1
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Waneka G, Stewart J, Anderson JR, Li W, Wilusz J, Argueso JL, Sloan DB. UV damage induces production of mitochondrial DNA fragments with specific length profiles. Genetics 2024; 227:iyae070. [PMID: 38722894 PMCID: PMC11228841 DOI: 10.1093/genetics/iyae070] [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: 02/08/2024] [Revised: 02/08/2024] [Accepted: 04/22/2024] [Indexed: 05/21/2024] Open
Abstract
UV light is a potent mutagen that induces bulky DNA damage in the form of cyclobutane pyrimidine dimers (CPDs). Photodamage and other bulky lesions occurring in nuclear genomes can be repaired through nucleotide excision repair (NER), where incisions on both sides of a damaged site precede the removal of a single-stranded oligonucleotide containing the damage. Mitochondrial genomes (mtDNAs) are also susceptible to damage from UV light, but current evidence suggests that the only way to eliminate bulky mtDNA damage is through mtDNA degradation. Damage-containing oligonucleotides excised during NER can be captured with antidamage antibodies and sequenced (XR-seq) to produce high-resolution maps of active repair locations following UV exposure. We analyzed previously published datasets from Arabidopsis thaliana, Saccharomyces cerevisiae, and Drosophila melanogaster to identify reads originating from the mtDNA (and plastid genome in A. thaliana). In A. thaliana and S. cerevisiae, the mtDNA-mapping reads have unique length distributions compared to the nuclear-mapping reads. The dominant fragment size was 26 nt in S. cerevisiae and 28 nt in A. thaliana with distinct secondary peaks occurring in regular intervals. These reads also show a nonrandom distribution of di-pyrimidines (the substrate for CPD formation) with TT enrichment at positions 7-8 of the reads. Therefore, UV damage to mtDNA appears to result in production of DNA fragments of characteristic lengths and positions relative to the damaged location. The mechanisms producing these fragments are unclear, but we hypothesize that they result from a previously uncharacterized DNA degradation pathway or repair mechanism in mitochondria.
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Affiliation(s)
- Gus Waneka
- Department of Biology, Colorado State University, Fort Collins 80521, CO, USA
| | - Joseph Stewart
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins 80521, CO, USA
- Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins 80521, CO, USA
| | - John R Anderson
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins 80521, CO, USA
| | - Wentao Li
- Department of Environmental Health Science, University of Georgia, Athens 30602, GA, USA
| | - Jeffrey Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins 80521, CO, USA
| | - Juan Lucas Argueso
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins 80521, CO, USA
- Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins 80521, CO, USA
| | - Daniel B Sloan
- Department of Biology, Colorado State University, Fort Collins 80521, CO, USA
- Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins 80521, CO, USA
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2
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Karanja CW, Naganna N, Abutaleb NS, Dayal N, Onyedibe KI, Aryal U, Seleem MN, Sintim HO. Isoquinoline Antimicrobial Agent: Activity against Intracellular Bacteria and Effect on Global Bacterial Proteome. Molecules 2022; 27:5085. [PMID: 36014324 PMCID: PMC9416421 DOI: 10.3390/molecules27165085] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/01/2022] [Accepted: 08/02/2022] [Indexed: 11/16/2022] Open
Abstract
A new class of alkynyl isoquinoline antibacterial compounds, synthesized via Sonogashira coupling, with strong bactericidal activity against a plethora of Gram-positive bacteria including methicillin- and vancomycin-resistant Staphylococcus aureus (S. aureus) strains is presented. HSN584 and HSN739, representative compounds in this class, reduce methicillin-resistant S. aureus (MRSA) load in macrophages, whilst vancomycin, a drug of choice for MRSA infections, was unable to clear intracellular MRSA. Additionally, both HSN584 and HSN739 exhibited a low propensity to develop resistance. We utilized comparative global proteomics and macromolecule biosynthesis assays to gain insight into the alkynyl isoquinoline mechanism of action. Our preliminary data show that HSN584 perturb S. aureus cell wall and nucleic acid biosynthesis. The alkynyl isoquinoline moiety is a new scaffold for the development of potent antibacterial agents against fatal multidrug-resistant Gram-positive bacteria.
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Affiliation(s)
- Caroline W. Karanja
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - Nimishetti Naganna
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - Nader S. Abutaleb
- Department of Comparative Pathobiology, Purdue University College of Veterinary Medicine, 625 Harrison Street, West Lafayette, IN 47907, USA
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, 1410 Prices Fork Rd, Blacksburg, VA 24061, USA
| | - Neetu Dayal
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
| | - Kenneth I. Onyedibe
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
- Purdue Institute of Inflammation, Immunology and Infectious Disease, West Lafayette, IN 47907, USA
| | - Uma Aryal
- Department of Comparative Pathobiology, Purdue University College of Veterinary Medicine, 625 Harrison Street, West Lafayette, IN 47907, USA
- Purdue Proteomics Facility, Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907, USA
| | - Mohamed N. Seleem
- Department of Comparative Pathobiology, Purdue University College of Veterinary Medicine, 625 Harrison Street, West Lafayette, IN 47907, USA
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, 1410 Prices Fork Rd, Blacksburg, VA 24061, USA
| | - Herman O. Sintim
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, USA
- Purdue Institute of Inflammation, Immunology and Infectious Disease, West Lafayette, IN 47907, USA
- Institute for Drug Discovery, Purdue University, 720 Clinic Drive, West Lafayette, IN 47907, USA
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3
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Han S, Gong Z, Liang T, Chen Y, Xie J. The role of Mfd in Mycobacterium tuberculosis physiology and underlying regulatory network. Microbiol Res 2021; 246:126718. [PMID: 33588338 DOI: 10.1016/j.micres.2021.126718] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 01/18/2021] [Accepted: 01/26/2021] [Indexed: 12/23/2022]
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis with millions of deaths annually, remains one of the most formidable pathogen to global public health. As the most successful intracellular pathogens, Mtb can spatiotemporally coordinate the transcription and translation timely to reconcile the inevitable transcription-replication conflicts. Mutation frequency decline (Mfd) is a bacterial ATP-dependent DNA translocase that couples DNA repair to transcription via hydrolyzing ATP as energy, which preferentially acts on the damaged DNA transcribed strand to rescue stalled RNAP or dissociate RNAP to terminate the transcription depending on impediment severity, mitigating the damage to bacteria. In addition to the traditional damage repair effect, Mfd may also promote bacteria mutagenesis under stresses and boost the drug resistance. Mfd is widespread among bacteria and intensively studied, but there are very few studies in Mycobacteria, especially Mtb. In this review, the structure, function and mechanism characteristics of Mfd in Mtb (MtbMfd, Rv1020) are explored, with emphasis on the regulatory network of MtbMfd and its potential as a prime target for antibiotic drugs against tuberculosis.
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Affiliation(s)
- Shuang Han
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing, 400715, China
| | - Zhen Gong
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing, 400715, China
| | - Tian Liang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing, 400715, China
| | - Yu Chen
- Department of Tuberculosis, Shenyang Tenth People's Hospital and Shenyang Chest Hospital, Shenyang, Liaoning Province, 110044, China.
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, Ministry of Education, Chongqing Municipal Key Laboratory of Karst Environment, School of Life Sciences, Southwest University, Beibei, Chongqing, 400715, China.
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4
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Hinzke T, Kleiner M, Meister M, Schlüter R, Hentschker C, Pané-Farré J, Hildebrandt P, Felbeck H, Sievert SM, Bonn F, Völker U, Becher D, Schweder T, Markert S. Bacterial symbiont subpopulations have different roles in a deep-sea symbiosis. eLife 2021; 10:58371. [PMID: 33404502 PMCID: PMC7787665 DOI: 10.7554/elife.58371] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 12/05/2020] [Indexed: 12/13/2022] Open
Abstract
The hydrothermal vent tubeworm Riftia pachyptila hosts a single 16S rRNA phylotype of intracellular sulfur-oxidizing symbionts, which vary considerably in cell morphology and exhibit a remarkable degree of physiological diversity and redundancy, even in the same host. To elucidate whether multiple metabolic routes are employed in the same cells or rather in distinct symbiont subpopulations, we enriched symbionts according to cell size by density gradient centrifugation. Metaproteomic analysis, microscopy, and flow cytometry strongly suggest that Riftia symbiont cells of different sizes represent metabolically dissimilar stages of a physiological differentiation process: While small symbionts actively divide and may establish cellular symbiont-host interaction, large symbionts apparently do not divide, but still replicate DNA, leading to DNA endoreduplication. Moreover, in large symbionts, carbon fixation and biomass production seem to be metabolic priorities. We propose that this division of labor between smaller and larger symbionts benefits the productivity of the symbiosis as a whole.
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Affiliation(s)
- Tjorven Hinzke
- Institute of Pharmacy, University of Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology, Greifswald, Germany.,Energy Bioengineering Group, University of Calgary, Calgary, Canada
| | - Manuel Kleiner
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, United States
| | - Mareike Meister
- Institute of Microbiology, University of Greifswald, Greifswald, Germany.,Leibniz Institute for Plasma Science and Technology, Greifswald, Germany
| | - Rabea Schlüter
- Imaging Center of the Department of Biology, University of Greifswald, Greifswald, Germany
| | - Christian Hentschker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Jan Pané-Farré
- Center for Synthetic Microbiology (SYNMIKRO), Philipps-University Marburg, Marburg, Germany
| | - Petra Hildebrandt
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Horst Felbeck
- Scripps Institution of Oceanography, University of California San Diego, San Diego, United States
| | - Stefan M Sievert
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, United States
| | - Florian Bonn
- Institute of Biochemistry, University Hospital, Goethe University School of Medicine Frankfurt, Frankfurt, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Dörte Becher
- Institute of Microbiology, University of Greifswald, Greifswald, Germany
| | - Thomas Schweder
- Institute of Pharmacy, University of Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology, Greifswald, Germany
| | - Stephanie Markert
- Institute of Pharmacy, University of Greifswald, Greifswald, Germany.,Institute of Marine Biotechnology, Greifswald, Germany
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5
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Jaiswal AK, Tiwari S, Jamal SB, de Castro Oliveira L, Alves LG, Azevedo V, Ghosh P, Oliveira CJF, Soares SC. The pan-genome of Treponema pallidum reveals differences in genome plasticity between subspecies related to venereal and non-venereal syphilis. BMC Genomics 2020; 21:33. [PMID: 31924165 PMCID: PMC6953169 DOI: 10.1186/s12864-019-6430-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 12/24/2019] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Spirochetal organisms of the Treponema genus are responsible for causing Treponematoses. Pathogenic treponemes is a Gram-negative, motile, spirochete pathogen that causes syphilis in human. Treponema pallidum subsp. endemicum (TEN) causes endemic syphilis (bejel); T. pallidum subsp. pallidum (TPA) causes venereal syphilis; T. pallidum subsp. pertenue (TPE) causes yaws; and T. pallidum subsp. Ccarateum causes pinta. Out of these four high morbidity diseases, venereal syphilis is mediated by sexual contact; the other three diseases are transmitted by close personal contact. The global distribution of syphilis is alarming and there is an increasing need of proper treatment and preventive measures. Unfortunately, effective measures are limited. RESULTS Here, the genome sequences of 53 T. pallidum strains isolated from different parts of the world and a diverse range of hosts were comparatively analysed using pan-genomic strategy. Phylogenomic, pan-genomic, core genomic and singleton analysis disclosed the close connection among all strains of the pathogen T. pallidum, its clonal behaviour and showed increases in the sizes of the pan-genome. Based on the genome plasticity analysis of the subsets containing the subspecies T pallidum subsp. pallidum, T. pallidum subsp. endemicum and T. pallidum subsp. pertenue, we found differences in the presence/absence of pathogenicity islands (PAIs) and genomic islands (GIs) on subsp.-based study. CONCLUSIONS In summary, we identified four pathogenicity islands (PAIs), eight genomic islands (GIs) in subsp. pallidum, whereas subsp. endemicum has three PAIs and seven GIs and subsp. pertenue harbours three PAIs and eight GIs. Concerning the presence of genes in PAIs and GIs, we found some genes related to lipid and amino acid biosynthesis that were only present in the subsp. of T. pallidum, compared to T. pallidum subsp. endemicum and T. pallidum subsp. pertenue.
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Affiliation(s)
- Arun Kumar Jaiswal
- PG Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.,Department of Immunology, Microbiology and Parasitology, Institute of Biological Sciences and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil
| | - Sandeep Tiwari
- PG Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
| | - Syed Babar Jamal
- Department of Biological Sciences, National University of Medical Sciences, Abid Majeed Road, Rawalpindi, Punjab, 46000, Pakistan
| | - Letícia de Castro Oliveira
- PG Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.,Department of Immunology, Microbiology and Parasitology, Institute of Biological Sciences and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil
| | - Leandro Gomes Alves
- Department of Immunology, Microbiology and Parasitology, Institute of Biological Sciences and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil
| | - Vasco Azevedo
- PG Program in Bioinformatics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
| | - Preetam Ghosh
- Department of Computer Science, Virginia Commonwealth University, Richmond, VA-23284, USA
| | - Carlo Jose Freira Oliveira
- Department of Immunology, Microbiology and Parasitology, Institute of Biological Sciences and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil
| | - Siomar C Soares
- Department of Immunology, Microbiology and Parasitology, Institute of Biological Sciences and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba, MG, Brazil.
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6
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Warren GM, Stein RA, Mchaourab HS, Eichman BF. Movement of the RecG Motor Domain upon DNA Binding Is Required for Efficient Fork Reversal. Int J Mol Sci 2018; 19:ijms19103049. [PMID: 30301235 PMCID: PMC6213257 DOI: 10.3390/ijms19103049] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 09/29/2018] [Accepted: 10/04/2018] [Indexed: 01/20/2023] Open
Abstract
RecG catalyzes reversal of stalled replication forks in response to replication stress in bacteria. The protein contains a fork recognition (“wedge”) domain that binds branched DNA and a superfamily II (SF2) ATPase motor that drives translocation on double-stranded (ds)DNA. The mechanism by which the wedge and motor domains collaborate to catalyze fork reversal in RecG and analogous eukaryotic fork remodelers is unknown. Here, we used electron paramagnetic resonance (EPR) spectroscopy to probe conformational changes between the wedge and ATPase domains in response to fork DNA binding by Thermotoga maritima RecG. Upon binding DNA, the ATPase-C lobe moves away from both the wedge and ATPase-N domains. This conformational change is consistent with a model of RecG fully engaged with a DNA fork substrate constructed from a crystal structure of RecG bound to a DNA junction together with recent cryo-electron microscopy (EM) structures of chromatin remodelers in complex with dsDNA. We show by mutational analysis that a conserved loop within the translocation in RecG (TRG) motif that was unstructured in the RecG crystal structure is essential for fork reversal and DNA-dependent conformational changes. Together, this work helps provide a more coherent model of fork binding and remodeling by RecG and related eukaryotic enzymes.
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Affiliation(s)
- Garrett M Warren
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA.
| | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
| | - Brandt F Eichman
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA.
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7
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Deaconescu AM, Suhanovsky MM. From Mfd to TRCF and Back Again-A Perspective on Bacterial Transcription-coupled Nucleotide Excision Repair. Photochem Photobiol 2017; 93:268-279. [PMID: 27859304 PMCID: PMC5672955 DOI: 10.1111/php.12661] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/08/2016] [Indexed: 12/17/2022]
Abstract
Photochemical and other reactions on DNA cause damage and corrupt genetic information. To counteract this damage, organisms have evolved intricate repair mechanisms that often crosstalk with other DNA-based processes such as transcription. Intriguing observations in the late 1980s and early 1990s led to the discovery of transcription-coupled repair (TCR), a subpathway of nucleotide excision repair. TCR, found in all domains of life, prioritizes for repair lesions located in the transcribed DNA strand, directly read by RNA polymerase. Here, we give a historical overview of developments in the field of bacterial TCR, starting from the pioneering work of Evelyn Witkin and Aziz Sancar, which led to the identification of the first transcription-repair coupling factor (the Mfd protein), to recent studies that have uncovered alternative TCR pathways and regulators.
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Affiliation(s)
- Alexandra M. Deaconescu
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02903, USA
| | - Margaret M. Suhanovsky
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02903, USA
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8
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Willing SE, Richards EJ, Sempere L, Dale AG, Cutting SM, Fairweather NF. Increased toxin expression in a Clostridium difficile mfd mutant. BMC Microbiol 2015; 15:280. [PMID: 26679502 PMCID: PMC4683965 DOI: 10.1186/s12866-015-0611-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 12/03/2015] [Indexed: 12/18/2022] Open
Abstract
Background The symptoms of Clostridium difficile infection are mediated primarily by two toxins, TcdA and TcdB, the expression of which is governed by a multitude of factors including nutrient availability, growth phase and cell stress. Several global regulators have been implicated in the regulation of toxin expression, such as CcpA and CodY. Results During attempts to insertionally inactivate a putative secondary cell wall polysaccharide synthesis gene, we obtained several mutants containing off-target insertions. One mutant displayed an unusual branched colony morphology and was investigated further. Marker recovery revealed an insertion in mfd, a gene encoding a transcription-coupled repair factor. The mfd mutant exhibited pleiotropic effects, in particular increased expression of both toxin A and B (TcdA and TcdB) compared to the parental strain. Western blotting and cellular cytotoxicity assays revealed increased expression across all time points over a 24 h period, with inactivation of mfd resulting in at least a 10 fold increase in cell cytotoxicity. qRT-PCR demonstrated the upregulation of both toxins occurred on a transcriptional level. All effects of the mfd mutation were complemented by a plasmid-encoded copy of mfd, showing the effects are not due to polar effects of the intron insertion or to second site mutations. Conclusions This study adds Mfd to the repertoire of factors involved in regulation of toxin expression in Clostridium difficile. Mfd is known to remove RNA polymerase molecules from transcriptional sites where it has stalled due to repressor action, preventing transcriptional read through. The consistently high levels of toxin in the C. difficile mfd mutant indicate this process is inefficient leading to transcriptional de-repression.
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Affiliation(s)
- Stephanie E Willing
- Department of Life Sciences, Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, UK. .,School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.
| | - Emma J Richards
- Department of Life Sciences, Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, UK.
| | - Lluis Sempere
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.
| | - Aaron G Dale
- Department of Life Sciences, Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, UK.
| | - Simon M Cutting
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.
| | - Neil F Fairweather
- Department of Life Sciences, Centre for Molecular Bacteriology and Infection, Imperial College London, London, SW7 2AZ, UK.
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9
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Structure-function dissection of Myxococcus xanthus CarD N-terminal domain, a defining member of the CarD_CdnL_TRCF family of RNA polymerase interacting proteins. PLoS One 2015; 10:e0121322. [PMID: 25811865 PMCID: PMC4374960 DOI: 10.1371/journal.pone.0121322] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 01/30/2015] [Indexed: 01/08/2023] Open
Abstract
Two prototypes of the large CarD_CdnL_TRCF family of bacterial RNA polymerase (RNAP)-binding proteins, Myxococcus xanthus CarD and CdnL, have distinct functions whose molecular basis remain elusive. CarD, a global regulator linked to the action of several extracytoplasmic function (ECF) σ-factors, binds to the RNAP β subunit (RNAP-β) and to protein CarG via an N-terminal domain, CarDNt, and to DNA via an intrinsically unfolded C-terminal domain resembling eukaryotic high-mobility-group A (HMGA) proteins. CdnL, a CarDNt-like protein that is essential for cell viability, is implicated in σA-dependent rRNA promoter activation and interacts with RNAP-β but not with CarG. While the HMGA-like domain of CarD by itself is inactive, we find that CarDNt has low but observable ability to activate ECF σ-dependent promoters in vivo, indicating that the C-terminal DNA-binding domain is required to maximize activity. Our structure-function dissection of CarDNt reveals an N-terminal, five-stranded β -sheet Tudor-like domain, CarD1-72, whose structure and contacts with RNAP-β mimic those of CdnL. Intriguingly, and in marked contrast to CdnL, CarD mutations that disrupt its interaction with RNAP-β did not annul activity. Our data suggest that the CarDNt C-terminal segment, CarD61-179, may be structurally distinct from its CdnL counterpart, and that it houses at least two distinct and crucial function determinants: (a) CarG-binding, which is specific to CarD; and (b) a basic residue stretch, which is also conserved and functionally required in CdnL. This study highlights the evolution of shared and divergent interactions in similar protein modules that enable the distinct activities of two related members of a functionally important and widespread bacterial protein family.
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10
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Sidorenko J, Ukkivi K, Kivisaar M. NER enzymes maintain genome integrity and suppress homologous recombination in the absence of exogenously induced DNA damage in Pseudomonas putida. DNA Repair (Amst) 2015; 25:15-26. [DOI: 10.1016/j.dnarep.2014.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/29/2014] [Accepted: 11/05/2014] [Indexed: 02/04/2023]
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11
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Gallego-García A, Mirassou Y, García-Moreno D, Elías-Arnanz M, Jiménez MA, Padmanabhan S. Structural insights into RNA polymerase recognition and essential function of Myxococcus xanthus CdnL. PLoS One 2014; 9:e108946. [PMID: 25272012 PMCID: PMC4182748 DOI: 10.1371/journal.pone.0108946] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/28/2014] [Indexed: 11/18/2022] Open
Abstract
CdnL and CarD are two functionally distinct members of the CarD_CdnL_TRCF family of bacterial RNA polymerase (RNAP)-interacting proteins, which co-exist in Myxococcus xanthus. While CarD, found exclusively in myxobacteria, has been implicated in the activity of various extracytoplasmic function (ECF) σ-factors, the function and mode of action of the essential CdnL, whose homologs are widespread among bacteria, remain to be elucidated in M. xanthus. Here, we report the NMR solution structure of CdnL and present a structure-based mutational analysis of its function. An N-terminal five-stranded β-sheet Tudor-like module in the two-domain CdnL mediates binding to RNAP-β, and mutations that disrupt this interaction impair cell growth. The compact CdnL C-terminal domain consists of five α-helices folded as in some tetratricopeptide repeat-like protein-protein interaction domains, and contains a patch of solvent-exposed nonpolar and basic residues, among which a set of basic residues is shown to be crucial for CdnL function. We show that CdnL, but not its loss-of-function mutants, stabilizes formation of transcriptionally competent, open complexes by the primary σA-RNAP holoenzyme at an rRNA promoter in vitro. Consistent with this, CdnL is present at rRNA promoters in vivo. Implication of CdnL in RNAP-σA activity and of CarD in ECF-σ function in M. xanthus exemplifies how two related members within a widespread bacterial protein family have evolved to enable distinct σ-dependent promoter activity.
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Affiliation(s)
- Aránzazu Gallego-García
- Departamento de Genética y Microbiología, Área de Genética (Unidad Asociada al IQFR-CSIC), Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Yasmina Mirassou
- Instituto de Química Física ‘Rocasolano’, Consejo Superior de Investigaciones Científicas (IQFR-CSIC), Madrid, Spain
| | - Diana García-Moreno
- Departamento de Genética y Microbiología, Área de Genética (Unidad Asociada al IQFR-CSIC), Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Montserrat Elías-Arnanz
- Departamento de Genética y Microbiología, Área de Genética (Unidad Asociada al IQFR-CSIC), Facultad de Biología, Universidad de Murcia, Murcia, Spain
- * E-mail: (MEA); (MAJ); (SP)
| | - María Angeles Jiménez
- Instituto de Química Física ‘Rocasolano’, Consejo Superior de Investigaciones Científicas (IQFR-CSIC), Madrid, Spain
- * E-mail: (MEA); (MAJ); (SP)
| | - S. Padmanabhan
- Instituto de Química Física ‘Rocasolano’, Consejo Superior de Investigaciones Científicas (IQFR-CSIC), Madrid, Spain
- * E-mail: (MEA); (MAJ); (SP)
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12
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Stubben CJ, Micheva-Viteva SN, Shou Y, Buddenborg SK, Dunbar JM, Hong-Geller E. Differential expression of small RNAs from Burkholderia thailandensis in response to varying environmental and stress conditions. BMC Genomics 2014; 15:385. [PMID: 24884623 PMCID: PMC4035088 DOI: 10.1186/1471-2164-15-385] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 05/06/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Bacterial small RNAs (sRNAs) regulate gene expression by base-pairing with downstream target mRNAs to attenuate translation of mRNA into protein at the post-transcriptional level. In response to specific environmental changes, sRNAs can modulate the expression levels of target genes, thus enabling adaptation of cellular physiology. RESULTS We profiled sRNA expression in the Gram-negative bacteria Burkholderia thailandensis cultured under 54 distinct growth conditions using a Burkholderia-specific microarray that contains probe sets to all intergenic regions greater than 90 bases. We identified 38 novel sRNAs and performed experimental validation on five sRNAs that play a role in adaptation of Burkholderia to cell stressors. In particular, the trans-encoded BTH_s1 and s39 exhibited differential expression profiles dependent on growth phase and cell stimuli, such as antibiotics and serum. Furthermore, knockdown of the highly-expressed BTH_s39 by antisense transcripts reduced B. thailandensis cell growth and attenuated host immune response upon infection, indicating that BTH_s39 functions in bacterial metabolism and adaptation to the host. In addition, expression of cis-encoded BTH_s13 and s19 found in the 5' untranslated regions of their cognate genes correlated with tight regulation of gene transcript levels. This sRNA-mediated downregulation of gene expression may be a conserved mechanism of post-transcriptional gene dosage control. CONCLUSIONS These studies provide a broad analysis of differential Burkholderia sRNA expression profiles and illustrate the complexity of bacterial gene regulation in response to different environmental stress conditions.
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13
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Monnet J, Grange W, Strick TR, Joly N. Mfd as a central partner of transcription coupled repair. Transcription 2013; 4:109-13. [PMID: 23756341 PMCID: PMC4042583 DOI: 10.4161/trns.24934] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/03/2013] [Accepted: 05/03/2013] [Indexed: 01/14/2023] Open
Abstract
Transcription-coupled repair (TCR) is one of the key of the nucleotide excision repair (NER) pathways required to preserve genome integrity. Although understanding TCR is still a major challenge, recent single-molecule experiments have brought new insights into the initial steps of TCR leading to new perspectives.
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Affiliation(s)
- Jordan Monnet
- Institut Jacques Monod; CNRS UMR 7592; Université Paris Diderot; Sorbonne Paris Cité F-75205; Paris, France
| | - Wilfried Grange
- Institut Jacques Monod; CNRS UMR 7592; Université Paris Diderot; Sorbonne Paris Cité F-75205; Paris, France
| | - Terence R Strick
- Institut Jacques Monod; CNRS UMR 7592; Université Paris Diderot; Sorbonne Paris Cité F-75205; Paris, France
| | - Nicolas Joly
- Institut Jacques Monod; CNRS UMR 7592; Université Paris Diderot; Sorbonne Paris Cité F-75205; Paris, France
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14
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Deaconescu AM, Artsimovitch I, Grigorieff N. Interplay of DNA repair with transcription: from structures to mechanisms. Trends Biochem Sci 2012; 37:543-52. [PMID: 23084398 DOI: 10.1016/j.tibs.2012.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 09/10/2012] [Accepted: 09/14/2012] [Indexed: 01/29/2023]
Abstract
Many DNA transactions are crucial for maintaining genomic integrity and faithful transfer of genetic information but remain poorly understood. An example is the interplay between nucleotide excision repair (NER) and transcription, also known as transcription-coupled DNA repair (TCR). Discovered decades ago, the mechanisms for TCR have remained elusive, not in small part due to the scarcity of structural studies of key players. Here we summarize recent structural information on NER/TCR factors, focusing on bacterial systems, and integrate it with existing genetic, biochemical, and biophysical data to delineate the mechanisms at play. We also review emerging, alternative modalities for recruitment of NER proteins to DNA lesions.
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Affiliation(s)
- Alexandra M Deaconescu
- Howard Hughes Medical Institute, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, 415 South St., MS 029, Waltham, MA 02454, USA.
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15
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Howan K, Smith AJ, Westblade LF, Joly N, Grange W, Zorman S, Darst SA, Savery NJ, Strick TR. Initiation of transcription-coupled repair characterized at single-molecule resolution. Nature 2012; 490:431-4. [PMID: 22960746 PMCID: PMC3475728 DOI: 10.1038/nature11430] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 07/20/2012] [Indexed: 12/02/2022]
Abstract
Transcription-coupled repair employs components of the transcription machinery to identify DNA lesions and initiate their repair. These repair pathways are complex so their mechanistic features remain poorly understood. Bacterial transcription-coupled repair is initiated when RNA polymerase stalled at a DNA lesion is removed by Mfd, an ATP-dependent DNA translocase [1–3]. Here we use single-molecule DNA nanomanipulation to observe the dynamic interactions of E. coli Mfd with RNA polymerase elongation complexes stalled by a cyclopyrimidine dimer or by nucleotide starvation. We show that Mfd acts by catalyzing two irreversible, ATP-dependent steps with different structural, kinetic, and mechanistic features. Mfd remains bound to the DNA in a long-lived complex that could serve as a marker for sites of DNA damage, directing assembly of subsequent DNA repair factors. These results provide a framework for considering the kinetics of transcription-coupled repair in vivo, and open the way to reconstruction of complete DNA repair pathways at single-molecule resolution.
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Affiliation(s)
- Kévin Howan
- Institut Jacques Monod, CNRS, UMR 7592, University Paris Diderot, Sorbonne Paris Cité F-75205 Paris, France
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16
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Nucleotide excision repair (NER) machinery recruitment by the transcription-repair coupling factor involves unmasking of a conserved intramolecular interface. Proc Natl Acad Sci U S A 2012; 109:3353-8. [PMID: 22331906 DOI: 10.1073/pnas.1115105109] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Transcription-coupled DNA repair targets DNA lesions that block progression of elongating RNA polymerases. In bacteria, the transcription-repair coupling factor (TRCF; also known as Mfd) SF2 ATPase recognizes RNA polymerase stalled at a site of DNA damage, removes the enzyme from the DNA, and recruits the Uvr(A)BC nucleotide excision repair machinery via UvrA binding. Previous studies of TRCF revealed a molecular architecture incompatible with UvrA binding, leaving its recruitment mechanism unclear. Here, we examine the UvrA recognition determinants of TRCF using X-ray crystallography of a core TRCF-UvrA complex and probe the conformational flexibility of TRCF in the absence and presence of nucleotides using small-angle X-ray scattering. We demonstrate that the C-terminal domain of TRCF is inhibitory for UvrA binding, but not RNA polymerase release, and show that nucleotide binding induces concerted multidomain motions. Our studies suggest that autoinhibition of UvrA binding in TRCF may be relieved only upon engaging the DNA damage.
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17
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Pomerantz RT, O'Donnell M. What happens when replication and transcription complexes collide? Cell Cycle 2011; 9:2537-43. [PMID: 20581460 DOI: 10.4161/cc.9.13.12122] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The arrest of replication forks due to collisions with transcription complexes leads to genomic instability and cell death. Mechanisms that promote the progression of replication forks past transcription complexes are therefore essential for propagation and preservation of the genome. Recent studies of E. coli directly investigate the consequences of collisions of the replisome with RNAP polymerase (RNAP) in vitro and provide novel mechanisms by which these encounters may be resolved. Additionally, recent in vivo and in vitro studies support the longstanding hypothesis that auxiliary DNA helicases promote replication through roadblocks such as transcription complexes. Here we review past and recent advances that formulate our current understanding of how the bacterial replisome deals with transcription complexes along the path of chromosome duplication.
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Affiliation(s)
- Richard T Pomerantz
- The Rockefeller University, Howard Hughes Medical Institute, New York, NY, USA
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18
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Nozawa T, Furukawa N, Aikawa C, Watanabe T, Haobam B, Kurokawa K, Maruyama F, Nakagawa I. CRISPR inhibition of prophage acquisition in Streptococcus pyogenes. PLoS One 2011; 6:e19543. [PMID: 21573110 PMCID: PMC3089615 DOI: 10.1371/journal.pone.0019543] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 03/31/2011] [Indexed: 01/21/2023] Open
Abstract
Streptococcus pyogenes, one of the major human pathogens, is a unique species since it has acquired diverse strain-specific virulence properties mainly through the acquisition of streptococcal prophages. In addition, S. pyogenes possesses clustered regularly interspaced short palindromic repeats (CRISPR)/Cas systems that can restrict horizontal gene transfer (HGT) including phage insertion. Therefore, it was of interest to examine the relationship between CRISPR and acquisition of prophages in S. pyogenes. Although two distinct CRISPR loci were found in S. pyogenes, some strains lacked CRISPR and these strains possess significantly more prophages than CRISPR harboring strains. We also found that the number of spacers of S. pyogenes CRISPR was less than for other streptococci. The demonstrated spacer contents, however, suggested that the CRISPR appear to limit phage insertions. In addition, we found a significant inverse correlation between the number of spacers and prophages in S. pyogenes. It was therefore suggested that S. pyogenes CRISPR have permitted phage insertion by lacking its own spacers. Interestingly, in two closely related S. pyogenes strains (SSI-1 and MGAS315), CRISPR activity appeared to be impaired following the insertion of phage genomes into the repeat sequences. Detailed analysis of this prophage insertion site suggested that MGAS315 is the ancestral strain of SSI-1. As a result of analysis of 35 additional streptococcal genomes, it was suggested that the influences of the CRISPR on the phage insertion vary among species even within the same genus. Our results suggested that limitations in CRISPR content could explain the characteristic acquisition of prophages and might contribute to strain-specific pathogenesis in S. pyogenes.
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Affiliation(s)
- Takashi Nozawa
- Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Nayuta Furukawa
- Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Chihiro Aikawa
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Takayasu Watanabe
- Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Bijaya Haobam
- Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ken Kurokawa
- Division of Information Biotechnology, Department of Bioinformation Engineering, Tokyo Institute of Technology School and Graduate School of Bioscience and Biotechnology, Yokohama, Japan
| | - Fumito Maruyama
- Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
- * E-mail:
| | - Ichiro Nakagawa
- Section of Bacterial Pathogenesis, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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Srivastava DB, Darst SA. Derepression of bacterial transcription-repair coupling factor is associated with a profound conformational change. J Mol Biol 2010; 406:275-84. [PMID: 21185303 DOI: 10.1016/j.jmb.2010.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/28/2010] [Accepted: 12/02/2010] [Indexed: 11/16/2022]
Abstract
Transcription-repair coupling factor (TRCF; the product of the mfd gene) is a widely conserved bacterial protein that couples DNA repair with transcription. TRCF recognizes RNA polymerase stalled at a noncoding lesion in the DNA template strand, uses the energy from ATP hydrolysis to disrupt the transcription complex, and stimulates DNA repair by recruiting UvrA, a component of the nucleotide excision repair machinery, to the site. TRCF is a large (130 kDa) multifunctional protein with a complex structure-function relationship consisting of a compact arrangement of eight structured domains linked by flexible linkers. Through a conserved, intramolecular, interdomain interaction, TRCF is held in a conformation in which its enzymatic activities (ATPase activity and DNA translocase activity) are strongly repressed. Disruption of the repressive interdomain interaction by amino acid substitutions within the interface derepresses ATPase and DNA translocase activities. In this work, we have shown that derepressed TRCF mutants are dramatically sensitized to limited proteolysis compared with repressed TRCF, pointing to an altered conformational state. Analysis of the protease cleavage sites mapped onto the structure of the repressed TRCF conformation indicates that (1) the cleavage sites tend to cluster at linkers connecting the TRCF structured domains, and (2) many of the cleavage sites sensitized in the derepressed TRCF are partially or completely buried to protease access in the repressed TRCF structure. We conclude that TRCF derepression is associated with profound conformational changes that primarily involve a reorganization of the interdomain interactions.
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20
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Proteomic and physiological responses of Kineococcus radiotolerans to copper. PLoS One 2010; 5:e12427. [PMID: 20865147 PMCID: PMC2928746 DOI: 10.1371/journal.pone.0012427] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 07/14/2010] [Indexed: 01/21/2023] Open
Abstract
Copper is a highly reactive, toxic metal; consequently, transport of this metal within the cell is tightly regulated. Intriguingly, the actinobacterium Kineococcus radiotolerans has been shown to not only accumulate soluble copper to high levels within the cytoplasm, but the phenotype also correlated with enhanced cell growth during chronic exposure to ionizing radiation. This study offers a first glimpse into the physiological and proteomic responses of K. radiotolerans to copper at increasing concentration and distinct growth phases. Aerobic growth rates and biomass yields were similar over a range of Cu(II) concentrations (0–1.5 mM) in complex medium. Copper uptake coincided with active cell growth and intracellular accumulation was positively correlated with Cu(II) concentration in the growth medium (R2 = 0.7). Approximately 40% of protein coding ORFs on the K. radiotolerans genome were differentially expressed in response to the copper treatments imposed. Copper accumulation coincided with increased abundance of proteins involved in oxidative stress and defense, DNA stabilization and repair, and protein turnover. Interestingly, the specific activity of superoxide dismutase was repressed by low to moderate concentrations of copper during exponential growth, and activity was unresponsive to perturbation with paraquot. The biochemical response pathways invoked by sub-lethal copper concentrations are exceptionally complex; though integral cellular functions are preserved, in part, through the coordination of defense enzymes, chaperones, antioxidants and protective osmolytes that likely help maintain cellular redox. This study extends our understanding of the ecology and physiology of this unique actinobacterium that could potentially inspire new biotechnologies in metal recovery and sequestration, and environmental restoration.
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21
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Ganesan AK, Hanawalt PC. Transcription-coupled nucleotide excision repair of a gene transcribed by bacteriophage T7 RNA polymerase in Escherichia coli. DNA Repair (Amst) 2010; 9:958-63. [PMID: 20638914 DOI: 10.1016/j.dnarep.2010.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 05/28/2010] [Accepted: 06/22/2010] [Indexed: 11/17/2022]
Abstract
Transcription-coupled nucleotide excision repair (TC-NER) removes certain kinds of lesions from the transcribed strand of expressed genes. The signal for TC-NER is thought to be RNA polymerase stalled at a lesion in the DNA template. In Escherichia coli, the stalled polymerase is dissociated from the lesion by the transcription repair coupling factor (Mfd protein), which also recruits excision repair proteins to the site resulting in efficient removal of the lesion. TC-NER has been documented in cells from a variety of organisms ranging from bacteria to humans. In each case, the RNA polymerase involved has been a multimeric protein complex. To ascertain whether a gene transcribed by the monomeric RNA polymerase of bacteriophage T7 could be repaired by TC-NER, we constructed strains of E. coli in which the chromosomal lacZ gene is controlled by a T7 promoter. In the absence of T7 RNA polymerase, little or no beta-galactosidase is produced, indicating that the E. coli RNA polymerase does not transcribe lacZ efficiently, if at all, in these strains. By introducing a plasmid (pAR1219) carrying the T7 gene 1 under control of the E. coli lac UV5 promoter into these strains, we obtained derivatives in which the level of T7 RNA polymerase could be regulated. In cultures containing upregulated levels of the polymerase, beta-galactosidase was actively produced indicating that the T7 RNA polymerase transcribes the lacZ gene efficiently. Under these conditions, we observed that UV-induced cyclobutane pyrimidine dimers were removed more rapidly from the transcribed strand of lacZ than from the nontranscribed strand, supporting the conclusion that TC-NER occurred in this gene. This response was absent in an mfd-1 mutant, indicating that the underlying mechanism may be similar to that for the bacterial RNA polymerase.
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Affiliation(s)
- Ann K Ganesan
- Department of Biology, Stanford University, Stanford, CA 94305-5020, USA.
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22
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Contribution of transcription-coupled DNA repair to MMS-induced mutagenesis in E. coli strains deficient in functional AlkB protein. Mutat Res 2010; 688:19-27. [PMID: 20178806 DOI: 10.1016/j.mrfmmm.2010.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 02/10/2010] [Accepted: 02/15/2010] [Indexed: 11/20/2022]
Abstract
In Escherichia coli the alkylating agent methyl methanesulfonate (MMS) induces defense systems (adaptive and SOS responses), DNA repair pathways, and mutagenesis. We have previously found that AlkB protein induced as part of the adaptive (Ada) response protects cells from the genotoxic and mutagenic activity of MMS. AlkB is a non-heme iron (II), alpha-ketoglutarate-dependent dioxygenase that oxidatively demethylates 1meA and 3meC lesions in DNA, with recovery of A and C. Here, we studied the impact of transcription-coupled DNA repair (TCR) on MMS-induced mutagenesis in E. coli strain deficient in functional AlkB protein. Measuring the decline in the frequency of MMS-induced argE3-->Arg(+) revertants under transient amino acid starvation (conditions for TCR induction), we have found a less effective TCR in the BS87 (alkB(-)) strain in comparison with the AB1157 (alkB(+)) counterpart. Mutation in the mfd gene encoding the transcription-repair coupling factor Mfd, resulted in weaker TCR in MMS-treated and starved AB1157 mfd-1 cells in comparison to AB1157 mfd(+), and no repair in BS87 mfd(-) cells. Determination of specificity of Arg(+) revertants allowed to conclude that MMS-induced 1meA and 3meC lesions, unrepaired in bacteria deficient in AlkB, are the source of mutations. These include AT-->TA transversions by supL suppressor formation (1meA) and GC-->AT transitions by supB or supE(oc) formation (3meC). The repair of these lesions is partly Mfd-dependent in the AB1157 mfd-1 and totally Mfd-dependent in the BS87 mfd-1 strain. The nucleotide sequence of the mfd-1 allele shows that the mutated Mfd-1 protein, deprived of the C-terminal translocase domain, is unable to initiate TCR. It strongly enhances the SOS response in the alkB(-)mfd(-) bacteria but not in the alkB(+)mfd(-) counterpart.
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Busby S, Kolb A, Buc H. Where it all Begins: An Overview of Promoter Recognition and Open Complex Formation. RNA POLYMERASES AS MOLECULAR MOTORS 2009. [DOI: 10.1039/9781847559982-00013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Stephen Busby
- School of Biosciences, University of Birmingham Birmingham B15 2TT United Kingdom
| | - Annie Kolb
- Institut Pasteur, Molecular Genetics Unit and CNRS URA 2172 25 rue du Dr. Roux 75724 Paris Cedex 15 France
| | - Henri Buc
- CIS Institut Pasteur75724Paris Cedex 15France
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Differential expression of a putative CarD-like transcriptional regulator, LtpA, in Borrelia burgdorferi. Infect Immun 2008; 76:4439-44. [PMID: 18663002 DOI: 10.1128/iai.00740-08] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The availability of microbial genome information has provided a fruitful opportunity for studying regulatory networks in a variety of pathogenic bacteria. In an initial effort to elucidate regulatory networks potentially involved in differential gene expression by the Lyme disease pathogen Borrelia burgdorferi, we have been investigating the functions and regulation of putative transcriptional regulatory factors predicted to be encoded within the B. burgdorferi genome. Herein we report the regulation of one of the predicted transcriptional regulators, LtpA (BB0355), which is homologous to the transcriptional regulator CarD from Myxococcus xanthus. LtpA expression was assessed in response to various environmental stimuli. Immunoblot and quantitative reverse transcription-PCR analyses revealed that unlike many well-characterized differentially regulated Borrelia genes whose expression is induced by elevated temperature, the expression of LtpA was significantly downregulated when spirochetes were grown at an elevated temperature (37 degrees C), as well as when the bacteria were cultivated in a mammalian host-adapted environment. In contrast, LtpA was induced at a lower culture temperature (23 degrees C). Further analyses indicated that the downregulation of LtpA was not dependent on the Rrp2-RpoN-RpoS regulatory pathway, which is involved in the downregulation of OspA when B. burgdorferi is grown in a mammalian host-adapted environment. LtpA protein levels in B. burgdorferi were unaltered in response to changes in the pH in the borrelial cultures. Multiple attempts to generate an LtpA-deficient mutant were unsuccessful, which has hampered the elucidation of its role in pathogenesis. Given that LtpA is exclusively expressed during borrelial cultivation at a lower temperature, a parameter that has been widely used as a surrogate condition to mimic B. burgdorferi in unfed (flat) ticks, and because LtpA is homologous to a known transcriptional regulator, we postulate that LtpA functions as a regulator modulating the expression of genes important to B. burgdorferi's survival within its arthropod vector.
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25
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Titz B, Rajagopala SV, Goll J, Häuser R, McKevitt MT, Palzkill T, Uetz P. The binary protein interactome of Treponema pallidum--the syphilis spirochete. PLoS One 2008; 3:e2292. [PMID: 18509523 PMCID: PMC2386257 DOI: 10.1371/journal.pone.0002292] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Accepted: 04/14/2008] [Indexed: 11/19/2022] Open
Abstract
Protein interaction networks shed light on the global organization of proteomes but can also place individual proteins into a functional context. If we know the function of bacterial proteins we will be able to understand how these species have adapted to diverse environments including many extreme habitats. Here we present the protein interaction network for the syphilis spirochete Treponema pallidum which encodes 1,039 proteins, 726 (or 70%) of which interact via 3,649 interactions as revealed by systematic yeast two-hybrid screens. A high-confidence subset of 991 interactions links 576 proteins. To derive further biological insights from our data, we constructed an integrated network of proteins involved in DNA metabolism. Combining our data with additional evidences, we provide improved annotations for at least 18 proteins (including TP0004, TP0050, and TP0183 which are suggested to be involved in DNA metabolism). We estimate that this "minimal" bacterium contains on the order of 3,000 protein interactions. Profiles of functional interconnections indicate that bacterial proteins interact more promiscuously than eukaryotic proteins, reflecting the non-compartmentalized structure of the bacterial cell. Using our high-confidence interactions, we also predict 417,329 homologous interactions ("interologs") for 372 completely sequenced genomes and provide evidence that at least one third of them can be experimentally confirmed.
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Affiliation(s)
- Björn Titz
- Institute of Genetics, Forschungszentrum Karlsruhe, Karlsruhe, Germany
| | - Seesandra V. Rajagopala
- Institute of Genetics, Forschungszentrum Karlsruhe, Karlsruhe, Germany
- The Institute of Genomic Research (TIGR) and J Craig Venter Institute (JCVI), Rockville, Maryland, United States of America
| | - Johannes Goll
- Institute of Genetics, Forschungszentrum Karlsruhe, Karlsruhe, Germany
| | - Roman Häuser
- Institute of Genetics, Forschungszentrum Karlsruhe, Karlsruhe, Germany
| | - Matthew T. McKevitt
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, Houston, United States of America
| | - Timothy Palzkill
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, Houston, United States of America
| | - Peter Uetz
- Institute of Genetics, Forschungszentrum Karlsruhe, Karlsruhe, Germany
- The Institute of Genomic Research (TIGR) and J Craig Venter Institute (JCVI), Rockville, Maryland, United States of America
- * E-mail:
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26
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Goosen N, Moolenaar GF. Repair of UV damage in bacteria. DNA Repair (Amst) 2008; 7:353-79. [DOI: 10.1016/j.dnarep.2007.09.002] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Accepted: 09/06/2007] [Indexed: 10/22/2022]
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Affiliation(s)
- David S Gilmour
- Center for Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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28
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Frosina G. The current evidence for defective repair of oxidatively damaged DNA in Cockayne syndrome. Free Radic Biol Med 2007; 43:165-77. [PMID: 17603927 DOI: 10.1016/j.freeradbiomed.2007.04.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Revised: 03/31/2007] [Accepted: 04/02/2007] [Indexed: 12/21/2022]
Abstract
Cockayne syndrome (CS) is a rare recessive disorder characterized by a number of developmental abnormalities and premature aging. Two complementation groups (A and B) have been identified so far in CS cases. Defective transcription-coupled nucleotide excision repair is the hallmark of these patients, but in recent years evidence has been presented for a possible defect in the base excision repair pathway that removes oxidized bases. Recent results indicate that both A and B complementation groups are involved but the phenotypical consequences of this flaw remain undetermined.
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Affiliation(s)
- Guido Frosina
- Department of Translational Oncology, Experimental Oncology "B" Laboratory, Istituto Nazionale Ricerca Cancro, Largo Rosanna Benzi n. 10, 16132 Genova, Italy.
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Ganesan AK, Smith AJ, Savery NJ, Zamos P, Hanawalt PC. Transcription coupled nucleotide excision repair in Escherichia coli can be affected by changing the arginine at position 529 of the beta subunit of RNA polymerase. DNA Repair (Amst) 2007; 6:1434-40. [PMID: 17532270 PMCID: PMC2578841 DOI: 10.1016/j.dnarep.2007.04.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2006] [Revised: 04/04/2007] [Accepted: 04/05/2007] [Indexed: 11/25/2022]
Abstract
The proposed mechanism for transcription coupled nucleotide excision repair (TCR) invokes RNA polymerase (RNAP) blocked at a DNA lesion as a signal to initiate repair. In Escherichia coli, TCR requires the interaction of RNAP with a transcription-repair coupling factor encoded by the mfd gene. The interaction between RNAP and Mfd depends upon amino acids 117, 118, and 119 of the beta subunit of RNAP; changing any one of these to alanine diminishes the interaction [1]. Using direct assays for TCR, and the lac operon of E. coli containing UV induced cyclobutane pyrimidine dimers (CPDs) as substrate, we have found that a change from arginine to cysteine at amino acid 529 of the beta subunit of the RNAP inactivates TCR, but does not prevent the interaction of RNAP with Mfd. Our results suggest that this interaction may be necessary but not sufficient to facilitate TCR.
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Affiliation(s)
- Ann K Ganesan
- Department of Biological Sciences, Stanford University, Stanford, CA 94303-5020, USA.
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