Maria Victoria Neguembor
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Laura Martin
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Álvaro Castells-García
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China
| | - Pablo Aurelio Gómez-García
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Chiara Vicario
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Davide Carnevali
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | | | - Alba Granados
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Ruben Sebastian-Perez
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Francesco Sottile
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain
| | - Jérôme Solon
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain; Instituto Biofisika (CSIC, UPV/EHU), Basque Excellence Research Centre, Barrio Sarriena, 48940, Leioa, Spain; Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Chao-Ting Wu
- Department of Genetics, Harvard Medical School, Boston, MA, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Melike Lakadamyali
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Maria Pia Cosma
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, 08003 Barcelona, Spain; Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, China; Universitat Pompeu Fabra (UPF), Dr Aiguader 88, 08003 Barcelona, Spain; ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Spain; CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.
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17
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Guo MS, Kawamura R, Littlehale ML, Marko JF, Laub MT. High-resolution, genome-wide mapping of positive supercoiling in chromosomes. eLife 2021; 10:e67236. [PMID: 34279217 PMCID: PMC8360656 DOI: 10.7554/elife.67236] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 07/16/2021] [Indexed: 12/15/2022] Open
Abstract
Supercoiling impacts DNA replication, transcription, protein binding to DNA, and the three-dimensional organization of chromosomes. However, there are currently no methods to directly interrogate or map positive supercoils, so their distribution in genomes remains unknown. Here, we describe a method, GapR-seq, based on the chromatin immunoprecipitation of GapR, a bacterial protein that preferentially recognizes overtwisted DNA, for generating high-resolution maps of positive supercoiling. Applying this method to Escherichia coli and Saccharomyces cerevisiae, we find that positive supercoiling is widespread, associated with transcription, and particularly enriched between convergently oriented genes, consistent with the 'twin-domain' model of supercoiling. In yeast, we also find positive supercoils associated with centromeres, cohesin-binding sites, autonomously replicating sites, and the borders of R-loops (DNA-RNA hybrids). Our results suggest that GapR-seq is a powerful approach, likely applicable in any organism, to investigate aspects of chromosome structure and organization not accessible by Hi-C or other existing methods.
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Affiliation(s)
- Monica S Guo
- Department of Biology, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Ryo Kawamura
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Megan L Littlehale
- Department of Biology, Massachusetts Institute of TechnologyCambridgeUnited States
| | - John F Marko
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
- Department of Physics and Astronomy, Northwestern UniversityEvanstonUnited States
| | - Michael T Laub
- Department of Biology, Massachusetts Institute of TechnologyCambridgeUnited States
- Howard Hughes Medical Institute, Massachusetts Institute of TechnologyCambridgeUnited States
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18
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Single-molecule micromanipulation studies of methylated DNA. Biophys J 2021; 120:2148-2155. [PMID: 33838135 DOI: 10.1016/j.bpj.2021.03.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 03/21/2021] [Accepted: 03/23/2021] [Indexed: 12/31/2022] Open
Abstract
Cytosine methylated at the five-carbon position is the most widely studied reversible DNA modification. Prior findings indicate that methylation can alter mechanical properties. However, those findings were qualitative and sometimes contradictory, leaving many aspects unclear. By applying single-molecule magnetic force spectroscopy techniques allowing for direct manipulation and dynamic observation of DNA mechanics and mechanically driven strand separation, we investigated how CpG and non-CpG cytosine methylation affects DNA micromechanical properties. We quantitatively characterized DNA stiffness using persistence length measurements from force-extension curves in the nanoscale length regime and demonstrated that cytosine methylation results in longer contour length and increased DNA flexibility (i.e., decreased persistence length). In addition, we observed the preferential formation of plectonemes over unwound single-stranded "bubbles" of DNA under physiologically relevant stretching forces and supercoiling densities. The flexibility and high structural stability of methylated DNA is likely to have significant consequences on the recruitment of proteins recognizing cytosine methylation and DNA packaging.
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19
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Nonequilibrium dynamics and action at a distance in transcriptionally driven DNA supercoiling. Proc Natl Acad Sci U S A 2021; 118:1905215118. [PMID: 33649196 DOI: 10.1073/pnas.1905215118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
We study the effect of transcription on the kinetics of DNA supercoiling in three dimensions by means of Brownian dynamics simulations of a single-nucleotide-resolution coarse-grained model for double-stranded DNA. By explicitly accounting for the action of a transcribing RNA polymerase (RNAP), we characterize the geometry and nonequilibrium dynamics of the ensuing twin supercoiling domains. Contrary to the typical textbook picture, we find that the generation of twist by RNAP results in the formation of plectonemes (writhed DNA) some distance away. We further demonstrate that this translates into an "action at a distance" on DNA-binding proteins; for instance, positive supercoils downstream of an elongating RNAP destabilize nucleosomes long before the transcriptional machinery reaches the histone octamer. We also analyze the relaxation dynamics of supercoiled double-stranded DNA, and characterize the widely different timescales of twist diffusion, which is a simple and fast process, and writhe relaxation, which is much slower and entails multiple steps.
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20
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Schvartzman JB, Martínez V, Hernández P, Krimer DB, Fernández-Nestosa MJ. Changes in the topology of DNA replication intermediates: Important discrepancies between in vitro and in vivo. Bioessays 2021; 43:e2000309. [PMID: 33629756 DOI: 10.1002/bies.202000309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 11/08/2022]
Abstract
The topology of DNA duplexes changes during replication and also after deproteinization in vitro. Here we describe these changes and then discuss for the first time how the distribution of superhelical stress affects the DNA topology of replication intermediates, taking into account the progression of replication forks. The high processivity of Topo IV to relax the left-handed (+) supercoiling that transiently accumulates ahead of the forks is not essential, since DNA gyrase and swiveling of the forks cooperate with Topo IV to accomplish this task in vivo. We conclude that despite Topo IV has a lower processivity to unlink the right-handed (+) crossings of pre-catenanes and fully replicated catenanes, this is indeed its main role in vivo. This would explain why in the absence of Topo IV replication goes-on, but fully replicated sister duplexes remain heavily catenated.
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Affiliation(s)
- Jorge B Schvartzman
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain
| | - Víctor Martínez
- Directorate of Research and Postgraduate Studies, Polytechnic School, National University of Asunción, P, San Lorenzo, Paraguay
| | - Pablo Hernández
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain
| | - Dora B Krimer
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain
| | - María-José Fernández-Nestosa
- Directorate of Research and Postgraduate Studies, Polytechnic School, National University of Asunción, P, San Lorenzo, Paraguay
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21
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Al-Natour Z, Chalissery J, Hassan AH. Fun30 chromatin remodeler helps in dealing with torsional stress and camptothecin-induced DNA damage. Yeast 2020; 38:170-182. [PMID: 33141948 DOI: 10.1002/yea.3534] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 10/04/2020] [Accepted: 10/26/2020] [Indexed: 12/19/2022] Open
Abstract
Fun30 is an ATP-dependent chromatin remodeler in budding yeast that is involved in cellular processes important for maintaining genomic stability such as gene silencing and DNA damage repair. Cells lacking Fun30 are moderately sensitive to the topoisomerase inhibitor camptothecin and exhibit a delay in cell cycle progression in the presence of camptothecin. Here, we show that Fun30 is required to cope with torsional stress in the absence of Top1. Moreover, we show through genetic studies that Fun30 acts in a parallel pathway to Mus81 endonuclease but is epistatic to Tdp1 phosphodiesterase and Rad1 endonuclease in the repair of camptothecin-induced DNA damage. More importantly, we show that DNA damage sensitivity of Fun30 deficient cells is enhanced in the absence of RNase H enzymes that remove RNA:DNA hybrids. We believe that chromatin remodeling by Fun30 may be important in dealing with torsional stress and camptothecin-induced DNA damage.
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Affiliation(s)
- Zeina Al-Natour
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Jisha Chalissery
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Ahmed H Hassan
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
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22
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Abstract
Physiological and pathological roles for R-loop structures continue to be discovered, and studies suggest that R-loops could contribute to human disease. R-loops are nucleic acid structures characterized by a DNA:RNA hybrid and displaced single-stranded DNA that occur in connection with transcription. R-loops form naturally and have been shown to be important for a number of physiological processes such as mitochondrial replication initiation, class switch recombination, DNA repair, modulating DNA topology, and regulation of gene expression. However, subsets of R-loops or persistent R-loops lead to DNA breaks, chromosome rearrangement, and genome instability. In addition, R-loops have been linked to human diseases, specifically neurological disorders and cancer. Of the large amount of research produced recently on R-loops, this review covers evidence for R-loop involvement in normal cellular physiology and pathophysiology, as well as describing factors that contribute to R-loop regulation.
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Affiliation(s)
- Ryan Patrick Mackay
- Department of Molecular and Cellular Physiology and Louisiana State University Health Sciences Center - Shreveport, Shreveport, Louisiana, USA
| | - Qinqin Xu
- Department of Otolaryngology - Head & Neck Surgery, Louisiana State University Health Sciences Center - Shreveport, Shreveport, Louisiana, USA
| | - Paul M Weinberger
- Department of Molecular and Cellular Physiology and Louisiana State University Health Sciences Center - Shreveport, Shreveport, Louisiana, USA.,Department of Otolaryngology - Head & Neck Surgery, Louisiana State University Health Sciences Center - Shreveport, Shreveport, Louisiana, USA
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23
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Duprey A, Groisman EA. DNA supercoiling differences in bacteria result from disparate DNA gyrase activation by polyamines. PLoS Genet 2020; 16:e1009085. [PMID: 33125364 PMCID: PMC7598504 DOI: 10.1371/journal.pgen.1009085] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 08/27/2020] [Indexed: 11/19/2022] Open
Abstract
DNA supercoiling is essential for all living cells because it controls all processes involving DNA. In bacteria, global DNA supercoiling results from the opposing activities of topoisomerase I, which relaxes DNA, and DNA gyrase, which compacts DNA. These enzymes are widely conserved, sharing >91% amino acid identity between the closely related species Escherichia coli and Salmonella enterica serovar Typhimurium. Why, then, do E. coli and Salmonella exhibit different DNA supercoiling when experiencing the same conditions? We now report that this surprising difference reflects disparate activation of their DNA gyrases by the polyamine spermidine and its precursor putrescine. In vitro, Salmonella DNA gyrase activity was sensitive to changes in putrescine concentration within the physiological range, whereas activity of the E. coli enzyme was not. In vivo, putrescine activated the Salmonella DNA gyrase and spermidine the E. coli enzyme. High extracellular Mg2+ decreased DNA supercoiling exclusively in Salmonella by reducing the putrescine concentration. Our results establish the basis for the differences in global DNA supercoiling between E. coli and Salmonella, define a signal transduction pathway regulating DNA supercoiling, and identify potential targets for antibacterial agents.
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Affiliation(s)
- Alexandre Duprey
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, United States of America
| | - Eduardo A. Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, United States of America
- Yale Microbial Sciences Institute, West Haven, CT, United States of America
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24
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Kantidze OL, Razin SV. Weak interactions in higher-order chromatin organization. Nucleic Acids Res 2020; 48:4614-4626. [PMID: 32313950 PMCID: PMC7229822 DOI: 10.1093/nar/gkaa261] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/30/2020] [Accepted: 04/03/2020] [Indexed: 12/20/2022] Open
Abstract
The detailed principles of the hierarchical folding of eukaryotic chromosomes have been revealed during the last two decades. Along with structures composing three-dimensional (3D) genome organization (chromatin compartments, topologically associating domains, chromatin loops, etc.), the molecular mechanisms that are involved in their establishment and maintenance have been characterized. Generally, protein-protein and protein-DNA interactions underlie the spatial genome organization in eukaryotes. However, it is becoming increasingly evident that weak interactions, which exist in biological systems, also contribute to the 3D genome. Here, we provide a snapshot of our current understanding of the role of the weak interactions in the establishment and maintenance of the 3D genome organization. We discuss how weak biological forces, such as entropic forces operating in crowded solutions, electrostatic interactions of the biomolecules, liquid-liquid phase separation, DNA supercoiling, and RNA environment participate in chromosome segregation into structural and functional units and drive intranuclear functional compartmentalization.
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Affiliation(s)
- Omar L Kantidze
- Institute of Gene Biology Russian Academy of Sciences, 119334 Moscow, Russia
| | - Sergey V Razin
- Institute of Gene Biology Russian Academy of Sciences, 119334 Moscow, Russia
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25
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Kim H, Lee WJ, Oh Y, Kang SH, Hur JK, Lee H, Song W, Lim KS, Park YH, Song BS, Jin YB, Jun BH, Jung C, Lee DS, Kim SU, Lee SH. Enhancement of target specificity of CRISPR-Cas12a by using a chimeric DNA-RNA guide. Nucleic Acids Res 2020; 48:8601-8616. [PMID: 32687187 PMCID: PMC7470973 DOI: 10.1093/nar/gkaa605] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/14/2020] [Accepted: 07/06/2020] [Indexed: 12/24/2022] Open
Abstract
The CRISPR-Cas9 system is widely used for target-specific genome engineering. CRISPR-Cas12a (Cpf1) is one of the CRISPR effectors that controls target genes by recognizing thymine-rich protospacer adjacent motif (PAM) sequences. Cas12a has a higher sensitivity to mismatches in the guide RNA than does Cas9; therefore, off-target sequence recognition and cleavage are lower. However, it tolerates mismatches in regions distant from the PAM sequence (TTTN or TTN) in the protospacer, and off-target cleavage issues may become more problematic when Cas12a activity is improved for therapeutic purposes. Therefore, we investigated off-target cleavage by Cas12a and modified the Cas12a (cr)RNA to address the off-target cleavage issue. We developed a CRISPR-Cas12a that can induce mutations in target DNA sequences in a highly specific and effective manner by partially substituting the (cr)RNA with DNA to change the energy potential of base pairing to the target DNA. A model to explain how chimeric (cr)RNA guided CRISPR-Cas12a and SpCas9 nickase effectively work in the intracellular genome is suggested. Chimeric guide-based CRISPR- Cas12a genome editing with reduced off-target cleavage, and the resultant, increased safety has potential for therapeutic applications in incurable diseases caused by genetic mutations.
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Affiliation(s)
- Hanseop Kim
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
- School of Life Sciences and Biotechnology, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Republic of Korea
| | - Wi-jae Lee
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Republic of Korea
| | - Yeounsun Oh
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Seung-Hun Kang
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
- Department of Medicine, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Junho K Hur
- Department of Pathology, College of Medicine, Kyung Hee University, Seoul 02447, Republic of Korea
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
- Department of Medical Genetics, College of Medicine, Hanyang University, Seoul, Republic of Korea
| | - Hyomin Lee
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
| | - WooJeung Song
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Kyung-Seob Lim
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
| | - Young-Ho Park
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
| | - Bong-Seok Song
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
| | - Yeung Bae Jin
- National Primate Research Center (NPRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Republic of Korea
| | - Bong-Hyun Jun
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 143-701, Republic of Korea
| | - Cheulhee Jung
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Dong-Seok Lee
- School of Life Sciences and Biotechnology, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu, Republic of Korea
| | - Sun-Uk Kim
- Futuristic Animal Resource & Research Center (FARRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Seung Hwan Lee
- National Primate Research Center (NPRC), Korea Research Institute of Bioscience and Biotechnology (KRIBB), Cheongju, Republic of Korea
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26
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El Houdaigui B, Meyer S. TwisTranscripT: stochastic simulation of the transcription-supercoiling coupling. Bioinformatics 2020; 36:3899-3901. [PMID: 32232442 DOI: 10.1093/bioinformatics/btaa221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 02/19/2020] [Accepted: 03/26/2020] [Indexed: 11/14/2022] Open
Abstract
SUMMARY Transcription and DNA supercoiling are involved in a complex, dynamical and non-linear coupling that results from the basal interaction between DNA and RNA polymerase. We present the first software to simulate this coupling, applicable to a wide range of bacterial organisms. TwisTranscripT allows quantifying its contribution in global transcriptional regulation, and provides a mechanistic basis for the widely observed, evolutionarily conserved and currently unexplained co-regulation of adjacent operons that might play an important role in genome evolution. AVAILABILITY AND IMPLEMENTATION TwisTranscripT is freely available at https://github.com/sammeyer2017/TwisTranscripT. It is implemented in Python3 and supported on MacOS X, Linux and Windows.
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Affiliation(s)
- Bilal El Houdaigui
- Laboratoire de Microbiologie, Adaptation et Pathogénie, CNRS UMR5240, Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne, France
| | - Sam Meyer
- Laboratoire de Microbiologie, Adaptation et Pathogénie, CNRS UMR5240, Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, 69621 Villeurbanne, France
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27
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Gasperini M, Tome JM, Shendure J. Towards a comprehensive catalogue of validated and target-linked human enhancers. Nat Rev Genet 2020; 21:292-310. [PMID: 31988385 PMCID: PMC7845138 DOI: 10.1038/s41576-019-0209-0] [Citation(s) in RCA: 159] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2019] [Indexed: 12/14/2022]
Abstract
The human gene catalogue is essentially complete, but we lack an equivalently vetted inventory of bona fide human enhancers. Hundreds of thousands of candidate enhancers have been nominated via biochemical annotations; however, only a handful of these have been validated and confidently linked to their target genes. Here we review emerging technologies for discovering, characterizing and validating human enhancers at scale. We furthermore propose a new framework for operationally defining enhancers that accommodates the heterogeneous and complementary results that are emerging from reporter assays, biochemical measurements and CRISPR screens.
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Affiliation(s)
- Molly Gasperini
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Jacob M Tome
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
- Brotman Baty Institute for Precision Medicine, Seattle, WA, USA.
- Allen Discovery Center for Cell Lineage, Seattle, WA, USA.
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA.
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28
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Hao N, Shearwin KE, Dodd IB. Positive and Negative Control of Enhancer-Promoter Interactions by Other DNA Loops Generates Specificity and Tunability. Cell Rep 2020; 26:2419-2433.e3. [PMID: 30811991 DOI: 10.1016/j.celrep.2019.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 01/08/2019] [Accepted: 02/01/2019] [Indexed: 12/15/2022] Open
Abstract
Enhancers are ubiquitous and critical gene-regulatory elements. However, quantitative understanding of the role of DNA looping in the regulation of enhancer action and specificity is limited. We used the Escherichia coli NtrC enhancer-σ54 promoter system as an in vivo model, finding that NtrC activation is highly sensitive to the enhancer-promoter (E-P) distance in the 300-6,000 bp range. DNA loops formed by Lac repressor were able to strongly regulate enhancer action either positively or negatively, recapitulating promoter targeting and insulation. A single LacI loop combining targeting and insulation produced a strong shift in specificity for enhancer choice between two σ54 promoters. A combined kinetic-thermodynamic model was used to quantify the effect of DNA-looping interactions on promoter activity and revealed that sensitivity to E-P distance and to control by other loops is itself dependent on enhancer and promoter parameters that may be subject to regulation.
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Affiliation(s)
- Nan Hao
- Department of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA 5005, Australia; CSIRO Synthetic Biology Future Science Platform, Canberra, ACT 2601, Australia
| | - Keith E Shearwin
- Department of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Ian B Dodd
- Department of Molecular and Biomedical Science, The University of Adelaide, Adelaide, SA 5005, Australia.
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29
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Chedin F, Benham CJ. Emerging roles for R-loop structures in the management of topological stress. J Biol Chem 2020; 295:4684-4695. [PMID: 32107311 DOI: 10.1074/jbc.rev119.006364] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
R-loop structures are a prevalent class of alternative non-B DNA structures that form during transcription upon invasion of the DNA template by the nascent RNA. R-loops form universally in the genomes of organisms ranging from bacteriophages, bacteria, and yeasts to plants and animals, including mammals. A growing body of work has linked these structures to both physiological and pathological processes, in particular to genome instability. The rising interest in R-loops is placing new emphasis on understanding the fundamental physicochemical forces driving their formation and stability. Pioneering work in Escherichia coli revealed that DNA topology, in particular negative DNA superhelicity, plays a key role in driving R-loops. A clear role for DNA sequence was later uncovered. Here, we review and synthesize available evidence on the roles of DNA sequence and DNA topology in controlling R-loop formation and stability. Factoring in recent developments in R-loop modeling and single-molecule profiling, we propose a coherent model accounting for the interplay between DNA sequence and DNA topology in driving R-loop structure formation. This model reveals R-loops in a new light as powerful and reversible topological stress relievers, an insight that significantly expands the repertoire of R-loops' potential biological roles under both normal and aberrant conditions.
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Affiliation(s)
- Frederic Chedin
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616 .,Genome Center, University of California, Davis, California 95616
| | - Craig J Benham
- Genome Center, University of California, Davis, California 95616 .,Departments of Mathematics and Biomedical Engineering, University of California, Davis, California 95616
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30
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Abstract
Antibacterial agents are a group of materials that selectively destroy bacteria by interfering with bacterial growth or survival. With the emergence of resistance phenomenon of bacterial pathogens to current antibiotics, new drugs are frequently entering into the market along with the existing drugs, and the alternative compounds with antibacterial functions are being explored. Due to the advantages of their inherent biochemical and biophysical properties including precise targeting ability, biocompatibility, biodegradability, long blood circulation time, and low cytotoxicity, biomolecules such as peptides, carbohydrates, and nucleic acids have huge potential for the antimicrobial application and have been extensively studied in recent years. In this review, antimicrobial therapeutic agents composed of three kinds of functional biological molecules were summarized. In addition, the research progress of antibacterial mechanism, chemical modification, and nanoparticle coupling of those biomolecules were also discussed.
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31
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Schvartzman JB, Hernández P, Krimer DB, Dorier J, Stasiak A. Closing the DNA replication cycle: from simple circular molecules to supercoiled and knotted DNA catenanes. Nucleic Acids Res 2019; 47:7182-7198. [PMID: 31276584 PMCID: PMC6698734 DOI: 10.1093/nar/gkz586] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/20/2019] [Accepted: 07/02/2019] [Indexed: 01/28/2023] Open
Abstract
Due to helical structure of DNA, massive amounts of positive supercoils are constantly introduced ahead of each replication fork. Positive supercoiling inhibits progression of replication forks but various mechanisms evolved that permit very efficient relaxation of that positive supercoiling. Some of these mechanisms lead to interesting topological situations where DNA supercoiling, catenation and knotting coexist and influence each other in DNA molecules being replicated. Here, we first review fundamental aspects of DNA supercoiling, catenation and knotting when these qualitatively different topological states do not coexist in the same circular DNA but also when they are present at the same time in replicating DNA molecules. We also review differences between eukaryotic and prokaryotic cellular strategies that permit relaxation of positive supercoiling arising ahead of the replication forks. We end our review by discussing very recent studies giving a long-sought answer to the question of how slow DNA topoisomerases capable of relaxing just a few positive supercoils per second can counteract the introduction of hundreds of positive supercoils per second ahead of advancing replication forks.
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Affiliation(s)
- Jorge B Schvartzman
- Department of Cell and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Pablo Hernández
- Department of Cell and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Dora B Krimer
- Department of Cell and Molecular Biology, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Julien Dorier
- SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Andrzej Stasiak
- SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland.,Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
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32
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Defez R, Valenti A, Andreozzi A, Romano S, Ciaramella M, Pesaresi P, Forlani S, Bianco C. New Insights into Structural and Functional Roles of Indole-3-acetic acid (IAA): Changes in DNA Topology and Gene Expression in Bacteria. Biomolecules 2019; 9:biom9100522. [PMID: 31547634 PMCID: PMC6843775 DOI: 10.3390/biom9100522] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/18/2019] [Accepted: 09/21/2019] [Indexed: 12/11/2022] Open
Abstract
: Indole-3-acetic acid (IAA) is a major plant hormone that affects many cellular processes in plants, bacteria, yeast, and human cells through still unknown mechanisms. In this study, we demonstrated that the IAA-treatment of two unrelated bacteria, the Ensifer meliloti 1021 and Escherichia coli, harboring two different host range plasmids, influences the supercoiled state of the two plasmid DNAs in vivo. Results obtained from in vitro assays show that IAA interacts with DNA, leading to DNA conformational changes commonly induced by intercalating agents. We provide evidence that IAA inhibits the activity of the type IA topoisomerase, which regulates the DNA topological state in bacteria, through the relaxation of the negative supercoiled DNA. In addition, we demonstrate that the treatment of E. meliloti cells with IAA induces the expression of some genes, including the ones related to nitrogen fixation. In contrast, these genes were significantly repressed by the treatment with novobiocin, which reduces the DNA supercoiling in bacterial cells. Taking into account the overall results reported, we hypothesize that the IAA action and the DNA structure/function might be correlated and involved in the regulation of gene expression. This work points out that checking whether IAA influences the DNA topology under physiological conditions could be a useful strategy to clarify the mechanism of action of this hormone, not only in plants but also in other unrelated organisms.
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Affiliation(s)
- Roberto Defez
- Istituto di Bioscienze e BioRisorse, via P. Castellino 111, 80131 Naples, Italy.
| | - Anna Valenti
- Istituto di Bioscienze e BioRisorse, via P. Castellino 111, 80131 Naples, Italy.
| | - Anna Andreozzi
- Istituto di Bioscienze e BioRisorse, via P. Castellino 111, 80131 Naples, Italy.
| | - Silvia Romano
- Istituto di Bioscienze e BioRisorse, via P. Castellino 111, 80131 Naples, Italy.
| | - Maria Ciaramella
- Istituto di Bioscienze e BioRisorse, via P. Castellino 111, 80131 Naples, Italy.
| | - Paolo Pesaresi
- Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, 20133 Milan, Italy.
| | - Sara Forlani
- Dipartimento di Bioscienze, Università degli Studi di Milano, via Celoria 26, 20133 Milan, Italy.
| | - Carmen Bianco
- Istituto di Bioscienze e BioRisorse, via P. Castellino 111, 80131 Naples, Italy.
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33
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Brackley CA, Johnson J, Michieletto D, Morozov AN, Nicodemi M, Cook PR, Marenduzzo D. Extrusion without a motor: a new take on the loop extrusion model of genome organization. Nucleus 2019; 9:95-103. [PMID: 29300120 PMCID: PMC5973195 DOI: 10.1080/19491034.2017.1421825] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Chromatin loop extrusion is a popular model for the formation of CTCF loops and topological domains. Recent HiC data have revealed a strong bias in favour of a particular arrangement of the CTCF binding motifs that stabilize loops, and extrusion is the only model to date which can explain this. However, the model requires a motor to generate the loops, and although cohesin is a strong candidate for the extruding factor, a suitable motor protein (or a motor activity in cohesin itself) has yet to be found. Here we explore a new hypothesis: that there is no motor, and thermal motion within the nucleus drives extrusion. Using theoretical modelling and computer simulations we ask whether such diffusive extrusion could feasibly generate loops. Our simulations uncover an interesting ratchet effect (where an osmotic pressure promotes loop growth), and suggest, by comparison to recent in vitro and in vivo measurements, that diffusive extrusion can in principle generate loops of the size observed in the data. Extra View on : C. A. Brackley, J. Johnson, D. Michieletto, A. N. Morozov, M. Nicodemi, P. R. Cook, and D. Marenduzzo “Non-equilibrium chromosome looping via molecular slip-links”, Physical Review Letters 119 138101 (2017)
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Affiliation(s)
- C A Brackley
- a SUPA, School of Physics and Astronomy , University of Edinburgh , Peter Guthrie Tait Road, Edinburgh , EH9 3FD , UK
| | - J Johnson
- a SUPA, School of Physics and Astronomy , University of Edinburgh , Peter Guthrie Tait Road, Edinburgh , EH9 3FD , UK
| | - D Michieletto
- a SUPA, School of Physics and Astronomy , University of Edinburgh , Peter Guthrie Tait Road, Edinburgh , EH9 3FD , UK
| | - A N Morozov
- a SUPA, School of Physics and Astronomy , University of Edinburgh , Peter Guthrie Tait Road, Edinburgh , EH9 3FD , UK
| | - M Nicodemi
- b Dipartimento di Fisica , Universita' di Napoli Federico II, INFN Napoli, CNR, SPIN, Complesso Universitario di Monte Sant'Angelo , Naples , Italy
| | - P R Cook
- c Sir William Dunn School of Pathology , University of Oxford , South Parks Road, Oxford , OX1 3RE , UK
| | - D Marenduzzo
- a SUPA, School of Physics and Astronomy , University of Edinburgh , Peter Guthrie Tait Road, Edinburgh , EH9 3FD , UK
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34
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Racko D, Benedetti F, Dorier J, Stasiak A. Are TADs supercoiled? Nucleic Acids Res 2019; 47:521-532. [PMID: 30395328 PMCID: PMC6344874 DOI: 10.1093/nar/gky1091] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/22/2018] [Indexed: 12/13/2022] Open
Abstract
Topologically associating domains (TADs) are megabase-sized building blocks of interphase chromosomes in higher eukaryotes. TADs are chromosomal regions with increased frequency of internal interactions. On average a pair of loci separated by a given genomic distance contact each other 2–3 times more frequently when they are in the same TAD as compared to a pair of loci located in two neighbouring TADs. TADs are also functional blocks of chromosomes as enhancers and their cognate promoters are normally located in the same TAD, even if their genomic distance from each other can be as large as a megabase. The internal structure of TADs, causing their increased frequency of internal interactions, is not established yet. We survey here experimental studies investigating presence of supercoiling in interphase chromosomes. We also review numerical simulation studies testing whether transcription-induced supercoiling of chromatin fibres can explain how TADs are formed and how they can assure very efficient interactions between enhancers and their cognate promoters located in the same TAD.
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Affiliation(s)
- Dusan Racko
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.,SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland.,Polymer Institute of the Slovak Academy of Sciences, 842 36 Bratislava, Slovakia
| | - Fabrizio Benedetti
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.,Vital-IT, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Julien Dorier
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.,Vital-IT, SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Andrzej Stasiak
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.,SIB Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
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35
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Martis B S, Forquet R, Reverchon S, Nasser W, Meyer S. DNA Supercoiling: an Ancestral Regulator of Gene Expression in Pathogenic Bacteria? Comput Struct Biotechnol J 2019; 17:1047-1055. [PMID: 31452857 PMCID: PMC6700405 DOI: 10.1016/j.csbj.2019.07.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/17/2019] [Accepted: 07/24/2019] [Indexed: 12/28/2022] Open
Abstract
DNA supercoiling acts as a global and ancestral regulator of bacterial gene expression. In this review, we advocate that it plays a pivotal role in host-pathogen interactions by transducing environmental signals to the bacterial chromosome and coordinating its transcriptional response. We present available evidence that DNA supercoiling is modulated by environmental stress conditions relevant to the infection process according to ancestral mechanisms, in zoopathogens as well as phytopathogens. We review the results of transcriptomics studies obtained in widely distant bacterial species, showing that such structural transitions of the chromosome are associated to a complex transcriptional response affecting a large fraction of the genome. Mechanisms and computational models of the transcriptional regulation by DNA supercoiling are then discussed, involving both basal interactions of RNA Polymerase with promoter DNA, and more specific interactions with regulatory proteins. A final part is specifically focused on the regulation of virulence genes within pathogenicity islands of several pathogenic bacterial species.
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Affiliation(s)
- Shiny Martis B
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS UMR5240, Laboratoire de Microbiologie, Adaptation et Pathogénie, 11 avenue Jean Capelle, 69621 Villeurbanne, France
| | - Raphaël Forquet
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS UMR5240, Laboratoire de Microbiologie, Adaptation et Pathogénie, 11 avenue Jean Capelle, 69621 Villeurbanne, France
| | - Sylvie Reverchon
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS UMR5240, Laboratoire de Microbiologie, Adaptation et Pathogénie, 11 avenue Jean Capelle, 69621 Villeurbanne, France
| | - William Nasser
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS UMR5240, Laboratoire de Microbiologie, Adaptation et Pathogénie, 11 avenue Jean Capelle, 69621 Villeurbanne, France
| | - Sam Meyer
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS UMR5240, Laboratoire de Microbiologie, Adaptation et Pathogénie, 11 avenue Jean Capelle, 69621 Villeurbanne, France
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36
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El Houdaigui B, Forquet R, Hindré T, Schneider D, Nasser W, Reverchon S, Meyer S. Bacterial genome architecture shapes global transcriptional regulation by DNA supercoiling. Nucleic Acids Res 2019; 47:5648-5657. [PMID: 31216038 PMCID: PMC6582348 DOI: 10.1093/nar/gkz300] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/15/2019] [Accepted: 04/16/2019] [Indexed: 01/20/2023] Open
Abstract
DNA supercoiling acts as a global transcriptional regulator in bacteria, that plays an important role in adapting their expression programme to environmental changes, but for which no quantitative or even qualitative regulatory model is available. Here, we focus on spatial supercoiling heterogeneities caused by the transcription process itself, which strongly contribute to this regulation mode. We propose a new mechanistic modeling of the transcription-supercoiling dynamical coupling along a genome, which allows simulating and quantitatively reproducing in vitro and in vivo transcription assays, and highlights the role of genes' local orientation in their supercoiling sensitivity. Consistently with predictions, we show that chromosomal relaxation artificially induced by gyrase inhibitors selectively activates convergent genes in several enterobacteria, while conversely, an increase in DNA supercoiling naturally selected in a long-term evolution experiment with Escherichia coli favours divergent genes. Simulations show that these global expression responses to changes in DNA supercoiling result from fundamental mechanical constraints imposed by transcription, independently from more specific regulation of each promoter. These constraints underpin a significant and predictable contribution to the complex rules by which bacteria use DNA supercoiling as a global but fine-tuned transcriptional regulator.
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Affiliation(s)
- Bilal El Houdaigui
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS UMR5240, Laboratoire de Microbiologie, Adaptation et Pathogénie, 69621 Villeurbanne, France
| | - Raphaël Forquet
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS UMR5240, Laboratoire de Microbiologie, Adaptation et Pathogénie, 69621 Villeurbanne, France
| | - Thomas Hindré
- Université Grenoble-Alpes, CNRS, Grenoble INP, TIMC-IMAG, 38000 Grenoble, France
| | - Dominique Schneider
- Université Grenoble-Alpes, CNRS, Grenoble INP, TIMC-IMAG, 38000 Grenoble, France
| | - William Nasser
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS UMR5240, Laboratoire de Microbiologie, Adaptation et Pathogénie, 69621 Villeurbanne, France
| | - Sylvie Reverchon
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS UMR5240, Laboratoire de Microbiologie, Adaptation et Pathogénie, 69621 Villeurbanne, France
| | - Sam Meyer
- Université de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS UMR5240, Laboratoire de Microbiologie, Adaptation et Pathogénie, 69621 Villeurbanne, France
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37
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Hegedüs É, Kókai E, Nánási P, Imre L, Halász L, Jossé R, Antunovics Z, Webb MR, El Hage A, Pommier Y, Székvölgyi L, Dombrádi V, Szabó G. Endogenous single-strand DNA breaks at RNA polymerase II promoters in Saccharomyces cerevisiae. Nucleic Acids Res 2019; 46:10649-10668. [PMID: 30445637 PMCID: PMC6237785 DOI: 10.1093/nar/gky743] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 08/16/2018] [Indexed: 12/12/2022] Open
Abstract
Molecular combing and gel electrophoretic studies revealed endogenous nicks with free 3'OH ends at ∼100 kb intervals in the genomic DNA (gDNA) of unperturbed and G1-synchronized Saccharomyces cerevisiae cells. Analysis of the distribution of endogenous nicks by Nick ChIP-chip indicated that these breaks accumulated at active RNA polymerase II (RNAP II) promoters, reminiscent of the promoter-proximal transient DNA breaks of higher eukaryotes. Similar periodicity of endogenous nicks was found within the ribosomal rDNA cluster, involving every ∼10th of the tandemly repeated 9.1 kb units of identical sequence. Nicks were mapped by Southern blotting to a few narrow regions within the affected units. Three of them were overlapping the RNAP II promoters, while the ARS-containing IGS2 region was spared of nicks. By using a highly sensitive reverse-Southwestern blot method to map free DNA ends with 3'OH, nicks were shown to be distinct from other known rDNA breaks and linked to the regulation of rDNA silencing. Nicks in rDNA and the rest of the genome were typically found at the ends of combed DNA molecules, occasionally together with R-loops, comprising a major pool of vulnerable sites that are connected with transcriptional regulation.
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Affiliation(s)
- Éva Hegedüs
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Endre Kókai
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter Nánási
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - László Imre
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - László Halász
- MTA-DE Momentum Genome Architecture and Recombination Research Group, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Rozenn Jossé
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute (CCR-NCI), NIH, Bethesda, MD, USA
| | - Zsuzsa Antunovics
- Department of Genetics and Applied Microbiology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | | | - Aziz El Hage
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute (CCR-NCI), NIH, Bethesda, MD, USA
| | - Lóránt Székvölgyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,MTA-DE Momentum Genome Architecture and Recombination Research Group, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Viktor Dombrádi
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Gábor Szabó
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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38
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Li D, Wang Q, Zhou B, Zhuge Q, Lv B. Small DNA circles as bacterial topoisomerase I inhibitors. RSC Adv 2019; 9:18415-18419. [PMID: 35515216 PMCID: PMC9064831 DOI: 10.1039/c9ra02398d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 06/06/2019] [Indexed: 11/21/2022] Open
Abstract
Bacterial topoisomerase I is a potential target during the course of antibacterial drug therapy. In our studies, specifically designed small DNA circles with high bending stress were synthesized. It is demonstrated that small DNA circles showed high inhibitory effect on the activity of bacterial topoisomerase I and the single-stranded regions associated with bending deformation in DNA circles are believed to be the crucial factor for trapping the enzymes and decreasing the effective concentration of the topoisomerases in the reaction solution. In addition, the DNA circles showed high thermal stability and excellent nuclease resistance. In consideration of the low cytotoxicity of DNA-based biopharmaceuticals, our results may provide a new idea for the future design and optimization of DNA-based therapeutic agents for antibacterial therapy.
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Affiliation(s)
- Dawei Li
- College of Biology and the Environment, Nanjing Forestry University 159 Longpan Road Nanjing 210037 China
- The Southern Modern Forestry Collaborative Innovation Center, Nanjing Forestry University 159 Longpan Road Nanjing 210037 China
| | - Qiang Wang
- College of Biology and the Environment, Nanjing Forestry University 159 Longpan Road Nanjing 210037 China
| | - Bing Zhou
- College of Biology and the Environment, Nanjing Forestry University 159 Longpan Road Nanjing 210037 China
| | - Qiang Zhuge
- College of Biology and the Environment, Nanjing Forestry University 159 Longpan Road Nanjing 210037 China
- The Southern Modern Forestry Collaborative Innovation Center, Nanjing Forestry University 159 Longpan Road Nanjing 210037 China
| | - Bei Lv
- Jiangsu Key Laboratory for Biofunctional Molecules, College of Life Science and Chemistry, Jiangsu Second Normal University Nanjing 210013 China
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39
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Cellular DNA Topoisomerases Are Required for the Synthesis of Hepatitis B Virus Covalently Closed Circular DNA. J Virol 2019; 93:JVI.02230-18. [PMID: 30867306 DOI: 10.1128/jvi.02230-18] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/01/2019] [Indexed: 12/18/2022] Open
Abstract
In order to identify host cellular DNA metabolic enzymes that are involved in the biosynthesis of hepatitis B virus (HBV) covalently closed circular (ccc) DNA, we developed a cell-based assay supporting synchronized and rapid cccDNA synthesis from intracellular progeny nucleocapsid DNA. This was achieved by arresting HBV DNA replication in HepAD38 cells with phosphonoformic acid (PFA), a reversible HBV DNA polymerase inhibitor, at the stage of single-stranded DNA and was followed by removal of PFA to allow the synchronized synthesis of relaxed circular DNA (rcDNA) and subsequent conversion into cccDNA within 12 to 24 h. This cccDNA formation assay allows systematic screening of the effects of small molecular inhibitors of DNA metabolic enzymes on cccDNA synthesis but avoids cytotoxic effects upon long-term treatment. Using this assay, we found that all the tested topoisomerase I and II (TOP1 and TOP2, respectively) poisons as well as topoisomerase II DNA binding and ATPase inhibitors significantly reduced the levels of cccDNA. It was further demonstrated that these inhibitors also disrupted cccDNA synthesis during de novo HBV infection of HepG2 cells expressing sodium taurocholate cotransporting polypeptide (NTCP). Mechanistic analyses indicate that whereas TOP1 inhibitor treatment prevented the production of covalently closed negative-strand rcDNA, TOP2 inhibitors reduced the production of this cccDNA synthesis intermediate to a lesser extent. Moreover, small interfering RNA (siRNA) knockdown of topoisomerase II significantly reduced cccDNA amplification. Taking these observations together, our study demonstrates that topoisomerase I and II may catalyze distinct steps of HBV cccDNA synthesis and that pharmacologic targeting of these cellular enzymes may facilitate the cure of chronic hepatitis B.IMPORTANCE Persistent HBV infection relies on stable maintenance and proper functioning of a nuclear episomal form of the viral genome called cccDNA, the most stable HBV replication intermediate. One of the major reasons for the failure of currently available antiviral therapeutics to cure chronic HBV infection is their inability to eradicate or inactivate cccDNA. We report here a chemical genetics approach to identify host cellular factors essential for the biosynthesis and maintenance of cccDNA and reveal that cellular DNA topoisomerases are required for both de novo synthesis and intracellular amplification of cccDNA. This approach is suitable for systematic screening of compounds targeting cellular DNA metabolic enzymes and chromatin remodelers for their ability to disrupt cccDNA biosynthesis and function. Identification of key host factors required for cccDNA metabolism and function will reveal molecular targets for developing curative therapeutics of chronic HBV infection.
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40
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Gilbert N. Biophysical regulation of local chromatin structure. Curr Opin Genet Dev 2019; 55:66-75. [DOI: 10.1016/j.gde.2019.06.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/31/2019] [Accepted: 06/02/2019] [Indexed: 10/26/2022]
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Abstract
Three-stranded R-loop structures form during transcription when the nascent RNA transcript rehybridizes to the template DNA strand. This creates an RNA:DNA hybrid and forces the nontemplate DNA strand into a single-stranded, looped-out state. R-loops form universally over conserved hotspot regions. To date, the physicochemical bases underlying R-loop formation remain unclear. Using a “first-principle” mathematical approach backed by experimental validation, we elucidated the relative contributions of DNA sequence and DNA topology to R-loop formation. Our work provides a quantitative assessment of the energies underlying R-loop formation and of their interplay. It further reveals these structures as important regulators of the DNA topological state. R-loops are abundant three-stranded nucleic-acid structures that form in cis during transcription. Experimental evidence suggests that R-loop formation is affected by DNA sequence and topology. However, the exact manner by which these factors interact to determine R-loop susceptibility is unclear. To investigate this, we developed a statistical mechanical equilibrium model of R-loop formation in superhelical DNA. In this model, the energy involved in forming an R-loop includes four terms—junctional and base-pairing energies and energies associated with superhelicity and with the torsional winding of the displaced DNA single strand around the RNA:DNA hybrid. This model shows that the significant energy barrier imposed by the formation of junctions can be overcome in two ways. First, base-pairing energy can favor RNA:DNA over DNA:DNA duplexes in favorable sequences. Second, R-loops, by absorbing negative superhelicity, partially or fully relax the rest of the DNA domain, thereby returning it to a lower energy state. In vitro transcription assays confirmed that R-loops cause plasmid relaxation and that negative superhelicity is required for R-loops to form, even in a favorable region. Single-molecule R-loop footprinting following in vitro transcription showed a strong agreement between theoretical predictions and experimental mapping of stable R-loop positions and further revealed the impact of DNA topology on the R-loop distribution landscape. Our results clarify the interplay between base sequence and DNA superhelicity in controlling R-loop stability. They also reveal R-loops as powerful and reversible topology sinks that cells may use to nonenzymatically relieve superhelical stress during transcription.
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42
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Kizer M, Huntress ID, Walcott BD, Fraser K, Bystroff C, Wang X. Complex between a Multicrossover DNA Nanostructure, PX-DNA, and T7 Endonuclease I. Biochemistry 2019; 58:1332-1342. [PMID: 30794750 DOI: 10.1021/acs.biochem.9b00057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Paranemic crossover DNA (PX-DNA) is a four-stranded multicrossover structure that has been implicated in recombination-independent recognition of homology. Although existing evidence has suggested that PX is the DNA motif in homologous pairing (HP), this conclusion remains ambiguous. Further investigation is needed but will require development of new tools. Here, we report characterization of the complex between PX-DNA and T7 endonuclease I (T7endoI), a junction-resolving protein that could serve as the prototype of an anti-PX ligand (a critical prerequisite for the future development of such tools). Specifically, nuclease-inactive T7endoI was produced and its ability to bind to PX-DNA was analyzed using a gel retardation assay. The molar ratio of PX to T7endoI was determined using gel electrophoresis and confirmed by the Hill equation. Hydroxyl radical footprinting of T7endoI on PX-DNA is used to verify the positive interaction between PX and T7endoI and to provide insight into the binding region. Cleavage of PX-DNA by wild-type T7endoI produces DNA fragments, which were used to identify the interacting sites on PX for T7endoI and led to a computational model of their interaction. Altogether, this study has identified a stable complex of PX-DNA and T7endoI and lays the foundation for engineering an anti-PX ligand, which can potentially assist in the study of molecular mechanisms for HP at an advanced level.
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Affiliation(s)
- Megan Kizer
- Department of Chemistry and Chemical Biology , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Ian D Huntress
- Programs of Bioinformatics and Molecular Biology , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Benjamin D Walcott
- Department of Biology , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Keith Fraser
- Department of Biology , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Christopher Bystroff
- Department of Biology , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Xing Wang
- Department of Chemistry and Chemical Biology , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States.,Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
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43
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Li D, Peng P, Yang Z, Lv B. Formation of G-quadruplex structure in supercoiled DNA under molecularly crowded conditions. RSC Adv 2019; 9:26248-26251. [PMID: 35531037 PMCID: PMC9070399 DOI: 10.1039/c9ra06370f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 11/29/2022] Open
Abstract
G-quadruplex is a secondary structure of nucleic acids that plays crucial roles in many significant biological processes. Potential G-quadruplex-forming sequences exist widely in various regions of the genome such as telomeres and gene promoters. In spite of the fact that G-quadruplex can be readily assembled from a single-stranded segment of DNA, its formation from duplex DNA is very difficult under physiological conditions because Watson–Crick interactions in guanine rich segments need to be weakened first. It is demonstrated in our studies that intrastrand G-quadruplex generated from a perfectly matched guanine-rich duplex in a circular DNA as a result of significant quadruplex stabilization and duplex destabilization created by the combined actions of negative DNA supercoiling and molecular crowding conditions. It is demonstrated that G-quadruplex generated from G-rich duplex in a circular DNA as a result of quadruplex stabilization and duplex destabilization created by the combined actions of negative DNA supercoiling and molecular crowding condition.![]()
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Affiliation(s)
- Dawei Li
- The Southern Modern Forestry Collaborative Innovation Center
- College of Biology and the Environment
- Nanjing Forestry University
- Nanjing
- China
| | - Peiwen Peng
- The Southern Modern Forestry Collaborative Innovation Center
- College of Biology and the Environment
- Nanjing Forestry University
- Nanjing
- China
| | - Zhaoqi Yang
- School of Pharmaceutical Sciences
- Jiangnan University
- Wuxi
- China
| | - Bei Lv
- Jiangsu Key Laboratory for Biofunctional Molecules
- College of Life Science and Chemistry
- Jiangsu Second Normal University
- Nanjing
- China
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44
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Cinelli MA. Topoisomerase 1B poisons: Over a half-century of drug leads, clinical candidates, and serendipitous discoveries. Med Res Rev 2018; 39:1294-1337. [PMID: 30456874 DOI: 10.1002/med.21546] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 12/17/2022]
Abstract
Topoisomerases are DNA processing enzymes that relieve supercoiling (torsional strain) in DNA, are necessary for normal cellular division, and act by nicking (and then religating) DNA strands. Type 1B topoisomerase (Top1) is overexpressed in certain tumors, and the enzyme has been extensively investigated as a target for cancer chemotherapy. Various chemical agents can act as "poisons" of the enzyme's religation step, leading to Top1-DNA lesions, DNA breakage, and eventual cellular death. In this review, agents that poison Top1 (and have thus been investigated for their anticancer properties) are surveyed, including natural products (such as camptothecins and indolocarbazoles), semisynthetic camptothecin and luotonin derivatives, and synthetic compounds (such as benzonaphthyridines, aromathecins, and indenoisoquinolines), as well as targeted therapies and conjugates. Top1 has also been investigated as a therapeutic target in certain viral and parasitic infections, as well as autoimmune, inflammatory, and neurological disorders, and a summary of literature describing alternative indications is also provided. This review should provide both a reference for the medicinal chemist and potentially offer clues to aid in the development of new Top1 poisons.
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Affiliation(s)
- Maris A Cinelli
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
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45
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Krajewski WA. Effects of DNA Superhelical Stress on the Stability of H2B-Ubiquitylated Nucleosomes. J Mol Biol 2018; 430:5002-5014. [PMID: 30267746 DOI: 10.1016/j.jmb.2018.09.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/27/2018] [Accepted: 09/21/2018] [Indexed: 01/31/2023]
Abstract
On the nucleosome level, histone posttranslational modifications function mainly as the regulatory signals; in addition, some posttranslational modifications can enhance nucleosome stochastic folding, which is restricted in "canonic" nucleosomes. Recently, it has been shown in vitro that symmetric or asymmetric nucleosome ubiquitylation at H2BK34 (and H2BK120, to a lesser extent) can destabilize one of the nucleosomal H2A-H2B dimers and promote nucleosome conversion to a hexasome particle [Krajewski et al. (2018). Nucleic Acids Res., 46, 7631-7642]. Such lability of H2Bub nucleosomes raises a question of whether they could accommodate transient changes in DNA torsional tensions, which are generated by virtually any process that manipulates DNA strands. Using positively or negatively supercoiled DNA minicircles and homogeneously-modified H2Bub histones, we have found that DNA topology could strongly and selectively affect nucleosome stability depending on its ubiquitylation state (here the term "nucleosome stability" means the nucleosome property to maintain its structural integrity and dynamics characteristic to "canonic" nucleosomes). The results point to a role for H2B ubiquitylation in amplifying or mitigating the effects of a DNA torque on the nucleosome stability and dynamics.
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Affiliation(s)
- Wladyslaw A Krajewski
- N.K. Koltsov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova str. 26, Moscow 119334, Russia.
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46
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Krogh TJ, Møller-Jensen J, Kaleta C. Impact of Chromosomal Architecture on the Function and Evolution of Bacterial Genomes. Front Microbiol 2018; 9:2019. [PMID: 30210483 PMCID: PMC6119826 DOI: 10.3389/fmicb.2018.02019] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/09/2018] [Indexed: 12/14/2022] Open
Abstract
The bacterial nucleoid is highly condensed and forms compartment-like structures within the cell. Much attention has been devoted to investigating the dynamic topology and organization of the nucleoid. In contrast, the specific nucleoid organization, and the relationship between nucleoid structure and function is often neglected with regard to importance for adaption to changing environments and horizontal gene acquisition. In this review, we focus on the structure-function relationship in the bacterial nucleoid. We provide an overview of the fundamental properties that shape the chromosome as a structured yet dynamic macromolecule. These fundamental properties are then considered in the context of the living cell, with focus on how the informational flow affects the nucleoid structure, which in turn impacts on the genetic output. Subsequently, the dynamic living nucleoid will be discussed in the context of evolution. We will address how the acquisition of foreign DNA impacts nucleoid structure, and conversely, how nucleoid structure constrains the successful and sustainable chromosomal integration of novel DNA. Finally, we will discuss current challenges and directions of research in understanding the role of chromosomal architecture in bacterial survival and adaptation.
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Affiliation(s)
- Thøger J Krogh
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Jakob Møller-Jensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Christoph Kaleta
- Institute of Experimental Medicine, Christian-Albrechts-University Kiel, Kiel, Germany
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47
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Killelea T, Hawkins M, Howard JL, McGlynn P, Bolt EL. DNA replication roadblocks caused by Cascade interference complexes are alleviated by RecG DNA repair helicase. RNA Biol 2018; 16:543-548. [PMID: 30096986 PMCID: PMC6546356 DOI: 10.1080/15476286.2018.1496773] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cascade complexes underpin E. coli CRISPR-Cas immunity systems by stimulating 'adaptation' reactions that update immunity and by initiating 'interference' reactions that destroy invader DNA. Recognition of invader DNA in Cascade catalysed R-loops provokes DNA capture and its subsequent integration into CRISPR loci by Cas1 and Cas2. DNA capture processes are unclear but may involve RecG helicase, which stimulates adaptation during its role responding to genome instability. We show that Cascade is a potential source of genome instability because it blocks DNA replication and that RecG helicase alleviates this by dissociating Cascade. This highlights how integrating in vitro CRISPR-Cas interference and adaptation reactions with DNA replication and repair reactions will help to determine precise mechanisms underpinning prokaryotic adaptive immunity.
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Affiliation(s)
- Tom Killelea
- a School of Life Sciences, Queen's Medical Centre , University of Nottingham , Nottingham , UK
| | | | | | - Peter McGlynn
- b Department of Biology , University of York , York , UK
| | - Edward L Bolt
- a School of Life Sciences, Queen's Medical Centre , University of Nottingham , Nottingham , UK
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48
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Hadwiger LA, Tanaka K. DNA Damage and Chromatin Conformation Changes Confer Nonhost Resistance: A Hypothesis Based on Effects of Anti-cancer Agents on Plant Defense Responses. FRONTIERS IN PLANT SCIENCE 2018; 9:1056. [PMID: 30087685 PMCID: PMC6066612 DOI: 10.3389/fpls.2018.01056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/28/2018] [Indexed: 05/06/2023]
Abstract
Over the last decades, medical research has utilized DNA altering procedures in cancer treatments with the objective of killing cells or suppressing cell proliferation. Simultaneous research related to enhancing disease resistance in plants reported that alterations in DNA can enhance defense responses. These two opposite perspectives have in common their effects on the center for gene transcription, the nuclear chromatin. A review of selected research from both anticancer- and plant defense-related research provides examples of some specific DNA altering actions: DNA helical distortion, DNA intercalation, DNA base substitution, DNA single cleavage by DNases, DNA alkylation/methylation, and DNA binding/exclusion. The actions of the pertinent agents are compared, and their proposed modes of action are described in this study. Many of the DNA specific agents affecting resistance responses in plants, e.g., the model system using pea endocarp tissue, are indeed anticancer agents. The tumor cell death or growth suppression in cancer cells following high level treatments may be accompanied with chromatin distortions. Likewise, in plants, DNA-specific agents activate enhanced expression of many genes including defense genes, probably due to the chromatin alterations resulting from the agents. Here, we propose a hypothesis that DNA damage and chromatin structural changes are central mechanisms in initiating defense gene transcription during the nonhost resistance response in plants.
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Affiliation(s)
- Lee A. Hadwiger
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
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49
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Wang X, Chandrasekaran AR, Shen Z, Ohayon YP, Wang T, Kizer ME, Sha R, Mao C, Yan H, Zhang X, Liao S, Ding B, Chakraborty B, Jonoska N, Niu D, Gu H, Chao J, Gao X, Li Y, Ciengshin T, Seeman NC. Paranemic Crossover DNA: There and Back Again. Chem Rev 2018; 119:6273-6289. [PMID: 29911864 DOI: 10.1021/acs.chemrev.8b00207] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Over the past 35 years, DNA has been used to produce various nanometer-scale constructs, nanomechanical devices, and walkers. Construction of complex DNA nanostructures relies on the creation of rigid DNA motifs. Paranemic crossover (PX) DNA is one such motif that has played many roles in DNA nanotechnology. Specifically, PX cohesion has been used to connect topologically closed molecules, to assemble a three-dimensional object, and to create two-dimensional DNA crystals. Additionally, a sequence-dependent nanodevice based on conformational change between PX and its topoisomer, JX2, has been used in robust nanoscale assembly lines, as a key component in a DNA transducer, and to dictate polymer assembly. Furthermore, the PX motif has recently found a new role directly in basic biology, by possibly serving as the molecular structure for double-stranded DNA homology recognition, a prominent feature of molecular biology and essential for many crucial biological processes. This review discusses the many attributes and usages of PX-DNA-its design, characteristics, applications, and potential biological relevance-and aims to accelerate the understanding of PX-DNA motif in its many roles and manifestations.
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Affiliation(s)
- Xing Wang
- Department of Chemistry and Chemical Biology and The Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | | | - Zhiyong Shen
- College of Chemistry and Materials Science , Anhui Normal University , Wuhu , Anhui 241000 , China
| | - Yoel P Ohayon
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Tong Wang
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Megan E Kizer
- Department of Chemistry and Chemical Biology and The Center for Biotechnology and Interdisciplinary Studies , Rensselaer Polytechnic Institute , Troy , New York 12180 , United States
| | - Ruojie Sha
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Chengde Mao
- Department of Chemistry , Purdue University , West Lafayette , Indiana 47907 , United States
| | - Hao Yan
- Department of Chemistry and Biochemistry and The Biodesign Institute , Arizona State University , Tempe , Arizona 85287 , United States
| | - Xiaoping Zhang
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Shiping Liao
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Baoquan Ding
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Banani Chakraborty
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Natasha Jonoska
- Department of Mathematics and Statistics , University of South Florida , Tampa , Florida 33620 , United States
| | - Dong Niu
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Hongzhou Gu
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Jie Chao
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Xiang Gao
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Yuhang Li
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Tanashaya Ciengshin
- Department of Chemistry , New York University , New York , New York 10012 , United States
| | - Nadrian C Seeman
- Department of Chemistry , New York University , New York , New York 10012 , United States
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50
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Prakash A, Garcia-Moreno JF, Brown JAL, Bourke E. Clinically Applicable Inhibitors Impacting Genome Stability. Molecules 2018; 23:E1166. [PMID: 29757235 PMCID: PMC6100577 DOI: 10.3390/molecules23051166] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 04/27/2018] [Accepted: 05/01/2018] [Indexed: 12/14/2022] Open
Abstract
Advances in technology have facilitated the molecular profiling (genomic and transcriptomic) of tumours, and has led to improved stratification of patients and the individualisation of treatment regimes. To fully realize the potential of truly personalised treatment options, we need targeted therapies that precisely disrupt the compensatory pathways identified by profiling which allow tumours to survive or gain resistance to treatments. Here, we discuss recent advances in novel therapies that impact the genome (chromosomes and chromatin), pathways targeted and the stage of the pathways targeted. The current state of research will be discussed, with a focus on compounds that have advanced into trials (clinical and pre-clinical). We will discuss inhibitors of specific DNA damage responses and other genome stability pathways, including those in development, which are likely to synergistically combine with current therapeutic options. Tumour profiling data, combined with the knowledge of new treatments that affect the regulation of essential tumour signalling pathways, is revealing fundamental insights into cancer progression and resistance mechanisms. This is the forefront of the next evolution of advanced oncology medicine that will ultimately lead to improved survival and may, one day, result in many cancers becoming chronic conditions, rather than fatal diseases.
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Affiliation(s)
- Anu Prakash
- Discipline of Pathology, Lambe Institute for Translational Research, School of Medicine, National University of Ireland Galway, H91 YR71 Galway, Ireland.
| | - Juan F Garcia-Moreno
- Discipline of Surgery, Lambe Institute for Translational Research, School of Medicine, National University of Ireland Galway, H91 YR71 Galway, Ireland.
| | - James A L Brown
- Discipline of Surgery, Lambe Institute for Translational Research, School of Medicine, National University of Ireland Galway, H91 YR71 Galway, Ireland.
| | - Emer Bourke
- Discipline of Pathology, Lambe Institute for Translational Research, School of Medicine, National University of Ireland Galway, H91 YR71 Galway, Ireland.
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