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Bruun N, Laursen MF, Carmelo R, Christensen E, Jensen TS, Christiansen G, Birkelund S, Agger R, Kofod-Olsen E. Novel nucleotide-packaging vaccine delivers antigen and poly(I:C) to dendritic cells and generate a potent antibody response in vivo. Vaccine 2024; 42:2909-2918. [PMID: 38538405 DOI: 10.1016/j.vaccine.2024.03.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 03/10/2024] [Accepted: 03/22/2024] [Indexed: 04/16/2024]
Abstract
An issue with many current vaccines is the dependency on broadly inflammatory adjuvants, such as aluminum hydroxide or aluminum salts that affect many immune- and non-immune cells. These adjuvants are not necessarily activating all antigen-presenting cells (APCs) that take up the antigen and most likely they also activate APCs with no antigen uptake, as well as many non-immune cells. Conjugation of antigen and adjuvant would enable the use of smaller amounts of adjuvant and avoid unnecessary tissue damage and activation of bystander cells. It would ensure that all APCs that take up the antigen would also become activated and avoid that immature and non-activated APCs present the antigen to T cells without a co-stimulatory signal, leading to tolerogenesis. We have developed a novel vaccine that co-deliver antigen and a nucleotide adjuvant to the same APC and lead to a strong activation response in dendritic cells and macrophages. The vaccine is constructed as a fusion-protein with an antigen fused to the DNA/RNA-binding domain from the Hc2 protein from Chlamydia trachomatis. We have found that the fusion protein is able to package polyinosinic:polycytidylic acid (poly(I:C)) or dsDNA into small particles. These particles were taken up by macrophages and dendritic cells and led to strong activation and maturation of these cells. Immunization of mice with the fusion protein packaged poly(I:C) led to a stronger antibody response compared to immunization with a combination of poly(I:C) and antigen without the Hc2 DNA/RNA-binding domain.
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Affiliation(s)
- Natasja Bruun
- Aalborg University, Department of Health Science and Technology, Denmark
| | - Marlene F Laursen
- Aalborg University, Department of Health Science and Technology, Denmark
| | - Rita Carmelo
- Aalborg University, Department of Health Science and Technology, Denmark
| | - Esben Christensen
- Aalborg University, Department of Health Science and Technology, Denmark
| | - Trine S Jensen
- Aalborg University, Department of Health Science and Technology, Denmark
| | - Gunna Christiansen
- Aalborg University, Department of Health Science and Technology, Denmark
| | - Svend Birkelund
- Aalborg University, Department of Health Science and Technology, Denmark
| | - Ralf Agger
- Aalborg University, Department of Health Science and Technology, Denmark
| | - Emil Kofod-Olsen
- Aalborg University, Department of Health Science and Technology, Denmark.
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The repeated 36 amino acid motif of Chlamydia trachomatis Hc2 protein binds to the major groove of DNA. Res Microbiol 2019; 170:256-262. [DOI: 10.1016/j.resmic.2019.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 07/16/2019] [Accepted: 08/07/2019] [Indexed: 11/19/2022]
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Rolando M, Gomez-Valero L, Buchrieser C. Bacterial remodelling of the host epigenome: functional role and evolution of effectors methylating host histones. Cell Microbiol 2016; 17:1098-107. [PMID: 26031999 DOI: 10.1111/cmi.12463] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 05/15/2015] [Accepted: 05/25/2015] [Indexed: 12/25/2022]
Abstract
The modulation of the chromatin organization of eukaryotic cells plays an important role in regulating key cellular processes including host defence mechanisms against pathogens. Thus, to successfully survive in a host cell, a sophisticated bacterial strategy is the subversion of nuclear processes of the eukaryotic cell. Indeed, the number of bacterial proteins that target host chromatin to remodel the host epigenetic machinery is expanding. Some of the identified bacterial effectors that target the chromatin machinery are 'eukaryotic-like' proteins as they mimic eukaryotic histone writers in carrying the same enzymatic activities. The best-studied examples are the SET domain proteins that methylate histones to change the chromatin landscape. In this review, we will discuss SET domain proteins identified in the Legionella, Chlamydia and Bacillus genomes that encode enzymatic activities targeting host histones. Moreover, we discuss their possible origin as having evolved from prokaryotic ancestors or having been acquired from their eukaryotic hosts during their co-evolution. The characterization of such bacterial effectors as modifiers of the host chromatin landscape is an exciting field of research as it elucidates new bacterial strategies to not only manipulate host functions through histone modifications but it may also identify new modifications of the mammalian host cells not known before.
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Affiliation(s)
- Monica Rolando
- Institut Pasteur, Biologie des Bactéries Intracellulaires, Paris, France.,CNRS UMR 3525, Paris, France
| | - Laura Gomez-Valero
- Institut Pasteur, Biologie des Bactéries Intracellulaires, Paris, France.,CNRS UMR 3525, Paris, France
| | - Carmen Buchrieser
- Institut Pasteur, Biologie des Bactéries Intracellulaires, Paris, France.,CNRS UMR 3525, Paris, France
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Emancipating Chlamydia: Advances in the Genetic Manipulation of a Recalcitrant Intracellular Pathogen. Microbiol Mol Biol Rev 2016; 80:411-27. [PMID: 27030552 DOI: 10.1128/mmbr.00071-15] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Chlamydia species infect millions of individuals worldwide and are important etiological agents of sexually transmitted disease, infertility, and blinding trachoma. Historically, the genetic intractability of this intracellular pathogen has hindered the molecular dissection of virulence factors contributing to its pathogenesis. The obligate intracellular life cycle of Chlamydia and restrictions on the use of antibiotics as selectable markers have impeded the development of molecular tools to genetically manipulate these pathogens. However, recent developments in the field have resulted in significant gains in our ability to alter the genome of Chlamydia, which will expedite the elucidation of virulence mechanisms. In this review, we discuss the challenges affecting the development of molecular genetic tools for Chlamydia and the work that laid the foundation for recent advancements in the genetic analysis of this recalcitrant pathogen.
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5
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Abstract
The lifestyle of Chlamydiae is unique: the bacteria alternate between two morphologically distinct forms, an infectious non-replicative elementary body (EB), and a replicative, non-infectious reticulate body (RB). This review focuses on recent advances in understanding the structure and function of the infectious form of the best-studied member of the phylum, the human pathogen Chlamydia trachomatis. Once considered as an inert particle of little functional capacity, the EB is now perceived as a sophisticated entity that encounters at least three different environments during each infectious cycle. We review current knowledge on its composition and morphology, and emerging metabolic activities. These features confer resistance to the extracellular environment, the ability to penetrate a host cell and ultimately enable the EB to establish a niche enabling bacterial survival and growth. The bacterial and host molecules involved in these processes are beginning to emerge.
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Omsland A, Sixt BS, Horn M, Hackstadt T. Chlamydial metabolism revisited: interspecies metabolic variability and developmental stage-specific physiologic activities. FEMS Microbiol Rev 2014; 38:779-801. [PMID: 24484402 DOI: 10.1111/1574-6976.12059] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/08/2014] [Accepted: 01/13/2014] [Indexed: 01/07/2023] Open
Abstract
Chlamydiae are a group of obligate intracellular bacteria comprising important human and animal pathogens as well as symbionts of ubiquitous protists. They are characterized by a developmental cycle including two main morphologically and physiologically distinct stages, the replicating reticulate body and the infectious nondividing elementary body. In this review, we reconstruct the history of studies that have led to our current perception of chlamydial physiology, focusing on their energy and central carbon metabolism. We then compare the metabolic capabilities of pathogenic and environmental chlamydiae highlighting interspecies variability among the metabolically more flexible environmental strains. We discuss recent findings suggesting that chlamydiae may not live as energy parasites throughout the developmental cycle and that elementary bodies are not metabolically inert but exhibit metabolic activity under appropriate axenic conditions. The observed host-free metabolic activity of elementary bodies may reflect adequate recapitulation of the intracellular environment, but there is evidence that this activity is biologically relevant and required for extracellular survival and maintenance of infectivity. The recent discoveries call for a reconsideration of chlamydial metabolism and future in-depth analyses to better understand how species- and stage-specific differences in chlamydial physiology may affect virulence, tissue tropism, and host adaptation.
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Affiliation(s)
- Anders Omsland
- Host-Parasite Interactions Section, Laboratory of Intracellular Parasites, NIAID, NIH, Hamilton, MT, USA
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8
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Tirapelle EF, Müller-Santos M, Tadra-Sfeir MZ, Kadowaki MAS, Steffens MBR, Monteiro RA, Souza EM, Pedrosa FO, Chubatsu LS. Identification of proteins associated with polyhydroxybutyrate granules from Herbaspirillum seropedicae SmR1--old partners, new players. PLoS One 2013; 8:e75066. [PMID: 24086439 PMCID: PMC3783465 DOI: 10.1371/journal.pone.0075066] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 08/12/2013] [Indexed: 11/19/2022] Open
Abstract
Herbaspirillum seropedicae is a diazotrophic ß-Proteobacterium found associated with important agricultural crops. This bacterium produces polyhydroxybutyrate (PHB), an aliphatic polyester, as a carbon storage and/or source of reducing equivalents. The PHB polymer is stored as intracellular insoluble granules coated mainly with proteins, some of which are directly involved in PHB synthesis, degradation and granule biogenesis. In this work, we have extracted the PHB granules from H. seropedicae and identified their associated-proteins by mass spectrometry. This analysis allowed us to identify the main phasin (PhaP1) coating the PHB granule as well as the PHB synthase (PhbC1) responsible for its synthesis. A phbC1 mutant is impaired in PHB synthesis, confirming its role in H. seropedicae. On the other hand, a phaP1 mutant produces PHB granules but coated mainly with the secondary phasin (PhaP2). Furthermore, some novel proteins not previously described to be involved with PHB metabolism were also identified, bringing new possibilities to PHB function in H. seropedicae.
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Affiliation(s)
- Evandro F. Tirapelle
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Marcelo Müller-Santos
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Michelle Z. Tadra-Sfeir
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Marco A. S. Kadowaki
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Maria B. R. Steffens
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Rose A. Monteiro
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Emanuel M. Souza
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Fabio O. Pedrosa
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Leda S. Chubatsu
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
- * E-mail:
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Sixt BS, Siegl A, Müller C, Watzka M, Wultsch A, Tziotis D, Montanaro J, Richter A, Schmitt-Kopplin P, Horn M. Metabolic features of Protochlamydia amoebophila elementary bodies--a link between activity and infectivity in Chlamydiae. PLoS Pathog 2013; 9:e1003553. [PMID: 23950718 PMCID: PMC3738481 DOI: 10.1371/journal.ppat.1003553] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 06/28/2013] [Indexed: 01/07/2023] Open
Abstract
The Chlamydiae are a highly successful group of obligate intracellular bacteria, whose members are remarkably diverse, ranging from major pathogens of humans and animals to symbionts of ubiquitous protozoa. While their infective developmental stage, the elementary body (EB), has long been accepted to be completely metabolically inert, it has recently been shown to sustain some activities, including uptake of amino acids and protein biosynthesis. In the current study, we performed an in-depth characterization of the metabolic capabilities of EBs of the amoeba symbiont Protochlamydia amoebophila. A combined metabolomics approach, including fluorescence microscopy-based assays, isotope-ratio mass spectrometry (IRMS), ion cyclotron resonance Fourier transform mass spectrometry (ICR/FT-MS), and ultra-performance liquid chromatography mass spectrometry (UPLC-MS) was conducted, with a particular focus on the central carbon metabolism. In addition, the effect of nutrient deprivation on chlamydial infectivity was analyzed. Our investigations revealed that host-free P. amoebophila EBs maintain respiratory activity and metabolize D-glucose, including substrate uptake as well as host-free synthesis of labeled metabolites and release of labeled CO2 from 13C-labeled D-glucose. The pentose phosphate pathway was identified as major route of D-glucose catabolism and host-independent activity of the tricarboxylic acid (TCA) cycle was observed. Our data strongly suggest anabolic reactions in P. amoebophila EBs and demonstrate that under the applied conditions D-glucose availability is essential to sustain metabolic activity. Replacement of this substrate by L-glucose, a non-metabolizable sugar, led to a rapid decline in the number of infectious particles. Likewise, infectivity of Chlamydia trachomatis, a major human pathogen, also declined more rapidly in the absence of nutrients. Collectively, these findings demonstrate that D-glucose is utilized by P. amoebophila EBs and provide evidence that metabolic activity in the extracellular stage of chlamydiae is of major biological relevance as it is a critical factor affecting maintenance of infectivity. The Chlamydiae are a group of bacteria that strictly rely on eukaryotic host cells as a niche for intracellular growth. This group includes major pathogens of humans and animals as well as symbionts of protists. Unlike most other bacteria, chlamydiae alternate between two distinct developmental stages. Here we provide novel insights into the infective stage, the elementary body (EB), which has been described almost a century ago and is commonly referred to as an inert spore-like particle. Our analyses of EBs of the amoeba symbiont Protochlamydia amoebophila provide a detailed overview of their metabolism outside of, and independent from, their natural host cells. We demonstrated that these EBs are capable of respiration and are active in the major routes of central carbon metabolism, including glucose import, biosynthetic reactions, and catabolism for energy generation. Glucose starvation resulted in a rapid decline of metabolic activity in P. amoebophila EBs and a concomitant decrease in their potential to infect new host cells. The human pathogen Chlamydia trachomatis was also dependent on nutrient availability for extracellular survival. The extent of metabolic activity in chlamydial EBs and its consequences for infectivity challenge long-standing textbook knowledge and demonstrate that the infective stage is far more dependent on its environment than previously recognized.
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Affiliation(s)
- Barbara S. Sixt
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Alexander Siegl
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Constanze Müller
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg, Germany
| | - Margarete Watzka
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Anna Wultsch
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Dimitrios Tziotis
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg, Germany
| | - Jacqueline Montanaro
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Andreas Richter
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | | | - Matthias Horn
- Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
- * E-mail:
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Tattersall J, Rao GV, Runac J, Hackstadt T, Grieshaber SS, Grieshaber NA. Translation inhibition of the developmental cycle protein HctA by the small RNA IhtA is conserved across Chlamydia. PLoS One 2012; 7:e47439. [PMID: 23071807 PMCID: PMC3469542 DOI: 10.1371/journal.pone.0047439] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 09/17/2012] [Indexed: 11/18/2022] Open
Abstract
The developmental cycle of the obligate intracellular pathogen Chlamydia trachomatis serovar L2 is controlled in part by the small non-coding RNA (sRNA), IhtA. All Chlamydia alternate in a regulated fashion between the infectious elementary body (EB) and the replicative reticulate body (RB) which asynchronously re-differentiates back to the terminal EB form at the end of the cycle. The histone like protein HctA is central to RB:EB differentiation late in the cycle as it binds to and occludes the genome, thereby repressing transcription and translation. The sRNA IhtA is a critical component of this regulatory loop as it represses translation of hctA until late in infection at which point IhtA transcription decreases, allowing HctA expression to occur and RB to EB differentiation to proceed. It has been reported that IhtA is expressed during infection by the human pathogens C. trachomatis serovars L2, D and L2b and C. pneumoniae. We show in this work that IhtA is also expressed by the animal pathogens C. caviae and C. muridarum. Expression of HctA in E. coli is lethal and co-expression of IhtA relieves this phenotype. To determine if regulation of HctA by IhtA is a conserved mechanism across pathogenic chlamydial species, we cloned hctA and ihtA from C. trachomatis serovar D, C. muridarum, C. caviae and C. pneumoniae and assayed for rescue of growth repression in E. coli co-expression studies. In each case, co-expression of ihtA with the cognate hctA resulted in relief of growth repression. In addition, expression of each chlamydial species IhtA rescued the lethal phenotype of C. trachomatis serovar L2 HctA expression. As biolayer interferometry studies indicate that IhtA interacts directly with hctA message for all species tested, we predict that conserved sequences of IhtA are necessary for function and/or binding.
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Affiliation(s)
- Jeremiah Tattersall
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, United States of America
| | - Geeta Vittal Rao
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, United States of America
| | - Justin Runac
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, United States of America
| | - Ted Hackstadt
- Host-Parasite Interactions Section, Laboratory of Intracellular Parasites, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, Montana, United States of America
| | - Scott S. Grieshaber
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, United States of America
| | - Nicole A. Grieshaber
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, United States of America
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Aravind L, Abhiman S, Iyer LM. Natural history of the eukaryotic chromatin protein methylation system. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 101:105-76. [PMID: 21507350 DOI: 10.1016/b978-0-12-387685-0.00004-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
In eukaryotes, methylation of nucleosomal histones and other nuclear proteins is a central aspect of chromatin structure and dynamics. The past 15 years have seen an enormous advance in our understanding of the biochemistry of these modifications, and of their role in establishing the epigenetic code. We provide a synthetic overview, from an evolutionary perspective, of the main players in the eukaryotic chromatin protein methylation system, with an emphasis on catalytic domains. Several components of the eukaryotic protein methylation system had their origins in bacteria. In particular, the Rossmann fold protein methylases (PRMTs and DOT1), and the LSD1 and jumonji-related demethylases and oxidases, appear to have emerged in the context of bacterial peptide methylation and hydroxylation systems. These systems were originally involved in synthesis of peptide secondary metabolites, such as antibiotics, toxins, and siderophores. The peptidylarginine deiminases appear to have been acquired by animals from bacterial enzymes that modify cell-surface proteins. SET domain methylases, which display the β-clip fold, apparently first emerged in prokaryotes from the SAF superfamily of carbohydrate-binding domains. However, even in bacteria, a subset of the SET domains might have evolved a chromatin-related role in conjunction with a BAF60a/b-like SWIB domain protein and topoisomerases. By the time of the last eukaryotic common ancestor, multiple SET and PRMT methylases were already in place and are likely to have mediated methylation at the H3K4, H3K9, H3K36, and H4K20 positions, and carried out both asymmetric and symmetric arginine dimethylation. Inference of H3K27 methylation in the ancestral eukaryote appears uncertain, though it was certainly in place a little later in eukaryotic evolution. Current data suggest that unlike SET methylases, which are universally present in eukaryotes, demethylases are not. They appear to be absent in the earliest-branching eukaryotic lineages, and emerged later along with several other chromatin proteins, such as the Dot1-methylase, prior to divergence of the kinetoplastid-heterolobosean lineage from the remaining eukaryotes. This period also corresponds to the point of origin of DNA cytosine methylation by DNMT1. Origin of major lineages of SET domains such as the Trithorax, Su(var)3-9, Ash1, SMYD, and TTLL12 and E(Z) might have played the initial role in the establishment of multiple distinct heterochromatic and euchromatic states that are likely to have been present, in some form, through much of eukaryotic evolution. Elaboration of these chromatin states might have gone hand-in-hand with acquisition of multiple jumonji-related and LSD1-like demethylases, and functional linkages with the DNA methylation and RNAi systems. Throughout eukaryotic evolution, there were several lineage-specific expansions of SET domain proteins, which might be related to a special transcription regulation process in trypanosomes, acquisition of new meiotic recombination hotspots in animals, and methylation and associated modifications of the diatom silaffin proteins involved in silica biomineralization. The use of specific domains to "read" the methylation marks appears to have been present in the ancestral eukaryote itself. Of these the chromo-like domains appear to have been acquired from bacterial secreted proteins that might have a role in binding cell-surface peptides or peptidoglycan. Domain architectures of the primary enzymes involved in the eukaryotic protein methylation system indicate key features relating to interactions with each other and other modifications in chromatin, such as acetylation. They also emphasize the profound functional distinction between the role of demethylation and deacetylation in regulation of chromatin dynamics.
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Affiliation(s)
- L Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, USA
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Klint M, Thollesson M, Bongcam-Rudloff E, Birkelund S, Nilsson A, Herrmann B. Mosaic structure of intragenic repetitive elements in histone H1-like protein Hc2 varies within serovars of Chlamydia trachomatis. BMC Microbiol 2010; 10:81. [PMID: 20236532 PMCID: PMC2848022 DOI: 10.1186/1471-2180-10-81] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 03/17/2010] [Indexed: 11/10/2022] Open
Abstract
Background The histone-like protein Hc2 binds DNA in Chlamydia trachomatis and is known to vary in size between 165 and 237 amino acids, which is caused by different numbers of lysine-rich pentamers. A more complex structure was seen in this study when sequences from 378 specimens covering the hctB gene, which encodes Hc2, were compared. Results This study shows that the size variation is due to different numbers of 36-amino acid long repetitive elements built up of five pentamers and one hexamer. Deletions and amino acid substitutions result in 14 variants of repetitive elements and these elements are combined into 22 configurations. A protein with similar structure has been described in Bordetella but was now also found in other genera, including Burkholderia, Herminiimonas, Minibacterium and Ralstonia. Sequence determination resulted in 41 hctB variants that formed four clades in phylogenetic analysis. Strains causing the eye disease trachoma and strains causing invasive lymphogranuloma venereum infections formed separate clades, while strains from urogenital infections were more heterogeneous. Three cases of recombination were identified. The size variation of Hc2 has previously been attributed to deletions of pentamers but we show that the structure is more complex with both duplication and deletions of 36-amino acid long elements. Conclusions The polymorphisms in Hc2 need to be further investigated in experimental studies since DNA binding is essential for the unique biphasic life cycle of the Chlamydiacae. The high sequence variation in the corresponding hctB gene enables phylogenetic analysis and provides a suitable target for the genotyping of C. trachomatis.
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Affiliation(s)
- Markus Klint
- Department of Clinical Microbiology, Uppsala University, Uppsala, Sweden.
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Yu HHY, Kibler D, Tan M. In silico prediction and functional validation of sigma28-regulated genes in Chlamydia and Escherichia coli. J Bacteriol 2006; 188:8206-12. [PMID: 16997971 PMCID: PMC1698183 DOI: 10.1128/jb.01082-06] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
sigma(28) RNA polymerase is an alternative RNA polymerase that has been proposed to have a role in late developmental gene regulation in Chlamydia, but only a single target gene has been identified. To discover additional sigma(28)-dependent genes in the Chlamydia trachomatis genome, we applied bioinformatic methods using a probability weight matrix based on known sigma(28) promoters in other bacteria and a second matrix based on a functional analysis of the sigma(28) promoter. We tested 16 candidate sigma(28) promoters predicted with these algorithms and found that 5 were active in a chlamydial sigma(28) in vitro transcription assay. hctB, the known sigma(28)-regulated gene, is only expressed late in the chlamydial developmental cycle only, and two of the newly identified sigma(28) target genes (tsp and tlyC_1) also have late expression profiles, providing support for sigma(28) as a regulator of late gene expression. One of the other novel sigma(28)-regulated genes is dnaK, a known heat shock-responsive gene, suggesting that sigma(28) RNA polymerase may be involved in the response to cellular stress. Our sigma(28) prediction algorithm can be applied to other bacteria, and by performing a similar analysis on the Escherichia coli genome, we have predicted and functionally identified five previously unknown sigma(28)-regulated genes in E. coli.
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Affiliation(s)
- Hilda Hiu Yin Yu
- Institute for Genomics and Bioinformatics, University of California, Irvine, California 92697-4025, USA
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Grieshaber NA, Sager JB, Dooley CA, Hayes SF, Hackstadt T. Regulation of the Chlamydia trachomatis histone H1-like protein Hc2 is IspE dependent and IhtA independent. J Bacteriol 2006; 188:5289-92. [PMID: 16816202 PMCID: PMC1539943 DOI: 10.1128/jb.00526-06] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The chlamydial histone-like proteins, Hc1 and Hc2, function as global regulators of chromatin structure and gene expression. Hc1 and Hc2 expression and activity are developmentally regulated. A small metabolite that disrupts Hc1 interaction with DNA also disrupts Hc2 interactions; however, the small regulatory RNA that inhibits Hc1 translation is specific to Hc1.
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Affiliation(s)
- Nicole A Grieshaber
- Host-Parasite Interactions Section, Laboratory of Intracellular Parasites, NIAID, NIH, Rocky Mountain Laboratories, Hamilton, MT 59840, USA
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Elwell C, Engel JN. Drosophila melanogaster S2 cells: a model system to study Chlamydia interaction with host cells. Cell Microbiol 2006; 7:725-39. [PMID: 15839901 PMCID: PMC1236988 DOI: 10.1111/j.1462-5822.2005.00508.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chlamydia spp. are major causes of important human diseases, but dissecting the host-pathogen interactions has been hampered by the lack of bacterial genetics and the difficulty in carrying out forward genetic screens in mammalian hosts. RNA interference (RNAi)-based methodologies for gene inactivation can now be easily carried out in genetically tractable model hosts, such as Drosophila melanogaster, and offer a new approach to identifying host genes required for pathogenesis. We tested whether Chlamydia trachomatis infection of D. melanogaster S2 cells recapitulated critical aspects of mammalian cell infections. As in mammalian cells, C. trachomatis entry was greatly reduced by heparin and cytochalasin D. Inclusions were formed in S2 cells, acquired Golgi-derived sphingolipids, and avoided phagolysosomal fusion. Elementary body (EB) to reticulate body (RB) differentiation was observed, however, no RB to EB development or host cell killing was observed. RNAi-mediated inactivation of Rac, a Rho GTPase recently shown to be required for C. trachomatis entry in mammalian cells, inhibits C. trachomatis infection in S2 cells. We conclude that Drosophila S2 cells faithfully mimic early events in Chlamydia host cell interactions and provides a bona fide system to systematically dissect host functions important in the pathogenesis of obligate intracellular pathogens.
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Affiliation(s)
| | - J. N. Engel
- Departments of Medicine
- Microbiology and Immunology University of California, San Francisco, CA 94143, USA
- *For correspondence. E-mail
; Tel. (+415) 476 7355; Fax (+415) 476 9364
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Abstract
Chlamydia is predicted to encode two alternative sigma factors that could provide a mechanism for the regulation of gene expression via alternative forms of RNA polymerase. We have demonstrated that sigma 28, one of these alternative sigma factors, is transcriptionally active. Chlamydial sigma 28 RNA polymerase was reconstituted from recombinant sigma 28 protein and core enzyme that was biochemically isolated from chlamydiae. In an in vitro transcription assay, sigma 28 RNA polymerase transcribed the hctB promoter in a sigma 28-dependent manner. Transcription by sigma 28 RNA polymerase was salt tolerant compared with transcription by sigma 66 RNA polymerase, the major form of chlamydial RNA polymerase. As hctB encodes a histone-like protein that is only expressed late in the developmental cycle, our results suggest that sigma 28 RNA polymerase has a role in the regulation of late gene expression in Chlamydia.
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Affiliation(s)
- Hilda Hiu Yin Yu
- Department of Microbiology and Molecular Genetics, College of Medicine, University of California, Irvine, CA 92697-4025, USA
| | - Ming Tan
- Department of Microbiology and Molecular Genetics, College of Medicine, University of California, Irvine, CA 92697-4025, USA
- Department of Medicine, College of Medicine, University of California, Irvine, CA 92697-4025, USA
- For correspondence. ; Tel. (+1) 949 824 3397; Fax (+1) 949 824 8598
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Jones ML, Gaston JS, Pearce JH. Induction of abnormal Chlamydia trachomatis by exposure to interferon-gamma or amino acid deprivation and comparative antigenic analysis. Microb Pathog 2001; 30:299-309. [PMID: 11373124 DOI: 10.1006/mpat.2001.0433] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Abnormal forms of Chlamydia trachomatis have been induced in vitro by a variety of methods including nutrient deprivation, addition of cytokines and addition of antibiotics. These forms have been shown to have altered morphology and infectivity and have been implicated in persistent infections in vivo although there is little direct evidence for their presence. Likely sites for abnormal forms in vivo are the genital tract and the synovial tissue of reactive arthritis patients, and T cells isolated from the synovial tissue have been shown to be specific for chlamydial antigens, in particular the Hsp60. Since T cell specificity is so important in reactive arthritis disease the antigenic composition of abnormal forms induced by Interferon-gamma and amino acid deprivation has been examined by western blotting in two strains of C. trachomatis belonging to different biovars. The degree of abnormality of the organisms was found to increase as the treatments became more severe. No simple patterns of antigenic changes were found and differences in the antigenic composition were seen in abnormal forms induced by the different treatments and also in the different strains.
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Affiliation(s)
- M L Jones
- Microbial Molecular Genetics and Cell Biology Group, School of Biological Sciences, University of Birmingham, Birmingham B15 2TT, UK.
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Le Dantec L, Castroviejo M, Bové JM, Saillard C. Purification, cloning, and preliminary characterization of a Spiroplasma citri ribosomal protein with DNA binding capacity. J Biol Chem 1998; 273:24379-86. [PMID: 9733727 DOI: 10.1074/jbc.273.38.24379] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The rpsB-tsf-x operon of Spiroplasma citri encodes ribosomal protein S2 and elongation factor Ts, two components of the translational apparatus, and an unidentified X protein. A potential DNA-binding site (a 20-base pair (bp) inverted repeat sequence) is located at the 3' end of rpsB. Southwestern analysis of S. citri proteins, with a 30-bp double-stranded oligonucleotide probe (IRS), containing the 20-bp inverted repeat sequence and the genomic flanking sequences, detected an IRS-binding protein of 46 kDa (P46). P46 protein, which displays preferential affinity for the IRS, was purified from S. citri by a combination of affinity and gel filtration chromatographies. The native form of P46 seems to be homomultimeric as estimated by SDS-polyacrylamide gel electrophoresis analysis and gel filtration. A 3.5-kilobase pair S. citri DNA fragment comprising the P46 gene and flanking sequences was cloned and sequenced. Sequence analysis of this DNA fragment indicated that the P46 gene is located within the S10-spc operon of S. citri at the position of the gene coding for ribosomal protein L29 in the known S10-spc operons. The similarity between the N-terminal domain of P46 and the L29 ribosomal protein family and the presence of a 46-kDa IRS-binding protein in S. citri ribosomes indicated that P46 is the L29 ribosomal protein of S. citri. We suggest that P46 is a bifunctional protein with an L29 N-terminal domain and a C-terminal domain involved in IRS binding.
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Affiliation(s)
- L Le Dantec
- Laboratoire de Biologie Cellulaire et Moléculaire, Institut National de la Recherche Agronomique and Université Victor Segalen Bordeaux 2, 33883 Villenave d'Ornon Cedex, France
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Zhang L, Douglas AL, Hatch TP. Characterization of a Chlamydia psittaci DNA binding protein (EUO) synthesized during the early and middle phases of the developmental cycle. Infect Immun 1998; 66:1167-73. [PMID: 9488410 PMCID: PMC108030 DOI: 10.1128/iai.66.3.1167-1173.1998] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The EUO gene (for early upstream open reading frame) of Chlamydia psittaci was previously found to be transcribed better at 1 than at 24 h postinfection. We found that the EUO gene encodes a minor protein that is expressed within 1 h of infection of host cells with C. psittaci 6BC but that protein quantity peaks during the logarithmic growth phase of reticulate bodies (RBs), declines late in the infection (after 20 h) when RBs reorganize into elementary bodies (EBs), and is absent in infectious EBs. EUO protein lacks homology to known proteins but does contain a putative helix-turn-helix motif. We found that recombinant EUO binds to DNA in vitro with a relatively broad specificity. Using the bp -200 to +67 promoter region of the cysteine-rich envelope protein (crp) operon as a model, we show that EUO protein preferentially binds to AT-rich sequences and protects crp DNA from DNase I from approximately bp -60 to -9. We also found that native EUO protein in extracts of RBs binds to the promoter region of the crp operon, demonstrating that the DNA binding property of EUO protein is not an artifact of recombinant methods. Although EUO protein appears to bind to the crp operon with high affinity in vitro (Kd of about 15 nM), it is not known whether the protein binds the crp DNA in vivo.
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Affiliation(s)
- L Zhang
- Department of Microbiology and Immunology, University of Tennessee, Memphis 38163, USA
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