1
|
Uesaka K, Banba M, Chiba S, Fujita Y. Restoration of the Functional nif Gene Cluster by Complex Recombination Events during Heterocyst Development in the Nitrogen-Fixing Cyanobacterium Calothrix sp. NIES-4101. PLANT & CELL PHYSIOLOGY 2024; 65:1050-1064. [PMID: 38305573 PMCID: PMC11249958 DOI: 10.1093/pcp/pcae011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/17/2024] [Accepted: 02/01/2024] [Indexed: 02/03/2024]
Abstract
In the genome of the heterocystous cyanobacterium Calothrix sp. NIES-4101 (NIES-4101), the four genes essential for nitrogen fixation (nifB, nifH, nifD and nifK) are highly fragmented into 13 parts in a 350-kb chromosomal region, and four of these parts are encoded in the reverse strand. Such a complex fragmentation feature makes it difficult to restore the intact nifBHDK genes by the excision mechanism found in the nifD gene of the Anabaena sp. PCC 7120 heterocyst. To examine the nitrogen-fixing ability of NIES-4101, we confirmed that NIES-4101 grew well on a combined nitrogen-free medium and showed high nitrogenase activity, which strongly suggested that the complete nifBHDK genes are restored by a complex recombination process in heterocysts. Next, we resequenced the genome prepared from cells grown under nitrogen-fixing conditions. Two contigs covering the complete nifHDK and nifB genes were found by de novo assembly of the sequencing reads. In addition, the DNA fragments covering the nifBHDK operon were successfully amplified by PCR. We propose that the process of nifBHDK restoration occurs as follows. First, the nifD-nifK genes are restored by four excision events. Then, the complete nifH and nifB genes are restored by two excision events followed by two successive inversion events between the inverted repeat sequences and one excision event, forming the functional nif gene cluster, nifB-fdxN-nifS-nifU-nifH-nifD-nifK. All genes coding recombinases responsible for these nine recombination events are located close to the terminal repeat sequences. The restoration of the nifBHDK genes in NIES-4101 is the most complex genome reorganization reported in heterocystous cyanobacteria.
Collapse
Affiliation(s)
- Kazuma Uesaka
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
| | - Mari Banba
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
| | - Sotaro Chiba
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
| | - Yuichi Fujita
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
| |
Collapse
|
2
|
Douillard FP, Portinha IM, Derman Y, Woudstra C, Mäklin T, Dorner MB, Korkeala H, Henriques AO, Lindström M. A Novel Prophage-like Insertion Element within yabG Triggers Early Entry into Sporulation in Clostridium botulinum. Viruses 2023; 15:2431. [PMID: 38140671 PMCID: PMC10747680 DOI: 10.3390/v15122431] [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: 05/25/2023] [Revised: 12/12/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Sporulation is a finely regulated morphogenetic program important in the ecology and epidemiology of Clostridium botulinum. Exogenous elements disrupting sporulation-associated genes contribute to sporulation regulation and introduce diversity in the generally conserved sporulation programs of endospore formers. We identified a novel prophage-like DNA segment, termed the yin element, inserted within yabG, encoding a sporulation-specific cysteine protease, in an environmental isolate of C. botulinum. Bioinformatic analysis revealed that the genetic structure of the yin element resembles previously reported mobile intervening elements associated with sporulation genes. Within a pure C. botulinum culture, we observed two subpopulations of cells with the yin element either integrated into the yabG locus or excised as a circular DNA molecule. The dynamics between the two observed conformations of the yin element was growth-phase dependent and likely mediated by recombination events. The yin element was not required for sporulation by C. botulinum but triggered an earlier entry into sporulation than in a related isolate lacking this element. So far, the yin element has not been found in any other C. botulinum strains or other endospore-forming species. It remains to be demonstrated what kind of competitive edge it provides for C. botulinum survival and persistence.
Collapse
Affiliation(s)
- François P. Douillard
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
| | - Inês Martins Portinha
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
| | - Yağmur Derman
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
| | - Cédric Woudstra
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
| | - Tommi Mäklin
- Department of Mathematics and Statistics, Faculty of Science, University of Helsinki, 00560 Helsinki, Finland;
| | - Martin B. Dorner
- Centre for Biological Threats and Special Pathogens, ZBS3—Biological Toxins, Robert Koch Institute, 13353 Berlin, Germany;
| | - Hannu Korkeala
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
| | - Adriano O. Henriques
- Institute of Chemical and Biological Technology, NOVA University Lisbon, 2780-157 Oeiras, Portugal;
| | - Miia Lindström
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00350 Helsinki, Finland; (F.P.D.); (I.M.P.); (Y.D.); (C.W.); (H.K.)
| |
Collapse
|
3
|
Gummelt C, Dupke S, Howaldt S, Zimmermann F, Scholz HC, Laue M, Klee SR. Analysis of Sporulation in Bacillus cereus Biovar anthracis Which Contains an Insertion in the Gene for the Sporulation Factor σ K. Pathogens 2023; 12:1442. [PMID: 38133325 PMCID: PMC10745906 DOI: 10.3390/pathogens12121442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023] Open
Abstract
Bacillus cereus biovar anthracis (Bcbva) is an untypical pathogen causing a fatal anthrax-like disease in a variety of wildlife species in African rainforest areas. In contrast to Bacillus anthracis and most species of the B. cereus group, all strains of the Bcbva cluster contain a 22 kb insertion in the sigK gene which encodes the essential late sporulation sigma factor σK. This insertion is excised during sporulation in a site-specific recombination process resulting in an intact sigK gene and a circular molecule. The sporulation kinetics of two strains each of Bcbva and B. anthracis were compared by the expression analysis of eight sporulation-associated genes, including sigK, using reverse transcriptase quantitative real-time PCR. In addition, morphological sporulation stages were analyzed and quantified by electron microscopy. Our results indicated that the necessary excision of the insertion in Bcbva neither delayed nor inhibited its sporulation. In two spontaneous mutants of Bcbva, the excision of the sigK insertion and sporulation were impeded due to mutations in the spo0A and spoVG regulator genes, respectively. The spo0A frameshift mutation was overcome by intragenic suppression in a revertant which was able to sporulate normally, despite an M171S amino acid exchange in the global regulator Spo0A. A screening of the NCBI database identified further strains of the B. cereus group which possess unrelated insertions in the sigK gene, and two strains containing almost identical insertions at the same gene position. Some of the sigK insertions encode putative prophages, whereas the Bcbva insertion encoded a type I restriction-modification system. The function of these insertions and if they are possibly essential for sporulation remains to be assessed.
Collapse
Affiliation(s)
- Constanze Gummelt
- Highly Pathogenic Microorganisms (ZBS 2), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, 13353 Berlin, Germany; (C.G.); (S.D.); (S.H.); (H.C.S.)
| | - Susann Dupke
- Highly Pathogenic Microorganisms (ZBS 2), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, 13353 Berlin, Germany; (C.G.); (S.D.); (S.H.); (H.C.S.)
| | - Sabine Howaldt
- Highly Pathogenic Microorganisms (ZBS 2), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, 13353 Berlin, Germany; (C.G.); (S.D.); (S.H.); (H.C.S.)
| | - Fee Zimmermann
- Epidemiology of Highly Pathogenic Microorganisms (P3), Robert Koch Institute, 13353 Berlin, Germany;
| | - Holger C. Scholz
- Highly Pathogenic Microorganisms (ZBS 2), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, 13353 Berlin, Germany; (C.G.); (S.D.); (S.H.); (H.C.S.)
| | - Michael Laue
- Advanced Light and Electron Microscopy (ZBS 4), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, 13353 Berlin, Germany;
| | - Silke R. Klee
- Highly Pathogenic Microorganisms (ZBS 2), Centre for Biological Threats and Special Pathogens, Robert Koch Institute, 13353 Berlin, Germany; (C.G.); (S.D.); (S.H.); (H.C.S.)
| |
Collapse
|
4
|
Bazin-Gélis M, Eleftheriou E, Zangarelli C, Lelandais G, Sperling L, Arnaiz O, Bétermier M. Inter-generational nuclear crosstalk links the control of gene expression to programmed genome rearrangement during the Paramecium sexual cycle. Nucleic Acids Res 2023; 51:12337-12351. [PMID: 37953377 PMCID: PMC10711438 DOI: 10.1093/nar/gkad1006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 10/09/2023] [Accepted: 10/23/2023] [Indexed: 11/14/2023] Open
Abstract
Multinucleate cells are found in many eukaryotes, but how multiple nuclei coordinate their functions is still poorly understood. In the cytoplasm of the ciliate Paramecium tetraurelia, two micronuclei (MIC) serving sexual reproduction coexist with a somatic macronucleus (MAC) dedicated to gene expression. During sexual processes, the MAC is progressively destroyed while still ensuring transcription, and new MACs develop from copies of the zygotic MIC. Several gene clusters are successively induced and switched off before vegetative growth resumes. Concomitantly, programmed genome rearrangement (PGR) removes transposons and their relics from the new MACs. Development of the new MACs is controlled by the old MAC, since the latter expresses genes involved in PGR, including the PGM gene encoding the essential PiggyMac endonuclease that cleaves the ends of eliminated sequences. Using RNA deep sequencing and transcriptome analysis, we show that impairing PGR upregulates key known PGR genes, together with ∼600 other genes possibly also involved in PGR. Among these genes, 42% are no longer induced when no new MACs are formed, including 180 genes that are co-expressed with PGM under all tested conditions. We propose that bi-directional crosstalk between the two coexisting generations of MACs links gene expression to the progression of MAC development.
Collapse
Affiliation(s)
- Mélanie Bazin-Gélis
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Evangelia Eleftheriou
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
- Institut Pasteur, Université Paris Cité, Inserm U1223, Innate Immunity Unit, Paris, France
| | - Coralie Zangarelli
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Gaëlle Lelandais
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Linda Sperling
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Olivier Arnaiz
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Mireille Bétermier
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| |
Collapse
|
5
|
Jun JS, Jeong HE, Moon SY, Shin SH, Hong KW. Time-Course Transcriptome Analysis of Bacillus subtilis DB104 during Growth. Microorganisms 2023; 11:1928. [PMID: 37630488 PMCID: PMC10458515 DOI: 10.3390/microorganisms11081928] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 08/27/2023] Open
Abstract
Bacillus subtilis DB104, an extracellular protease-deficient derivative of B. subtilis 168, is widely used for recombinant protein expression. An understanding of the changes in gene expression during growth is essential for the commercial use of bacterial strains. Transcriptome and proteome analyses are ideal methods to study the genomic response of microorganisms. In this study, transcriptome analysis was performed to monitor changes in the gene expression level of B. subtilis DB104 while growing on a complete medium. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, K-mean cluster analysis, gene ontology (GO) enrichment analysis, and the function of sigma factors were used to divide 2122 differentially expressed genes (DEGs) into 10 clusters and identified gene functions according to expression patterns. The results of KEGG pathway analysis indicated that ABC transporter is down-regulated during exponential growth and metabolic changes occur at the transition point where sporulation starts. At this point, several stress response genes were also turned on. The genes involved in the lipid catabolic process were up-regulated briefly at 15 h as an outcome of the programmed cell death that postpones sporulation. The results suggest that changes in the gene expression of B. subtilis DB104 were dependent on the initiation of sporulation. However, the expression timing of the spore coat gene was only affected by the relevant sigma factor. This study can help to understand gene expression and regulatory mechanisms in B. subtilis species by providing an overall view of transcriptional changes during the growth of B. subtilis DB104.
Collapse
Affiliation(s)
| | | | | | | | - Kwang-Won Hong
- Department of Food Science and Biotechnology, College of Life Science and Biotechnology, Dongguk University, Goyang-si 10326, Republic of Korea; (J.-S.J.); (H.-E.J.); (S.-Y.M.); (S.-H.S.)
| |
Collapse
|
6
|
Butala M, Dragoš A. Unique relationships between phages and endospore-forming hosts. Trends Microbiol 2022; 31:498-510. [PMID: 36535834 DOI: 10.1016/j.tim.2022.11.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 11/23/2022] [Accepted: 11/23/2022] [Indexed: 12/23/2022]
Abstract
As part of their survival strategy under harsh environmental conditions, endospore-forming bacteria can trigger a sporulation developmental program. Although the regulatory cascades that precisely control the transformation of vegetative bacteria into mother cells and resilient spores have been described in detail, less is known about how bacteriophages that prey on endospore-formers exploit sporulation. Herein, we argue that phages infecting these bacteria have evolved several specific molecular mechanisms, not yet known in other bacteria, that manifest from the phage-driven alliance to negative effects on the host. We anticipate that the relationships between phages and endospore-formers outlined here will inspire studies on phage ecology and evolution, and could facilitate important advances in the development of phage therapies against pathogenic spore-formers.
Collapse
Affiliation(s)
- Matej Butala
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Anna Dragoš
- Department of Microbiology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia.
| |
Collapse
|
7
|
Bean EL, McLellan LK, Grossman AD. Activation of the integrative and conjugative element Tn916 causes growth arrest and death of host bacteria. PLoS Genet 2022; 18:e1010467. [PMID: 36279314 PMCID: PMC9632896 DOI: 10.1371/journal.pgen.1010467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/03/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022] Open
Abstract
Integrative and conjugative elements (ICEs) serve as major drivers of bacterial evolution. These elements often confer some benefit to host cells, including antibiotic resistance, metabolic capabilities, or pathogenic determinants. ICEs can also have negative effects on host cells. Here, we investigated the effects of the ICE (conjugative transposon) Tn916 on host cells. Because Tn916 is active in a relatively small subpopulation of host cells, we developed a fluorescent reporter system for monitoring activation of Tn916 in single cells. Using this reporter, we found that cell division was arrested in cells of Bacillus subtilis and Enterococcus faecalis (a natural host for Tn916) that contained an activated (excised) Tn916. Furthermore, most of the cells with the activated Tn916 subsequently died. We also observed these phenotypes on the population level in B. subtilis utilizing a modified version of Tn916 that can be activated in the majority of cells. We identified two genes (orf17 and orf16) in Tn916 that were sufficient to cause growth defects in B. subtilis and identified a single gene, yqaR, that is in a defective phage (skin) in the B. subtilis chromosome that was required for this phenotype. These three genes were only partially responsible for the growth defect caused by Tn916, indicating that Tn916 possesses multiple mechanisms to affect growth and viability of host cells. These results highlight the complex relationships that conjugative elements have with their host cells and the interplay between mobile genetic elements.
Collapse
Affiliation(s)
- Emily L. Bean
- Department of Biology Massachusetts, Institute of Technology Cambridge, Massachusetts, United States of America
| | - Lisa K. McLellan
- Department of Biology Massachusetts, Institute of Technology Cambridge, Massachusetts, United States of America
| | - Alan D. Grossman
- Department of Biology Massachusetts, Institute of Technology Cambridge, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
8
|
Conservation and Evolution of the Sporulation Gene Set in Diverse Members of the Firmicutes. J Bacteriol 2022; 204:e0007922. [PMID: 35638784 DOI: 10.1128/jb.00079-22] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The current classification of the phylum Firmicutes (new name, Bacillota) features eight distinct classes, six of which include known spore-forming bacteria. In Bacillus subtilis, sporulation involves up to 500 genes, many of which do not have orthologs in other bacilli and/or clostridia. Previous studies identified about 60 sporulation genes of B. subtilis that were shared by all spore-forming members of the Firmicutes. These genes are referred to as the sporulation core or signature, although many of these are also found in genomes of nonsporeformers. Using an expanded set of 180 firmicute genomes from 160 genera, including 76 spore-forming species, we investigated the conservation of the sporulation genes, in particular seeking to identify lineages that lack some of the genes from the conserved sporulation core. The results of this analysis confirmed that many small acid-soluble spore proteins (SASPs), spore coat proteins, and germination proteins, which were previously characterized in bacilli, are missing in spore-forming members of Clostridia and other classes of Firmicutes. A particularly dramatic loss of sporulation genes was observed in the spore-forming members of the families Planococcaceae and Erysipelotrichaceae. Fifteen species from diverse lineages were found to carry skin (sigK-interrupting) elements of different sizes that all encoded SpoIVCA-like recombinases but did not share any other genes. Phylogenetic trees built from concatenated alignments of sporulation proteins and ribosomal proteins showed similar topology, indicating an early origin and subsequent vertical inheritance of the sporulation genes. IMPORTANCE Many members of the phylum Firmicutes (Bacillota) are capable of producing endospores, which enhance the survival of important Gram-positive pathogens that cause such diseases as anthrax, botulism, colitis, gas gangrene, and tetanus. We show that the core set of sporulation genes, defined previously through genome comparisons of several bacilli and clostridia, is conserved in a wide variety of sporeformers from several distinct lineages of Firmicutes. We also detected widespread loss of sporulation genes in many organisms, particularly within the families Planococcaceae and Erysipelotrichaceae. Members of these families, such as Lysinibacillus sphaericus and Clostridium innocuum, could be excellent model organisms for studying sporulation mechanisms, such as engulfment, formation of the spore coat, and spore germination.
Collapse
|
9
|
Abe K, Kato H, Hasegawa Y, Yamamoto T, Nomura N, Obana N. Visualization and characterization of spore morphogenesis in Paenibacillus polymyxa ATCC39564. J GEN APPL MICROBIOL 2022; 68:79-86. [PMID: 35418538 DOI: 10.2323/jgam.2021.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Paenibacillus polymyxa is a spore-forming Gram-positive bacterial species. Both its sporulation process and the spore properties are poorly understood. Here, we investigated sporulation in P. polymyxa ATCC39564. When cultured at 37℃ for 24 h in sporulation medium, more than 80% of the total cells in the culture were spores. Time-lapse imaging revealed that cellular morphological changes during sporulation of P. polymyxa were highly similar to those of B. subtilis. We demonstrated that genetic deletion of spo0A, sigE, sigF, sigG, or sigK, which are highly conserved transcriptional regulators in spore forming bacteria, abolished spore formation. In P. polymyxa, spo0A was required for cell growth in sporulation medium, as well as for the initiation of sporulation. The sigE and sigF mutants formed abnormal multiple asymmetric septa during the early stage of sporulation. The sigG and sigK mutants formed forespores in the sporangium, but they did not become mature. Moreover, fluorescence reporter analysis confirmed compartment-specific gene expression of spoIID and spoVFA in the mother cell and spoIIQ and sspF in the forespore. Transmission electron microscopy imaging revealed that P. polymyxa produces multilayered endospores but lacking a balloon-shaped exosporium. Our results indicate that spore morphogenesis is conserved between P. polymyxa and B. subtilis. However, P. polymyxa genomes lack many homologues encoding spore-coat proteins that are found in B. subtills, suggesting that there are differences in the spore coat composition and surface structure between P. polymyxa and B. subtilis.
Collapse
Affiliation(s)
- Kimihiro Abe
- Faculty of Life and Environmental Sciences, University of Tsukuba
| | - Hiroko Kato
- Gradudate School of Life and Environmental Sciences, University of Tsukuba
| | - Yuta Hasegawa
- Gradudate School of Life and Environmental Sciences, University of Tsukuba
| | - Tatsuya Yamamoto
- Faculty of Life and Environmental Sciences, University of Tsukuba
| | - Nobuhiko Nomura
- Faculty of Life and Environmental Sciences, University of Tsukuba.,Microbiology Research Center for Sustainability, University of Tsukuba
| | - Nozomu Obana
- Microbiology Research Center for Sustainability, University of Tsukuba.,Transborder Medical Research Center, Faculty of Medicine, University of Tsukuba
| |
Collapse
|
10
|
Marshall CW, Gloag ES, Lim C, Wozniak DJ, Cooper VS. Rampant prophage movement among transient competitors drives rapid adaptation during infection. SCIENCE ADVANCES 2021; 7:7/29/eabh1489. [PMID: 34272240 PMCID: PMC8284892 DOI: 10.1126/sciadv.abh1489] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 06/03/2021] [Indexed: 05/11/2023]
Abstract
Interactions between bacteria, their close competitors, and viral parasites are common in infections, but understanding of these eco-evolutionary dynamics is limited. Most examples of adaptations caused by phage lysogeny are through the acquisition of new genes. However, integrated prophages can also insert into functional genes and impart a fitness benefit by disrupting their expression, a process called active lysogeny. Here, we show that active lysogeny can fuel rapid, parallel adaptations in establishing a chronic infection. These recombination events repeatedly disrupted genes encoding global regulators, leading to increased cyclic di-GMP levels and elevated biofilm production. The implications of prophage-mediated adaptation are broad, as even transient members of microbial communities can alter the course of evolution and generate persistent phenotypes associated with poor clinical outcomes.
Collapse
Affiliation(s)
| | - Erin S Gloag
- Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH, USA
| | - Christina Lim
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Daniel J Wozniak
- Department of Microbial Infection and Immunity, Ohio State University, Columbus, OH, USA
- Department of Microbiology, Ohio State University, Columbus, OH, USA
| | - Vaughn S Cooper
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA, USA.
- Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| |
Collapse
|
11
|
Dragoš A, Priyadarshini B, Hasan Z, Strube ML, Kempen PJ, Maróti G, Kaspar C, Bose B, Burton BM, Bischofs IB, Kovács ÁT. Pervasive prophage recombination occurs during evolution of spore-forming Bacilli. ISME JOURNAL 2020; 15:1344-1358. [PMID: 33343000 DOI: 10.1038/s41396-020-00854-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/12/2020] [Accepted: 11/20/2020] [Indexed: 02/06/2023]
Abstract
Phages are the main source of within-species bacterial diversity and drivers of horizontal gene transfer, but we know little about the mechanisms that drive genetic diversity of these mobile genetic elements (MGEs). Recently, we showed that a sporulation selection regime promotes evolutionary changes within SPβ prophage of Bacillus subtilis, leading to direct antagonistic interactions within the population. Herein, we reveal that under a sporulation selection regime, SPβ recombines with low copy number phi3Ts phage DNA present within the B. subtilis population. Recombination results in a new prophage occupying a different integration site, as well as the spontaneous release of virulent phage hybrids. Analysis of Bacillus sp. strains suggests that SPβ and phi3T belong to a distinct cluster of unusually large phages inserted into sporulation-related genes that are equipped with a spore-related genetic arsenal. Comparison of Bacillus sp. genomes indicates that similar diversification of SPβ-like phages takes place in nature. Our work is a stepping stone toward empirical studies on phage evolution, and understanding the eco-evolutionary relationships between bacteria and their phages. By capturing the first steps of new phage evolution, we reveal striking relationship between survival strategy of bacteria and evolution of their phages.
Collapse
Affiliation(s)
- Anna Dragoš
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
| | - B Priyadarshini
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Zahraa Hasan
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Mikael Lenz Strube
- Bacterial Ecophysiology and Biotechnology Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Paul J Kempen
- Department of Health Technology, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Gergely Maróti
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, H-6701, Hungary
| | - Charlotte Kaspar
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | | | - Briana M Burton
- Department of Bacteriology, University of Wisconsin, Madison, WI, 53706, USA
| | - Ilka B Bischofs
- BioQuant Center of the University of Heidelberg, 69120, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, 35043, Marburg, Germany
| | - Ákos T Kovács
- Bacterial Interactions and Evolution Group, Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
| |
Collapse
|
12
|
Abe K, Takahashi T, Sato T. Extreme C-terminal element of SprA serine integrase is a potential component of the "molecular toggle switch" which controls the recombination and its directionality. Mol Microbiol 2020; 115:1110-1121. [PMID: 33244797 DOI: 10.1111/mmi.14654] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 10/26/2020] [Accepted: 11/21/2020] [Indexed: 12/11/2022]
Abstract
In Bacillus subtilis, a sporulation-related gene, spsM, is disrupted by SPβ prophage, but reconstituted during sporulation through SPβ excision. The spsM reconstitution is catalyzed by a site-specific DNA recombinase, SprA, and its cognate recombination directionality factor, SprB. SprB interacts with SprA, directing the SprA-mediated recombination reaction from integration to excision; however, the details of the directionality control remains unclear. Here, we demonstrate the importance of the extreme C-terminal region (ECT) of SprA in the DNA recombination and directionality control. We created a series of SprA C-terminal deletants and examined their DNA-binding and recombination activities. Deletions in the ECT caused a loss of integration and excision activity, the magnitudes of which positively correlated with the deletion size. Gel shift study revealed that the loss of the integration activity was attributable to the failure of synaptic complex formation. The excision deficiency was caused by defective interaction with SprB. Moreover, alanine scanning analysis revealed that Phe532 is essential to interact with SprB. SprAF532A , therefore, showed almost no excision activity, while retaining the integration activity. Collectively, these results suggest that the ECT plays the crucial roles in the interaction of SprA with SprB and possibly in the directional control of the recombination.
Collapse
Affiliation(s)
- Kimihiro Abe
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Japan
| | - Takumi Takahashi
- Department of Frontier Bioscience, Hosei University, Koganei, Japan
| | - Tsutomu Sato
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Japan.,Department of Frontier Bioscience, Hosei University, Koganei, Japan
| |
Collapse
|
13
|
Johnson GE, Lalanne JB, Peters ML, Li GW. Functionally uncoupled transcription-translation in Bacillus subtilis. Nature 2020; 585:124-128. [PMID: 32848247 PMCID: PMC7483943 DOI: 10.1038/s41586-020-2638-5] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/22/2020] [Indexed: 11/10/2022]
Abstract
Tight coupling of transcription and translation is considered a defining feature of bacterial gene expression1,2. The pioneering ribosome can both physically associate and kinetically coordinate with RNA polymerase (RNAP)3-11, forming a signal-integration hub for co-transcriptional regulation that includes translation-based attenuation12,13 and RNA quality control2. However, it remains unclear whether transcription-translation coupling-together with its broad functional consequences-is indeed a fundamental characteristic of bacteria other than Escherichia coli. Here we show that RNAPs outpace pioneering ribosomes in the Gram-positive model bacterium Bacillus subtilis, and that this 'runaway transcription' creates alternative rules for both global RNA surveillance and translational control of nascent RNA. In particular, uncoupled RNAPs in B. subtilis explain the diminished role of Rho-dependent transcription termination, as well as the prevalence of mRNA leaders that use riboswitches and RNA-binding proteins. More broadly, we identified widespread genomic signatures of runaway transcription in distinct phyla across the bacterial domain. Our results show that coupled RNAP-ribosome movement is not a general hallmark of bacteria. Instead, translation-coupled transcription and runaway transcription constitute two principal modes of gene expression that determine genome-specific regulatory mechanisms in prokaryotes.
Collapse
Affiliation(s)
- Grace E Johnson
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jean-Benoît Lalanne
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Michelle L Peters
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gene-Wei Li
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
| |
Collapse
|
14
|
Compatibility of Site-Specific Recombination Units between Mobile Genetic Elements. iScience 2019; 23:100805. [PMID: 31926432 PMCID: PMC6957869 DOI: 10.1016/j.isci.2019.100805] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/06/2019] [Accepted: 12/19/2019] [Indexed: 12/17/2022] Open
Abstract
Site-specific recombination (SSR) systems are employed for transfer of mobile genetic elements (MGEs), such as lysogenic phages and integrative conjugative elements (ICEs). SSR between attP/I and attB sites is mediated by an integrase (Int) and a recombination directionality factor (RDF). The genome of Bacillus subtilis 168 contains SPβ, an active prophage, skin, a defective prophage, and ICEBs1, an integrative conjugative element. Each of these MGEs harbors the classic SSR unit attL-int-rdf-attR. Here, we demonstrate that these SSR units are all compatible and can substitute for one another. Specifically, when SPβ is turned into a defective prophage by deletion of its SSR unit, introduction of the SSR unit of skin or ICE converts it back to an active prophage. We also identified closely related prophages with distinct SSR units that control developmentally regulated gene rearrangements of kamA (L-lysine 2,3-aminomutase). These results suggest that SSR units are interchangeable components of MGEs. Lysogenic phage-derived SSR unit is sufficient to drive SSR of ICE and vice versa Defective prophage-derived SSR unit can drive the excision of the active lysogenic phage Closely related prophages with distinct SSR units control each gene rearrangements Correspondence between MGEs and their cognate SSR units is not absolute
Collapse
|
15
|
Ramírez-Guadiana FH, Rodrigues CDA, Marquis KA, Campo N, Barajas-Ornelas RDC, Brock K, Marks DS, Kruse AC, Rudner DZ. Evidence that regulation of intramembrane proteolysis is mediated by substrate gating during sporulation in Bacillus subtilis. PLoS Genet 2018; 14:e1007753. [PMID: 30403663 PMCID: PMC6242693 DOI: 10.1371/journal.pgen.1007753] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 11/19/2018] [Accepted: 10/10/2018] [Indexed: 01/11/2023] Open
Abstract
During the morphological process of sporulation in Bacillus subtilis two adjacent daughter cells (called the mother cell and forespore) follow different programs of gene expression that are linked to each other by signal transduction pathways. At a late stage in development, a signaling pathway emanating from the forespore triggers the proteolytic activation of the mother cell transcription factor σK. Cleavage of pro-σK to its mature and active form is catalyzed by the intramembrane cleaving metalloprotease SpoIVFB (B), a Site-2 Protease (S2P) family member. B is held inactive by two mother-cell membrane proteins SpoIVFA (A) and BofA. Activation of pro-σK processing requires a site-1 signaling protease SpoIVB (IVB) that is secreted from the forespore into the space between the two cells. IVB cleaves the extracellular domain of A but how this cleavage activates intramembrane proteolysis has remained unclear. Structural studies of the Methanocaldococcus jannaschii S2P homolog identified closed (substrate-occluded) and open (substrate-accessible) conformations of the protease, but the biological relevance of these conformations has not been established. Here, using co-immunoprecipitation and fluorescence microscopy, we show that stable association between the membrane-embedded protease and its substrate requires IVB signaling. We further show that the cytoplasmic cystathionine-β-synthase (CBS) domain of the B protease is not critical for this interaction or for pro-σK processing, suggesting the IVB-dependent interaction site is in the membrane protease domain. Finally, we provide evidence that the B protease domain adopts both open and closed conformations in vivo. Collectively, our data support a substrate-gating model in which IVB-dependent cleavage of A on one side of the membrane triggers a conformational change in the membrane-embedded protease from a closed to an open state allowing pro-σK access to the caged interior of the protease. Regulated Intramembrane Proteolysis is a broadly conserved mechanism for transducing information across lipid bilayers. In these signaling pathways a protease on one side of the membrane triggers the activation of a membrane-embedded protease that cleaves its substrate within or adjacent to the cytoplasmic face of the membrane. Site-2 metalloproteases (S2P) are the most commonly used intramembrane cleaving proteases in these pathways but the mechanism by which cleavage on one side of the membrane triggers intramembrane proteolysis remains poorly understood. Here, we provide evidence for a substrate-gating model in which an extracellular signaling protease triggers a conformational change in a S2P family member from a closed to an open conformation allowing its substrate access to the catalytic center of the enzyme.
Collapse
Affiliation(s)
| | | | - Kathleen A. Marquis
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA United States of America
| | - Nathalie Campo
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA United States of America
| | | | - Kelly Brock
- Department of Systems Biology, Harvard Medical School, Boston, MA
| | - Debora S. Marks
- Department of Systems Biology, Harvard Medical School, Boston, MA
| | - Andrew C. Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA
| | - David Z. Rudner
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston MA United States of America
- * E-mail:
| |
Collapse
|
16
|
Brito PH, Chevreux B, Serra CR, Schyns G, Henriques AO, Pereira-Leal JB. Genetic Competence Drives Genome Diversity in Bacillus subtilis. Genome Biol Evol 2018; 10:108-124. [PMID: 29272410 PMCID: PMC5765554 DOI: 10.1093/gbe/evx270] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2017] [Indexed: 12/18/2022] Open
Abstract
Prokaryote genomes are the result of a dynamic flux of genes, with increases achieved via horizontal gene transfer and reductions occurring through gene loss. The ecological and selective forces that drive this genomic flexibility vary across species. Bacillus subtilis is a naturally competent bacterium that occupies various environments, including plant-associated, soil, and marine niches, and the gut of both invertebrates and vertebrates. Here, we quantify the genomic diversity of B. subtilis and infer the genome dynamics that explain the high genetic and phenotypic diversity observed. Phylogenomic and comparative genomic analyses of 42 B. subtilis genomes uncover a remarkable genome diversity that translates into a core genome of 1,659 genes and an asymptotic pangenome growth rate of 57 new genes per new genome added. This diversity is due to a large proportion of low-frequency genes that are acquired from closely related species. We find no gene-loss bias among wild isolates, which explains why the cloud genome, 43% of the species pangenome, represents only a small proportion of each genome. We show that B. subtilis can acquire xenologous copies of core genes that propagate laterally among strains within a niche. While not excluding the contributions of other mechanisms, our results strongly suggest a process of gene acquisition that is largely driven by competence, where the long-term maintenance of acquired genes depends on local and global fitness effects. This competence-driven genomic diversity provides B. subtilis with its generalist character, enabling it to occupy a wide range of ecological niches and cycle through them.
Collapse
Affiliation(s)
- Patrícia H Brito
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Nova Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Portugal
| | - Bastien Chevreux
- DSM Nutritional Products, Ltd., 60 Westview street, Lexington MA, USA
| | - Cláudia R Serra
- Instituto de Tecnologia Química e Biológica, Oeiras, Portugal
| | - Ghislain Schyns
- DSM Nutritional Products, Ltd., 60 Westview street, Lexington MA, USA
| | | | - José B Pereira-Leal
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Ophiomics—Precision Medicine, Lisbon, Portugal
| |
Collapse
|
17
|
Abe K, Takamatsu T, Sato T. Mechanism of bacterial gene rearrangement: SprA-catalyzed precise DNA recombination and its directionality control by SprB ensure the gene rearrangement and stable expression of spsM during sporulation in Bacillus subtilis. Nucleic Acids Res 2017; 45:6669-6683. [PMID: 28535266 PMCID: PMC5499854 DOI: 10.1093/nar/gkx466] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/12/2017] [Indexed: 12/17/2022] Open
Abstract
A sporulation-specific gene, spsM, is disrupted by an active prophage, SPβ, in the genome of Bacillus subtilis. SPβ excision is required for two critical steps: the onset of the phage lytic cycle and the reconstitution of the spsM-coding frame during sporulation. Our in vitro study demonstrated that SprA, a serine-type integrase, catalyzed integration and excision reactions between attP of SPβ and attB within spsM, while SprB, a recombination directionality factor, was necessary only for the excision between attL and attR in the SPβ lysogenic chromosome. DNA recombination occurred at the center of the short inverted repeat motif in the unique conserved 16 bp sequence among the att sites (5΄-ACAGATAA/AGCTGTAT-3΄; slash, breakpoint; underlines, inverted repeat), where SprA produced the 3΄-overhanging AA and TT dinucleotides for rejoining the DNA ends through base-pairing. Electrophoretic mobility shift assay showed that SprB promoted synapsis of SprA subunits bound to the two target sites during excision but impaired it during integration. In vivo data demonstrated that sprB expression that lasts until the late stage of sporulation is crucial for stable expression of reconstituted spsM without reintegration of the SPβ prophage. These results present a deeper understanding of the mechanism of the prophage-mediated bacterial gene regulatory system.
Collapse
Affiliation(s)
- Kimihiro Abe
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-0003, Japan
| | - Takuo Takamatsu
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan
| | - Tsutomu Sato
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-0003, Japan.,Department of Frontier Bioscience, Hosei University, Koganei, Tokyo 184-8584, Japan
| |
Collapse
|
18
|
Abe K, Shimizu SY, Tsuda S, Sato T. A novel non prophage(-like) gene-intervening element within gerE that is reconstituted during sporulation in Bacillus cereus ATCC10987. Sci Rep 2017; 7:11426. [PMID: 28900282 PMCID: PMC5595907 DOI: 10.1038/s41598-017-11796-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 08/30/2017] [Indexed: 11/10/2022] Open
Abstract
Gene rearrangement is a widely-shared phenomenon in spore forming bacteria, in which prophage(-like) elements interrupting sporulation-specific genes are excised from the host genome to reconstitute the intact gene. Here, we report a novel class of gene-intervening elements, named gin, inserted in the 225 bp gerE-coding region of the B. cereus ATCC10987 genome, which generates a sporulation-specific rearrangement. gin has no phage-related genes and possesses three site-specific recombinase genes; girA, girB, and girC. We demonstrated that the gerE rearrangement occurs at the middle stage of sporulation, in which site-specific DNA recombination took place within the 9 bp consensus sequence flanking the disrupted gerE segments. Deletion analysis of gin uncovered that GirC and an additional factor, GirX, are responsible for gerE reconstitution. Involvement of GirC and GirX in DNA recombination was confirmed by an in vitro recombination assay. These results broaden the definition of the sporulation-specific gene rearrangement phenomenon: gene-intervening elements are not limited to phage DNA but may include non-viral genetic elements that carry a developmentally-regulated site-specific recombination system.
Collapse
Affiliation(s)
- Kimihiro Abe
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan
| | - Shin-Ya Shimizu
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Shuhei Tsuda
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Tsutomu Sato
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan. .,Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan.
| |
Collapse
|
19
|
Cohen JE, Wang R, Shen RF, Wu WW, Keller JE. Comparative pathogenomics of Clostridium tetani. PLoS One 2017; 12:e0182909. [PMID: 28800585 PMCID: PMC5553647 DOI: 10.1371/journal.pone.0182909] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 07/26/2017] [Indexed: 01/27/2023] Open
Abstract
Clostridium tetani and Clostridium botulinum produce two of the most potent neurotoxins known, tetanus neurotoxin and botulinum neurotoxin, respectively. Extensive biochemical and genetic investigation has been devoted to identifying and characterizing various C. botulinum strains. Less effort has been focused on studying C. tetani likely because recently sequenced strains of C. tetani show much less genetic diversity than C. botulinum strains and because widespread vaccination efforts have reduced the public health threat from tetanus. Our aim was to acquire genomic data on the U.S. vaccine strain of C. tetani to better understand its genetic relationship to previously published genomic data from European vaccine strains. We performed high throughput genomic sequence analysis on two wild-type and two vaccine C. tetani strains. Comparative genomic analysis was performed using these and previously published genomic data for seven other C. tetani strains. Our analysis focused on single nucleotide polymorphisms (SNP) and four distinct constituents of the mobile genome (mobilome): a hypervariable flagellar glycosylation island region, five conserved bacteriophage insertion regions, variations in three CRISPR (clustered regularly interspaced short palindromic repeats)-Cas (CRISPR-associated) systems, and a single plasmid. Intact type IA and IB CRISPR/Cas systems were within 10 of 11 strains. A type IIIA CRISPR/Cas system was present in two strains. Phage infection histories derived from CRISPR-Cas sequences indicate C. tetani encounters phages common among commensal gut bacteria and soil-borne organisms consistent with C. tetani distribution in nature. All vaccine strains form a clade distinct from currently sequenced wild type strains when considering variations in these mobile elements. SNP, flagellar glycosylation island, prophage content and CRISPR/Cas phylogenic histories provide tentative evidence suggesting vaccine and wild type strains share a common ancestor.
Collapse
Affiliation(s)
- Jonathan E. Cohen
- Laboratory of Respiratory and Special Pathogens, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Rong Wang
- Facility for Biotechnology Resources, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Rong-Fong Shen
- Facility for Biotechnology Resources, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Wells W. Wu
- Facility for Biotechnology Resources, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - James E. Keller
- Laboratory of Respiratory and Special Pathogens, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, United States of America
| |
Collapse
|
20
|
Genome-Wide Analysis of ResD, NsrR, and Fur Binding in Bacillus subtilis during Anaerobic Fermentative Growth by In Vivo Footprinting. J Bacteriol 2017; 199:JB.00086-17. [PMID: 28439033 DOI: 10.1128/jb.00086-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/13/2017] [Indexed: 12/20/2022] Open
Abstract
Upon oxygen limitation, the Bacillus subtilis ResE sensor kinase and its cognate ResD response regulator play primary roles in the transcriptional activation of genes functioning in anaerobic respiration. The nitric oxide (NO)-sensitive NsrR repressor controls transcription to support nitrate respiration. In addition, the ferric uptake repressor (Fur) can modulate transcription under anaerobic conditions. However, whether these controls are direct or indirect has been investigated only in a gene-specific manner. To gain a genomic view of anaerobic gene regulation, we determined the genome-wide in vivo DNA binding of ResD, NsrR, and Fur transcription factors (TFs) using in situ DNase I footprinting combined with chromatin affinity precipitation sequencing (ChAP-seq; genome footprinting by high-throughput sequencing [GeF-seq]). A significant number of sites were targets of ResD and NsrR, and a majority of them were also bound by Fur. The binding of multiple TFs to overlapping targets affected each individual TF's binding, which led to combinatorial transcriptional control. ResD bound to both the promoters and the coding regions of genes under its positive control. Other genes showing enrichment of ResD at only the promoter regions are targets of direct ResD-dependent repression or antirepression. The results support previous findings of ResD as an RNA polymerase (RNAP)-binding protein and indicated that ResD can associate with the transcription elongation complex. The data set allowed us to reexamine consensus sequence motifs of Fur, ResD, and NsrR and uncovered evidence that multiple TGW (where W is A or T) sequences surrounded by an A- and T-rich sequence are often found at sites where all three TFs competitively bind.IMPORTANCE Bacteria encounter oxygen fluctuation in their natural environment as well as in host organisms. Hence, understanding how bacteria respond to oxygen limitation will impact environmental and human health. ResD, NsrR, and Fur control transcription under anaerobic conditions. This work using in situ DNase I footprinting uncovered the genome-wide binding profile of the three transcription factors (TFs). Binding of the TFs is often competitive or cooperative depending on the promoters and the presence of other TFs, indicating that transcriptional regulation by multiple TFs is much more complex than we originally thought. The results from this study provide a more complete picture of anaerobic gene regulation governed by ResD, NsrR, and Fur and contribute to our further understanding of anaerobic physiology.
Collapse
|
21
|
Abstract
The large serine recombinases (LSRs) are a family of enzymes, encoded in temperate phage genomes or on mobile elements, that precisely cut and recombine DNA in a highly controllable and predictable way. In phage integration, the LSRs act at specific sites, the attP site in the phage and the attB site in the host chromosome, where cleavage and strand exchange leads to the integrated prophage flanked by the recombinant sites attL and attR. The prophage can excise by recombination between attL and attR but this requires a phage-encoded accessory protein, the recombination directionality factor (RDF). Although the LSRs can bind specifically to all the recombination sites, only specific integrase-bound sites can pair in a synaptic complex prior to strand exchange. Recent structural information has led to a breakthrough in our understanding of the mechanism of the LSRs, notably how the LSRs bind to their substrates and how LSRs display this site-selectivity. We also understand that the RDFs exercise control over the LSRs by protein-protein interactions. Other recent work with the LSRs have contributed to our understanding of how all serine recombinases undergo strand exchange subunit rotation, facilitated by surfaces that resemble a molecular bearing.
Collapse
|
22
|
Feiner R, Argov T, Rabinovich L, Sigal N, Borovok I, Herskovits AA. A new perspective on lysogeny: prophages as active regulatory switches of bacteria. Nat Rev Microbiol 2016; 13:641-50. [PMID: 26373372 DOI: 10.1038/nrmicro3527] [Citation(s) in RCA: 269] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Unlike lytic phages, temperate phages that enter lysogeny maintain a long-term association with their bacterial host. In this context, mutually beneficial interactions can evolve that support efficient reproduction of both phages and bacteria. Temperate phages are integrated into the bacterial chromosome as large DNA insertions that can disrupt gene expression, and they may pose a fitness burden on the cell. However, they have also been shown to benefit their bacterial hosts by providing new functions in a bacterium-phage symbiotic interaction termed lysogenic conversion. In this Opinion article, we discuss another type of bacterium-phage interaction, active lysogeny, in which phages or phage-like elements are integrated into the bacterial chromosome within critical genes or operons and serve as switches that regulate bacterial genes via genome excision.
Collapse
Affiliation(s)
- Ron Feiner
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Tal Argov
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Lev Rabinovich
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Nadejda Sigal
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ilya Borovok
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Anat A Herskovits
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| |
Collapse
|
23
|
Ambroset C, Coluzzi C, Guédon G, Devignes MD, Loux V, Lacroix T, Payot S, Leblond-Bourget N. New Insights into the Classification and Integration Specificity of Streptococcus Integrative Conjugative Elements through Extensive Genome Exploration. Front Microbiol 2016; 6:1483. [PMID: 26779141 PMCID: PMC4701971 DOI: 10.3389/fmicb.2015.01483] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 12/08/2015] [Indexed: 12/30/2022] Open
Abstract
Recent genome analyses suggest that integrative and conjugative elements (ICEs) are widespread in bacterial genomes and therefore play an essential role in horizontal transfer. However, only a few of these elements are precisely characterized and correctly delineated within sequenced bacterial genomes. Even though previous analysis showed the presence of ICEs in some species of Streptococci, the global prevalence and diversity of ICEs was not analyzed in this genus. In this study, we searched for ICEs in the completely sequenced genomes of 124 strains belonging to 27 streptococcal species. These exhaustive analyses revealed 105 putative ICEs and 26 slightly decayed elements whose limits were assessed and whose insertion site was identified. These ICEs were grouped in seven distinct unrelated or distantly related families, according to their conjugation modules. Integration of these streptococcal ICEs is catalyzed either by a site-specific tyrosine integrase, a low-specificity tyrosine integrase, a site-specific single serine integrase, a triplet of site-specific serine integrases or a DDE transposase. Analysis of their integration site led to the detection of 18 target-genes for streptococcal ICE insertion including eight that had not been identified previously (ftsK, guaA, lysS, mutT, rpmG, rpsI, traG, and ebfC). It also suggests that all specificities have evolved to minimize the impact of the insertion on the host. This overall analysis of streptococcal ICEs emphasizes their prevalence and diversity and demonstrates that exchanges or acquisitions of conjugation and recombination modules are frequent.
Collapse
Affiliation(s)
- Chloé Ambroset
- DynAMic, Faculté des Sciences et Technologies, Université de Lorraine, UMR 1128Vandœuvre-lès-Nancy, France; DynAMic, Institut National de la Recherche Agronomique, UMR 1128Vandœuvre-lès-Nancy, France
| | - Charles Coluzzi
- DynAMic, Faculté des Sciences et Technologies, Université de Lorraine, UMR 1128Vandœuvre-lès-Nancy, France; DynAMic, Institut National de la Recherche Agronomique, UMR 1128Vandœuvre-lès-Nancy, France
| | - Gérard Guédon
- DynAMic, Faculté des Sciences et Technologies, Université de Lorraine, UMR 1128Vandœuvre-lès-Nancy, France; DynAMic, Institut National de la Recherche Agronomique, UMR 1128Vandœuvre-lès-Nancy, France
| | - Marie-Dominique Devignes
- Laboratoire Lorrain de Recherche en Informatique et ses Applications, Faculté des Sciences et Technologies, Université de Lorraine, UMR 7503Vandœuvre-lès-Nancy, France; CNRS, Laboratoire Lorrain de Recherche en Informatique et ses Applications, UMR 7503Vandśuvre-lès-Nancy, France
| | - Valentin Loux
- UR 1404 Mathématiques et Informatique Appliquées du Génome à l'Environnement, Institut National de la Recherche Agronomique Jouy-en-Josas, France
| | - Thomas Lacroix
- UR 1404 Mathématiques et Informatique Appliquées du Génome à l'Environnement, Institut National de la Recherche Agronomique Jouy-en-Josas, France
| | - Sophie Payot
- DynAMic, Faculté des Sciences et Technologies, Université de Lorraine, UMR 1128Vandœuvre-lès-Nancy, France; DynAMic, Institut National de la Recherche Agronomique, UMR 1128Vandœuvre-lès-Nancy, France
| | - Nathalie Leblond-Bourget
- DynAMic, Faculté des Sciences et Technologies, Université de Lorraine, UMR 1128Vandœuvre-lès-Nancy, France; DynAMic, Institut National de la Recherche Agronomique, UMR 1128Vandœuvre-lès-Nancy, France
| |
Collapse
|
24
|
Touchon M, Rocha EPC. Coevolution of the Organization and Structure of Prokaryotic Genomes. Cold Spring Harb Perspect Biol 2016; 8:a018168. [PMID: 26729648 DOI: 10.1101/cshperspect.a018168] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The cytoplasm of prokaryotes contains many molecular machines interacting directly with the chromosome. These vital interactions depend on the chromosome structure, as a molecule, and on the genome organization, as a unit of genetic information. Strong selection for the organization of the genetic elements implicated in these interactions drives replicon ploidy, gene distribution, operon conservation, and the formation of replication-associated traits. The genomes of prokaryotes are also very plastic with high rates of horizontal gene transfer and gene loss. The evolutionary conflicts between plasticity and organization lead to the formation of regions with high genetic diversity whose impact on chromosome structure is poorly understood. Prokaryotic genomes are remarkable documents of natural history because they carry the imprint of all of these selective and mutational forces. Their study allows a better understanding of molecular mechanisms, their impact on microbial evolution, and how they can be tinkered in synthetic biology.
Collapse
Affiliation(s)
- Marie Touchon
- Microbial Evolutionary Genomics, Institut Pasteur, 75015 Paris, France CNRS, UMR3525, 75015 Paris, France
| | - Eduardo P C Rocha
- Microbial Evolutionary Genomics, Institut Pasteur, 75015 Paris, France CNRS, UMR3525, 75015 Paris, France
| |
Collapse
|
25
|
The Clostridium sporulation programs: diversity and preservation of endospore differentiation. Microbiol Mol Biol Rev 2015; 79:19-37. [PMID: 25631287 DOI: 10.1128/mmbr.00025-14] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
SUMMARY Bacillus and Clostridium organisms initiate the sporulation process when unfavorable conditions are detected. The sporulation process is a carefully orchestrated cascade of events at both the transcriptional and posttranslational levels involving a multitude of sigma factors, transcription factors, proteases, and phosphatases. Like Bacillus genomes, sequenced Clostridium genomes contain genes for all major sporulation-specific transcription and sigma factors (spo0A, sigH, sigF, sigE, sigG, and sigK) that orchestrate the sporulation program. However, recent studies have shown that there are substantial differences in the sporulation programs between the two genera as well as among different Clostridium species. First, in the absence of a Bacillus-like phosphorelay system, activation of Spo0A in Clostridium organisms is carried out by a number of orphan histidine kinases. Second, downstream of Spo0A, the transcriptional and posttranslational regulation of the canonical set of four sporulation-specific sigma factors (σ(F), σ(E), σ(G), and σ(K)) display different patterns, not only compared to Bacillus but also among Clostridium organisms. Finally, recent studies demonstrated that σ(K), the last sigma factor to be activated according to the Bacillus subtilis model, is involved in the very early stages of sporulation in Clostridium acetobutylicum, C. perfringens, and C. botulinum as well as in the very late stages of spore maturation in C. acetobutylicum. Despite profound differences in initiation, propagation, and orchestration of expression of spore morphogenetic components, these findings demonstrate not only the robustness of the endospore sporulation program but also the plasticity of the program to generate different complex phenotypes, some apparently regulated at the epigenetic level.
Collapse
|
26
|
Abstract
Since the first application of high hydrostatic pressure (HHP) for food preservation more than 100 years ago, a wealth of knowledge has been gained on molecular mechanisms underlying the HHP-mediated destruction of microorganisms. However, one observation made back then is still valid, i.e. that HHP alone is not sufficient for the complete inactivation of bacterial endospores. To achieve "commercial sterility" of low-acid foods, i.e. inactivation of spores capable of growing in a specific product under typical storage conditions, a combination of HHP with other hurdles is required (most effectively with heat (HPT)). Although HPT processes are not yet industrially applied, continuous technical progress and increasing consumer demand for minimally processed, additive-free food with long shelf life, makes HPT sterilization a promising alternative to thermal processing.In recent years, considerable progress has been made in understanding the response of spores of the model organism B. subtilis to HPT treatments and detailed insights into some basic mechanisms in Clostridium species shed new light on differences in the HPT-mediated inactivation of Bacillus and Clostridium spores. In this chapter, current knowledge on sporulation and germination processes, which presents the basis for understanding development and loss of the extreme resistance properties of spores, is summarized highlighting commonalities and differences between Bacillus and Clostridium species. In this context, the effect of HPT treatments on spores, inactivation mechanism and kinetics, the role of population heterogeneity, and influence factors on the results of inactivation studies are discussed.
Collapse
Affiliation(s)
- Christian A Lenz
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München, 85354, Freising, Germany
| | | |
Collapse
|
27
|
Abstract
My career in science was launched when I was an undergraduate at Princeton University and reinforced by graduate training at the Massachusetts Institute of Technology. However, it was only after I moved to Harvard University as a junior fellow that my affections were captured by a seemingly mundane soil bacterium. What Bacillus subtilis offered was endless fascinating biological problems (alternative sigma factors, sporulation, swarming, biofilm formation, stochastic cell fate switching) embedded in a uniquely powerful genetic system. Along the way, my career in science became inseparably interwoven with teaching and mentoring, which proved to be as rewarding as the thrill of discovery.
Collapse
Affiliation(s)
- Richard Losick
- From the Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 01238
| |
Collapse
|
28
|
Pishdadian K, Fimlaid KA, Shen A. SpoIIID-mediated regulation of σK function during Clostridium difficile sporulation. Mol Microbiol 2014; 95:189-208. [PMID: 25393584 DOI: 10.1111/mmi.12856] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/05/2014] [Indexed: 02/04/2023]
Abstract
The spore-forming bacterial pathogen Clostridium difficile is a leading cause of health-care-associated diarrhea worldwide. Although C. difficile spore formation is essential for disease transmission, the regulatory pathways that control this developmental process have only been partially characterized. In the well-studied spore-former Bacillus subtilis, the highly conserved σ(E) , SpoIIID and σ(K) regulatory proteins control gene expression in the mother cell to ensure proper spore formation. To define the precise requirement for SpoIIID and σ(K) during C. difficile sporulation, we analyzed spoIIID and sigK mutants using heterologous expression systems and RNA-Seq transcriptional profiling. These analyses revealed that expression of sigK from a SpoIIID-independent promoter largely bypasses the need for SpoIIID to produce heat-resistant spores. We also observed that σ(K) is active upon translation, suggesting that SpoIIID primarily functions to activate sigK. SpoIIID nevertheless plays auxiliary roles during sporulation, as it enhances levels of the exosporium morphogenetic protein CdeC in a σ(K) -dependent manner. Analyses of purified spores further revealed that SpoIIID and σ(K) control the adherence of the CotB coat protein to C. difficile spores, indicating that these proteins regulate multiple stages of spore formation. Collectively, these results highlight that diverse mechanisms control spore formation in the Firmicutes.
Collapse
Affiliation(s)
- Keyan Pishdadian
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, 05405, USA
| | | | | |
Collapse
|
29
|
Kim KP, Born Y, Lurz R, Eichenseher F, Zimmer M, Loessner MJ, Klumpp J. Inducible Clostridium perfringens bacteriophages ΦS9 and ΦS63: Different genome structures and a fully functional sigK intervening element. BACTERIOPHAGE 2014; 2:89-97. [PMID: 23050219 PMCID: PMC3442830 DOI: 10.4161/bact.21363] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Two inducible temperate bacteriophages ΦS9 and ΦS63 from Clostridium perfringens were sequenced and analyzed. Isometric heads and long non-contractile tails classify ΦS9 and ΦS63 in the Siphoviridae family, and their genomes consist of 39,457 bp (ΦS9) and 33,609 bp (ΦS63) linear dsDNA, respectively. ΦS63 has 3′-overlapping cohesive genome ends, whereas ΦS9 is the first Clostridium phage featuring an experimentally proven terminally redundant and circularly permuted genome. A total of 50 and 43 coding sequences were predicted for ΦS9 and ΦS63, respectively, organized into 6 distinct lifestyle-associated modules typical for temperate Siphoviruses. Putative functions could be assigned to 26 gene products of ΦS9, and to 25 of ΦS63. The ΦS9 attB attachment and insertion site is located in a non-coding region upstream of a putative phosphorylase gene. Interestingly, ΦS63 integrates into the 3′ part of sigK in C. perfringens, and represents the first functional skin-element-like phage described for this genus. With respect to possible effects of lysogeny, we did not obtain evidence that ΦS9 may influence sporulation of a lysogenized host. In contrast, interruption of sigK, a sporulation associated gene in various bacteria, by the ΦS63 prophage insertion is more likely to affect sporulation of its carrier.
Collapse
Affiliation(s)
- Kwang-Pyo Kim
- Department of Food Science and Technology; Chonbuk National University; Jeonbuk, South Korea ; Institute of Food; Nutrition and Health; ETH Zurich; Zurich, Switzerland
| | | | | | | | | | | | | |
Collapse
|
30
|
Abe K, Kawano Y, Iwamoto K, Arai K, Maruyama Y, Eichenberger P, Sato T. Developmentally-regulated excision of the SPβ prophage reconstitutes a gene required for spore envelope maturation in Bacillus subtilis. PLoS Genet 2014; 10:e1004636. [PMID: 25299644 PMCID: PMC4191935 DOI: 10.1371/journal.pgen.1004636] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 07/29/2014] [Indexed: 01/25/2023] Open
Abstract
Temperate phages infect bacteria by injecting their DNA into bacterial cells, where it becomes incorporated into the host genome as a prophage. In the genome of Bacillus subtilis 168, an active prophage, SPβ, is inserted into a polysaccharide synthesis gene, spsM. Here, we show that a rearrangement occurs during sporulation to reconstitute a functional composite spsM gene by precise excision of SPβ from the chromosome. SPβ excision requires a putative site-specific recombinase, SprA, and an accessory protein, SprB. A minimized SPβ, where all the SPβ genes were deleted, except sprA and sprB, retained the SPβ excision activity during sporulation, demonstrating that sprA and sprB are necessary and sufficient for the excision. While expression of sprA was observed during vegetative growth, sprB was induced during sporulation and upon mitomycin C treatment, which triggers the phage lytic cycle. We also demonstrated that overexpression of sprB (but not of sprA) resulted in SPβ prophage excision without triggering the lytic cycle. These results suggest that sprB is the factor that controls the timing of phage excision. Furthermore, we provide evidence that spsM is essential for the addition of polysaccharides to the spore envelope. The presence of polysaccharides on the spore surface renders the spore hydrophilic in water. This property may be beneficial in allowing spores to disperse in natural environments via water flow. A similar rearrangement occurs in Bacillus amyloliquefaciens FZB42, where a SPβ-like element is excised during sporulation to reconstitute a polysaccharide synthesis gene, suggesting that this type of gene rearrangement is common in spore-forming bacteria because it can be spread by phage infection. Integration of prophages into protein-coding sequences of the host chromosome generally results in loss of function of the interrupted gene. In the endospore-forming organism Bacillus subtilis strain 168, the SPβ prophage is inserted into a previously-uncharacterized spore polysaccharide synthesis gene, spsM. In vegetative cells, the lytic cycle is induced in response to DNA damage. In the process, SPβ is excised from the genome to form phage particles. Here, we demonstrate that SPβ excision is also a developmentally-regulated event that occurs systematically during sporulation to reconstitute a functional spsM gene. Following asymmetric division of the sporulating cell, two cellular compartments are generated, the forespore, which will mature into a spore, and the mother cell, which is essential to the process of spore maturation. Because phage excision is limited to the mother cell genome, and does not occur in the forespore genome, SPβ is an integral part of the spore genome. Thus, after the spores germinate, the vegetative cells resume growth and the SPβ prophage is propagated vertically to the progeny along with the rest of the host genome. Our results suggest that the two pathways of SPβ excision support both the phage life cycle and normal sporulation of the host cells.
Collapse
Affiliation(s)
- Kimihiro Abe
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan
| | - Yuta Kawano
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Keito Iwamoto
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Kenji Arai
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Yuki Maruyama
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
| | - Patrick Eichenberger
- Center for Genomics and Systems Biology, New York University, New York, New York, United States of America
| | - Tsutomu Sato
- Research Center of Micro-Nano Technology, Hosei University, Koganei, Tokyo, Japan
- Department of Frontier Bioscience, Hosei University, Koganei, Tokyo, Japan
- * E-mail:
| |
Collapse
|
31
|
Nguyen SV, McShan WM. Chromosomal islands of Streptococcus pyogenes and related streptococci: molecular switches for survival and virulence. Front Cell Infect Microbiol 2014; 4:109. [PMID: 25161960 PMCID: PMC4129442 DOI: 10.3389/fcimb.2014.00109] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/25/2014] [Indexed: 01/19/2023] Open
Abstract
Streptococcus pyogenes is a significant pathogen of humans, annually causing over 700,000,000 infections and 500,000 deaths. Virulence in S. pyogenes is closely linked to mobile genetic elements like phages and chromosomal islands (CI). S. pyogenes phage-like chromosomal islands (SpyCI) confer a complex mutator phenotype on their host. SpyCI integrate into the 5′ end of DNA mismatch repair (MMR) gene mutL, which also disrupts downstream operon genes lmrP, ruvA, and tag. During early logarithmic growth, SpyCI excise from the bacterial chromosome and replicate as episomes, relieving the mutator phenotype. As growth slows and the cells enter stationary phase, SpyCI reintegrate into the chromosome, again silencing the MMR operon. This system creates a unique growth-dependent and reversible mutator phenotype. Additional CI using the identical attachment site in mutL have been identified in related species, including Streptococcus dysgalactiae subsp. equisimilis, Streptococcus anginosus, Streptococcus intermedius, Streptococcus parauberis, and Streptococcus canis. These CI have small genomes, which range from 13 to 20 kB, conserved integrase and DNA replication genes, and no identifiable genes encoding capsid proteins. SpyCI may employ a helper phage for packaging and dissemination in a fashion similar to the Staphylococcus aureus pathogenicity islands (SaPI). Outside of the core replication and integration genes, SpyCI and related CI show considerable diversity with the presence of many indels that may contribute to the host cell phenotype or fitness. SpyCI are a subset of a larger family of streptococcal CI who potentially regulate the expression of other host genes. The biological and phylogenetic analysis of streptococcal chromosomal islands provides important clues as to how these chromosomal islands help S. pyogenes and other streptococcal species persist in human populations in spite of antibiotic therapy and immune challenges.
Collapse
Affiliation(s)
- Scott V Nguyen
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center Oklahoma City, OK, USA
| | - William M McShan
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center Oklahoma City, OK, USA ; Department of Pharmaceutical Sciences, The University of Oklahoma Health Sciences Center Oklahoma City, OK, USA
| |
Collapse
|
32
|
Abstract
Discoveries in cytogenetics, molecular biology, and genomics have revealed that genome change is an active cell-mediated physiological process. This is distinctly at variance with the pre-DNA assumption that genetic changes arise accidentally and sporadically. The discovery that DNA changes arise as the result of regulated cell biochemistry means that the genome is best modelled as a read-write (RW) data storage system rather than a read-only memory (ROM). The evidence behind this change in thinking and a consideration of some of its implications are the subjects of this article. Specific points include the following: cells protect themselves from accidental genome change with proofreading and DNA damage repair systems; localized point mutations result from the action of specialized trans-lesion mutator DNA polymerases; cells can join broken chromosomes and generate genome rearrangements by non-homologous end-joining (NHEJ) processes in specialized subnuclear repair centres; cells have a broad variety of natural genetic engineering (NGE) functions for transporting, diversifying and reorganizing DNA sequences in ways that generate many classes of genomic novelties; natural genetic engineering functions are regulated and subject to activation by a range of challenging life history events; cells can target the action of natural genetic engineering functions to particular genome locations by a range of well-established molecular interactions, including protein binding with regulatory factors and linkage to transcription; and genome changes in cancer can usefully be considered as consequences of the loss of homeostatic control over natural genetic engineering functions.
Collapse
Affiliation(s)
- James A Shapiro
- Department of Biochemistry and Molecular Biology, University of Chicago, GCISW123B, 979 E. 57th Street, Chicago, IL 60637, USA
| |
Collapse
|
33
|
|
34
|
Konovalova A, Søgaard-Andersen L, Kroos L. Regulated proteolysis in bacterial development. FEMS Microbiol Rev 2013; 38:493-522. [PMID: 24354618 DOI: 10.1111/1574-6976.12050] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 09/03/2013] [Accepted: 10/14/2013] [Indexed: 11/30/2022] Open
Abstract
Bacteria use proteases to control three types of events temporally and spatially during the processes of morphological development. These events are the destruction of regulatory proteins, activation of regulatory proteins, and production of signals. While some of these events are entirely cytoplasmic, others involve intramembrane proteolysis of a substrate, transmembrane signaling, or secretion. In some cases, multiple proteolytic events are organized into pathways, for example turnover of a regulatory protein activates a protease that generates a signal. We review well-studied and emerging examples and identify recurring themes and important questions for future research. We focus primarily on paradigms learned from studies of model organisms, but we note connections to regulated proteolytic events that govern bacterial adaptation, biofilm formation and disassembly, and pathogenesis.
Collapse
Affiliation(s)
- Anna Konovalova
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | | | | |
Collapse
|
35
|
Abe K, Yoshinari A, Aoyagi T, Hirota Y, Iwamoto K, Sato T. Regulated DNA rearrangement during sporulation inBacillus weihenstephanensis KBAB4. Mol Microbiol 2013; 90:415-27. [DOI: 10.1111/mmi.12375] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/20/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Kimihiro Abe
- Research Center of Micro-Nano Technology; Hosei University; Koganei; 184-0003; Tokyo; Japan
| | - Akira Yoshinari
- Department of Frontier Bioscience; Hosei University; Koganei; 184-8584; Tokyo; Japan
| | - Takahiro Aoyagi
- Department of Frontier Bioscience; Hosei University; Koganei; 184-8584; Tokyo; Japan
| | - Yasunori Hirota
- Department of Frontier Bioscience; Hosei University; Koganei; 184-8584; Tokyo; Japan
| | - Keito Iwamoto
- Department of Frontier Bioscience; Hosei University; Koganei; 184-8584; Tokyo; Japan
| | | |
Collapse
|
36
|
Sirigi Reddy AR, Girinathan BP, Zapotocny R, Govind R. Identification and characterization of Clostridium sordellii toxin gene regulator. J Bacteriol 2013; 195:4246-54. [PMID: 23873908 PMCID: PMC3754755 DOI: 10.1128/jb.00711-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 07/12/2013] [Indexed: 02/05/2023] Open
Abstract
Toxigenic Clostridium sordellii causes uncommon but highly lethal infections in humans and animals. Recently, an increased incidence of C. sordellii infections has been reported in women undergoing obstetric interventions. Pathogenic strains of C. sordellii produce numerous virulence factors, including sordellilysin, phospholipase, neuraminidase, and two large clostridial glucosylating toxins, TcsL and TcsH. Recent studies have demonstrated that TcsL toxin is an essential virulence factor for the pathogenicity of C. sordellii. In this study, we identified and characterized TcsR as the toxin gene (tcsL) regulator in C. sordellii. High-throughput sequencing of two C. sordellii strains revealed that tcsR lies within a genomic region that encodes TcsL, TcsH, and TcsE, a putative holin. By using ClosTron technology, we inactivated the tcsR gene in strain ATCC 9714. Toxin production and tcsL transcription were decreased in the tcsR mutant strain. However, the complemented tcsR mutant produced large amounts of toxins, similar to the parental strain. Expression of the Clostridium difficile toxin gene regulator tcdR also restored toxin production to the C. sordellii tcsR mutant, showing that these sigma factors are functionally interchangeable.
Collapse
|
37
|
Abstract
Bacteriophages, or simply phages, are viruses infecting bacteria. With an estimated 1031 particles in the biosphere, phages outnumber bacteria by a factor of at least 10 and not surprisingly, they influence the evolution of most bacterial species, sometimes in unexpected ways. “Temperate” phages have the ability to integrate into the chromosome of their host upon infection, where they can reside as “quiescent” prophages until conditions favor their reactivation. Lysogenic conversion resulting from the integration of prophages encoding powerful toxins is probably the most determinant contribution of prophages to the evolution of pathogenic bacteria. We currently grasp only a small fraction of the total phage diversity. Phage biologists keep unraveling novel mechanisms developed by phages to parasitize their host. The purpose of this review is to give an overview of some of the various ways by which prophages change the lifestyle and boost virulence of some of the most dangerous bacterial pathogens.
Collapse
Affiliation(s)
- Louis-Charles Fortier
- Département de Microbiologie et d'Infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC Canada.
| | | |
Collapse
|
38
|
Features of Pro-σK important for cleavage by SpoIVFB, an intramembrane metalloprotease. J Bacteriol 2013; 195:2793-806. [PMID: 23585539 DOI: 10.1128/jb.00229-13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Intramembrane proteases regulate diverse processes by cleaving substrates within a transmembrane segment or near the membrane surface. Bacillus subtilis SpoIVFB is an intramembrane metalloprotease that cleaves Pro-σ(K) during sporulation. To elucidate features of Pro-σ(K) important for cleavage by SpoIVFB, coexpression of the two proteins in Escherichia coli was used along with cell fractionation. In the absence of SpoIVFB, a portion of the Pro-σ(K) was peripherally membrane associated. This portion was not observed in the presence of SpoIVFB, suggesting that it serves as the substrate. Deletion of Pro-σ(K) residues 2 to 8, addition of residues at its N terminus, or certain single-residue substitutions near the cleavage site impaired cleavage. Certain multiresidue substitutions near the cleavage site changed the position of cleavage, revealing preferences for a small residue preceding the cleavage site N-terminally (i.e., at the P1 position) and a hydrophobic residue at the second position following the cleavage site C-terminally (i.e., P2'). These features appear to be conserved among Pro-σ(K) orthologs. SpoIVFB did not tolerate an aromatic residue at P1 or P2' of Pro-σ(K). A Lys residue at P3' of Pro-σ(K) could not be replaced with Ala unless a Lys was provided farther C-terminally (e.g., at P9'). α-Helix-destabilizing residues near the cleavage site were not crucial for SpoIVFB to cleave Pro-σ(K). The preferences and tolerances of SpoIVFB are somewhat different from those of other intramembrane metalloproteases, perhaps reflecting differences in the interaction of the substrate with the membrane and the enzyme.
Collapse
|
39
|
Complete sequence of the first chimera genome constructed by cloning the whole genome of Synechocystis strain PCC6803 into the Bacillus subtilis 168 genome. J Bacteriol 2013; 194:7007. [PMID: 23209249 DOI: 10.1128/jb.01798-12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genome synthesis of existing or designed genomes is made feasible by the first successful cloning of a cyanobacterium, Synechocystis PCC6803, in Gram-positive, endospore-forming Bacillus subtilis. Whole-genome sequence analysis of the isolate and parental B. subtilis strains provides clues for identifying single nucleotide polymorphisms (SNPs) in the 2 complete bacterial genomes in one cell.
Collapse
|
40
|
Abstract
Large cell size is not restricted to a particular bacterial lifestyle, dispersal method, or cell envelope type. What is conserved among the very large bacteria are the quantity and arrangement of their genomic resources. All large bacteria described to date appear to be highly polyploid. This review focuses on Epulopiscium sp. type B, which maintains tens of thousands of genome copies throughout its life cycle. Only a tiny proportion of mother cell DNA is inherited by intracellular offspring, but surprisingly DNA replication takes place in the terminally differentiated mother cell as offspring grow. Massive polyploidy supports the acquisition of unstable genetic elements normally not seen in essential genes. Further studies of how large bacteria manage their genomic resources will provide insight into how simple cellular modifications can support unusual lifestyles and exceptional cell forms.
Collapse
Affiliation(s)
- Esther R Angert
- Department of Microbiology, Cornell University, Ithaca, New York 14853, USA.
| |
Collapse
|
41
|
Prophage Excision Activates Listeria Competence Genes that Promote Phagosomal Escape and Virulence. Cell 2012; 150:792-802. [DOI: 10.1016/j.cell.2012.06.036] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 03/03/2012] [Accepted: 06/25/2012] [Indexed: 11/23/2022]
|
42
|
The genomic basis for the evolution of a novel form of cellular reproduction in the bacterium Epulopiscium. BMC Genomics 2012; 13:265. [PMID: 22721417 PMCID: PMC3416734 DOI: 10.1186/1471-2164-13-265] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Accepted: 06/21/2012] [Indexed: 11/23/2022] Open
Abstract
Background Epulopiscium sp. type B, a large intestinal bacterial symbiont of the surgeonfish Naso tonganus, does not reproduce by binary fission. Instead, it forms multiple intracellular offspring using a process with morphological features similar to the survival strategy of endospore formation in other Firmicutes. We hypothesize that intracellular offspring formation in Epulopiscium evolved from endospore formation and these two developmental programs share molecular mechanisms that are responsible for the observed morphological similarities. Results To test this, we sequenced the genome of Epulopiscium sp. type B to draft quality. Comparative analysis with the complete genome of its close, endospore-forming relative, Cellulosilyticum lentocellum, identified homologs of well-known sporulation genes characterized in Bacillus subtilis. Of the 147 highly conserved B. subtilis sporulation genes used in this analysis, we found 57 homologs in the Epulopiscium genome and 87 homologs in the C. lentocellum genome. Conclusions Genes coding for components of the central regulatory network which govern the expression of forespore and mother-cell-specific sporulation genes and the machinery used for engulfment appear best conserved. Low conservation of genes expressed late in endospore formation, particularly those that confer resistance properties and encode germinant receptors, suggest that Epulopiscium has lost the ability to form a mature spore. Our findings provide a framework for understanding the evolution of a novel form of cellular reproduction.
Collapse
|
43
|
Sequence Analysis of Inducible Prophage phIS3501 Integrated into the Haemolysin II Gene of Bacillus thuringiensis var israelensis ATCC35646. GENETICS RESEARCH INTERNATIONAL 2012; 2012:543286. [PMID: 22567391 PMCID: PMC3335513 DOI: 10.1155/2012/543286] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 11/30/2011] [Indexed: 02/07/2023]
Abstract
Diarrheic food poisoning by bacteria of the Bacillus cereus group is mostly due to several toxins encoded in the genomes. One of them, cytotoxin K, was recently identified as responsible for severe necrotic syndromes. Cytotoxin K is similar to a class of proteins encoded by genes usually annotated as haemolysin II (hlyII) in the majority of genomes of the B. cereus group. The partially sequenced genome of Bacillus thuringiensis var israelensis ATCC35646 contains several potentially induced prophages, one of them integrated into the hlyII gene. We determined the complete sequence and established the genomic organization of this prophage-designated phIS3501. During induction of excision of this prophage with mitomycin C, intact hlyII gene is formed, thus providing to cells a genetic ability to synthesize the active toxin. Therefore, this prophage, upon its excision, can be implicated in the regulation of synthesis of the active toxin and thus in the virulence of bacterial host. A generality of selection for such systems in bacterial pathogens is indicated by the similarity of this genetic arrangement to that of Staphylococcus aureus β-haemolysin.
Collapse
|
44
|
YjbH-enhanced proteolysis of Spx by ClpXP in Bacillus subtilis is inhibited by the small protein YirB (YuzO). J Bacteriol 2011; 193:2133-40. [PMID: 21378193 DOI: 10.1128/jb.01350-10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Spx protein of Bacillus subtilis is a global regulator of the oxidative stress response. Spx concentration is controlled at the level of proteolysis by the ATP-dependent protease ClpXP and a substrate-binding protein, YjbH, which interacts with Spx. A yeast two-hybrid screen was carried out using yjbH as bait to uncover additional substrates or regulators of YjbH activity. Of the several genes identified in the screen, one encoded a small protein, YirB (YuzO), which elevated Spx concentration and activity in vivo when overproduced from an isopropyl-β-D-thiogalactopyranoside (IPTG)-inducible yirB construct. Pulldown experiments using extracts of B. subtilis cells producing a His-tagged YirB showed that native YjbH interacts with YirB in B. subtilis. Pulldown experiments using affinity-tagged Spx showed that YirB inhibited YjbH interaction with Spx. In vitro, YjbH-mediated proteolysis of Spx by ClpXP was inhibited by YirB. The activity of YirB is similar to that of the antiadaptor proteins that were previously shown to reduce proteolysis of a specific ClpXP substrate by interacting with a substrate-binding protein.
Collapse
|
45
|
Repression of sigK intervening (skin) element gene expression by the CI-like protein SknR and effect of SknR depletion on growth of Bacillus subtilis cells. J Bacteriol 2010; 192:6209-16. [PMID: 20889742 DOI: 10.1128/jb.00625-10] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Bacillus subtilis phage DNA-like sigK intervening (skin) element (48 kb) is excised from the chromosome by DNA rearrangement, and a composite gene, sigK (spoIIIC and spoIVCB), is created on the chromosome during sporulation. In this study, we first focused on the role of sknR (skin repressor), which has homology with the gene encoding the Xre repressor of defective phage PBSX. The depletion of SknR caused overexpression of the region between yqaF and yqaN (the yqaF-yqaN operon) and a growth defect in B. subtilis. Point mutation analysis and an electrophoretic mobility shift assay (EMSA) suggested that SknR functions as a negative regulator of gene expression in the yqaF-yqaN operon of the skin element through direct interaction with operators of 2-fold symmetry located in the intergenic region between sknR and yqaF. Deletion analysis revealed that the lethal effect of depletion of SknR was related to overexpression of yqaH and yqaM, whose products were previously reported to associate with DnaA and DnaC, respectively. Furthermore, overexpression of either yqaH or yqaM caused cell filamentation and abnormal chromosome segregation, which suggested that overproduction of these proteins inhibits DNA replication. Moreover, overexpression of yqaM inhibited the initiation of replication. Taken together, these data demonstrate that the B. subtilis skin element carries lethal genes, which are induced by the depletion of sknR.
Collapse
|
46
|
Barends S, Kraal B, van Wezel GP. The tmRNA-tagging mechanism and the control of gene expression: a review. WILEY INTERDISCIPLINARY REVIEWS-RNA 2010; 2:233-46. [PMID: 21957008 DOI: 10.1002/wrna.48] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The tmRNA-mediated trans-translation system is a unique quality control system in eubacteria that combines translational surveillance with the rescue of stalled ribosomes. During trans-translation, the chimeric tmRNA molecule--which acts as both tRNA and mRNA--is delivered to the ribosomal A site by a ribonucleoprotein complex of SmpB and EF-Tu-GTP, allowing the stalled ribosome to switch template and resume translation on a small coding sequence inside the tmRNA molecule. As a result, the aberrant protein becomes tagged by a sequence that is a target for proteolytic degradation. Thus, the system elegantly combines ribosome recycling with a clean-up function when triggered by truncated transcripts or rare codons. In addition, recent observations point to a specific regulation of the translation of a small number of genes by tmRNA-mediated inhibition or stimulation. In this review, we discuss the most prominent biochemical and structural aspects of trans-translation and then focus on the specific role of tmRNA in stress management and cell-cycle control of morphologically complex bacteria.
Collapse
Affiliation(s)
- Sharief Barends
- ProteoNic, Niels Bohrweg 11-13, 2333 CA Leiden, The Netherlands
| | | | | |
Collapse
|
47
|
Loss of compartmentalization of σ(E) activity need not prevent formation of spores by Bacillus subtilis. J Bacteriol 2010; 192:5616-24. [PMID: 20802044 DOI: 10.1128/jb.00572-10] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Compartmentalization of the activities of RNA polymerase sigma factors is a hallmark of formation of spores by Bacillus subtilis. It is initiated soon after the asymmetrically located sporulation division takes place with the activation of σ(F) in the smaller cell, the prespore. σ(F) then directs a signal via the membrane protease SpoIIGA to activate σ(E) in the larger mother cell by processing of pro-σ(E). Here, we show that σ(E) can be activated in the prespore with little effect on sporulation efficiency, implying that complete compartmentalization of σ(E) activity is not essential for spore formation. σ(E) activity in the prespore can be obtained by inducing transcription in the prespore of spoIIGA or of sigE*, which encodes a constitutively active form of σ(E), but not of spoIIGB, which encodes pro-σ(E). We infer that σ(E) compartmentalization is partially attributed to a competition between the compartments for the activation signaling protein SpoIIR. Normally, SpoIIGA is predominantly located in the mother cell and as a consequence confines σ(E) activation to it. In addition, we find that CsfB, previously shown to inhibit σ(G), is independently inhibiting σ(E) activity in the prespore. CsfB thus appears to serve a gatekeeper function in blocking the action of two sigma factors in the prespore: it prevents σ(G) from becoming active before completion of engulfment and helps prevent σ(E) from becoming active at all.
Collapse
|
48
|
Klee SR, Brzuszkiewicz EB, Nattermann H, Brüggemann H, Dupke S, Wollherr A, Franz T, Pauli G, Appel B, Liebl W, Couacy-Hymann E, Boesch C, Meyer FD, Leendertz FH, Ellerbrok H, Gottschalk G, Grunow R, Liesegang H. The genome of a Bacillus isolate causing anthrax in chimpanzees combines chromosomal properties of B. cereus with B. anthracis virulence plasmids. PLoS One 2010; 5:e10986. [PMID: 20634886 PMCID: PMC2901330 DOI: 10.1371/journal.pone.0010986] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 05/05/2010] [Indexed: 11/18/2022] Open
Abstract
Anthrax is a fatal disease caused by strains of Bacillus anthracis. Members of this monophyletic species are non motile and are all characterized by the presence of four prophages and a nonsense mutation in the plcR regulator gene. Here we report the complete genome sequence of a Bacillus strain isolated from a chimpanzee that had died with clinical symptoms of anthrax. Unlike classic B. anthracis, this strain was motile and lacked the four prohages and the nonsense mutation. Four replicons were identified, a chromosome and three plasmids. Comparative genome analysis revealed that the chromosome resembles those of non-B. anthracis members of the Bacillus cereus group, whereas two plasmids were identical to the anthrax virulence plasmids pXO1 and pXO2. The function of the newly discovered third plasmid with a length of 14 kbp is unknown. A detailed comparison of genomic loci encoding key features confirmed a higher similarity to B. thuringiensis serovar konkukian strain 97-27 and B. cereus E33L than to B. anthracis strains. For the first time we describe the sequence of an anthrax causing bacterium possessing both anthrax plasmids that apparently does not belong to the monophyletic group of all so far known B. anthracis strains and that differs in important diagnostic features. The data suggest that this bacterium has evolved from a B. cereus strain independently from the classic B. anthracis strains and established a B. anthracis lifestyle. Therefore we suggest to designate this isolate as "B. cereus variety (var.) anthracis".
Collapse
Affiliation(s)
- Silke R Klee
- Centre for Biological Security (ZBS), Robert Koch-Institut, Berlin, Germany.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Sporulation and enterotoxin (CPE) synthesis are controlled by the sporulation-specific sigma factors SigE and SigK in Clostridium perfringens. J Bacteriol 2009; 191:2728-42. [PMID: 19201796 DOI: 10.1128/jb.01839-08] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Clostridium perfringens is the third most frequent cause of bacterial food poisoning annually in the United States. Ingested C. perfringens vegetative cells sporulate in the intestinal tract and produce an enterotoxin (CPE) that is responsible for the symptoms of acute food poisoning. Studies of Bacillus subtilis have shown that gene expression during sporulation is compartmentalized, with different genes expressed in the mother cell and the forespore. The cell-specific RNA polymerase sigma factors sigma(F), sigma(E), sigma(G), and sigma(K) coordinate much of the developmental process. The C. perfringens cpe gene, encoding CPE, is transcribed from three promoters, where P1 was proposed to be sigma(K) dependent, while P2 and P3 were proposed to be sigma(E) dependent based on consensus promoter recognition sequences. In this study, mutations were introduced into the sigE and sigK genes of C. perfringens. With the sigE and sigK mutants, gusA fusion assays indicated that there was no expression of cpe in either mutant. Results from gusA fusion assays and immunoblotting experiments indicate that sigma(E)-associated RNA polymerase and sigma(K)-associated RNA polymerase coregulate each other's expression. Transcription and translation of the spoIIID gene in C. perfringens were not affected by mutations in sigE and sigK, which differs from B. subtilis, in which spoIIID transcription requires sigma(E)-associated RNA polymerase. The results presented here show that the regulation of developmental events in the mother cell compartment of C. perfringens is not the same as that in B. subtilis and Clostridium acetobutylicum.
Collapse
|
50
|
|