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Lu X, Liu T, Zhou J, Liu J, Yuan Z, Guo L. Subgingival microbiome in periodontitis and type 2 diabetes mellitus: an exploratory study using metagenomic sequencing. J Periodontal Implant Sci 2022; 52:282-297. [PMID: 36047582 PMCID: PMC9436641 DOI: 10.5051/jpis.2103460173] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 11/20/2021] [Accepted: 12/23/2021] [Indexed: 11/08/2022] Open
Abstract
Purpose To explore differences in the subgingival microbiome according to the presence of periodontitis and/or type 2 diabetes mellitus (T2D), a metagenomic sequencing analysis of the subgingival microbiome was performed. Methods Twelve participants were divided into 4 groups based on their health conditions (periodontitis, T2D, T2D complicated with periodontitis, and generally healthy). Subgingival plaque was collected for metagenomic sequencing, and gingival crevicular fluids were collected to analyze the concentrations of short-chain fatty acids. Results The shifts in the subgingival flora from the healthy to periodontitis states were less prominent in T2D subjects than in subjects without T2D. The pentose and glucuronate interconversion, fructose and mannose metabolism, and galactose metabolism pathways were enriched in the periodontitis state, while the phosphotransferase system, lipopolysaccharide (LPS) and peptidoglycan biosynthesis, bacterial secretion system, sulfur metabolism, and glycolysis pathways were enriched in the T2D state. Multiple genes whose expression was upregulated from the red and orange complex bacterial genomes were associated with bacterial biofilm formation and pathogenicity. The concentrations of propionic acid and butyric acid were significantly higher in subjects with periodontitis, with or without T2D, than in healthy subjects. Conclusions T2D patients are more susceptible to the presence of periodontal pathogens and have a higher risk of developing periodontitis. The pentose and glucuronate interconversion, fructose and mannose metabolism, galactose metabolism, and glycolysis pathways may represent the potential microbial functional association between periodontitis and T2D, and butyric acid may play an important role in the interaction between these 2 diseases. The enrichment of the LPS and peptidoglycan biosynthesis, bacterial secretion system, and sulfur metabolism pathways may cause T2D patients to be more susceptible to periodontitis.
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Affiliation(s)
- Xianjun Lu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Tingjun Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Jiani Zhou
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Jia Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Zijian Yuan
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Lihong Guo
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
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2
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Hakim MS, Annisa L, Jariah ROA, Vink C. The mechanisms underlying antigenic variation and maintenance of genomic integrity in Mycoplasma pneumoniae and Mycoplasma genitalium. Arch Microbiol 2020; 203:413-429. [PMID: 32970220 DOI: 10.1007/s00203-020-02041-4] [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: 05/28/2020] [Revised: 08/02/2020] [Accepted: 09/12/2020] [Indexed: 11/28/2022]
Abstract
Mycoplasma pneumoniae and Mycoplasma genitalium are important causative agents of infections in humans. Like all other mycoplasmas, these species possess genomes that are significantly smaller than that of other prokaryotes. Moreover, both organisms possess an exceptionally compact set of DNA recombination and repair-associated genes. These genes, however, are sufficient to generate antigenic variation by means of homologous recombination between specific repetitive genomic elements. At the same time, these mycoplasmas have likely evolved strategies to maintain the stability and integrity of their 'minimal' genomes. Previous studies have indicated that there are considerable differences between mycoplasmas and other bacteria in the composition of their DNA recombination and repair machinery. However, the complete repertoire of activities executed by the putative recombination and repair enzymes encoded by Mycoplasma species is not yet fully understood. In this paper, we review the current knowledge on the proteins that likely form part of the DNA repair and recombination pathways of two of the most clinically relevant Mycoplasma species, M. pneumoniae and M. genitalium. The characterization of these proteins will help to define the minimal enzymatic requirements for creating bacterial genetic diversity (antigenic variation) on the one hand, while maintaining genomic integrity on the other.
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Affiliation(s)
- Mohamad S Hakim
- Department of Microbiology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, 55281, Yogyakarta, Indonesia. .,Postgraduate School of Molecular Medicine, Erasmus MC-University Medical Center Rotterdam, Rotterdam, The Netherlands.
| | - Luthvia Annisa
- Department of Microbiology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, 55281, Yogyakarta, Indonesia
| | - Rizka O A Jariah
- Department of Health Science, Faculty of Vocational Studies, Universitas Airlangga, Surabaya, Indonesia
| | - Cornelis Vink
- Department of Life Sciences, Erasmus University College, Erasmus University, 3011 HP, Rotterdam, The Netherlands.
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3
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Qin L, Chen Y, You X. Subversion of the Immune Response by Human Pathogenic Mycoplasmas. Front Microbiol 2019; 10:1934. [PMID: 31497004 PMCID: PMC6712165 DOI: 10.3389/fmicb.2019.01934] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/06/2019] [Indexed: 12/17/2022] Open
Abstract
Mycoplasmas are a large group of prokaryotes which is believed to be originated from Gram-positive bacteria via degenerative evolution, and mainly capable of causing a wide range of human and animal infections. Although innate immunity and adaptive immunity play crucial roles in preventing mycoplasma infection, immune response that develops after infection fails to completely eliminate this bacterium under certain circumstances. Thus, it is reasonable to speculate that mycoplasmas employ some mechanisms to deal with coercion of host defense system. In this review, we will highlight and provide a comprehensive overview of immune evasion strategies that have emerged in mycoplasma infection, which can be divided into four aspects: (i) Molecular mimicry and antigenic variation on the surface of the bacteria to evade the immune surveillance; (ii) Overcoming the immune effector molecules assaults: Induction of detoxified enzymes to degradation of reactive oxygen species; Expression of nucleases to degrade the neutrophil extracellular traps to avoid killing by Neutrophil; Capture and cleavage of immunoglobulins to evade humoral immune response; (iii) Persistent survival: Invading into the host cell to escape the immune damage; Formation of a biofilm to establish a persistent infection; (iv) Modulation of the immune system to down-regulate the intensity of immune response. All of these features increase the probability of mycoplasma survival in the host and lead to a persistent, chronic infections. A profound understanding on the mycoplasma to subvert the immune system will help us to better understand why mycoplasma is so difficult to eradicate and ultimately provide new insights on the development of therapeutic regimens against this bacterium in future.
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Affiliation(s)
- Lianmei Qin
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Yiwen Chen
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Xiaoxing You
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
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Limudomporn P, Moonsom S, Leartsakulpanich U, Suntornthiticharoen P, Petmitr S, Weinfeld M, Chavalitshewinkoon-Petmitr P. Characterization of Plasmodium falciparum ATP-dependent DNA helicase RuvB3. Malar J 2016; 15:526. [PMID: 27809838 PMCID: PMC5093981 DOI: 10.1186/s12936-016-1573-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 10/18/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria is one of the most serious and widespread parasitic diseases affecting humans. Because of the spread of resistance in both parasites and the mosquito vectors to anti-malarial drugs and insecticides, controlling the spread of malaria is becoming difficult. Thus, identifying new drug targets is urgently needed. Helicases play key roles in a wide range of cellular activities involving DNA and RNA transactions, making them attractive anti-malarial drug targets. METHODS ATP-dependent DNA helicase gene (PfRuvB3) of Plasmodium falciparum strain K1, a chloroquine and pyrimethamine-resistant strain, was inserted into pQE-TriSystem His-Strep 2 vector, heterologously expressed and affinity purified. Identity of recombinant PfRuvB3 was confirmed by western blotting coupled with tandem mass spectrometry. Helicase and ATPase activities were characterized as well as co-factors required for optimal function. RESULTS Recombinant PfRuvB3 has molecular size of 59 kDa, showing both DNA helicase and ATPase activities. Its helicase activity is dependent on divalent cations (Cu2+, Mg2+, Ni+2 or Zn+2) and ATP or dATP but is inhibited by high NaCl concentration (>100 mM). PfPuvB3 is unable to act on blunt-ended duplex DNA, but manifests ATPase activity in the presence of either single- or double-stranded DNA. PfRuvB3.is inhibited by doxorubicin, daunorubicin and netropsin, known DNA helicase inhibitors. CONCLUSIONS Purified recombinant PfRuvB3 contains both DNA helicase and ATPase activities. Differences in properties of RuvB between the malaria parasite obtained from the study and human host provide an avenue leading to the development of novel drugs targeting specifically the malaria form of RuvB family of DNA helicases.
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Affiliation(s)
- Paviga Limudomporn
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok, 10400, Thailand
| | - Saengduen Moonsom
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok, 10400, Thailand
| | - Ubolsree Leartsakulpanich
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Pahonyothin Rd, Pathumthani, 12120, Thailand
| | - Pattra Suntornthiticharoen
- Department of Biomedical Sciences, Faculty of Science, Rangsit University, Lak Hok, Pathumthani, 12000, Thailand
| | - Songsak Petmitr
- Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, 10400, Thailand
| | - Michael Weinfeld
- Department of Oncology, Cross Cancer Institute, University of Alberta, Edmonton, AB, T6G 1Z2, Canada
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Cañas C, Suzuki Y, Marchisone C, Carrasco B, Freire-Benéitez V, Takeyasu K, Alonso JC, Ayora S. Interaction of branch migration translocases with the Holliday junction-resolving enzyme and their implications in Holliday junction resolution. J Biol Chem 2014; 289:17634-46. [PMID: 24770420 DOI: 10.1074/jbc.m114.552794] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Double-strand break repair involves the formation of Holliday junction (HJ) structures that need to be resolved to promote correct replication and chromosomal segregation. The molecular mechanisms of HJ branch migration and/or resolution are poorly characterized in Firmicutes. Genetic evidence suggested that the absence of the RuvAB branch migration translocase and the RecU HJ resolvase is synthetically lethal in Bacillus subtilis, whereas a recU recG mutant was viable. In vitro RecU, which is restricted to bacteria of the Firmicutes phylum, binds HJs with high affinity. In this work we found that RecU does not bind simultaneously with RecG to a HJ. RuvB by interacting with RecU bound to the central region of HJ DNA, loses its nonspecific association with DNA, and re-localizes with RecU to form a ternary complex. RecU cannot stimulate the ATPase or branch migration activity of RuvB. The presence of RuvB·ATPγS greatly stimulates RecU-mediated HJ resolution, but the addition of ATP or RuvA abolishes this stimulatory effect. A RecU·HJ·RuvAB complex might be formed. RecU does not increase the RuvAB activities but slightly inhibits them.
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Affiliation(s)
- Cristina Cañas
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
| | - Yuki Suzuki
- Graduate School of Biostudies, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Chiara Marchisone
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
| | - Begoña Carrasco
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
| | - Verónica Freire-Benéitez
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
| | - Kunio Takeyasu
- Graduate School of Biostudies, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Juan C Alonso
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
| | - Silvia Ayora
- From the Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Departamento de Biotecnología Microbiana, 28049 Madrid, Spain and
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Estevão S, van der Spek PE, van Rossum AMC, Vink C. Uncoupling of the apyrimidinic/apurinic endonucleolytic and 3'→5' exonucleolytic activities of the Nfo protein of Mycoplasma pneumoniae through mutation of specific amino acid residues. MICROBIOLOGY-SGM 2014; 160:1087-1100. [PMID: 24694374 DOI: 10.1099/mic.0.077578-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The DNA recombination and repair machineries of Mycoplasma pneumoniae and Mycoplasma genitalium were predicted to consist of a set of ~11 proteins. The function of one of these proteins was inferred from its homology with proteins belonging to the Endo IV enzyme family. The members of this family function in the repair of apyrimidinic/apurinic (AP) sites in DNA. As such activity may be crucial in the mycoplasmal life cycle, we set out to study the Endo IV-like proteins encoded by M. pneumoniae and M. genitalium. Both proteins, termed NfoMpn and NfoMge, respectively, were assessed for their ability to interact with damaged and undamaged DNA. In the absence of divalent cations, both proteins exhibited specific cleavage of AP sites. Surprisingly, the proteins also recognized and cleaved cholesteryl-bound deoxyribose moieties in DNA, showing that these Nfo proteins may also function in repair of large DNA adducts. In the presence of Mg(2+), NfoMpn and NfoMge also showed 3'→5' exonucleolytic activity. By introduction of 13 single point mutations at highly conserved positions within NfoMpn, two major types of mutants could be distinguished: (i) mutants that showed no, or limited, AP cleavage activity in the presence of EDTA, but displayed significant levels of AP cleavage activity in the presence of Mg(2+); these mutants displayed no, or very low, exonucleolytic activity; and (ii) mutants that only demonstrated marginal levels of AP site cleavage activity in the presence of Mg(2+) and did not show exonucleolytic activity. Together, these results indicated that the AP endonucleolytic activity of the NfoMpn protein can be uncoupled from its 3'→5' exonucleolytic activity.
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Affiliation(s)
- Silvia Estevão
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Pieternella E van der Spek
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Annemarie M C van Rossum
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Cornelis Vink
- Erasmus University College, Department Life Sciences, Erasmus University Rotterdam, The Netherlands
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
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7
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Characterization of the operon encoding the Holliday junction helicase RuvAB from Mycoplasma genitalium and its role in mgpB and mgpC gene variation. J Bacteriol 2014; 196:1608-18. [PMID: 24532771 DOI: 10.1128/jb.01385-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Mycoplasma genitalium is an emerging sexually transmitted pathogen associated with reproductive tract disease in men and women, and it can persist for months to years despite the development of a robust antibody response. Mechanisms that may contribute to persistence in vivo include phase and antigenic variation of the MgpB and MgpC adhesins. These processes occur by segmental recombination between discrete variable regions within mgpB and mgpC and multiple archived donor sequences termed MgPa repeats (MgPars). The molecular factors governing mgpB and mgpC variation are poorly understood and obscured by the paucity of recombination genes conserved in the M. genitalium genome. Recently, we demonstrated the requirement for RecA using a quantitative PCR (qPCR) assay developed to measure recombination between the mgpB and mgpC genes and MgPars. Here, we expand these studies by examining the roles of M. genitalium ruvA and ruvB homologs. Deletion of ruvA and ruvB impaired the ability to generate mgpB and mgpC phase and sequence variants, and these deficiencies could be complemented with wild-type copies, including the ruvA gene from Mycoplasma pneumoniae. In contrast, ruvA and ruvB deletions did not affect the sensitivity to UV irradiation, reinforcing our previous findings that the recombinational repair pathway plays a minor role in M. genitalium. Reverse transcription-PCR (RT-PCR) and primer extension analyses also revealed a complex transcriptional organization of the RuvAB system of M. genitalium, which is cotranscribed with two novel open reading frames (ORFs) (termed ORF1 and ORF2 herein) conserved only in M. pneumoniae. These findings suggest that these novel ORFs may play a role in recombination in these two closely related bacteria.
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8
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Estevão S, van der Heul HU, Sluijter M, Hoogenboezem T, Hartwig NG, van Rossum AMC, Vink C. Functional analysis of the superfamily 1 DNA helicases encoded by Mycoplasma pneumoniae and Mycoplasma genitalium. PLoS One 2013; 8:e70870. [PMID: 23894687 PMCID: PMC3720892 DOI: 10.1371/journal.pone.0070870] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 06/24/2013] [Indexed: 11/18/2022] Open
Abstract
The DNA recombination and repair machinery of Mycoplasma pneumoniae is composed of a limited set of approximately 11 proteins. Two of these proteins were predicted to be encoded by neighboring open reading frames (ORFs) MPN340 and MPN341. Both ORFs were found to have sequence similarity with genes that encode proteins belonging to the DNA helicase superfamily 1 (SF1). Interestingly, while a homolog of the MPN341 ORF is present in the genome of Mycoplasma genitalium (ORF MG244), MPN340 is an M. pneumoniae-specific ORF that is not found in other mycoplasmas. Moreover, the length of MPN340 (1590 base pairs [bp]) is considerably shorter than that of MPN341 (2148 bp). Examination of the MPN340-encoded amino acid sequence indicated that it may lack a so-called 2B subdomain, which is found in most SF1 DNA helicases. Also, the MPN340-encoded amino acid sequence was found to differ between subtype 1 strain M129 and subtype 2 strain FH at three amino acid positions. Both protein variants, which were termed PcrAsM129 and PcrAsFH, respectively, as well as the MPN341- and MG244-encoded proteins (PcrAMpn and PcrAMge, respectively), were purified, and tested for their ability to interact with DNA. While PcrAMpn and PcrAMge were found to bind preferentially to single-stranded DNA, both PcrAsM129 and PcrAsFH did not demonstrate significant DNA binding. However, all four proteins were found to have divalent cation- and ATP-dependent DNA helicase activity. The proteins displayed highest activity on partially double-stranded DNA substrates carrying 3′ single-stranded extensions.
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Affiliation(s)
- Silvia Estevão
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children’s Hospital, Rotterdam, The Netherlands
| | - Helga U. van der Heul
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children’s Hospital, Rotterdam, The Netherlands
| | - Marcel Sluijter
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children’s Hospital, Rotterdam, The Netherlands
| | - Theo Hoogenboezem
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children’s Hospital, Rotterdam, The Netherlands
| | - Nico G. Hartwig
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children’s Hospital, Rotterdam, The Netherlands
| | - Annemarie M. C. van Rossum
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children’s Hospital, Rotterdam, The Netherlands
| | - Cornelis Vink
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children’s Hospital, Rotterdam, The Netherlands
- * E-mail:
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Ahmad M, Tuteja R. Plasmodium falciparum RuvB proteins: Emerging importance and expectations beyond cell cycle progression. Commun Integr Biol 2012; 5:350-61. [PMID: 23060959 PMCID: PMC3460840 DOI: 10.4161/cib.20005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The urgent requirement of next generation antimalarials has been of recent interest due to the emergence of drug-resistant parasite. The genome-wide analysis of Plasmodium falciparum helicases revealed three RuvB proteins. Due to the presence of helicase motif I and II in PfRuvBs, there is a high probability that they contain ATPase and possibly helicase activity. The Plasmodium database has homologs of several key proteins that interact with RuvBs and are most likely involved in the cell cycle progression, chromatin remodeling, and other cellular activities. Phylogenetically PfRuvBs are closely related to Saccharomyces cerevisiae RuvB, which is essential for cell cycle progression and survival of yeast. Thus PfRuvBs can serve as potential drug target if they show an essential role in the survival of parasite.
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Affiliation(s)
- Moaz Ahmad
- Malaria Group; International Centre for Genetic Engineering and Biotechnology; New Delhi, India
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10
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Vink C, Rudenko G, Seifert HS. Microbial antigenic variation mediated by homologous DNA recombination. FEMS Microbiol Rev 2012; 36:917-948. [PMID: 22212019 PMCID: PMC3334452 DOI: 10.1111/j.1574-6976.2011.00321.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 12/12/2011] [Accepted: 12/13/2011] [Indexed: 11/27/2022] Open
Abstract
Pathogenic microorganisms employ numerous molecular strategies in order to delay or circumvent recognition by the immune system of their host. One of the most widely used strategies of immune evasion is antigenic variation, in which immunogenic molecules expressed on the surface of a microorganism are continuously modified. As a consequence, the host is forced to constantly adapt its humoral immune response against this pathogen. An antigenic change thus provides the microorganism with an opportunity to persist and/or replicate within the host (population) for an extended period of time or to effectively infect a previously infected host. In most cases, antigenic variation is caused by genetic processes that lead to the modification of the amino acid sequence of a particular antigen or to alterations in the expression of biosynthesis genes that induce changes in the expression of a variant antigen. Here, we will review antigenic variation systems that rely on homologous DNA recombination and that are found in a wide range of cellular, human pathogens, including bacteria (such as Neisseria spp., Borrelia spp., Treponema pallidum, and Mycoplasma spp.), fungi (such as Pneumocystis carinii) and parasites (such as the African trypanosome Trypanosoma brucei). Specifically, the various DNA recombination-based antigenic variation systems will be discussed with a focus on the employed mechanisms of recombination, the DNA substrates, and the enzymatic machinery involved.
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Affiliation(s)
- Cornelis Vink
- Department of Pediatrics, Erasmus MC, Rotterdam, The Netherlands
| | - Gloria Rudenko
- Division of Cell and Molecular Biology, Imperial College-South Kensington, London, UK
| | - H. Steven Seifert
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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11
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Novel RuvB nuclear ATPase is specific to intraerythrocytic mitosis during schizogony of Plasmodium falciparum. Mol Biochem Parasitol 2012; 185:58-65. [DOI: 10.1016/j.molbiopara.2012.06.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 06/01/2012] [Accepted: 06/06/2012] [Indexed: 12/17/2022]
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12
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Burgos R, Wood GE, Young L, Glass JI, Totten PA. RecA mediates MgpB and MgpC phase and antigenic variation in Mycoplasma genitalium, but plays a minor role in DNA repair. Mol Microbiol 2012; 85:669-83. [PMID: 22686427 DOI: 10.1111/j.1365-2958.2012.08130.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mycoplasma genitalium, a sexually transmitted human pathogen, encodes MgpB and MgpC adhesins that undergo phase and antigenic variation through recombination with archived 'MgPar' donor sequences. The mechanism and molecular factors required for this genetic variation are poorly understood. In this study, we estimate that sequence variation at the mgpB/C locus occurs in vitro at a frequency of > 1.25 × 10(-4) events per genome per generation using a quantitative anchored PCR assay. This rate was dramatically reduced in a recA deletion mutant and increased in a complemented strain overexpressing RecA. Similarly, the frequency of haemadsorption-deficient phase variants was reduced in the recA mutant, but restored by complementation. Unlike Escherichia coli, inactivation of recA in M. genitalium had a minimal effect on survival after exposure to mitomycin C or UV irradiation. In contrast, a deletion mutant for the predicted nucleotide excision repair uvrC gene showed growth defects and was exquisitely sensitive to DNA damage. We conclude that M. genitalium RecA has a primary role in mgpB/C-MgPar recombination leading to antigenic and phase variation, yet plays a minor role in DNA repair. Our results also suggest that M. genitalium possesses an active nucleotide excision repair system, possibly representing the main DNA repair pathway in this minimal bacterium.
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Affiliation(s)
- Raul Burgos
- Division of Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA 98104, USA
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13
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Sluijter M, Estevão S, Hoogenboezem T, Hartwig NG, van Rossum AMC, Vink C. The RuvA homologues from Mycoplasma genitalium and Mycoplasma pneumoniae exhibit unique functional characteristics. PLoS One 2012; 7:e38301. [PMID: 22666500 PMCID: PMC3364216 DOI: 10.1371/journal.pone.0038301] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 05/03/2012] [Indexed: 11/18/2022] Open
Abstract
The DNA recombination and repair machineries of Mycoplasma genitalium and Mycoplasma pneumoniae differ considerably from those of gram-positive and gram-negative bacteria. Most notably, M. pneumoniae is unable to express a functional RecU Holliday junction (HJ) resolvase. In addition, the RuvB homologues from both M. pneumoniae and M. genitalium only exhibit DNA helicase activity but not HJ branch migration activity in vitro. To identify a putative role of the RuvA homologues of these mycoplasmas in DNA recombination, both proteins (RuvAMpn and RuvAMge, respectively) were studied for their ability to bind DNA and to interact with RuvB and RecU. In spite of a high level of sequence conservation between RuvAMpn and RuvAMge (68.8% identity), substantial differences were found between these proteins in their activities. First, RuvAMge was found to preferentially bind to HJs, whereas RuvAMpn displayed similar affinities for both HJs and single-stranded DNA. Second, while RuvAMpn is able to form two distinct complexes with HJs, RuvAMge only produced a single HJ complex. Third, RuvAMge stimulated the DNA helicase and ATPase activities of RuvBMge, whereas RuvAMpn did not augment RuvB activity. Finally, while both RuvAMge and RecUMge efficiently bind to HJs, they did not compete with each other for HJ binding, but formed stable complexes with HJs over a wide protein concentration range. This interaction, however, resulted in inhibition of the HJ resolution activity of RecUMge.
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Affiliation(s)
- Marcel Sluijter
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Silvia Estevão
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Theo Hoogenboezem
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Nico G. Hartwig
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Annemarie M. C. van Rossum
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Cornelis Vink
- Laboratory of Pediatrics, Pediatric Infectious Diseases and Immunity, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands
- * E-mail:
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