1
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Maina AN, Mwaura FB, Wagacha JM, Jumba M, Aziz RK, Nour El-Din HT. Phenotypic characterization of phage vB_vcM_Kuja. J Basic Microbiol 2023; 63:481-488. [PMID: 36670071 DOI: 10.1002/jobm.202200635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/07/2022] [Accepted: 01/08/2023] [Indexed: 01/22/2023]
Abstract
Bacteriophage therapy targeting the increasingly resistant Vibrio cholerae is highly needed. Hence, studying the phenotypic behavior of potential phages under different conditions is a prerequisite to delivering the phage in an active infective form. The objective of this study was to characterize phage VP4 (vB_vcM_Kuja), an environmental vibriophage isolated from River Kuja in Migori County, Kenya in 2015. The phenotypic characteristics of the phage were determined using a one-step growth curve, restriction digestion profile, pH, and temperature stability tests. The results revealed that the phage is stable through a wide range of temperatures (20-50°C) and maintains its plaque-forming ability at pH ranging from 6 to 12. The one-step growth curve showed a latent period falling between 40 and 60 min, while burst size ranged from 23 to 30 plaque-forming units/10 µl at the same host strain. The restriction digestion pattern using EcoRI, SalI, HindIII, and XhoI enzymes showed that HindIII could cut the phage genome. The phage DNA could not be restricted by the other three enzymes. The findings of this study can be used in future studies to determine phage-host interactions.
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Affiliation(s)
- Alice N Maina
- Department of Biology, University of Nairobi, Nairobi, Kenya
| | | | - John M Wagacha
- Department of Biology, University of Nairobi, Nairobi, Kenya
| | - Miriam Jumba
- Department of Biology, University of Nairobi, Nairobi, Kenya
| | - Ramy K Aziz
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.,Microbiology and Immunology Research Program, Children's Cancer Hospital Egypt 57357, Cairo, Egypt
| | - Hanzada T Nour El-Din
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
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2
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Affiliation(s)
- Yilun Sun
- Laboratory of Molecular Pharmacology, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Yilun Sun, ; John L. Nitiss, ; Yves Pommier,
| | - John L. Nitiss
- Pharmaceutical Sciences Department, University of Illinois College of Pharmacy, Rockford, IL, United States
- *Correspondence: Yilun Sun, ; John L. Nitiss, ; Yves Pommier,
| | - Yves Pommier
- Laboratory of Molecular Pharmacology, Developmental Therapeutics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Yilun Sun, ; John L. Nitiss, ; Yves Pommier,
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3
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Nguyen GT, Dhingra Y, Sashital DG. Miniature CRISPR-Cas12 endonucleases - Programmed DNA targeting in a smaller package. Curr Opin Struct Biol 2022; 77:102466. [PMID: 36170778 PMCID: PMC10114186 DOI: 10.1016/j.sbi.2022.102466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/11/2022] [Accepted: 08/18/2022] [Indexed: 12/14/2022]
Abstract
CRISPR-associated (Cas) endonucleases specifically target and cleave RNA or DNA based on complementarity to a guide RNA. Cas endonucleases - including Cas9, Cas12a, and Cas13 - have been adopted for a wide array of biotechnological tools, including gene editing, transcriptional modulation, and diagnostics. These tools are facilitated by ready reprogramming of guide RNA sequences and the varied nucleic acid binding and cleavage activities observed across diverse Cas endonucleases. However, the large size of most Cas endonucleases (950-1400 amino acids) can restrict applications. The recent discovery of miniature Cas endonucleases (400-800 amino acids) provides the potential to overcome this limitation. Here, we review recent advances in understanding the structural mechanisms of two miniature Cas endonucleases, Cas12f and Cas12j.
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Affiliation(s)
- Giang T Nguyen
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50010, USA. https://twitter.com/GiangNg12638532
| | - Yukti Dhingra
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50010, USA. https://twitter.com/yukti__dhingra
| | - Dipali G Sashital
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50010, USA.
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4
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Frazier MN, Riccio AA, Wilson IM, Copeland WC, Stanley RE. Recent insights into the structure and function of coronavirus ribonucleases. FEBS Open Bio 2022; 12:1567-1583. [PMID: 35445579 PMCID: PMC9110870 DOI: 10.1002/2211-5463.13414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/07/2022] [Accepted: 04/19/2022] [Indexed: 11/10/2022] Open
Abstract
Coronaviruses use approximately two-thirds of their 30-kb genomes to encode nonstructural proteins (nsps) with diverse functions that assist in viral replication and transcription, and evasion of the host immune response. The SARS-CoV-2 pandemic has led to renewed interest in the molecular mechanisms used by coronaviruses to infect cells and replicate. Among the 16 Nsps involved in replication and transcription, coronaviruses encode two ribonucleases that process the viral RNA-an exonuclease (Nsp14) and an endonuclease (Nsp15). In this review, we discuss recent structural and biochemical studies of these nucleases and the implications for drug discovery.
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Affiliation(s)
- Meredith N. Frazier
- Signal Transduction LaboratoryDepartment of Health and Human ServicesNational Institute of Environmental Health SciencesNational Institutes of HealthResearch Triangle ParkNCUSA
| | - Amanda A. Riccio
- Genome Integrity and Structural Biology LaboratoryDepartment of Health and Human ServicesNational Institute of Environmental Health SciencesNational Institutes of HealthResearch Triangle ParkNCUSA
| | - Isha M. Wilson
- Signal Transduction LaboratoryDepartment of Health and Human ServicesNational Institute of Environmental Health SciencesNational Institutes of HealthResearch Triangle ParkNCUSA
| | - William C. Copeland
- Genome Integrity and Structural Biology LaboratoryDepartment of Health and Human ServicesNational Institute of Environmental Health SciencesNational Institutes of HealthResearch Triangle ParkNCUSA
| | - Robin E. Stanley
- Signal Transduction LaboratoryDepartment of Health and Human ServicesNational Institute of Environmental Health SciencesNational Institutes of HealthResearch Triangle ParkNCUSA
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5
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Xin Y, Piskunen P, Suma A, Li C, Ijäs H, Ojasalo S, Seitz I, Kostiainen MA, Grundmeier G, Linko V, Keller A. Environment-Dependent Stability and Mechanical Properties of DNA Origami Six-Helix Bundles with Different Crossover Spacings. Small 2022; 18:e2107393. [PMID: 35363419 DOI: 10.1002/smll.202107393] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 03/14/2022] [Indexed: 05/25/2023]
Abstract
The internal design of DNA nanostructures defines how they behave in different environmental conditions, such as endonuclease-rich or low-Mg2+ solutions. Notably, the inter-helical crossovers that form the core of such DNA objects have a major impact on their mechanical properties and stability. Importantly, crossover design can be used to optimize DNA nanostructures for target applications, especially when developing them for biomedical environments. To elucidate this, two otherwise identical DNA origami designs are presented that have a different number of staple crossovers between neighboring helices, spaced at 42- and 21- basepair (bp) intervals, respectively. The behavior of these structures is then compared in various buffer conditions, as well as when they are exposed to enzymatic digestion by DNase I. The results show that an increased number of crossovers significantly improves the nuclease resistance of the DNA origami by making it less accessible to digestion enzymes but simultaneously lowers its stability under Mg2+ -free conditions by reducing the malleability of the structures. Therefore, these results represent an important step toward rational, application-specific DNA nanostructure design.
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Affiliation(s)
- Yang Xin
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098, Paderborn, Germany
| | - Petteri Piskunen
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Antonio Suma
- Dipartimento di Fisica, Università di Bari and Sezione INFN di Bari, Bari, 70126, Italy
| | - Changyong Li
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098, Paderborn, Germany
| | - Heini Ijäs
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Sofia Ojasalo
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Iris Seitz
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Mauri A Kostiainen
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Guido Grundmeier
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098, Paderborn, Germany
| | - Veikko Linko
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16100, Aalto, 00076, Finland
| | - Adrian Keller
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098, Paderborn, Germany
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6
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Lai M, Maori E, Quaranta P, Matteoli G, Maggi F, Sgarbanti M, Crucitta S, Pacini S, Turriziani O, Antonelli G, Heeney JL, Freer G, Pistello M. CRISPR/Cas9 Ablation of Integrated HIV-1 Accumulates Proviral DNA Circles with Reformed Long Terminal Repeats. J Virol 2021; 95:e0135821. [PMID: 34549986 PMCID: PMC8577360 DOI: 10.1128/jvi.01358-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/12/2021] [Indexed: 12/03/2022] Open
Abstract
Gene editing may be used to excise the human immunodeficiency virus type 1 (HIV-1) provirus from the host cell genome, possibly eradicating the infection. Here, using cells acutely or latently infected by HIV-1 and treated with long terminal repeat (LTR)-targeting CRISPR/Cas9, we show that the excised HIV-1 provirus persists for a few weeks and may rearrange in circular molecules. Although circular proviral DNA is naturally formed during HIV-1 replication, we observed that gene editing might increase proviral DNA circles with restored LTRs. These extrachromosomal elements were recovered and probed for residual activity through their transfection in uninfected cells. We discovered that they can be transcriptionally active in the presence of Tat and Rev. Although confirming that gene editing is a powerful tool to eradicate HIV-1 infection, this work highlights that, to achieve this goal, the LTRs must be cleaved in several pieces to avoid residual activity and minimize the risk of reintegration in the context of genomic instability, possibly caused by the off-target activity of Cas9. IMPORTANCE The excision of HIV-1 provirus from the host cell genome has proven feasible in vitro and, to some extent, in vivo. Among the different approaches, CRISPR/Cas9 is the most promising tool for gene editing. The present study underlines the remarkable effectiveness of CRISPR/Cas9 in removing the HIV-1 provirus from infected cells and investigates the fate of the excised HIV-1 genome. This study demonstrates that the free provirus may persist in the cell after editing and in appropriate circumstances may reactivate. As an episome, it might be transcriptionally active, especially in the presence of Tat and Rev. The persistence of the HIV-1 episome was strongly decreased by gene editing with multiple targets. Although gene editing has the potential to eradicate HIV-1 infection, this work highlights a potential issue that warrants further investigation.
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Affiliation(s)
- Michele Lai
- Retrovirus Center, Virology Section, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
- Laboratory of Viral Zoonotics, Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Eyal Maori
- Laboratory of Viral Zoonotics, Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Paola Quaranta
- Retrovirus Center, Virology Section, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Giulia Matteoli
- Retrovirus Center, Virology Section, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
- Laboratory of Viral Zoonotics, Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Fabrizio Maggi
- Department of Medicine and Surgery, University of Insubria, Varese, Italy
- Virology Unit, Pisa University Hospital, Pisa, Italy
| | | | - Stefania Crucitta
- Pharmacology Unit, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Simone Pacini
- Hematology Unit, Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Ombretta Turriziani
- Laboratory of Virology, Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
- Pasteur Institute-Cenci Bolognetti Foundation, Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Guido Antonelli
- Laboratory of Virology, Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
- Pasteur Institute-Cenci Bolognetti Foundation, Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy
| | - Jonathan L. Heeney
- Laboratory of Viral Zoonotics, Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Giulia Freer
- Retrovirus Center, Virology Section, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Mauro Pistello
- Retrovirus Center, Virology Section, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
- Virology Unit, Pisa University Hospital, Pisa, Italy
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7
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Grogan DW. Editorial: Mechanisms of Preservation and Change in Archaeal Genomes. Front Microbiol 2021; 12:722509. [PMID: 34394067 PMCID: PMC8358315 DOI: 10.3389/fmicb.2021.722509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 07/05/2021] [Indexed: 11/30/2022] Open
Affiliation(s)
- Dennis W Grogan
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
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8
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Kim DG, Lee KY, Lee SJ, Cheon SH, Choi Y, Lee HH, Ahn HC, Lee BJ. Structural and functional studies of SAV1707 from Staphylococcus aureus elucidate its distinct metal-dependent activity and a crucial residue for catalysis. Acta Crystallogr D Struct Biol 2021; 77:587-598. [PMID: 33950015 DOI: 10.1107/s2059798321001923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/17/2021] [Indexed: 11/10/2022]
Abstract
The metallo-β-lactamase fold is the most abundant metal-binding domain found in two major kingdoms: bacteria and archaea. Despite the rapid growth in genomic information, most of these enzymes, which may play critical roles in cellular metabolism, remain uncharacterized in terms of structure and function. In this study, X-ray crystal structures of SAV1707, a hypothetical metalloenzyme from Staphylococcus aureus, and its complex with cAMP are reported at high resolutions of 2.05 and 1.55 Å, respectively, with a detailed atomic description. Through a functional study, it was verified that SAV1707 has Ni2+-dependent phosphodiesterase activity and Mn2+-dependent endonuclease activity, revealing a different metal selectivity depending on the reaction. In addition, the crystal structure of cAMP-bound SAV1707 shows a unique snapshot of cAMP that reveals the binding mode of the intermediate, and a key residue Phe511 that forms π-π interactions with cAMP was verified as contributing to substrate recognition by functional studies of its mutant. Overall, these findings characterized the relationship between the structure and function of SAV1707 and may provide further understanding of metalloenzymes possessing the metallo-β-lactamase fold.
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Affiliation(s)
- Dong Gyun Kim
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Kyu Yeon Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Sang Jae Lee
- PAL-XFEL, Pohang Accelerator Laboratory, POSTECH, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Seung Ho Cheon
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
| | - Yuri Choi
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyung Ho Lee
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Hee Chul Ahn
- Department of Pharmacy, Dongguk University-Seoul, Dongguk-ro 32, Ilsandong-gu, Goyang, Geonggi-do 10326, Republic of Korea
| | - Bong Jin Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, Republic of Korea
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9
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Xing J, Ma L, Cheng X, Ma J, Wang R, Xu K, Mymryk JS, Zhang Z. Expression and Functional Analysis of the Argonaute Protein of Thermus thermophilus (TtAgo) in E. coli BL21(DE3). Biomolecules 2021; 11:524. [PMID: 33807395 DOI: 10.3390/biom11040524] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 11/24/2022] Open
Abstract
The prokaryotic Argonaute proteins (pAgos) have been reported to cleave or interfere with DNA targets in a guide-dependent or independent manner. It is often difficult to characterize pAgos in vivo due to the extreme environments favored by their hosts. In the present study, we expressed functional Thermus thermophilus pAgo (TtAgo) in E. coli BL21 (DE3) cells at 37 °C. Initial attempts to express TtAgo in BL21(DE3) cells at 37 °C failed. This was not because of TtAgo mediated general toxicity to the host cells, but instead because of TtAgo-induced loss of its expression plasmid. We employed this discovery to establish a screening system for isolating loss-of-function mutants of TtAgo. The E. colifabI gene was used to help select for full-length TtAgo loss of function mutants, as overexpression of fabI renders the cell to be resistant to the triclosan. We isolated and characterized eight mutations in TtAgo that abrogated function. The ability of TtAgo to induce loss of its expression vector in vivo at 37 °C is an unreported function that is mechanistically different from its reported in vitro activity. These results shed light on the mechanisms by which TtAgo functions as a defense against foreign DNA invasion.
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Moore CL, Savenka AV, Basnakian AG. TUNEL Assay: A Powerful Tool for Kidney Injury Evaluation. Int J Mol Sci 2021; 22:ijms22010412. [PMID: 33401733 PMCID: PMC7795088 DOI: 10.3390/ijms22010412] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/23/2020] [Accepted: 12/28/2020] [Indexed: 02/06/2023] Open
Abstract
Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay is a long-established assay used to detect cell death-associated DNA fragmentation (3'-OH DNA termini) by endonucleases. Because these enzymes are particularly active in the kidney, TUNEL is widely used to identify and quantify DNA fragmentation and cell death in cultured kidney cells and animal and human kidneys resulting from toxic or hypoxic injury. The early characterization of TUNEL as an apoptotic assay has led to numerous misinterpretations of the mechanisms of kidney cell injury. Nevertheless, TUNEL is becoming increasingly popular for kidney injury assessment because it can be used universally in cultured and tissue cells and for all mechanisms of cell death. Furthermore, it is sensitive, accurate, quantitative, easily linked to particular cells or tissue compartments, and can be combined with immunohistochemistry to allow reliable identification of cell types or likely mechanisms of cell death. Traditionally, TUNEL analysis has been limited to the presence or absence of a TUNEL signal. However, additional information on the mechanism of cell death can be obtained from the analysis of TUNEL patterns.
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Affiliation(s)
- Christopher L. Moore
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham Street, #638, Little Rock, AR 72205, USA; (C.L.M.); (A.V.S.)
| | - Alena V. Savenka
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham Street, #638, Little Rock, AR 72205, USA; (C.L.M.); (A.V.S.)
| | - Alexei G. Basnakian
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham Street, #638, Little Rock, AR 72205, USA; (C.L.M.); (A.V.S.)
- John L. McClellan Memorial VA Hospital, Central Arkansas Veterans Healthcare System, 4300 West 7th Street, Little Rock, AR 72205, USA
- Correspondence: ; Tel.: +1-501-352-2870
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11
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Fahmi T, Wang X, Zhdanov DD, Islam I, Apostolov EO, Savenka AV, Basnakian AG. DNase I Induces Other Endonucleases in Kidney Tubular Epithelial Cells by Its DNA-Degrading Activity. Int J Mol Sci 2020; 21:ijms21228665. [PMID: 33212932 PMCID: PMC7698339 DOI: 10.3390/ijms21228665] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/08/2020] [Accepted: 11/12/2020] [Indexed: 02/03/2023] Open
Abstract
Endonuclease-mediated DNA fragmentation is both an immediate cause and a result of apoptosis and of all other types of irreversible cell death after injury. It is produced by nine enzymes including DNase I, DNase 2, their homologs, caspase-activated DNase (CAD) and endonuclease G (EndoG). The endonucleases act simultaneously during cell death; however, regulatory links between these enzymes have not been established. We hypothesized that DNase I, the most abundant of endonucleases, may regulate other endonucleases. To test this hypothesis, rat kidney tubular epithelial NRK-52E cells were transfected with the DNase I gene or its inactive mutant in a pECFP expression vector, while control cells were transfected with the empty vector. mRNA expression of all nine endonucleases was studied using real-time RT-PCR; DNA strand breaks in endonuclease genes were determined by PCR and protein expression of the enzymes was measured by Western blotting and quantitative immunocytochemistry. Our data showed that DNase I, but not its inactive mutant, induces all other endonucleases at varying time periods after transfection, causes DNA breaks in endonuclease genes, and elevates protein expression of several endonucleases. This is the first evidence that endonucleases seem to be induced by the DNA-degrading activity of DNase I.
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Affiliation(s)
- Tariq Fahmi
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham Street, #638, Little Rock, AR 72205, USA; (T.F.); (X.W.); (D.D.Z.); (I.I.); (E.O.A.); (A.V.S.)
| | - Xiaoying Wang
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham Street, #638, Little Rock, AR 72205, USA; (T.F.); (X.W.); (D.D.Z.); (I.I.); (E.O.A.); (A.V.S.)
| | - Dmitry D. Zhdanov
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham Street, #638, Little Rock, AR 72205, USA; (T.F.); (X.W.); (D.D.Z.); (I.I.); (E.O.A.); (A.V.S.)
| | - Intisar Islam
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham Street, #638, Little Rock, AR 72205, USA; (T.F.); (X.W.); (D.D.Z.); (I.I.); (E.O.A.); (A.V.S.)
| | - Eugene O. Apostolov
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham Street, #638, Little Rock, AR 72205, USA; (T.F.); (X.W.); (D.D.Z.); (I.I.); (E.O.A.); (A.V.S.)
| | - Alena V. Savenka
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham Street, #638, Little Rock, AR 72205, USA; (T.F.); (X.W.); (D.D.Z.); (I.I.); (E.O.A.); (A.V.S.)
| | - Alexei G. Basnakian
- Department of Pharmacology & Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham Street, #638, Little Rock, AR 72205, USA; (T.F.); (X.W.); (D.D.Z.); (I.I.); (E.O.A.); (A.V.S.)
- Central Arkansas Veterans Healthcare System, 4300 West 7th Street, Little Rock, AR 72205, USA
- Correspondence: ; Tel.: +1-501-352-2870
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12
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Kumar S, Bangru S, Kumar R, Rao DN. Promiscuous DNA cleavage by HpyAII endonuclease is modulated by the HNH catalytic residues. Biosci Rep 2020; 40:BSR20201633. [PMID: 32880391 DOI: 10.1042/BSR20201633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 08/21/2020] [Accepted: 09/02/2020] [Indexed: 11/17/2022] Open
Abstract
Helicobacter pylori is a carcinogenic bacterium that is responsible for 5.5% of all human gastric cancers. H. pylori codes for an unusually large number of restriction-modification (R-M) systems and several of them are strain-specific and phase-variable. HpyAII is a novel Type IIs phase-variable restriction endonuclease present in 26695 strain of H. pylori. We show that HpyAII prefers two-site substrates over one-site substrates for maximal cleavage activity. HpyAII is less stringent in metal ion requirement and shows higher cleavage activity with Ni2+ over Mg2+. Mutational analysis of the putative residues of the HNH motif of HpyAII confirms that the protein has an active HNH site for the cleavage of DNA. However, mutation of the first Histidine residue of the HNH motif to Alanine does not abolish the enzymatic activity, but instead causes loss of fidelity compared with wildtype HpyAII. Previous studies have shown that mutation of the first Histidine residue of the HNH motif of all other known HNH motif motif-containing enzymes completely abolishes enzymatic activity. We found, in the case of HpyAII, mutation of an active site residue leads to the loss of endonuclease fidelity. The present study provides further insights into the evolution of restriction enzymes.
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Abstract
RNA is a crucial component of every living organism and is necessary for gene expression and its regulation in the cell. Mechanisms of RNA synthesis (especially mRNA synthesis) were a subject of extensive study for a long time. More recently, RNA degradation pathways began to be considered as equally important part of eukaryotic cell metabolism. These pathways have been studied intensely, and ample information accumulated about RNA degradation systems and their role in cell life. It is currently obvious that RNA decay is of no less importance as RNA synthesis and contributes to regulating the RNA level in the cell. The review considers the main RNA degradation enzymes, the decay pathways of various coding and non-coding RNAs, the mechanisms providing RNA quality control in the nucleus and cytoplasm, and certain structural elements responsible for RNA stability or short life in the cell.
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Affiliation(s)
- K A Tatosyan
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia
| | - I G Ustyantsev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia
| | - D A Kramerov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991 Russia
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14
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Swartjes T, Staals RH, van der Oost J. Editor's cut: DNA cleavage by CRISPR RNA-guided nucleases Cas9 and Cas12a. Biochem Soc Trans 2020; 48:207-219. [PMID: 31872209 PMCID: PMC7054755 DOI: 10.1042/bst20190563] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 12/26/2022]
Abstract
Discovered as an adaptive immune system of prokaryotes, CRISPR-Cas provides many promising applications. DNA-cleaving Cas enzymes like Cas9 and Cas12a, are of great interest for genome editing. The specificity of these DNA nucleases is determined by RNA guides, providing great targeting adaptability. Besides this general method of programmable DNA cleavage, these nucleases have different biochemical characteristics, that can be exploited for different applications. Although Cas nucleases are highly promising, some room for improvement remains. New developments and discoveries like base editing, prime editing, and CRISPR-associated transposons might address some of these challenges.
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Affiliation(s)
- Thomas Swartjes
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, Netherlands
| | - Raymond H.J. Staals
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, Netherlands
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, Netherlands
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15
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Ramakrishnan S, Shen B, Kostiainen MA, Grundmeier G, Keller A, Linko V. Real-Time Observation of Superstructure-Dependent DNA Origami Digestion by DNase I Using High-Speed Atomic Force Microscopy. Chembiochem 2019; 20:2818-2823. [PMID: 31163091 DOI: 10.1002/cbic.201900369] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Indexed: 12/11/2022]
Abstract
DNA nanostructures have emerged as intriguing tools for numerous biomedical applications. However, in many of those applications and most notably in drug delivery, their stability and function may be compromised by the biological media. A particularly important issue for medical applications is their interaction with proteins such as endonucleases, which may degrade the well-defined nanoscale shapes. Herein, fundamental insights into this interaction are provided by monitoring DNase I digestion of four structurally distinct DNA origami nanostructures (DONs) in real time and at a single-structure level by using high-speed atomic force microscopy. The effect of the solid-liquid interface on DON digestion is also assessed by comparison with experiments in bulk solution. It is shown that DON digestion is strongly dependent on its superstructure and flexibility and on the local topology of the individual structure.
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Affiliation(s)
- Saminathan Ramakrishnan
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Strasse 100, 33098, Paderborn, Germany.,Present address: Structural Biophysics Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702-1201, USA
| | - Boxuan Shen
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P. O. Box 16100, 00076, Aalto, Finland
| | - Mauri A Kostiainen
- Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P. O. Box 16100, 00076, Aalto, Finland.,HYBER Center of Excellence, Department of Applied Physics, Aalto University, P. O. Box 16100, 00076, Aalto, Finland
| | - Guido Grundmeier
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Strasse 100, 33098, Paderborn, Germany
| | - Adrian Keller
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Strasse 100, 33098, Paderborn, Germany
| | - Veikko Linko
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Strasse 100, 33098, Paderborn, Germany.,Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, P. O. Box 16100, 00076, Aalto, Finland.,HYBER Center of Excellence, Department of Applied Physics, Aalto University, P. O. Box 16100, 00076, Aalto, Finland
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16
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Aubert M, O'Donohue MF, Lebaron S, Gleizes PE. Pre-Ribosomal RNA Processing in Human Cells: From Mechanisms to Congenital Diseases. Biomolecules 2018; 8:biom8040123. [PMID: 30356013 PMCID: PMC6315592 DOI: 10.3390/biom8040123] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 10/19/2018] [Accepted: 10/19/2018] [Indexed: 12/15/2022] Open
Abstract
Ribosomal RNAs, the most abundant cellular RNA species, have evolved as the structural scaffold and the catalytic center of protein synthesis in every living organism. In eukaryotes, they are produced from a long primary transcript through an intricate sequence of processing steps that include RNA cleavage and folding and nucleotide modification. The mechanisms underlying this process in human cells have long been investigated, but technological advances have accelerated their study in the past decade. In addition, the association of congenital diseases to defects in ribosome synthesis has highlighted the central place of ribosomal RNA maturation in cell physiology regulation and broadened the interest in these mechanisms. Here, we give an overview of the current knowledge of pre-ribosomal RNA processing in human cells in light of recent progress and discuss how dysfunction of this pathway may contribute to the physiopathology of congenital diseases.
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Affiliation(s)
- Maxime Aubert
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31000 Toulouse, France.
| | - Marie-Françoise O'Donohue
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31000 Toulouse, France.
| | - Simon Lebaron
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31000 Toulouse, France.
| | - Pierre-Emmanuel Gleizes
- Laboratoire de Biologie Moléculaire Eucaryote, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, 31000 Toulouse, France.
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17
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Saez-Ayala M, Yekwa EL, Carcelli M, Canard B, Alvarez K, Ferron F. Crystal structures of Lymphocytic choriomeningitis virus endonuclease domain complexed with diketo-acid ligands. IUCrJ 2018; 5:223-235. [PMID: 29765612 PMCID: PMC5947727 DOI: 10.1107/s2052252518001021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 01/17/2018] [Indexed: 06/08/2023]
Abstract
The Arenaviridae family, together with the Bunyaviridae and Orthomyxoviridae families, is one of the three negative-stranded RNA viral families that encode an endonuclease in their genome. The endonuclease domain is at the N-terminus of the L protein, a multifunctional protein that includes the RNA-dependent RNA polymerase. The synthesis of mRNA in arenaviruses is a process that is primed by capped nucleotides that are 'stolen' from the cellular mRNA by the endonuclease domain in cooperation with other domains of the L protein. This molecular mechanism has been demonstrated previously for the endonuclease of the prototype Lymphocytic choriomeningitis virus (LCMV). However, the mode of action of this enzyme is not fully understood as the original structure did not contain catalytic metal ions. The pivotal role played by the cap-snatching process in the life cycle of the virus and the highly conserved nature of the endonuclease domain make it a target of choice for the development of novel antiviral therapies. Here, the binding affinities of two diketo-acid (DKA) compounds (DPBA and L-742,001) for the endonuclease domain of LCMV were evaluated using biophysical methods. X-ray structures of the LCMV endonuclease domain with catalytic ions in complex with these two compounds were determined, and their efficacies were assessed in an in vitro endonuclease-activity assay. Based on these data and computational simulation, two new DKAs were synthesized. The LCMV endonuclease domain exhibits a good affinity for these DKAs, making them a good starting point for the design of arenavirus endonuclease inhibitors. In addition to providing the first example of an X-ray structure of an arenavirus endonuclease incorporating a ligand, this study provides a proof of concept that the design of optimized inhibitors against the arenavirus endonuclease is possible.
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Affiliation(s)
| | - Elsie Laban Yekwa
- Aix-Marseille Université, AFMB UMR 7257, 13288 Marseille, France
- CNRS, AFMB UMR 7257, 13288 Marseille, France
| | - Mauro Carcelli
- Dipartimento di Scienze Chimiche, della Vita, della Sostenibilità Ambientale, Università Di Parma, Parco Area delle Scienze 17/A, 43124 Parma, Italy
| | - Bruno Canard
- Aix-Marseille Université, AFMB UMR 7257, 13288 Marseille, France
- CNRS, AFMB UMR 7257, 13288 Marseille, France
| | - Karine Alvarez
- Aix-Marseille Université, AFMB UMR 7257, 13288 Marseille, France
- CNRS, AFMB UMR 7257, 13288 Marseille, France
| | - François Ferron
- Aix-Marseille Université, AFMB UMR 7257, 13288 Marseille, France
- CNRS, AFMB UMR 7257, 13288 Marseille, France
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18
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Long J, Hoban MD, Cooper AR, Kaufman ML, Kuo CY, Campo-Fernandez B, Lumaquin D, Hollis RP, Wang X, Kohn DB, Romero Z. Characterization of Gene Alterations following Editing of the β-Globin Gene Locus in Hematopoietic Stem/Progenitor Cells. Mol Ther 2017; 26:468-479. [PMID: 29221806 DOI: 10.1016/j.ymthe.2017.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 10/27/2017] [Accepted: 11/02/2017] [Indexed: 02/09/2023] Open
Abstract
The use of engineered nucleases combined with a homologous DNA donor template can result in targeted gene correction of the sickle cell disease mutation in hematopoietic stem and progenitor cells. However, because of the high homology between the adjacent human β- and δ-globin genes, off-target cleavage is observed at δ-globin when using some endonucleases targeted to the sickle mutation in β-globin. Introduction of multiple double-stranded breaks by endonucleases has the potential to induce intergenic alterations. Using a novel droplet digital PCR assay and high-throughput sequencing, we characterized the frequency of rearrangements between the β- and δ-globin paralogs when delivering these nucleases. Pooled CD34+ cells and colony-forming units from sickle bone marrow were treated with nuclease only or including a donor template and then analyzed for potential gene rearrangements. It was observed that, in pooled CD34+ cells and colony-forming units, the intergenic β-δ-globin deletion was the most frequent rearrangement, followed by inversion of the intergenic fragment, with the inter-chromosomal translocation as the least frequent. No rearrangements were observed when endonuclease activity was restricted to on-target β-globin cleavage. These findings demonstrate the need to develop site-specific endonucleases with high specificity to avoid unwanted gene alterations.
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Affiliation(s)
- Joseph Long
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; Biology Department, California State University, Northridge, Northridge, CA 91330, USA
| | - Megan D Hoban
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Aaron R Cooper
- Molecular Biology Interdepartmental Ph.D. Program, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Michael L Kaufman
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Caroline Y Kuo
- Division of Allergy and Immunology, Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Beatriz Campo-Fernandez
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Dianne Lumaquin
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Roger P Hollis
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Xiaoyan Wang
- Department of Internal Medicine and Health Services Research, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Donald B Kohn
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; Eli & Edythe Broad Center of Regenerative Medicine & Stem Cell Research, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Zulema Romero
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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19
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Abstract
DNA molecules are not completely stable, they are subject to chemical or photochemical damage and errors that occur during DNA replication resulting in mismatched base pairs. Through mechanistic studies Paul Modrich showed how replication errors are corrected by strand-directed mismatch repair in Escherichia coli and human cells.
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Affiliation(s)
- Paul Modrich
- Howard Hughes Medical Institute and Department of Biochemistry, Duke University, Medical Center, Durham, NC, 27710, USA.
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20
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Doherty R, Madhusudan S. DNA Repair Endonucleases: Physiological Roles and Potential as Drug Targets. ACTA ACUST UNITED AC 2015; 20:829-41. [PMID: 25877151 DOI: 10.1177/1087057115581581] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 03/22/2015] [Indexed: 12/15/2022]
Abstract
Genomic DNA is constantly exposed to endogenous and exogenous damaging agents. To overcome these damaging effects and maintain genomic stability, cells have robust coping mechanisms in place, including repair of the damaged DNA. There are a number of DNA repair pathways available to cells dependent on the type of damage induced. The removal of damaged DNA is essential to allow successful repair. Removal of DNA strands is achieved by nucleases. Exonucleases are those that progressively cut from DNA ends, and endonucleases make single incisions within strands of DNA. This review focuses on the group of endonucleases involved in DNA repair pathways, their mechanistic functions, roles in cancer development, and how targeting these enzymes is proving to be an exciting new strategy for personalized therapy in cancer.
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Affiliation(s)
- Rachel Doherty
- Laboratory of Molecular Oncology, Academic Unit of Oncology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham University Hospitals, Nottingham, UK
| | - Srinivasan Madhusudan
- Laboratory of Molecular Oncology, Academic Unit of Oncology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Nottingham University Hospitals, Nottingham, UK
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21
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Mukha DV, Pasyukova EG, Kapelinskaya TV, Kagramanova AS. Endonuclease domain of the Drosophila melanogaster R2 non-LTR retrotransposon and related retroelements: a new model for transposition. Front Genet 2013; 4:63. [PMID: 23637706 PMCID: PMC3636483 DOI: 10.3389/fgene.2013.00063] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Accepted: 04/05/2013] [Indexed: 01/25/2023] Open
Abstract
The molecular mechanisms of the transposition of non-long terminal repeat (non-LTR) retrotransposons are not well understood; the key questions of how the 3′-ends of cDNA copies integrate and how site-specific integration occurs remain unresolved. Integration depends on properties of the endonuclease (EN) domain of retrotransposons. Using the EN domain of the Drosophila R2 retrotransposon as a model for other, closely related non-LTR retrotransposons, we investigated the EN domain and found that it resembles archaeal Holliday-junction resolvases. We suggest that these non-LTR retrotransposons are co-transcribed with the host transcript. Combined with the proposed resolvase activity of the EN domain, this model yields a novel mechanism for site-specific retrotransposition within this class of retrotransposons, with resolution proceeding via a Holliday junction intermediate.
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Affiliation(s)
- Dmitry V Mukha
- Vavilov Institute of General Genetics, Russian Academy of Sciences Moscow, Russia
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22
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Durairaj A, Limbach PA. Matrix-assisted laser desorption/ionization mass spectrometry screening for pseudouridine in mixtures of small RNAs by chemical derivatization, RNase digestion and signature products. Rapid Commun Mass Spectrom 2008; 22:3727-34. [PMID: 18973194 PMCID: PMC3009585 DOI: 10.1002/rcm.3789] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
We have developed a method to screen for pseudouridines in complex mixtures of small RNAs using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). First, the unfractionated crude mixture of tRNAs is digested to completion with an endoribonuclease, such as RNase T1, and the digestion products are examined using MALDI-MS. Individual RNAs are identified by their signature digestion products, which arise through the detection of unique mass values after nuclease digestion. Next, the endonuclease digest is derivatized using N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide metho-p-toluenesulfonate (CMCT), which selectively modifies all pseudouridine, thiouridine and 2-methylthio-6-isopentenyladenosine nucleosides. MALDI-MS determination of the CMCT-derivatized endonuclease digest reveals the presence of pseudouridine through a 252 Da mass increase over the underivatized digest. Proof-of-concept experiments were conducted using a mixture of Escherichia coli transfer RNAs and endoribonucleases T1 and A. More than 80% of the expected pseudouridines from this mixture were detected using this screening approach, even on an unfractionated sample of tRNAs. This approach should be particularly useful in the identification of putative pseudouridine synthases through detection of their target RNAs and can provide insight into specific small RNAs that may contain pseudouridine.
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Affiliation(s)
| | - Patrick A. Limbach
- To whom correspondence should be addressed. Phone (513) 556-1871, Fax (513) 556-9239,
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23
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Durairaj A, Limbach PA. Improving CMC-derivatization of pseudouridine in RNA for mass spectrometric detection. Anal Chim Acta 2008; 612:173-81. [PMID: 18358863 PMCID: PMC2424252 DOI: 10.1016/j.aca.2008.02.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 02/12/2008] [Accepted: 02/13/2008] [Indexed: 10/22/2022]
Abstract
A protocol that utilizes matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and N-cyclohexyl-N'-beta-(4-methylmorpholinium)ethylcarbodiimide (CMC) derivatization to detect the post-transcriptionally modified nucleoside, pseudouridine, in RNA has been optimized for RNase digests. Because pseudouridine is mass-silent (i.e., the mass of pseudouridine is the same as the mass of uridine), after CMC-derivatization and alkaline treatment, all pseudouridine residues exhibit a mass shift of 252 Da that allows its presence to be easily detected by mass spectrometry. This protocol is illustrated by the direct MALDI-MS identification of pseudouridines within Escherichia coli tRNA(TyrII) starting from microgram amounts of sample. During this optimization study, it was discovered that the post-transcriptionally modified nucleoside 2-methylthio-N(6)-isopentenyladenosine, which is present in bacterial tRNAs, also retains a CMC unit after derivatization and incubation with base. Thus, care must be exercised when applying this MALDI-based CMC-derivatization approach for pseudouridine detection to samples containing transfer RNAs to minimize the misidentification of pseudouridine.
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Affiliation(s)
- Anita Durairaj
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, PO Box 210172, University of Cincinnati, Cincinnati, OH 45221-0172
| | - Patrick A. Limbach
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, PO Box 210172, University of Cincinnati, Cincinnati, OH 45221-0172
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Lapkouski M, Panjikar S, Kuta Smatanova I, Csefalvay E. Purification, crystallization and preliminary X-ray analysis of the HsdR subunit of the EcoR124I endonuclease from Escherichia coli. Acta Crystallogr Sect F Struct Biol Cryst Commun 2007; 63:582-5. [PMID: 17620716 PMCID: PMC2335136 DOI: 10.1107/s174430910702622x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 05/29/2007] [Indexed: 05/16/2023]
Abstract
EcoR124I is a multicomplex enzyme belonging to the type I restriction-modification system from Escherichia coli. Although EcoR124I has been extensively characterized biochemically, there is no direct structural information available about particular subunits. HsdR is a motor subunit that is responsible for ATP hydrolysis, DNA translocation and cleavage of the DNA substrate recognized by the complex. Recombinant HsdR subunit was crystallized using the sitting-drop vapour-diffusion method. Crystals belong to the primitive monoclinic space group, with unit-cell parameters a = 85.75, b = 124.71, c = 128.37 A, beta = 108.14 degrees. Native data were collected to 2.6 A resolution at the X12 beamline of EMBL Hamburg.
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Affiliation(s)
- Mikalai Lapkouski
- Institute of Physical Biology, University of South Bohemia in Ceske Budejovice, Zamek 136, CZ-373 33 Nove Hrady, Czech Republic
- Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic, Zamek 136, CZ-373 33 Nove Hrady, Czech Republic
| | - Santosh Panjikar
- EMBL Hamburg Outstation, c/o DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| | - Ivana Kuta Smatanova
- Institute of Physical Biology, University of South Bohemia in Ceske Budejovice, Zamek 136, CZ-373 33 Nove Hrady, Czech Republic
- Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic, Zamek 136, CZ-373 33 Nove Hrady, Czech Republic
| | - Eva Csefalvay
- Institute of Physical Biology, University of South Bohemia in Ceske Budejovice, Zamek 136, CZ-373 33 Nove Hrady, Czech Republic
- Institute of Systems Biology and Ecology, Academy of Sciences of the Czech Republic, Zamek 136, CZ-373 33 Nove Hrady, Czech Republic
- Correspondence e-mail:
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25
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Abstract
Metabotropic glutamate receptors (mGluRs) share a common molecular morphology with other G protein-linked receptors, but there expression throughout the mammalian nervous system places these receptors as essential mediators not only for the initial development of an organism, but also for the vital determination of a cell's fate during many disorders in the nervous system that include amyotrophic lateral sclerosis, Parkinson's disease, Alzheimer's disease, Huntington's disease, Multiple Sclerosis, epilepsy, trauma, and stroke. Given the ubiquitous distribution of these receptors, the mGluR system impacts upon neuronal, vascular, and glial cell function and is activated by a wide variety of stimuli that includes neurotransmitters, peptides, hormones, growth factors, ions, lipids, and light. Employing signal transduction pathways that can modulate both excitatory and inhibitory responses, the mGluR system drives a spectrum of cellular pathways that involve protein kinases, endonucleases, cellular acidity, energy metabolism, mitochondrial membrane potential, caspases, and specific mitogen-activated protein kinases. Ultimately these pathways can converge to regulate genomic DNA degradation, membrane phosphatidylserine (PS) residue exposure, and inflammatory microglial activation. As we continue to push the envelope for our understanding of this complex and critical family of metabotropic receptors, we should be able to reap enormous benefits for both clinical disease as well as our understanding of basic biology in the nervous system.
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Affiliation(s)
- Kenneth Maiese
- Division of Cellular and Molecular Cerebral Ischemia, Department of Neurology, 8C-1 UHC, Wayne State University School of Medicine, 4201 St. Antoine, Detroit, MI 48201, USA.
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26
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van den Bremer ETJ, Keeble AH, Jiskoot W, Spelbrink REJ, Maier CS, van Hoek A, Visser AJWG, James R, Moore GR, Kleanthous C, Heck AJR. Distinct conformational stability and functional activity of four highly homologous endonuclease colicins. Protein Sci 2004; 13:1391-401. [PMID: 15096639 PMCID: PMC2286750 DOI: 10.1110/ps.03508204] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2003] [Revised: 01/30/2004] [Accepted: 02/09/2004] [Indexed: 10/26/2022]
Abstract
The family of conserved colicin DNases E2, E7, E8, and E9 are microbial toxins that kill bacteria through random degradation of the chromosomal DNA. In the present work, we compare side by side the conformational stabilities of these four highly homologous colicin DNases. Our results indicate that the apo-forms of these colicins are at room temperature and neutral pH in a dynamic conformational equilibrium between at least two quite distinct conformers. We show that the thermal stabilities of the apo-proteins differ by up to 20 degrees C. The observed differences correlate with the observed conformational behavior, that is, the tendency of the protein to form either an open, less stable or closed, more stable conformation in solution, as deduced by both tryptophan accessibility studies and electrospray ionization mass spectrometry. Given these surprising structural differences, we next probed the catalytic activity of the four DNases and also observed a significant variation in relative activities. However, no unequivocal link between the activity of the protein and its thermal and structural stability could easily be made. The observed differences in conformational and functional properties of the four colicin DNases are surprising given that they are a closely related (> or =65% identity) family of enzymes containing a highly conserved (betabetaalpha-Me) active site motif. The different behavior of the apo-enzymes must therefore most likely depend on more subtle changes in amino acid sequences, most likely in the exosite region (residues 72-98) that is required for specific high-affinity binding of the cognate immunity protein.
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Affiliation(s)
- Ewald T J van den Bremer
- Department of Biomolecular Mass Spectrometry, Bijvoet Center for Biomolecular Research & Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CA Utrecht, The Netherlands. e.t.j.
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Fabre F, Chan A, Heyer WD, Gangloff S. Alternate pathways involving Sgs1/Top3, Mus81/ Mms4, and Srs2 prevent formation of toxic recombination intermediates from single-stranded gaps created by DNA replication. Proc Natl Acad Sci U S A 2002; 99:16887-92. [PMID: 12475932 PMCID: PMC139239 DOI: 10.1073/pnas.252652399] [Citation(s) in RCA: 263] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Toxic recombination events are detected in vegetative Saccharomyces cerevisiae cells through negative growth interactions between certain combinations of mutations. For example, mutations affecting both the Srs2 and Sgs1 helicases result in extremely poor growth, a phenotype suppressed by mutations in genes that govern early stages of recombination. Here, we identify a similar interaction involving double mutations affecting Sgs1 or Top3 and Mus81 or Mms4. We also find that the primary DNA structures that initiate these toxic recombination events cannot be double-strand breaks and thus are likely to be single-stranded DNA. We interpret our results in the context of the idea that replication stalling leaves single-stranded DNA, which can then be processed by two competing mechanisms: recombination and nonrecombination gap-filling. Functions involved in preventing toxic recombination would either avoid replicative defects or act on recombination intermediates. Our results suggest that Srs2 channels recombination intermediates back into the gap-filling route, whereas Sgs1Top3 and Mus81Mms4 are involved in recombination andor in replication to allow replication restart.
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Affiliation(s)
- Francis Fabre
- Unité Mixte de Recherche 217, Centre National de la Recherche Scientifique-Commissariat à l'Energie Atomique. Département de Radiobiologie et Radiopathologie BP6, 92265 Fontenay-aux-Roses, France.
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Lautenberger JA, Kan NC, Lackey D, Linn S, Edgell MH, Hutchison CA. Recognition site of Escherichia coli B restriction enzyme on phi XsB1 and simian virus 40 DNAs: an interrupted sequence. Proc Natl Acad Sci U S A 1978; 75:2271-5. [PMID: 209460 PMCID: PMC392534 DOI: 10.1073/pnas.75.5.2271] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Methyl groups placed on varphiXsB1 replicative form DNA by the Escherichia coli B modification enzyme are located in the overlap between fragments Mbo II-3 and Alu I-2, a 61-base-pair DNA segment. Mutations that led to loss of susceptibility to restriction by E. coli B occurred within this segment at three positions spanning 14 nucleotides. A sequence difference between varphiXsB1 and varphiXam3cs70, a varphiX174 strain not restricted by E. coli B, occurs at one of these positions. The site on simian virus 40 DNA methylated by the modification enzyme is located in the 115-base-pair overlap between fragments Hae III-I and Alu I-G. The sequences of these segments of varphiXsB1 and simian virus 40 DNA and two regions of phage f1 DNA recognized by the E. coli B restriction enzyme [Ravetch, J. V., Horiuchi, K. & Zinder, N. D. (1978) Proc. Natl. Acad. Sci. USA 75, 2266-2270] contain a homology of nine bases in the configuration:5'-T-G-A... 8N... T-G-C-T... 9N... T-N-N-T-3'. The sequence 5'-T-G-A... 8N... T-G-C-T-3' may constitute the restriction enzyme recognition site since it does not occur in varphiXam3cs70 DNA and occurs only once in simian virus 40 DNA, and since all observed mutations leading to loss of the site occur at one of the bases specified by this sequence. Analysis of the sequence of varphiXam3cs70 showed that if no other residues are recognized, all seven of these bases are essential for recognition and the interval between the two groups of specified bases must be precisely eight.
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