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Yang HW, Thapa R, Johnson K, DuPont ST, Khan A, Zhao Y. Examination of Large Chromosomal Inversions in the Genome of Erwinia amylovora Strains Reveals Worldwide Distribution and North America-Specific Types. PHYTOPATHOLOGY 2023; 113:2174-2186. [PMID: 36935376 DOI: 10.1094/phyto-01-23-0004-sa] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Erwinia amylovora is a relatively homogeneous species with low genetic diversity at the nucleotide level. However, phenotypic differences and genomic structural variations among E. amylovora strains have been documented. In this study, we identified 10 large chromosomal inversion (LCI) types in the Spiraeoideae-infecting (SI) E. amylovora strains by combining whole genome sequencing and PCR-based molecular markers. It was found that LCIs were mainly caused by homologous recombination events among seven rRNA operons (rrns) in SI E. amylovora strains. Although ribotyping results identified inter- and intra-variations in the internal transcribed spacer (ITS1 and ITS2) regions among rrns, LCIs tend to occur between rrns transcribed in the opposite directions and with the same tRNA content (tRNA-Glu or tRNA-Ile/Ala) in ITS1. Based on the LCI types, physical/estimated replichore imbalance (PRI/ERI) was examined and calculated. Among the 117 SI strains evaluated, the LCI types of Ea1189, CFBP1430, and Ea273 were the most common, with ERI values at 1.31, 7.87, and 4.47°, respectively. These three LCI types had worldwide distribution, whereas the remaining seven LCI types were restricted to North America (or certain regions of the United States). Our results indicated ongoing chromosomal recombination events in the SI E. amylovora population and showed that LCI events are mostly symmetrical, keeping the ERI less than 15°. These findings provide initial evidence about the prevalence of certain LCI types in E. amylovora strains, how LCI occurs, and its potential evolutionary advantage and history, which might help track the movement of the pathogen.
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Affiliation(s)
- Ho-Wen Yang
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802
| | - Ranjita Thapa
- School of Integrative Plant Science Plant Pathology and Plant-Microbe Biology, Cornell University, Geneva, NY 14456
| | - Kenneth Johnson
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
| | | | - Awais Khan
- School of Integrative Plant Science Plant Pathology and Plant-Microbe Biology, Cornell University, Geneva, NY 14456
| | - Youfu Zhao
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802
- Department of Plant Pathology, WSU-IAREC, Prosser, WA 99350
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2
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D’Iorio M, Dewar K. Replication-associated inversions are the dominant form of bacterial chromosome structural variation. Life Sci Alliance 2022; 6:6/1/e202201434. [PMID: 36261227 PMCID: PMC9584773 DOI: 10.26508/lsa.202201434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 11/24/2022] Open
Abstract
The structural arrangements of bacterial chromosomes vary widely between closely related species and can result in significant phenotypic outcomes. The appearance of large-scale chromosomal inversions that are symmetric relative to markers for the origin of replication (OriC) has been previously observed; however, the overall prevalence of replication-associated structural rearrangements (RASRs) in bacteria and their causal mechanisms are currently unknown. Here, we systematically identify the locations of RASRs in species with multiple complete-sequenced genomes and investigate potential mediating biological mechanisms. We found that 247 of 313 species contained sequences with at least one large (>50 Kb) inversion in their sequence comparisons, and the aggregated inversion distances away from symmetry were normally distributed with a mean of zero. Many inversions that were offset from dnaA were found to be centered on a different marker for the OriC Instances of flanking repeats provide evidence that breaks formed during the replication process could be repaired to opposing positions. We also found a strong relationship between the later stages of replication and the range in distance variation from symmetry.
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Affiliation(s)
- Matthew D’Iorio
- Quantitative Life Sciences, McGill University, Montreal, Canada,Correspondence:
| | - Ken Dewar
- Department of Human Genetics, McGill University, Montreal, Canada,Centre for Microbiome Research, McGill University, Montreal, Canada
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Shelyakin PV, Bochkareva OO, Karan AA, Gelfand MS. Micro-evolution of three Streptococcus species: selection, antigenic variation, and horizontal gene inflow. BMC Evol Biol 2019; 19:83. [PMID: 30917781 PMCID: PMC6437910 DOI: 10.1186/s12862-019-1403-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 02/25/2019] [Indexed: 02/07/2023] Open
Abstract
Background The genus Streptococcus comprises pathogens that strongly influence the health of humans and animals. Genome sequencing of multiple Streptococcus strains demonstrated high variability in gene content and order even in closely related strains of the same species and created a newly emerged object for genomic analysis, the pan-genome. Here we analysed the genome evolution of 25 strains of Streptococcus suis, 50 strains of Streptococcus pyogenes and 28 strains of Streptococcus pneumoniae. Results Fractions of the pan-genome, unique, periphery, and universal genes differ in size, functional composition, the level of nucleotide substitutions, and predisposition to horizontal gene transfer and genomic rearrangements. The density of substitutions in intergenic regions appears to be correlated with selection acting on adjacent genes, implying that more conserved genes tend to have more conserved regulatory regions. The total pan-genome of the genus is open, but only due to strain-specific genes, whereas other pan-genome fractions reach saturation. We have identified the set of genes with phylogenies inconsistent with species and non-conserved location in the chromosome; these genes are rare in at least one species and have likely experienced recent horizontal transfer between species. The strain-specific fraction is enriched with mobile elements and hypothetical proteins, but also contains a number of candidate virulence-related genes, so it may have a strong impact on adaptability and pathogenicity. Mapping the rearrangements to the phylogenetic tree revealed large parallel inversions in all species. A parallel inversion of length 15 kB with breakpoints formed by genes encoding surface antigen proteins PhtD and PhtB in S. pneumoniae leads to replacement of gene fragments that likely indicates the action of an antigen variation mechanism. Conclusions Members of genus Streptococcus have a highly dynamic, open pan-genome, that potentially confers them with the ability to adapt to changing environmental conditions, i.e. antibiotic resistance or transmission between different hosts. Hence, integrated analysis of all aspects of genome evolution is important for the identification of potential pathogens and design of drugs and vaccines. Electronic supplementary material The online version of this article (10.1186/s12862-019-1403-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Pavel V Shelyakin
- Vavilov Institute of General Genetics Russian Academy of Sciences, Gubkina str. 3, Moscow, 119991, Russia. .,Kharkevich Institute for Information Transmission Problems, 19, Bolshoy Karetny per., Moscow, 127051, Russia. .,Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia.
| | - Olga O Bochkareva
- Kharkevich Institute for Information Transmission Problems, 19, Bolshoy Karetny per., Moscow, 127051, Russia.,Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Anna A Karan
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
| | - Mikhail S Gelfand
- Kharkevich Institute for Information Transmission Problems, 19, Bolshoy Karetny per., Moscow, 127051, Russia.,Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia.,Faculty of Computer Science, Higher School of Economics, Moscow, Russia
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Repar J, Warnecke T. Non-Random Inversion Landscapes in Prokaryotic Genomes Are Shaped by Heterogeneous Selection Pressures. Mol Biol Evol 2018; 34:1902-1911. [PMID: 28407093 PMCID: PMC5850607 DOI: 10.1093/molbev/msx127] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Inversions are a major contributor to structural genome evolution in prokaryotes. Here, using a novel alignment-based method, we systematically compare 1,651 bacterial and 98 archaeal genomes to show that inversion landscapes are frequently biased toward (symmetric) inversions around the origin–terminus axis. However, symmetric inversion bias is not a universal feature of prokaryotic genome evolution but varies considerably across clades. At the extremes, inversion landscapes in Bacillus–Clostridium and Actinobacteria are dominated by symmetric inversions, while there is little or no systematic bias favoring symmetric rearrangements in archaea with a single origin of replication. Within clades, we find strong but clade-specific relationships between symmetric inversion bias and different features of adaptive genome architecture, including the distance of essential genes to the origin of replication and the preferential localization of genes on the leading strand. We suggest that heterogeneous selection pressures have converged to produce similar patterns of structural genome evolution across prokaryotes.
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Affiliation(s)
- Jelena Repar
- Molecular Systems Group, MRC London Institute of Medical Sciences (LMS), London, United Kingdom.,Institute of Clinical Sciences, Molecular Systems Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Tobias Warnecke
- Molecular Systems Group, MRC London Institute of Medical Sciences (LMS), London, United Kingdom.,Institute of Clinical Sciences, Molecular Systems Group, Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London, United Kingdom
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Maruyama F, Kobata M, Kurokawa K, Nishida K, Sakurai A, Nakano K, Nomura R, Kawabata S, Ooshima T, Nakai K, Hattori M, Hamada S, Nakagawa I. Comparative genomic analyses of Streptococcus mutans provide insights into chromosomal shuffling and species-specific content. BMC Genomics 2009; 10:358. [PMID: 19656368 PMCID: PMC2907686 DOI: 10.1186/1471-2164-10-358] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Accepted: 08/05/2009] [Indexed: 11/20/2022] Open
Abstract
Background Streptococcus mutans is the major pathogen of dental caries, and it occasionally causes infective endocarditis. While the pathogenicity of this species is distinct from other human pathogenic streptococci, the species-specific evolution of the genus Streptococcus and its genomic diversity are poorly understood. Results We have sequenced the complete genome of S. mutans serotype c strain NN2025, and compared it with the genome of UA159. The NN2025 genome is composed of 2,013,587 bp, and the two strains show highly conserved core-genome. However, comparison of the two S. mutans strains showed a large genomic inversion across the replication axis producing an X-shaped symmetrical DNA dot plot. This phenomenon was also observed between other streptococcal species, indicating that streptococcal genetic rearrangements across the replication axis play an important role in Streptococcus genetic shuffling. We further confirmed the genomic diversity among 95 clinical isolates using long-PCR analysis. Genomic diversity in S. mutans appears to occur frequently between insertion sequence (IS) elements and transposons, and these diversity regions consist of restriction/modification systems, antimicrobial peptide synthesis systems, and transporters. S. mutans may preferentially reject the phage infection by clustered regularly interspaced short palindromic repeats (CRISPRs). In particular, the CRISPR-2 region, which is highly divergent between strains, in NN2025 has long repeated spacer sequences corresponding to the streptococcal phage genome. Conclusion These observations suggest that S. mutans strains evolve through chromosomal shuffling and that phage infection is not needed for gene acquisition. In contrast, S. pyogenes tolerates phage infection for acquisition of virulence determinants for niche adaptation.
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Affiliation(s)
- Fumito Maruyama
- Division of Bacteriology, Department of Infectious Diseases Control, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan.
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Wright MA, Kharchenko P, Church GM, Segrè D. Chromosomal periodicity of evolutionarily conserved gene pairs. Proc Natl Acad Sci U S A 2007; 104:10559-64. [PMID: 17563360 PMCID: PMC1890563 DOI: 10.1073/pnas.0610776104] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Chromosomes are compacted hundreds of times to fit in the cell, packaged into dynamic folds whose structures are largely unknown. Here, we examine patterns in gene locations to infer large-scale features of bacterial chromosomes. Specifically, we analyzed >100 genomes and identified thousands of gene pairs that display two types of evolutionary correlations: a tendency to co-occur and a tendency to be located close together in many genomes. We then analyzed the detailed distribution of these pairs in Escherichia coli and found that genes in a pair tend to be separated by integral multiples of 117 kb along the genome and to be positioned in a 117-kb grid of genomic locations. In addition, the most pair-dense locations coincide with regions of intense transcriptional activity and the positions of top transcribed and conserved genes. These patterns suggest that the E. coli chromosome may be organized into a 117-kb helix-like topology that localizes a subset of the most essential and highly transcribed genes along a specific face of this structure. Our approach indicates an evolutionarily maintained preference in the spacing of genes along the chromosome and offers a general comparative genomics framework for studying chromosome structure, broadly applicable to other organisms.
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Affiliation(s)
- Matthew A. Wright
- *Department of Genetics
- Harvard–Massachusetts Institute of Technology Division of Health Sciences and Technology, and
| | - Peter Kharchenko
- Harvard–Partners Center for Genetics and Genomics, Harvard Medical School, Boston, MA 02115; and
| | | | - Daniel Segrè
- Departments of Biology and Biomedical Engineering, and Bioinformatics Program, Boston University, Boston, MA 02215
- To whom correspondence should be addressed. E-mail:
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Blanc G, Ogata H, Robert C, Audic S, Suhre K, Vestris G, Claverie JM, Raoult D. Reductive genome evolution from the mother of Rickettsia. PLoS Genet 2007; 3:e14. [PMID: 17238289 PMCID: PMC1779305 DOI: 10.1371/journal.pgen.0030014] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Accepted: 12/08/2006] [Indexed: 11/30/2022] Open
Abstract
The Rickettsia genus is a group of obligate intracellular α-proteobacteria representing a paradigm of reductive evolution. Here, we investigate the evolutionary processes that shaped the genomes of the genus. The reconstruction of ancestral genomes indicates that their last common ancestor contained more genes, but already possessed most traits associated with cellular parasitism. The differences in gene repertoires across modern Rickettsia are mainly the result of differential gene losses from the ancestor. We demonstrate using computer simulation that the propensity of loss was variable across genes during this process. We also analyzed the ratio of nonsynonymous to synonymous changes (Ka/Ks) calculated as an average over large sets of genes to assay the strength of selection acting on the genomes of Rickettsia, Anaplasmataceae, and free-living γ-proteobacteria. As a general trend, Ka/Ks were found to decrease with increasing divergence between genomes. The high Ka/Ks for closely related genomes are probably due to a lag in the removal of slightly deleterious nonsynonymous mutations by natural selection. Interestingly, we also observed a decrease of the rate of gene loss with increasing divergence, suggesting a similar lag in the removal of slightly deleterious pseudogene alleles. For larger divergence (Ks > 0.2), Ka/Ks converge toward similar values indicating that the levels of selection are roughly equivalent between intracellular α-proteobacteria and their free-living relatives. This contrasts with the view that obligate endocellular microorganisms tend to evolve faster as a consequence of reduced effectiveness of selection, and suggests a major role of enhanced background mutation rates on the fast protein divergence in the obligate intracellular α-proteobacteria. Genome downsizing and fast sequence divergence are frequently observed in bacteria living exclusively within the cells of higher eukaryotes. However, the driving forces and contributions of these processes to the genome diversity of the microorganisms remain poorly understood. The genus Rickettsia, a group of small obligate intracellular pathogens of humans, provides a fascinating model to study the genome downsizing process. In this article, we used seven Rickettsia genomes to reconstruct the genome of their ancestor and inferred the origin and fate of the genes found in today's species. We identify the process of gene loss as the main cause of genome diversification within the genus and show that the rate of gene loss, sequence divergence, and genome rearrangements are highly variable across the various Rickettsia lineages. This heterogeneity likely reflects the intricate effects of specialization to distinct arthropod hosts and critical alterations of the gene repertoire, such as the losses of DNA repair genes and the amplification of mobile genes. In contrast, we did not find evidence for the role of reduced population sizes on the long-term acceleration of sequence evolution. Overall, the data presented in this article shed new light on the fundamental evolutionary processes that drive the evolution of obligate intracellular bacteria.
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Affiliation(s)
- Guillaume Blanc
- Structural and Genomic Information Laboratory, Institut de Biologie Structurale et Microbiologie, Parc Scientifique de Luminy, Marseille, France
- * To whom correspondence should be addressed. E-mail: (GB), (DR)
| | - Hiroyuki Ogata
- Structural and Genomic Information Laboratory, Institut de Biologie Structurale et Microbiologie, Parc Scientifique de Luminy, Marseille, France
| | | | - Stéphane Audic
- Structural and Genomic Information Laboratory, Institut de Biologie Structurale et Microbiologie, Parc Scientifique de Luminy, Marseille, France
| | - Karsten Suhre
- Structural and Genomic Information Laboratory, Institut de Biologie Structurale et Microbiologie, Parc Scientifique de Luminy, Marseille, France
| | - Guy Vestris
- Unité des Rickettsies, Faculté de Médecine, Marseille, France
| | - Jean-Michel Claverie
- Structural and Genomic Information Laboratory, Institut de Biologie Structurale et Microbiologie, Parc Scientifique de Luminy, Marseille, France
| | - Didier Raoult
- Unité des Rickettsies, Faculté de Médecine, Marseille, France
- * To whom correspondence should be addressed. E-mail: (GB), (DR)
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Labarre C, van Tilbeurgh H, Blondeau K. Pichia pastoris is a valuable host for the expression of genes encoding membrane proteins from the hyperthermophilic Archeon Pyrococcus abyssi. Extremophiles 2006; 11:403-13. [PMID: 17091222 DOI: 10.1007/s00792-006-0036-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Accepted: 10/01/2006] [Indexed: 11/25/2022]
Abstract
We present here the experimental strategies, first results and identified bottlenecks of a structural genomics initiative on membrane proteins of the hyperthermophilic archaea Pyrococcus abyssi. Five ORFs coding for putative membrane proteins have been cloned and expressed in the methylotrophic Pichia pastoris expression system, using two different constructs, with or without the signal sequence alpha-mating factor of Saccharomyces cerevisiae. A c-myc epitope and 6 His codons were added at the 3'-end of the targeted genes to allow immunodetection of the recombinant proteins and to facilitate their further purification. We have selected at least one producer clone for each protein of interest and for almost every construction. All the membrane proteins were produced in Erlenmeyer flasks culture and in fed-batch cultivation for large-scale preparation. The proteins were detected in the membrane fractions of P. pastoris. Production efficiencies were relatively low in both production conditions but the quantities of biomass obtained during fed-batch cultivation have allowed us to collect sufficient amount of material for further purification. The proteins were extracted, solubilized and partially purified. Large-scale purification will be necessary for further structural work.
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Affiliation(s)
- Cécile Labarre
- Institut de Génétique et Microbiologie (UMR 8621 CNRS Université Paris XI), Université Paris-Sud, Bât 360, Orsay, 91405, France.
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Ogata H, La Scola B, Audic S, Renesto P, Blanc G, Robert C, Fournier PE, Claverie JM, Raoult D. Genome sequence of Rickettsia bellii illuminates the role of amoebae in gene exchanges between intracellular pathogens. PLoS Genet 2006; 2:e76. [PMID: 16703114 PMCID: PMC1458961 DOI: 10.1371/journal.pgen.0020076] [Citation(s) in RCA: 232] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2005] [Accepted: 04/04/2006] [Indexed: 11/18/2022] Open
Abstract
The recently sequenced Rickettsia felis genome revealed an unexpected plasmid carrying several genes usually associated with DNA transfer, suggesting that ancestral rickettsiae might have been endowed with a conjugation apparatus. Here we present the genome sequence of Rickettsia bellii, the earliest diverging species of known rickettsiae. The 1,552,076 base pair-long chromosome does not exhibit the colinearity observed between other rickettsia genomes, and encodes a complete set of putative conjugal DNA transfer genes most similar to homologues found in Protochlamydia amoebophila UWE25, an obligate symbiont of amoebae. The genome exhibits many other genes highly similar to homologues in intracellular bacteria of amoebae. We sought and observed sex pili-like cell surface appendages for R. bellii. We also found that R. bellii very efficiently multiplies in the nucleus of eukaryotic cells and survives in the phagocytic amoeba, Acanthamoeba polyphaga. These results suggest that amoeba-like ancestral protozoa could have served as a genetic "melting pot" where the ancestors of rickettsiae and other bacteria promiscuously exchanged genes, eventually leading to their adaptation to the intracellular lifestyle within eukaryotic cells.
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Affiliation(s)
- Hiroyuki Ogata
- Structural and Genomic Information Laboratory, Centre National de la Recherche Scientifique UPR-2589, Institut de Biologie Structurale et Microbiologie, Parc Scientifique de Luminy, Marseille, France
- * To whom correspondence should be addressed. E-mail: (HO); (DR)
| | - Bernard La Scola
- Unité des Rickettsies, Centre National de la Recherche Scientifique UMR-6020, IFR-48, Faculté de Médecine, Université de la Méditerranée, Marseille, France
| | - Stéphane Audic
- Structural and Genomic Information Laboratory, Centre National de la Recherche Scientifique UPR-2589, Institut de Biologie Structurale et Microbiologie, Parc Scientifique de Luminy, Marseille, France
| | - Patricia Renesto
- Unité des Rickettsies, Centre National de la Recherche Scientifique UMR-6020, IFR-48, Faculté de Médecine, Université de la Méditerranée, Marseille, France
| | - Guillaume Blanc
- Structural and Genomic Information Laboratory, Centre National de la Recherche Scientifique UPR-2589, Institut de Biologie Structurale et Microbiologie, Parc Scientifique de Luminy, Marseille, France
| | - Catherine Robert
- Unité des Rickettsies, Centre National de la Recherche Scientifique UMR-6020, IFR-48, Faculté de Médecine, Université de la Méditerranée, Marseille, France
| | - Pierre-Edouard Fournier
- Unité des Rickettsies, Centre National de la Recherche Scientifique UMR-6020, IFR-48, Faculté de Médecine, Université de la Méditerranée, Marseille, France
| | - Jean-Michel Claverie
- Structural and Genomic Information Laboratory, Centre National de la Recherche Scientifique UPR-2589, Institut de Biologie Structurale et Microbiologie, Parc Scientifique de Luminy, Marseille, France
| | - Didier Raoult
- Unité des Rickettsies, Centre National de la Recherche Scientifique UMR-6020, IFR-48, Faculté de Médecine, Université de la Méditerranée, Marseille, France
- * To whom correspondence should be addressed. E-mail: (HO); (DR)
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10
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Boubakri H, Beuf M, Simonet P, Vogel TM. Development of metagenomic DNA shuffling for the construction of a xenobiotic gene. Gene 2006; 375:87-94. [PMID: 16690231 DOI: 10.1016/j.gene.2006.02.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 01/13/2006] [Accepted: 02/26/2006] [Indexed: 10/24/2022]
Abstract
We describe a metagenomic DNA shuffling process by combining protein engineering process mutation generator and the high potential diversity of metagenomic DNA derived from the environment. Numerous previous shuffling processes attempted to recombine more or less related parental sequences. At the same time, metagenomic approaches unveiled a huge diversity of DNA sequences and genomes, which have not yet been identified to date. In this study, we attempted to combine these two approaches in order to regenerate a novel gene. Here, we present the possibility that DNA fragments from an entire microbial community (metagenome) might be available for the creation of novel genes capable of degrading pollutants. Metagenomic DNA extracted from non-polluted soil was shuffled in vitro to recreate the linA gene responsible for the first steps of lindane degradation. In this work, 74% of the ORF came from separate subsets of the metagenomic pool from a lindane-free and linA-free soil. Our results demonstrate that microbial community genetic diversity can serve as a source for novel gene construction during in vitro manipulation. This in vitro gene construction might also simulate the mosaic nature of novel genes. This demonstration might lead to other attempts to mimic bacterial adaptation and to construct degradative genes for novel compounds not yet released into the environment.
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Affiliation(s)
- Hasna Boubakri
- Ecologie Microbienne, UMR CNRS 5557, Université Claude Bernard Lyon I, 16 rue Dubois, F-69622 Villeurbanne Cedex, France
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11
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Raoult D, Ogata H, Audic S, Robert C, Suhre K, Drancourt M, Claverie JM. Tropheryma whipplei Twist: a human pathogenic Actinobacteria with a reduced genome. Genome Res 2003; 13:1800-9. [PMID: 12902375 PMCID: PMC403771 DOI: 10.1101/gr.1474603] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The human pathogen Tropheryma whipplei is the only known reduced genome species (<1 Mb) within the Actinobacteria [high G+C Gram-positive bacteria]. We present the sequence of the 927303-bp circular genome of T. whipplei Twist strain, encoding 808 predicted protein-coding genes. Specific genome features include deficiencies in amino acid metabolisms, the lack of clear thioredoxin and thioredoxin reductase homologs, and a mutation in DNA gyrase predicting a resistance to quinolone antibiotics. Moreover, the alignment of the two available T. whipplei genome sequences (Twist vs. TW08/27) revealed a large chromosomal inversion the extremities of which are located within two paralogous genes. These genes belong to a large cell-surface protein family defined by the presence of a common repeat highly conserved at the nucleotide level. The repeats appear to trigger frequent genome rearrangements in T. whipplei, potentially resulting in the expression of different subsets of cell surface proteins. This might represent a new mechanism for evading host defenses. The T. whipplei genome sequence was also compared to other reduced bacterial genomes to examine the generality of previously detected features. The analysis of the genome sequence of this previously largely unknown human pathogen is now guiding the development of molecular diagnostic tools and more convenient culture conditions.
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Affiliation(s)
- Didier Raoult
- Unité des Rickettsies, Faculté de Médecine, CNRS UMR6020, Université de la Méditerranée, 13385 Marseille Cedex 05, France.
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12
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Nakagawa I, Kurokawa K, Yamashita A, Nakata M, Tomiyasu Y, Okahashi N, Kawabata S, Yamazaki K, Shiba T, Yasunaga T, Hayashi H, Hattori M, Hamada S. Genome sequence of an M3 strain of Streptococcus pyogenes reveals a large-scale genomic rearrangement in invasive strains and new insights into phage evolution. Genome Res 2003; 13:1042-55. [PMID: 12799345 PMCID: PMC403657 DOI: 10.1101/gr.1096703] [Citation(s) in RCA: 196] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Group Astreptococcus (GAS) is a gram-positive bacterial pathogen that causes various suppurative infections and nonsuppurative sequelae. Since the late 1980s, streptococcal toxic-shock like syndrome (STSS) and severe invasive GAS infections have been reported globally. Here we sequenced the genome of serotype M3 strain SSI-1, isolated from an STSS patient in Japan, and compared it with those of other GAS strains. The SSI-1 genome is composed of 1,884,275 bp, and 1.7 Mb of the sequence is highly conserved relative to strain SF370 (serotype M1) and MGAS8232 (serotype M18), and almost completely conserved relative to strain MGAS315 (serotype M3). However, a large genomic rearrangement has been shown to occur across the replication axis between the homologous rrn-comX1 regions and between two prophage-coding regions across the replication axis. Atotal of 1 Mb of chromosomal DNA is inverted across the replication axis. Interestingly, the recombinations between the prophage regions are within the phage genes, and the genes encoding superantigens and mitogenic factors are interchanged between two prophages. This genomic rearrangement occurs in 65% of clinical isolates (64/94) collected after 1990, whereas it is found in only 25% of clinical isolates (7/28) collected before 1985. These observations indicate that streptococcal phages represent important plasticity regions in the GAS chromosome where recombination between homologous phage genes can occur and result not only in new phage derivatives, but also in large chromosomal rearrangements.
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Affiliation(s)
- Ichiro Nakagawa
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita-Osaka 565-0871, Japan.
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13
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Abstract
Whereas the process of DNA replication is fundamentally conserved in the three domains of life, the archaeal system is closer to that of eukarya than bacteria. In the time since the complete genome sequences of several members of the archaeal domain became available, there has been a burst of research on archaeal DNA replication. These studies have led to both expected and surprising findings. This review summarizes the search for origins of replication in archaea, and our current knowledge of initiation, the process by which replication origins are recognized, the DNA molecule is unwound and the replicative helicase is loaded onto the DNA in preparation for DNA synthesis. The similarities and differences of the initiation process in archea, bacteria and eukarya are also summarized.
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Affiliation(s)
- Lori M Kelman
- Montgomery College, 20200 Observation Drive, Germantown, MD 20876, USA.
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14
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Cohen GN, Barbe V, Flament D, Galperin M, Heilig R, Lecompte O, Poch O, Prieur D, Quérellou J, Ripp R, Thierry JC, Van der Oost J, Weissenbach J, Zivanovic Y, Forterre P. An integrated analysis of the genome of the hyperthermophilic archaeon Pyrococcus abyssi. Mol Microbiol 2003; 47:1495-512. [PMID: 12622808 DOI: 10.1046/j.1365-2958.2003.03381.x] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The hyperthermophilic euryarchaeon Pyrococcus abyssi and the related species Pyrococcus furiosus and Pyrococcus horikoshii, whose genomes have been completely sequenced, are presently used as model organisms in different laboratories to study archaeal DNA replication and gene expression and to develop genetic tools for hyperthermophiles. We have performed an extensive re-annotation of the genome of P. abyssi to obtain an integrated view of its phylogeny, molecular biology and physiology. Many new functions are predicted for both informational and operational proteins. Moreover, several candidate genes have been identified that might encode missing links in key metabolic pathways, some of which have unique biochemical features. The great majority of Pyrococcus proteins are typical archaeal proteins and their phylogenetic pattern agrees with its position near the root of the archaeal tree. However, proteins probably from bacterial origin, including some from mesophilic bacteria, are also present in the P. abyssi genome.
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Affiliation(s)
- Georges N Cohen
- Institut Pasteur, 25,28 rue du Docteur Roux, 75724 Paris CEDEX 15, France
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15
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Abstract
Archaea, members of the third domain of life, are bacterial-looking prokaryotes that harbour many unique genotypic and phenotypic properties, testifying for their peculiar evolutionary status. The archaeal ancestor was probably a hyperthermophilic anaerobe. Two archaeal phyla are presently recognized, the Euryarchaeota and the Crenarchaeota. Methanogenesis was the main invention that occurred in the euryarchaeal phylum and is now shared by several archaeal groups. Adaptation to aerobic conditions occurred several times independently in both Euryarchaeota and Crenarchaeota. Recently, many new groups of Archaea that have not yet been cultured have been detected by PCR amplification of 16S ribosomal RNA from environmental samples. The phenotypic and genotypic characterization of these new groups is now a top priority for further studies on archaeal evolution.
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Affiliation(s)
- Patrick Forterre
- Institut de Génétique et Microbiologie, UMR 8621 CNRS, Bat 409, Université Paris-Sud, 91405 Orsay Cedex, France.
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16
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Zivanovic Y, Lopez P, Philippe H, Forterre P. Pyrococcus genome comparison evidences chromosome shuffling-driven evolution. Nucleic Acids Res 2002; 30:1902-10. [PMID: 11972326 PMCID: PMC113857 DOI: 10.1093/nar/30.9.1902] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2002] [Accepted: 03/05/2002] [Indexed: 11/13/2022] Open
Abstract
The genomes of three Pyrococcus species, P.abyssi, P.furiosus and P.horikoshii, were compared at the DNA level, taking advantage of our identification of their replication origins. Three types of rearrangements have been identified: (i) inversion and translation across the replication axis (origin/terminus), (ii) inversion and translocation restricted to a replichore (the half chromosome divided by the replication axis) and (iii) apparent mobility of long clusters of repeated sequences. Rearrangements restricted within a replichore were more common between P.furiosus and the two other Pyrococcus species than between P.horikoshii and P.abyssi. A strong correlation was found between 23 homologous insertion sequence elements, present only in P.furiosus, and recombined segment boundaries, suggesting that transposition events have been a major cause of genomic disruption in this species. Moreover, gene orientation bias was much more disrupted than strand composition biases in fragments that switched their orientation within a replichore upon recombination. This allowed us to conclude that one reversion and one translation occurred in P.abyssi after its divergence from P.horikoshii, and that a smaller segment has specifically recombined in P.furiosus. Whereas a majority of genes are transcribed in the same direction as DNA replication in P.horikoshii and P.abyssi, the colinearity of transcription and replication is only maintained for highly transcribed genes in P.furiosus. We discuss the implications of genomic rearrangements on gene orientation and composition biases, and their consequences on sequence evolution.
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Affiliation(s)
- Yvan Zivanovic
- Institut de Génétique et Microbiologie, Université de Paris-Sud, UMR C8621 Centre Universitaire d'Orsay, Bâtiment 409, 91405 Orsay Cedex, France.
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17
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Lu XL, Qian KD, Tang XQ, Zhu YL, Du Q. Detection of H.pylori DNA in gastric epithelial cells by in situ hybridization. World J Gastroenterol 2002; 8:305-7. [PMID: 11925613 PMCID: PMC4658372 DOI: 10.3748/wjg.v8.i2.305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2001] [Revised: 10/22/2001] [Accepted: 11/01/2001] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the presence of H.pylori DNA within gastric epithelial cells in patients with H.pylori infection and its possible carcinogenic mechanism. METHODS Total 112 patients, with pathologically confirmed chronic superficial gastritis, chronic atrophic gastritis, intestinal metaplasia, atypical hyperplasia or gastric cancer were studied. Among them, 28 were H.pylori negative and 84 H.pylori positive. H.pylori DNA in gastric epithelial cells was detected by GenPoint catalyzed signal amplification system for in situ hybridization. RESULTS In the H.pylori positive group, zero out of 24 chronic superficial gastritis (0.0%), four out of 25 precancerous changes (16.0%) and thirteen out of 35 gastric cancers (37.1%) showed H.pylori DNA in the nucleus of gastric epithelial cells, the positive rates of H.pylori DNA in the nucleus of gastric epithelial cells were progressively increased in chronic superficial gastritis, precancerous changes and gastric cancer groups (chi(2)=12.56, P=0.002); One out of 24 chronic superficial gastritis (4.2%), eleven out of 25 precancerous changes (44.0%) and thirteen out of 35 gastric cancers (37.1%) showed H.pylori DNA in the cytoplasm of gastric epithelial cells (chi(2)=10.86, P=0.004). In the H.pylori negative group, only one patient with gastric cancer was found H.pylori DNA in the nucleus of gastric epithelial cells; Only two patients, one patient with precancerous changes and another with gastric cancer, showed H.pylori DNA in the cytoplasm of gastric epithelial cells. Furthermore, H.pylori DNA must have been in the cytoplasm as long as it existed in the nucleus of gastric epithelial cells. CONCLUSION H.pylori DNA exists both in the nucleus and the cytoplasm of gastric epithelial cells in patients with H.pylori infections. The pathological progression from chronic superficial gastritis, precancerous changes to gastric cancer is associated with higher positive rates of H.pylori DNA presence in the nucleus of gastric epithelial cells.
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Affiliation(s)
- Xin-Liang Lu
- Department of Digestive Diseases, Second Affiliated Hospital, Zhejiang University Medical College, Hangzhou 310009, Zhejiang Province, China.
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18
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Brügger K, Redder P, She Q, Confalonieri F, Zivanovic Y, Garrett RA. Mobile elements in archaeal genomes. FEMS Microbiol Lett 2002; 206:131-41. [PMID: 11814653 DOI: 10.1111/j.1574-6968.2002.tb10999.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The recent availability of several archaeal genome sequences has provided a basis for detailed analyses of the frequency, location and phylogeny of archaeal mobile elements. All the known elements fall into two main types, autonomous insertion sequence (IS) elements and the non-autonomous miniature inverted repeat element (MITE)-like elements. Both classes are considered to be mobilized via transposases that are encoded by the IS elements, although mobility has only been demonstrated experimentally for a few elements. The number, and diversity, of the elements differs greatly between the genomes. At one extreme Sulfolobus solfataricus P2 and Halobacterium NRC-1 are very rich in elements while Methanobacterium thermoautotrophicum contains none. The former also show examples of complex clusters of interwoven elements. An analysis of the genomic distribution in S. solfataricus suggests that the putative oriC and terC regions act as barriers for the mobility of both IS and MITE-like elements. Moreover, the very high level of truncated IS elements in the genomes of S. solfataricus, Sulfolobus tokodaii and Thermoplasma volcanium suggests that there may be a cellular mechanism for selectively inactivating IS elements at a point when they become too numerous and disadvantageous for the cell. Phylogenetically, archaeal IS elements are confined to 11 of the 17 known families of bacterial and eukaryal IS elements where some generate distinct subgroups. Finally, DNA viruses, plasmids and DNA fragments can also be inserted into, and excised from, archaeal genomes by means of an integrase-mediated mechanism that has special archaeal characteristics.
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Affiliation(s)
- Kim Brügger
- Microbiology Genome group, Institute of Molecular Biology, University of Copenhagen, Denmark
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