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Gallot-Lavallée L, Jerlström-Hultqvist J, Zegarra-Vidarte P, Salas-Leiva DE, Stairs CW, Čepička I, Roger AJ, Archibald JM. Massive intein content in Anaeramoeba reveals aspects of intein mobility in eukaryotes. Proc Natl Acad Sci U S A 2023; 120:e2306381120. [PMID: 38019867 PMCID: PMC10710043 DOI: 10.1073/pnas.2306381120] [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: 04/19/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
Inteins are self-splicing protein elements found in viruses and all three domains of life. How the DNA encoding these selfish elements spreads within and between genomes is poorly understood, particularly in eukaryotes where inteins are scarce. Here, we show that the nuclear genomes of three strains of Anaeramoeba encode between 45 and 103 inteins, in stark contrast to four found in the most intein-rich eukaryotic genome described previously. The Anaeramoeba inteins reside in a wide range of proteins, only some of which correspond to intein-containing proteins in other eukaryotes, prokaryotes, and viruses. Our data also suggest that viruses have contributed to the spread of inteins in Anaeramoeba and the colonization of new alleles. The persistence of Anaeramoeba inteins might be partly explained by intragenomic movement of intein-encoding regions from gene to gene. Our intein dataset greatly expands the spectrum of intein-containing proteins and provides insights into the evolution of inteins in eukaryotes.
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Affiliation(s)
- Lucie Gallot-Lavallée
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Institute for Comparative Genomics, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - Jon Jerlström-Hultqvist
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Institute for Comparative Genomics, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Microbiology and Immunology, Department of Cell and Molecular Biology, Biomedical Centre, Uppsala University, Uppsala751 24, Sweden
| | - Paula Zegarra-Vidarte
- Microbiology and Immunology, Department of Cell and Molecular Biology, Biomedical Centre, Uppsala University, Uppsala751 24, Sweden
| | - Dayana E. Salas-Leiva
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Institute for Comparative Genomics, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - Courtney W. Stairs
- Microbiology Group, Department of Biology, Lund University, Lund223 62, Sweden
| | - Ivan Čepička
- Department of Zoology, Charles University, Prague128 00, Czech Republic
| | - Andrew J. Roger
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Institute for Comparative Genomics, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
| | - John M. Archibald
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
- Institute for Comparative Genomics, Dalhousie University, Halifax, Nova ScotiaB3H 4R2, Canada
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Gophna U, Altman-Price N. Horizontal Gene Transfer in Archaea-From Mechanisms to Genome Evolution. Annu Rev Microbiol 2022; 76:481-502. [PMID: 35667126 DOI: 10.1146/annurev-micro-040820-124627] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Archaea remains the least-studied and least-characterized domain of life despite its significance not just to the ecology of our planet but also to the evolution of eukaryotes. It is therefore unsurprising that research into horizontal gene transfer (HGT) in archaea has lagged behind that of bacteria. Indeed, several archaeal lineages may owe their very existence to large-scale HGT events, and thus understanding both the molecular mechanisms and the evolutionary impact of HGT in archaea is highly important. Furthermore, some mechanisms of gene exchange, such as plasmids that transmit themselves via membrane vesicles and the formation of cytoplasmic bridges that allows transfer of both chromosomal and plasmid DNA, may be archaea specific. This review summarizes what we know about HGT in archaea, and the barriers that restrict it, highlighting exciting recent discoveries and pointing out opportunities for future research. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Uri Gophna
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; ,
| | - Neta Altman-Price
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; , .,Department of Natural and Life Sciences, The Open University of Israel, Raanana, Israel
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Bahrami A, Najafi A, Hashemi M, Miraie-Ashtiani SR. PSSP: Protein splice site prediction algorithm using Bayesian approach. J Bioinform Comput Biol 2020; 17:1950034. [PMID: 32019415 DOI: 10.1142/s0219720019500343] [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: 11/18/2022]
Abstract
This study aimed to introduce an algorithm and identify intein motif and blocks involved in protein splicing, and explore the underlying methods in the development of detection of protein motifs. Inteins are mobile protein splicing elements capable of self-splicing post-translationally. They exist in viruses and bacteriophage, notwithstanding this broad phylogenetic distribution, all inteins apportion common structural features. A method was developed to predict intein in a raw sequence, using a ranking and scoring scheme based on amino acid θ value tables. This method aided in the identification and assessment of patterns characterizing the intein sequences. New intein conserved properties are revealed and the known ones are described and localized. We have computed the θ value of each amino acid at block A positions +1 to +13, block B positions l+13 to l+26 and block G positions -7 to +1 for the three categories. The consensus amino acids thus found are listed at the end of each row. We gave statistics for the distance between the blocks, block A to B, block B to F, and block F to G with the average being 66.1, 294, and 10.2 amino acids, respectively. The actual blocks A, B, and G of the one intein found in vacuolar membrane ATPase subunit, a precursor protein, are ranked 1. The results indicate all of the block sequences that are found in nine proteins are ranked at top of the list. The intein sequence is used to search the databases for intein-like proteins. Understanding the functional, structural, and dynamical aspects of inteins is important for intein engineering and the betterment of intein database.
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Affiliation(s)
- Abolfazl Bahrami
- Department of Animal Science, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Islamic Republic of Iran
| | - Ali Najafi
- Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mohammadreza Hashemi
- Department of Animal Science, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Islamic Republic of Iran
| | - Seyed Reza Miraie-Ashtiani
- Department of Animal Science, University College of Agriculture and Natural Resources, University of Tehran, Karaj, Islamic Republic of Iran
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Rajasekharan SK, Ray AK, Ramesh S, Kannappan Mohanvel S. Species-specific detection of Candida tropicalis using evolutionary conserved intein DNA sequences. Lett Appl Microbiol 2018; 66:378-383. [PMID: 29427451 DOI: 10.1111/lam.12861] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 02/04/2018] [Accepted: 02/04/2018] [Indexed: 01/05/2023]
Abstract
Inteins (internal proteins) are self-splicing transportable genetic elements present in conserved regions of housekeeping genes. The study highlights the importance of intein as a potential diagnostic marker for species-specific identification of Candida tropicalis, a rapidly emerging opportunistic human pathogen. Initial steps of primer validation, sequence alignment, phylogenetic tree analysis, gel electrophoresis and real-time polymerase chain reaction (PCR) assays were performed to confirm the specificity of the designed primers. The primers were selective for C. tropicalis with 100% inclusivity and showed no cross-species or cross-genera matches. The established technique is a prototype for developing multifaceted PCR assays and for point-of-care testing in near future. SIGNIFICANCE AND IMPACT OF THE STUDY Development of molecular markers for specific detection of microbial pathogens using real-time polymerase chain reaction (PCR) is an appealing and challenging technique. A real-time PCR is an emerging technology frequently used to detect the aetiologic agents. In recent times, designing species-specific primers for pathogen detection is gaining momentum. The method offers rapid, accurate and cost-effective strategy to identify the target, thus providing sufficient time to instigate appropriate chemotherapy. The study highlights the use of intein DNA sequence as molecular markers for species-specific identification of Candida tropicalis. The study also offers a prototype model for developing multifaceted PCR assays using intein DNA sequences, and provides a developmental starting point for point-of-care testing in near future.
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Affiliation(s)
- S K Rajasekharan
- Centre for Research and Development, PRIST University, Thanjavur, India.,School of Chemical Engineering, Yeungnam University, Gyeongsan, Republic of Korea
| | - A K Ray
- Central Institute of Brackishwater Aquaculture-ICAR, Chennai, India
| | - S Ramesh
- Centre for Research and Development, PRIST University, Thanjavur, India
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Green CM, Novikova O, Belfort M. The dynamic intein landscape of eukaryotes. Mob DNA 2018; 9:4. [PMID: 29416568 PMCID: PMC5784728 DOI: 10.1186/s13100-018-0111-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 01/18/2018] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Inteins are mobile, self-splicing sequences that interrupt proteins and occur across all three domains of life. Scrutiny of the intein landscape in prokaryotes led to the hypothesis that some inteins are functionally important. Our focus shifts to eukaryotic inteins to assess their diversity, distribution, and dissemination, with the aim to comprehensively evaluate the eukaryotic intein landscape, understand intein maintenance, and dissect evolutionary relationships. RESULTS This bioinformatics study reveals that eukaryotic inteins are scarce, but present in nuclear genomes of fungi, chloroplast genomes of algae, and within some eukaryotic viruses. There is a preponderance of inteins in several fungal pathogens of humans and plants. Inteins are pervasive in certain proteins, including the nuclear RNA splicing factor, Prp8, and the chloroplast DNA helicase, DnaB. We find that eukaryotic inteins frequently localize to unstructured loops of the host protein, often at highly conserved sites. More broadly, a sequence similarity network analysis of all eukaryotic inteins uncovered several routes of intein mobility. Some eukaryotic inteins appear to have been acquired through horizontal transfer with dsDNA viruses, yet other inteins are spread through intragenomic transfer. Remarkably, endosymbiosis can explain patterns of DnaB intein inheritance across several algal phyla, a novel mechanism for intein acquisition and distribution. CONCLUSIONS Overall, an intriguing picture emerges for how the eukaryotic intein landscape arose, with many evolutionary forces having contributed to its current state. Our collective results provide a framework for exploring inteins as novel regulatory elements and innovative drug targets.
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Affiliation(s)
- Cathleen M. Green
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
| | - Olga Novikova
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
| | - Marlene Belfort
- Department of Biological Sciences and RNA Institute, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, 1400 Washington Avenue, Albany, NY 12222 USA
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Teixeira M, Moreno L, Stielow B, Muszewska A, Hainaut M, Gonzaga L, Abouelleil A, Patané J, Priest M, Souza R, Young S, Ferreira K, Zeng Q, da Cunha M, Gladki A, Barker B, Vicente V, de Souza E, Almeida S, Henrissat B, Vasconcelos A, Deng S, Voglmayr H, Moussa T, Gorbushina A, Felipe M, Cuomo C, de Hoog GS. Exploring the genomic diversity of black yeasts and relatives ( Chaetothyriales, Ascomycota). Stud Mycol 2017; 86:1-28. [PMID: 28348446 PMCID: PMC5358931 DOI: 10.1016/j.simyco.2017.01.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The order Chaetothyriales (Pezizomycotina, Ascomycetes) harbours obligatorily melanised fungi and includes numerous etiologic agents of chromoblastomycosis, phaeohyphomycosis and other diseases of vertebrate hosts. Diseases range from mild cutaneous to fatal cerebral or disseminated infections and affect humans and cold-blooded animals globally. In addition, Chaetothyriales comprise species with aquatic, rock-inhabiting, ant-associated, and mycoparasitic life-styles, as well as species that tolerate toxic compounds, suggesting a high degree of versatile extremotolerance. To understand their biology and divergent niche occupation, we sequenced and annotated a set of 23 genomes of main the human opportunists within the Chaetothyriales as well as related environmental species. Our analyses included fungi with diverse life-styles, namely opportunistic pathogens and closely related saprobes, to identify genomic adaptations related to pathogenesis. Furthermore, ecological preferences of Chaetothyriales were analysed, in conjuncture with the order-level phylogeny based on conserved ribosomal genes. General characteristics, phylogenomic relationships, transposable elements, sex-related genes, protein family evolution, genes related to protein degradation (MEROPS), carbohydrate-active enzymes (CAZymes), melanin synthesis and secondary metabolism were investigated and compared between species. Genome assemblies varied from 25.81 Mb (Capronia coronata) to 43.03 Mb (Cladophialophora immunda). The bantiana-clade contained the highest number of predicted genes (12 817 on average) as well as larger genomes. We found a low content of mobile elements, with DNA transposons from Tc1/Mariner superfamily being the most abundant across analysed species. Additionally, we identified a reduction of carbohydrate degrading enzymes, specifically many of the Glycosyl Hydrolase (GH) class, while most of the Pectin Lyase (PL) genes were lost in etiological agents of chromoblastomycosis and phaeohyphomycosis. An expansion was found in protein degrading peptidase enzyme families S12 (serine-type D-Ala-D-Ala carboxypeptidases) and M38 (isoaspartyl dipeptidases). Based on genomic information, a wide range of abilities of melanin biosynthesis was revealed; genes related to metabolically distinct DHN, DOPA and pyomelanin pathways were identified. The MAT (MAting Type) locus and other sex-related genes were recognized in all 23 black fungi. Members of the asexual genera Fonsecaea and Cladophialophora appear to be heterothallic with a single copy of either MAT-1-1 or MAT-1-2 in each individual. All Capronia species are homothallic as both MAT1-1 and MAT1-2 genes were found in each single genome. The genomic synteny of the MAT-locus flanking genes (SLA2-APN2-COX13) is not conserved in black fungi as is commonly observed in Eurotiomycetes, indicating a unique genomic context for MAT in those species. The heterokaryon (het) genes expansion associated with the low selective pressure at the MAT-locus suggests that a parasexual cycle may play an important role in generating diversity among those fungi.
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Affiliation(s)
- M.M. Teixeira
- Division of Pathogen Genomics, Translational Genomics Research Institute (TGen), Flagstaff, AZ, USA
- Department of Cell Biology, University of Brasília, Brasilia, Brazil
| | - L.F. Moreno
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
- Department of Basic Pathology, Federal University of Paraná State, Curitiba, PR, Brazi1
- Institute of Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - B.J. Stielow
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
| | - A. Muszewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - M. Hainaut
- Université Aix-Marseille (CNRS), Marseille, France
| | - L. Gonzaga
- The National Laboratory for Scientific Computing (LNCC), Petropolis, Brazil
| | | | - J.S.L. Patané
- Department of Biochemistry, University of São Paulo, Brazil
| | - M. Priest
- Broad Institute of MIT and Harvard, Cambridge, USA
| | - R. Souza
- The National Laboratory for Scientific Computing (LNCC), Petropolis, Brazil
| | - S. Young
- Broad Institute of MIT and Harvard, Cambridge, USA
| | - K.S. Ferreira
- Department of Biological Sciences, Federal University of São Paulo, Diadema, SP, Brazil
| | - Q. Zeng
- Broad Institute of MIT and Harvard, Cambridge, USA
| | - M.M.L. da Cunha
- Núcleo Multidisciplinar de Pesquisa em Biologia UFRJ-Xerém-NUMPEX-BIO, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - A. Gladki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - B. Barker
- Division of Pathogen Genomics, Translational Genomics Research Institute (TGen), Flagstaff, AZ, USA
| | - V.A. Vicente
- Department of Basic Pathology, Federal University of Paraná State, Curitiba, PR, Brazi1
| | - E.M. de Souza
- Department of Biochemistry and Molecular Biology, Federal University of Paraná, Curitiba, PR, Brazil
| | - S. Almeida
- Department of Clinical and Toxicological Analysis, University of São Paulo, São Paulo, SP, Brazil
| | - B. Henrissat
- Université Aix-Marseille (CNRS), Marseille, France
| | - A.T.R. Vasconcelos
- The National Laboratory for Scientific Computing (LNCC), Petropolis, Brazil
| | - S. Deng
- Shanghai Institute of Medical Mycology, Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - H. Voglmayr
- Department of Systematic and Evolutionary Botany, University of Vienna, Vienna, Austria
| | - T.A.A. Moussa
- Biological Sciences Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
- Botany and Microbiology Department, Faculty of Science, Cairo University, Giza, Egypt
| | - A. Gorbushina
- Federal Institute for Material Research and Testing (BAM), Berlin, Germany
| | - M.S.S. Felipe
- Department of Cell Biology, University of Brasília, Brasilia, Brazil
| | - C.A. Cuomo
- Broad Institute of MIT and Harvard, Cambridge, USA
| | - G. Sybren de Hoog
- Westerdijk Fungal Biodiversity Institute, Utrecht, The Netherlands
- Department of Basic Pathology, Federal University of Paraná State, Curitiba, PR, Brazi1
- Institute of Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
- Biological Sciences Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
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Patel S. Drivers of bacterial genomes plasticity and roles they play in pathogen virulence, persistence and drug resistance. INFECTION GENETICS AND EVOLUTION 2016; 45:151-164. [DOI: 10.1016/j.meegid.2016.08.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 08/26/2016] [Accepted: 08/27/2016] [Indexed: 12/11/2022]
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Andam CP, Carver SM, Berthrong ST. Horizontal Gene Flow in Managed Ecosystems. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2015. [DOI: 10.1146/annurev-ecolsys-112414-054126] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Cheryl P. Andam
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, Massachusetts 02115;
| | - Sarah M. Carver
- Central Research, The Kraft Heinz Company, Glenview, Illinois 60025;
| | - Sean T. Berthrong
- Department of Biological Sciences, Butler University, Indianapolis, Indiana 46208;
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Novikova O, Jayachandran P, Kelley DS, Morton Z, Merwin S, Topilina NI, Belfort M. Intein Clustering Suggests Functional Importance in Different Domains of Life. Mol Biol Evol 2015; 33:783-99. [PMID: 26609079 PMCID: PMC4760082 DOI: 10.1093/molbev/msv271] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Inteins, also called protein introns, are self-splicing mobile elements found in all domains of life. A bioinformatic survey of genomic data highlights a biased distribution of inteins among functional categories of proteins in both bacteria and archaea, with a strong preference for a single network of functions containing replisome proteins. Many nonorthologous, functionally equivalent replicative proteins in bacteria and archaea carry inteins, suggesting a selective retention of inteins in proteins of particular functions across domains of life. Inteins cluster not only in proteins with related roles but also in specific functional units of those proteins, like ATPase domains. This peculiar bias does not fully fit the models describing inteins exclusively as parasitic elements. In such models, evolutionary dynamics of inteins is viewed primarily through their mobility with the intein homing endonuclease (HEN) as the major factor of intein acquisition and loss. Although the HEN is essential for intein invasion and spread in populations, HEN dynamics does not explain the observed biased distribution of inteins among proteins in specific functional categories. We propose that the protein splicing domain of the intein can act as an environmental sensor that adapts to a particular niche and could increase the chance of the intein becoming fixed in a population. We argue that selective retention of some inteins might be beneficial under certain environmental stresses, to act as panic buttons that reversibly inhibit specific networks, consistent with the observed intein distribution.
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Affiliation(s)
- Olga Novikova
- Department of Biological Sciences and RNA Institute, University at Albany
| | | | - Danielle S Kelley
- Department of Biomedical Sciences, School of Public Health, University at Albany
| | - Zachary Morton
- Department of Biological Sciences and RNA Institute, University at Albany
| | | | - Natalya I Topilina
- Department of Biological Sciences and RNA Institute, University at Albany
| | - Marlene Belfort
- Department of Biological Sciences and RNA Institute, University at Albany Department of Biomedical Sciences, School of Public Health, University at Albany
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von der Heyde A, Lockhauserbäumer J, Uetrecht C, Elleuche S. A hydrolase-based reporter system to uncover the protein splicing performance of an archaeal intein. Appl Microbiol Biotechnol 2015; 99:7613-24. [PMID: 26026939 DOI: 10.1007/s00253-015-6689-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 05/06/2015] [Accepted: 05/17/2015] [Indexed: 11/30/2022]
Abstract
Extein amino acid residues around the splice site junctions affect the functionality of inteins. To identify an optimal sequence context for efficient protein splicing of an intein from the thermoacidophilic archaeon Picrophilus torridus, single extein amino acid residues at the splice site junctions were continuously deleted. The construction of a set of different truncated extein variants showed that this intein tolerates multiple amino acid variations near the excision sites and exhibits full activity when -1 and +1 extein amino acid residues are conserved in an artificial GST-intein-HIS fusion construct. Moreover, splicing of the recombinant intein took place at temperatures between 4 and 42 °C with high efficiency, when produced in Escherichia coli. Therefore, structural model predictions were used to identify optimal insertion sites for the intein to be embedded within a hemicellulase from the psychrophilic bacterium Pseudoalteromonas arctica. The P. torridus intein inserted before amino acid residue Thr75 of the reporter enzyme retained catalytic activity. Moreover, the catalytic activity of the xylan-degrading hydrolase could be easily monitored in routine plate assays and in liquid test measurements at room temperature when produced in recombinant form in E. coli. This tool allows the indirect detection of the intein's catalytic activity to be used in screenings.
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Affiliation(s)
- Amélie von der Heyde
- Hamburg University of Technology (TUHH), Institute of Technical Microbiology, Kasernenstr. 12, 21073, Hamburg, Germany
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Soucy SM, Fullmer MS, Papke RT, Gogarten JP. Inteins as indicators of gene flow in the halobacteria. Front Microbiol 2014; 5:299. [PMID: 25018750 PMCID: PMC4071816 DOI: 10.3389/fmicb.2014.00299] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 05/30/2014] [Indexed: 12/21/2022] Open
Abstract
This research uses inteins, a type of mobile genetic element, to infer patterns of gene transfer within the Halobacteria. We surveyed 118 genomes representing 26 genera of Halobacteria for intein sequences. We then used the presence-absence profile, sequence similarity and phylogenies from the inteins recovered to explore how intein distribution can provide insight on the dynamics of gene flow between closely related and divergent organisms. We identified 24 proteins in the Halobacteria that have been invaded by inteins at some point in their evolutionary history, including two proteins not previously reported to contain an intein. Furthermore, the size of an intein is used as a heuristic for the phase of the intein's life cycle. Larger size inteins are assumed to be the canonical two domain inteins, consisting of self-splicing and homing endonuclease domains (HEN); smaller sizes are assumed to have lost the HEN domain. For many halobacterial groups the consensus phylogenetic signal derived from intein sequences is compatible with vertical inheritance or with a strong gene transfer bias creating these clusters. Regardless, the coexistence of intein-free and intein-containing alleles reveal ongoing transfer and loss of inteins within these groups. Inteins were frequently shared with other Euryarchaeota and among the Bacteria, with members of the Cyanobacteria (Cyanothece, Anabaena), Bacteriodetes (Salinibacter), Betaproteobacteria (Delftia, Acidovorax), Firmicutes (Halanaerobium), Actinobacteria (Longispora), and Deinococcus-Thermus-group.
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Affiliation(s)
- Shannon M Soucy
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - Matthew S Fullmer
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
| | - R Thane Papke
- Department of Molecular and Cell Biology, University of Connecticut Storrs, CT, USA
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Fullmer MS, Soucy SM, Swithers KS, Makkay AM, Wheeler R, Ventosa A, Gogarten JP, Papke RT. Population and genomic analysis of the genus Halorubrum. Front Microbiol 2014; 5:140. [PMID: 24782836 PMCID: PMC3990103 DOI: 10.3389/fmicb.2014.00140] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 03/18/2014] [Indexed: 11/13/2022] Open
Abstract
The Halobacteria are known to engage in frequent gene transfer and homologous recombination. For stably diverged lineages to persist some checks on the rate of between lineage recombination must exist. We surveyed a group of isolates from the Aran-Bidgol endorheic lake in Iran and sequenced a selection of them. Multilocus Sequence Analysis (MLSA) and Average Nucleotide Identity (ANI) revealed multiple clusters (phylogroups) of organisms present in the lake. Patterns of intein and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs) presence/absence and their sequence similarity, GC usage along with the ANI and the identities of the genes used in the MLSA revealed that two of these clusters share an exchange bias toward others in their phylogroup while showing reduced rates of exchange with other organisms in the environment. However, a third cluster, composed in part of named species from other areas of central Asia, displayed many indications of variability in exchange partners, from within the lake as well as outside the lake. We conclude that barriers to gene exchange exist between the two purely Aran-Bidgol phylogroups, and that the third cluster with members from other regions is not a single population and likely reflects an amalgamation of several populations.
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Affiliation(s)
- Matthew S. Fullmer
- Department of Molecular and Cell Biology, University of ConnecticutStorrs, CT, USA
| | - Shannon M. Soucy
- Department of Molecular and Cell Biology, University of ConnecticutStorrs, CT, USA
| | - Kristen S. Swithers
- Department of Molecular and Cell Biology, University of ConnecticutStorrs, CT, USA
- Department of Cell Biology, Yale School of Medicine, Yale UniversityNew Haven, CT, USA
| | - Andrea M. Makkay
- Department of Molecular and Cell Biology, University of ConnecticutStorrs, CT, USA
| | - Ryan Wheeler
- Department of Molecular and Cell Biology, University of ConnecticutStorrs, CT, USA
| | - Antonio Ventosa
- Department of Microbiology and Parasitology, University of SevilleSeville, Spain
| | - J. Peter Gogarten
- Department of Molecular and Cell Biology, University of ConnecticutStorrs, CT, USA
| | - R. Thane Papke
- Department of Molecular and Cell Biology, University of ConnecticutStorrs, CT, USA
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