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Tsurumaki M, Sato A, Saito M, Kanai A. Comprehensive analysis of insertion sequences within rRNA genes of CPR bacteria and biochemical characterization of a homing endonuclease encoded by these sequences. J Bacteriol 2024:e0007424. [PMID: 38856219 DOI: 10.1128/jb.00074-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 05/11/2024] [Indexed: 06/11/2024] Open
Abstract
The Candidate Phyla Radiation (CPR) represents an extensive bacterial clade comprising primarily uncultured lineages and is distinguished from other bacteria by a significant prevalence of insertion sequences (ISs) within their rRNA genes. However, our understanding of the taxonomic distribution and characteristics of these ISs remains limited. In this study, we used a comprehensive approach to systematically determine the nature of the rRNA ISs in CPR bacteria. The analysis of hundreds of rRNA gene sequences across 65 CPR phyla revealed that ISs are present in 48% of 16S rRNA genes and 82% of 23S rRNA genes, indicating a broad distribution across the CPR clade, with exceptions in the 16S and 23S rRNA genes of Candidatus (Ca.) Saccharibacteria and the 16S rRNA genes of Ca. Peregrinibacteria. Over half the ISs display a group-I-intron-like structure, whereas specific 16S rRNA gene ISs display features reminiscent of group II introns. The ISs frequently encode proteins with homing endonuclease (HE) domains, centered around the LAGLIDADG motif. The LAGLIDADG HE (LHE) proteins encoded by the rRNA ISs of CPR bacteria predominantly have a single-domain structure, deviating from the usual single- or double-domain configuration observed in typical prokaryotic LHEs. Experimental analysis of one LHE protein, I-ShaI from Ca. Shapirobacteria, confirmed that its endonuclease activity targets the DNA sequence of its insertion site, and chemical cross-linking experiments demonstrated its capacity to form homodimers. These results provide robust evidence supporting the hypothesis that the explosive proliferation of rRNA ISs in CPR bacteria was facilitated by mechanisms involving LHEs. IMPORTANCE Insertion sequences (ISs) in rRNA genes are relatively limited and infrequent in most bacterial phyla. With a comprehensive bioinformatic analysis, we show that in CPR bacteria, these ISs occur in 48% of 16S rRNA genes and 82% of 23S rRNA genes. We also report the systematic and biochemical characterization of the LAGLIDADG homing endonucleases (LHEs) encoded by these ISs in the first such analysis of the CPR bacteria. This study significantly extends our understanding of the phylogenetic positions of rRNA ISs within CPR bacteria and the biochemical features of their LHEs.
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Affiliation(s)
- Megumi Tsurumaki
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Asako Sato
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
| | - Motofumi Saito
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Akio Kanai
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
- Faculty of Environment and Information Studies, Keio University, Fujisawa, Japan
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2
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Gomes RMODS, Silva KJGD, Theodoro RC. Group I introns: Structure, splicing and their applications in medical mycology. Genet Mol Biol 2024; 47Suppl 1:e20230228. [PMID: 38525907 DOI: 10.1590/1678-4685-gmb-2023-0228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 02/02/2024] [Indexed: 03/26/2024] Open
Abstract
Group I introns are small RNAs (250-500 nt) capable of catalyzing their own splicing from the precursor RNA. They are widely distributed across the tree of life and have intricate relationships with their host genomes. In this work, we review its basic structure, self-splicing and its mechanisms of gene mobility. As they are widely found in unicellular eukaryotes, especially fungi, we gathered information regarding their possible impact on the physiology of fungal cells and the possible application of these introns in medical mycology.
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Affiliation(s)
| | | | - Raquel Cordeiro Theodoro
- Universidade Federal do Rio Grande do Norte, Instituto de Medicina Tropical do Rio Grande do Norte, Natal, RN, Brazil
- Universidade Federal do Rio Grande do Norte, Centro de Biociências, Departamento de Biologia Celular de Genética, Natal, RN, Brazil
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3
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Kösoglu-Kind B, Loredo R, Grossi M, Bernecker C, Burks JM, Buchkremer R. A biological sequence comparison algorithm using quantum computers. Sci Rep 2023; 13:14552. [PMID: 37666875 PMCID: PMC10477269 DOI: 10.1038/s41598-023-41086-5] [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: 03/27/2023] [Accepted: 08/22/2023] [Indexed: 09/06/2023] Open
Abstract
Genetic information is encoded as linear sequences of nucleotides, represented by letters ranging from thousands to billions. Differences between sequences are identified through comparative approaches like sequence analysis, where variations can occur at the individual nucleotide level or collectively due to various phenomena such as recombination or deletion. Detecting these sequence differences is vital for understanding biology and medicine, but the complexity and size of genomic data require substantial classical computing power. Inspired by human visual perception and pixel representation on quantum computers, we leverage these techniques to implement pairwise sequence analysis. Our method utilizes the Flexible Representation of Quantum Images (FRQI) framework, enabling comparisons at a fine granularity to single letters or amino acids within gene sequences. This novel approach enhances accuracy and resolution, surpassing traditional methods by capturing subtle genetic variations with precision. In summary, our approach offers algorithmic advantages, including reduced time complexity, improved space efficiency, and accurate sequence comparisons. The novelty lies in applying the FRQI algorithm to compare quantum images in genome sequencing, allowing for examination at the individual letter or amino acid level. This breakthrough holds promise for advancing biological data analysis and enables a more comprehensive understanding of genetic information.
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Affiliation(s)
- Büsra Kösoglu-Kind
- Institute of IT Management and Digitization Research (IFID), FOM University of Applied Sciences in Economics and Management, 40476, Dusseldorf, Germany
| | - Robert Loredo
- International Business Machines Corporation (IBM), Armonk, NY, 10504, USA
- IBM Quantum, IBM Thomas J. Watson Research Center, 1101 Kitchawan Rd, NY, 10598, Yorktown Heights, USA
| | - Michele Grossi
- European Organization for Nuclear Research (CERN), 1211, Geneva, Switzerland
| | | | - Jody M Burks
- International Business Machines Corporation (IBM), Armonk, NY, 10504, USA
| | - Rüdiger Buchkremer
- Institute of IT Management and Digitization Research (IFID), FOM University of Applied Sciences in Economics and Management, 40476, Dusseldorf, Germany.
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Chakraborty C, Bhattacharya M, Chatterjee S, Sharma AR, Saha RP, Dhama K, Agoramoorthy G. Integrative Bioinformatics Approaches Indicate a Particular Pattern of Some SARS-CoV-2 and Non-SARS-CoV-2 Proteins. Vaccines (Basel) 2022; 11:vaccines11010038. [PMID: 36679883 PMCID: PMC9864461 DOI: 10.3390/vaccines11010038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/12/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
Pattern recognition plays a critical role in integrative bioinformatics to determine the structural patterns of proteins of viruses such as SARS-CoV-2. This study identifies the pattern of SARS-CoV-2 proteins to depict the structure-function relationships of the protein alphabets of SARS-CoV-2 and COVID-19. The assembly enumeration algorithm, Anisotropic Network Model, Gaussian Network Model, Markovian Stochastic Model, and image comparison protein-like alphabets were used. The distance score was the lowest with 22 for "I" and highest with 40 for "9". For post-processing and decision, two protein alphabets "C" (PDB ID: 6XC3) and "S" (PDB ID: 7OYG) were evaluated to understand the structural, functional, and evolutionary relationships, and we found uniqueness in the functionality of proteins. Here, models were constructed using "SARS-CoV-2 proteins" (12 numbers) and "non-SARS-CoV-2 proteins" (14 numbers) to create two words, "SARS-CoV-2" and "COVID-19". Similarly, we developed two slogans: "Vaccinate the world against COVID-19" and "Say no to SARS-CoV-2", which were made with the proteins structure. It might generate vaccine-related interest to broad reader categories. Finally, the evolutionary process appears to enhance the protein structure smoothly to provide suitable functionality shaped by natural selection.
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Affiliation(s)
- Chiranjib Chakraborty
- Department of Biotechnology, School of Life Science and Biotechnology, Adamas University, Kolkata 700126, West Bengal, India
- Correspondence:
| | - Manojit Bhattacharya
- Department of Zoology, Fakir Mohan University, Vyasa Vihar, Balasore 756020, Odisha, India
| | - Srijan Chatterjee
- Institute for Skeletal Aging and Orthopaedic Surgery, Hallym University-Chuncheon Sacred Heart Hospital, Chuncheon-si 24252, Gangwon-do, Republic of Korea
| | - Ashish Ranjan Sharma
- Institute for Skeletal Aging and Orthopaedic Surgery, Hallym University-Chuncheon Sacred Heart Hospital, Chuncheon-si 24252, Gangwon-do, Republic of Korea
| | - Rudra P. Saha
- Department of Biotechnology, School of Life Science and Biotechnology, Adamas University, Kolkata 700126, West Bengal, India
| | - Kuldeep Dhama
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly 243122, Uttar Pradesh, India
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Rehling D, Scaletti ER, Rozman Grinberg I, Lundin D, Sahlin M, Hofer A, Sjöberg BM, Stenmark P. Structural and Biochemical Investigation of Class I Ribonucleotide Reductase from the Hyperthermophile Aquifex aeolicus. Biochemistry 2021; 61:92-106. [PMID: 34941255 PMCID: PMC8772380 DOI: 10.1021/acs.biochem.1c00503] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Ribonucleotide reductase (RNR) is an essential enzyme with a complex mechanism of allosteric regulation found in nearly all living organisms. Class I RNRs are composed of two proteins, a large α-subunit (R1) and a smaller β-subunit (R2) that exist as homodimers, that combine to form an active heterotetramer. Aquifex aeolicus is a hyperthermophilic bacterium with an unusual RNR encoding a 346-residue intein in the DNA sequence encoding its R2 subunit. We present the first structures of the A. aeolicus R1 and R2 (AaR1 and AaR2, respectively) proteins as well as the biophysical and biochemical characterization of active and inactive A. aeolicus RNR. While the active oligomeric state and activity regulation of A. aeolicus RNR are similar to those of other characterized RNRs, the X-ray crystal structures also reveal distinct features and adaptations. Specifically, AaR1 contains a β-hairpin hook structure at the dimer interface, which has an interesting π-stacking interaction absent in other members of the NrdAh subclass, and its ATP cone houses two ATP molecules. We determined structures of two AaR2 proteins: one purified from a construct lacking the intein (AaR2) and a second purified from a construct including the intein sequence (AaR2_genomic). These structures in the context of metal content analysis and activity data indicate that AaR2_genomic displays much higher iron occupancy and activity compared to AaR2, suggesting that the intein is important for facilitating complete iron incorporation, particularly in the Fe2 site of the mature R2 protein, which may be important for the survival of A. aeolicus in low-oxygen environments.
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Affiliation(s)
- Daniel Rehling
- Department of Biochemistry and Biophysics, Stockholm University, S-106 91 Stockholm, Sweden
| | - Emma Rose Scaletti
- Department of Biochemistry and Biophysics, Stockholm University, S-106 91 Stockholm, Sweden
| | - Inna Rozman Grinberg
- Department of Biochemistry and Biophysics, Stockholm University, S-106 91 Stockholm, Sweden
| | - Daniel Lundin
- Department of Biochemistry and Biophysics, Stockholm University, S-106 91 Stockholm, Sweden
| | - Margareta Sahlin
- Department of Biochemistry and Biophysics, Stockholm University, S-106 91 Stockholm, Sweden
| | - Anders Hofer
- Department of Biochemistry and Biophysics, Umeå University, SE-907 36 Umeå, Sweden
| | - Britt-Marie Sjöberg
- Department of Biochemistry and Biophysics, Stockholm University, S-106 91 Stockholm, Sweden
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, S-106 91 Stockholm, Sweden.,Department of Experimental Medical Science, Lund University, 221 00 Lund, Sweden
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6
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Chuang CK, Lin WM. Points of View on the Tools for Genome/Gene Editing. Int J Mol Sci 2021; 22:9872. [PMID: 34576035 PMCID: PMC8470269 DOI: 10.3390/ijms22189872] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 08/26/2021] [Accepted: 09/09/2021] [Indexed: 12/25/2022] Open
Abstract
Theoretically, a DNA sequence-specific recognition protein that can distinguish a DNA sequence equal to or more than 16 bp could be unique to mammalian genomes. Long-sequence-specific nucleases, such as naturally occurring Homing Endonucleases and artificially engineered ZFN, TALEN, and Cas9-sgRNA, have been developed and widely applied in genome editing. In contrast to other counterparts, which recognize DNA target sites by the protein moieties themselves, Cas9 uses a single-guide RNA (sgRNA) as a template for DNA target recognition. Due to the simplicity in designing and synthesizing a sgRNA for a target site, Cas9-sgRNA has become the most current tool for genome editing. Moreover, the RNA-guided DNA recognition activity of Cas9-sgRNA is independent of both of the nuclease activities of it on the complementary strand by the HNH domain and the non-complementary strand by the RuvC domain, and HNH nuclease activity null mutant (H840A) and RuvC nuclease activity null mutant (D10A) were identified. In accompaniment with the sgRNA, Cas9, Cas9(D10A), Cas9(H840A), and Cas9(D10A, H840A) can be used to achieve double strand breakage, complementary strand breakage, non-complementary strand breakage, and no breakage on-target site, respectively. Based on such unique characteristics, many engineered enzyme activities, such as DNA methylation, histone methylation, histone acetylation, cytidine deamination, adenine deamination, and primer-directed mutation, could be introduced within or around the target site. In order to prevent off-targeting by the lasting expression of Cas9 derivatives, a lot of transient expression methods, including the direct delivery of Cas9-sgRNA riboprotein, were developed. The issue of biosafety is indispensable in in vivo applications; Cas9-sgRNA packaged into virus-like particles or extracellular vesicles have been designed and some in vivo therapeutic trials have been reported.
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Affiliation(s)
- Chin-Kai Chuang
- Animal Technology Research Center, Division of Animal Technology, Agricultural Technology Research Institute, No. 52, Kedong 2nd Rd., Zhunan Township, Miaoli County 35053, Taiwan;
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7
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Diversity of limestone bacteriophages infecting Dickeya solani isolated in the Czech Republic. Arch Virol 2021; 166:1171-1175. [PMID: 33559747 DOI: 10.1007/s00705-020-04926-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/05/2020] [Indexed: 10/22/2022]
Abstract
Seven novel tailed lytic viruses (Ds3CZ, Ds5CZ, Ds9CZ, Ds16CZ, Ds20CZ, Ds23CZ, Ds25CZ) infecting the bacterium Dickeya solani were isolated in the Czech Republic. Genomes of these viruses are dsDNA, 149,364 to 155,285 bp in length, and the genome arrangement is very similar to that of the type virus Dickeya virus LIMEstone 1. All but the Ds25CZ virus should be regarded as strains of a single species. Most of the sequence differences are due to the presence or absence of homing endonuclease (HE) genes, with 23 HEs found in Ds3CZ, Ds5CZ, and Ds20CZ, 22 in Ds9CZ, 19 in Ds16CZ, 18 in Ds25CZ, and 15 in Ds23CZ.
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8
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Zumkeller S, Gerke P, Knoop V. A functional twintron, 'zombie' twintrons and a hypermobile group II intron invading itself in plant mitochondria. Nucleic Acids Res 2020; 48:2661-2675. [PMID: 31915815 PMCID: PMC7049729 DOI: 10.1093/nar/gkz1194] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 11/26/2019] [Accepted: 12/11/2019] [Indexed: 02/06/2023] Open
Abstract
The occurrence of group II introns in plant mitochondrial genomes is strikingly different between the six major land plant clades, contrasting their highly conserved counterparts in chloroplast DNA. Their present distribution likely reflects numerous ancient intron gains and losses during early plant evolution before the emergence of seed plants. As a novelty for plant organelles, we here report on five cases of twintrons, introns-within-introns, in the mitogenomes of lycophytes and hornworts. An internal group II intron interrupts an intron-borne maturase of an atp9 intron in Lycopodiaceae, whose splicing precedes splicing of the external intron. An invasive, hypermobile group II intron in cox1, has conquered nine further locations including a previously overlooked sdh3 intron and, most surprisingly, also itself. In those cases, splicing of the external introns does not depend on splicing of the internal introns. Similar cases are identified in the mtDNAs of hornworts. Although disrupting a group I intron-encoded protein in one case, we could not detect splicing of the internal group II intron in this ‘mixed’ group I/II twintron. We suggest the name ‘zombie’ twintrons (half-dead, half-alive) for such cases where splicing of external introns does not depend any more on prior splicing of fossilized internal introns.
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Affiliation(s)
- Simon Zumkeller
- IZMB - Institut für Zelluläre und Molekulare Botanik, Abteilung Molekulare Evolution, Universität Bonn, Kirschallee 1, D-53115 Bonn, Germany
| | - Philipp Gerke
- IZMB - Institut für Zelluläre und Molekulare Botanik, Abteilung Molekulare Evolution, Universität Bonn, Kirschallee 1, D-53115 Bonn, Germany
| | - Volker Knoop
- IZMB - Institut für Zelluläre und Molekulare Botanik, Abteilung Molekulare Evolution, Universität Bonn, Kirschallee 1, D-53115 Bonn, Germany
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Camborde L, Raynaud C, Dumas B, Gaulin E. DNA-Damaging Effectors: New Players in the Effector Arena. TRENDS IN PLANT SCIENCE 2019; 24:1094-1101. [PMID: 31699522 DOI: 10.1016/j.tplants.2019.09.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/24/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
In animal cells, nuclear DNA is the target of genotoxins produced by bacterial pathogens that cause genomic mutations eventually leading to apoptosis, senescence, and carcinogenic development. In response to the insult, the DNA damage response (DDR) is activated to ensure lesion repair. Accumulation of DNA breaks is also detected in plants during microbial infection. In this opinion article we propose that phytopathogens can produce DNA-damaging effectors. The recent identification of a functional genotoxin in devastating eukaryotic plant pathogens, such as oomycetes, supports the concept that DNA-damaging effectors may contribute to pathogenicity. Additionally, this raises the question of how plants can perceive these damages and whether this perception can be connected to the plant immune system.
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Affiliation(s)
- Laurent Camborde
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, France
| | - Cécile Raynaud
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRA, Université Paris-Sud, Université Évry, Université Paris-Saclay, 91405, Orsay, Paris, France
| | - Bernard Dumas
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, France
| | - Elodie Gaulin
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, France.
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Schiltz CJ, Lee A, Partlow EA, Hosford CJ, Chappie JS. Structural characterization of Class 2 OLD family nucleases supports a two-metal catalysis mechanism for cleavage. Nucleic Acids Res 2019; 47:9448-9463. [PMID: 31400118 PMCID: PMC6755086 DOI: 10.1093/nar/gkz703] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 07/29/2019] [Accepted: 07/31/2019] [Indexed: 12/18/2022] Open
Abstract
Overcoming lysogenization defect (OLD) proteins constitute a family of uncharacterized nucleases present in bacteria, archaea, and some viruses. These enzymes contain an N-terminal ATPase domain and a C-terminal Toprim domain common amongst replication, recombination, and repair proteins. The in vivo activities of OLD proteins remain poorly understood and no definitive structural information exists. Here we identify and define two classes of OLD proteins based on differences in gene neighborhood and amino acid sequence conservation and present the crystal structures of the catalytic C-terminal regions from the Burkholderia pseudomallei and Xanthamonas campestris p.v. campestris Class 2 OLD proteins at 2.24 Å and 1.86 Å resolution respectively. The structures reveal a two-domain architecture containing a Toprim domain with altered architecture and a unique helical domain. Conserved side chains contributed by both domains coordinate two bound magnesium ions in the active site of B. pseudomallei OLD in a geometry that supports a two-metal catalysis mechanism for cleavage. The spatial organization of these domains additionally suggests a novel mode of DNA binding that is distinct from other Toprim containing proteins. Together, these findings define the fundamental structural properties of the OLD family catalytic core and the underlying mechanism controlling nuclease activity.
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Affiliation(s)
- Carl J Schiltz
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - April Lee
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Edward A Partlow
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | | | - Joshua S Chappie
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
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Ferrandi A, Castani F, Pitaro M, Tagliaferri S, de la Tour CB, Alduina R, Sommer S, Fasano M, Barbieri P, Mancini M, Bonapace IM. Deinococcus radiodurans' SRA-HNH domain containing protein Shp (Dr1533) is involved in faithful genome inheritance maintenance following DNA damage. Biochim Biophys Acta Gen Subj 2018; 1863:118-129. [PMID: 30308220 DOI: 10.1016/j.bbagen.2018.09.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 09/18/2018] [Accepted: 09/25/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND Deinococcus radiodurans R1 (DR) survives conditions of extreme desiccation, irradiation and exposure to genotoxic chemicals, due to efficient DNA breaks repair, also through Mn2+ protection of DNA repair enzymes. METHODS Possible annotated domains of the DR1533 locus protein (Shp) were searched by bioinformatic analysis. The gene was cloned and expressed as fusion protein. Band-shift assays of Shp or the SRA and HNH domains were performed on oligonucleotides, genomic DNA from E. coli and DR. shp knock-out mutant was generated by homologous recombination with a kanamycin resistance cassette. RESULTS DR1533 contains an N-terminal SRA domain and a C-terminal HNH motif (SRA-HNH Protein, Shp). Through its SRA domain, Shp binds double-strand oligonucleotides containing 5mC and 5hmC, but also unmethylated and mismatched cytosines in presence of Mn2+. Shp also binds to Escherichia coli dcm+ genomic DNA, and to cytosine unmethylated DR and E. coli dcm- genomic DNAs, but only in presence of Mn2+. Under these binding conditions, Shp displays DNAse activity through its HNH domain. Shp KO enhanced >100 fold the number of spontaneous mutants, whilst the treatment with DNA double strand break inducing agents enhanced up to 3-log the number of survivors. CONCLUSIONS The SRA-HNH containing protein Shp binds to and cuts 5mC DNA, and unmethylated DNA in a Mn2+ dependent manner, and might be involved in faithful genome inheritance maintenance following DNA damage. GENERAL SIGNIFICANCE Our results provide evidence for a potential role of DR Shp protein for genome integrity maintenance, following DNA double strand breaks induced by genotoxic agents.
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Affiliation(s)
- Alex Ferrandi
- Department of Biotechnology and Life Sciences, University of Insubria, Via Manara 7, Busto Arsizio, VA, Italy
| | - Federica Castani
- Department of Biotechnology and Life Sciences, University of Insubria, Via Manara 7, Busto Arsizio, VA, Italy
| | - Mauro Pitaro
- Department of Biotechnology and Life Sciences, University of Insubria, Via Manara 7, Busto Arsizio, VA, Italy
| | - Sara Tagliaferri
- Department of Biotechnology and Life Sciences, University of Insubria, Via Manara 7, Busto Arsizio, VA, Italy
| | - Claire Bouthier de la Tour
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, France and Institut de Génétique et Microbiologie - Université Paris-Sud, Paris, France
| | - Rosa Alduina
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze, Palermo, Italy
| | - Suzanne Sommer
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, France and Institut de Génétique et Microbiologie - Université Paris-Sud, Paris, France
| | - Mauro Fasano
- Department of Sciences and High technology, University of Insubria, Via Manara 7, Busto Arsizio, VA, Italy
| | - Paola Barbieri
- Department of Biotechnology and Life Sciences, University of Insubria, Via Manara 7, Busto Arsizio, VA, Italy
| | - Monica Mancini
- Department of Biotechnology and Life Sciences, University of Insubria, Via Manara 7, Busto Arsizio, VA, Italy.
| | - Ian Marc Bonapace
- Department of Biotechnology and Life Sciences, University of Insubria, Via Manara 7, Busto Arsizio, VA, Italy.
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Fang X, Jiang Y, Li K, Zeng Q. F-CphI represents a new homing endonuclease family using the Endo VII catalytic motif. Mob DNA 2018; 9:27. [PMID: 30100927 PMCID: PMC6083498 DOI: 10.1186/s13100-018-0132-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/31/2018] [Indexed: 11/16/2022] Open
Abstract
Background There are six known families of homing endonucleases, LAGLIDADG, GIY-YIG, HNH, His-Cys box, PD-(D/E)-XK, and EDxHD, which are characterized by their conserved residues. Previously, we discovered a novel homing endonuclease F-CphI encoded by ORF177 of cyanophage S-PM2. F-CphI does not resemble any characterized homing endonucleases. Instead, the C-terminus of F-CphI aligns well with the N-terminal catalytic domain of a Holliday junction DNA resolvase, phage T4 endonuclease VII (Endo VII). Results A PSI-BLAST search resulted in a total of 313 Endo VII motif–containing sequences in sequenced genomes. Multiple sequence alignment showed that the catalytically important residues of T4 Endo VII were all well conserved in these proteins. Our site-directed mutagenesis studies further confirmed that the catalytically important residues of T4 Endo VII were also essential for F-CphI activity, and thus F-CphI might use a similar protein fold as Endo VII for DNA cleavage. A phylogenetic tree of the Endo VII motif–containing sequences showed that putative resolvases grouped into one clade while putative homing endonucleases and restriction endonucleases grouped into another clade. Conclusions Based on the unique conserved residues, we proposed that F-CphI represents a new homing endonuclease family, which was named the DHHRN family. Our phylogenetic analysis could be used to predict the functions of many previously unknown proteins. Electronic supplementary material The online version of this article (10.1186/s13100-018-0132-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiaoting Fang
- Department of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - YongLiang Jiang
- 2School of Life Sciences, University of Science and Technology of China, Hefei, 230027 Anhui China
| | - Kim Li
- Department of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Qinglu Zeng
- Department of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.,Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.,HKUST Shenzhen Research Institute, Shenzhen, China
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Sokolov AS, Latypov OR, Kolosov PM, Shlyapnikov MG, Bezlepkina TA, Kholod NS, Kadyrov FA, Granovsky IE. Phage T4 endonuclease SegD that is similar to group I intron endonucleases does not initiate homing of its own gene. Virology 2018; 515:215-222. [PMID: 29306059 DOI: 10.1016/j.virol.2017.12.031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 12/25/2017] [Accepted: 12/26/2017] [Indexed: 11/30/2022]
Abstract
Homing endonucleases are a group of site-specific endonucleases that initiate homing, a nonreciprocal transfer of its own gene into a new allele lacking this gene. This work describes a novel phage T4 endonuclease, SegD, which is homologous to the GIY-YIG family of homing endonucleases. Like other T4 homing endonucleases SegD recognizes an extended, 16bp long, site, cleaves it asymmetrically to form 3'-protruding ends and digests both unmodified DNA and modified T-even phage DNA with similar efficiencies. Surprisingly, we revealed that SegD cleavage site was identical in the genomes of segD- and segD+ phages. We found that segD gene was expressed during the T4 developmental cycle. Nevertheless, endonuclease SegD was not able to initiate homing of its own gene as well as genetic recombination between phages in its site inserted into the rII locus.
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Affiliation(s)
- Andrey S Sokolov
- Laboratory of Genetic Enzymology, Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, Pushchino 142290, Russia
| | - Oleg R Latypov
- Laboratory of Genetic Enzymology, Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, Pushchino 142290, Russia
| | - Peter M Kolosov
- Laboratory of Genetic Enzymology, Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, Pushchino 142290, Russia
| | - Michael G Shlyapnikov
- Laboratory of Genetic Enzymology, Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, Pushchino 142290, Russia
| | - Tamara A Bezlepkina
- Laboratory of Genetic Enzymology, Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, Pushchino 142290, Russia
| | - Natalia S Kholod
- Laboratory of Genetic Enzymology, Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, Pushchino 142290, Russia
| | - Farid A Kadyrov
- Laboratory of Genetic Enzymology, Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, Pushchino 142290, Russia
| | - Igor E Granovsky
- Laboratory of Genetic Enzymology, Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, Pushchino 142290, Russia; Laboratory of Molecular and Cellular Biology, Pushchino State Institute of Natural Sciences, 3 Prospekt Nauki, Pushchino 142290, Russia.
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14
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Arkhipova IR. Using bioinformatic and phylogenetic approaches to classify transposable elements and understand their complex evolutionary histories. Mob DNA 2017; 8:19. [PMID: 29225705 PMCID: PMC5718144 DOI: 10.1186/s13100-017-0103-2] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 11/28/2017] [Indexed: 12/11/2022] Open
Abstract
In recent years, much attention has been paid to comparative genomic studies of transposable elements (TEs) and the ensuing problems of their identification, classification, and annotation. Different approaches and diverse automated pipelines are being used to catalogue and categorize mobile genetic elements in the ever-increasing number of prokaryotic and eukaryotic genomes, with little or no connectivity between different domains of life. Here, an overview of the current picture of TE classification and evolutionary relationships is presented, updating the diversity of TE types uncovered in sequenced genomes. A tripartite TE classification scheme is proposed to account for their replicative, integrative, and structural components, and the need to expand in vitro and in vivo studies of their structural and biological properties is emphasized. Bioinformatic studies have now become front and center of novel TE discovery, and experimental pursuits of these discoveries hold great promise for both basic and applied science.
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Affiliation(s)
- Irina R Arkhipova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543 USA
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15
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Kang X, Hu L, Shen P, Li R, Liu D. SMRT Sequencing Revealed Mitogenome Characteristics and Mitogenome-Wide DNA Modification Pattern in Ophiocordyceps sinensis. Front Microbiol 2017; 8:1422. [PMID: 28798740 PMCID: PMC5529405 DOI: 10.3389/fmicb.2017.01422] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 07/13/2017] [Indexed: 11/24/2022] Open
Abstract
Single molecule, real-time (SMRT) sequencing was used to characterize mitochondrial (mt) genome of Ophiocordyceps sinensis and to analyze the mt genome-wide pattern of epigenetic DNA modification. The complete mt genome of O. sinensis, with a size of 157,539 bp, is the fourth largest Ascomycota mt genome sequenced to date. It contained 14 conserved protein-coding genes (PCGs), 1 intronic protein rps3, 27 tRNAs and 2 rRNA subunits, which are common characteristics of the known mt genomes in Hypocreales. A phylogenetic tree inferred from 14 PCGs in Pezizomycotina fungi supports O. sinensis as most closely related to Hirsutella rhossiliensis in Ophiocordycipitaceae. A total of 36 sequence sites in rps3 were under positive selection, with dN/dS >1 in the 20 compared fungi. Among them, 16 sites were statistically significant. In addition, the mt genome-wide base modification pattern of O. sinensis was determined in this study, especially DNA methylation. The methylations were located in coding and uncoding regions of mt PCGs in O. sinensis, and might be closely related to the expression of PCGs or the binding affinity of transcription factor A to mtDNA. Consequently, these methylations may affect the enzymatic activity of oxidative phosphorylation and then the mt respiratory rate; or they may influence mt biogenesis. Therefore, methylations in the mitogenome of O. sinensis might be a genetic feature to adapt to the cold and low PO2 environment at high altitude, where O. sinensis is endemic. This is the first report on epigenetic modifications in a fungal mt genome.
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Affiliation(s)
- Xincong Kang
- Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural UniversityChangsha, China
- Horticulture and Landscape College, Hunan Agricultural UniversityChangsha, China
- State Key Laboratory of Subhealth Intervention TechnologyChangsha, China
| | - Liqin Hu
- Horticulture and Landscape College, Hunan Agricultural UniversityChangsha, China
- State Key Laboratory of Subhealth Intervention TechnologyChangsha, China
| | - Pengyuan Shen
- Horticulture and Landscape College, Hunan Agricultural UniversityChangsha, China
- State Key Laboratory of Subhealth Intervention TechnologyChangsha, China
| | - Rui Li
- Nextomics BiosciencesWuhan, China
| | - Dongbo Liu
- Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Agricultural UniversityChangsha, China
- Horticulture and Landscape College, Hunan Agricultural UniversityChangsha, China
- State Key Laboratory of Subhealth Intervention TechnologyChangsha, China
- Hunan Co-Innovation Center for Utilization of Botanical Functional IngredientsChangsha, China
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16
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Kingston AW, Ponkratz C, Raleigh EA. Rpn (YhgA-Like) Proteins of Escherichia coli K-12 and Their Contribution to RecA-Independent Horizontal Transfer. J Bacteriol 2017; 199:e00787-16. [PMID: 28096446 PMCID: PMC5350276 DOI: 10.1128/jb.00787-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/09/2017] [Indexed: 01/21/2023] Open
Abstract
Bacteria use a variety of DNA-mobilizing enzymes to facilitate environmental niche adaptation via horizontal gene transfer. This has led to real-world problems, like the spread of antibiotic resistance, yet many mobilization proteins remain undefined. In the study described here, we investigated the uncharacterized family of YhgA-like transposase_31 (Pfam PF04754) proteins. Our primary focus was the genetic and biochemical properties of the five Escherichia coli K-12 members of this family, which we designate RpnA to RpnE, where Rpn represents recombination-promoting nuclease. We employed a conjugal system developed by our lab that demanded RecA-independent recombination following transfer of chromosomal DNA. Overexpression of RpnA (YhgA), RpnB (YfcI), RpnC (YadD), and RpnD (YjiP) increased RecA-independent recombination, reduced cell viability, and induced the expression of reporter of DNA damage. For the exemplar of the family, RpnA, mutational changes in proposed catalytic residues reduced or abolished all three phenotypes in concert. In vitro, RpnA displayed magnesium-dependent, calcium-stimulated DNA endonuclease activity with little, if any, sequence specificity and a preference for double-strand cleavage. We propose that Rpn/YhgA-like family nucleases can participate in gene acquisition processes.IMPORTANCE Bacteria adapt to new environments by obtaining new genes from other bacteria. Here, we characterize a set of genes that can promote the acquisition process by a novel mechanism. Genome comparisons had suggested the horizontal spread of the genes for the YhgA-like family of proteins through bacteria. Although annotated as transposase_31, no member of the family has previously been characterized experimentally. We show that four Escherichia coli K-12 paralogs contribute to a novel RecA-independent recombination mechanism in vivo For RpnA, we demonstrate in vitro action as a magnesium-dependent, calcium-stimulated nonspecific DNA endonuclease. The cleavage products are capable of providing priming sites for DNA polymerase, which can enable DNA joining by primer-template switching.
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Ramirez-Garcés D, Camborde L, Pel MJC, Jauneau A, Martinez Y, Néant I, Leclerc C, Moreau M, Dumas B, Gaulin E. CRN13 candidate effectors from plant and animal eukaryotic pathogens are DNA-binding proteins which trigger host DNA damage response. THE NEW PHYTOLOGIST 2016; 210:602-17. [PMID: 26700936 DOI: 10.1111/nph.13774] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/21/2015] [Indexed: 05/20/2023]
Abstract
To successfully colonize their host, pathogens produce effectors that can interfere with host cellular processes. Here we investigated the function of CRN13 candidate effectors produced by plant pathogenic oomycetes and detected in the genome of the amphibian pathogenic chytrid fungus Batrachochytrium dendrobatidis (BdCRN13). When expressed in Nicotiana, AeCRN13, from the legume root pathogen Aphanomyces euteiches, increases the susceptibility of the leaves to the oomycete Phytophthora capsici. When transiently expressed in amphibians or plant cells, AeCRN13 and BdCRN13 localize to the cell nuclei, triggering aberrant cell development and eventually causing cell death. Using Förster resonance energy transfer experiments in plant cells, we showed that both CRN13s interact with nuclear DNA and trigger plant DNA damage response (DDR). Mutating key amino acid residues in a predicted HNH-like endonuclease motif abolished the interaction of AeCRN13 with DNA, the induction of DDR and the enhancement of Nicotiana susceptibility to P. capsici. Finally, H2AX phosphorylation, a marker of DNA damage, and enhanced expression of genes involved in the DDR were observed in A. euteiches-infected Medicago truncatula roots. These results show that CRN13 from plant and animal eukaryotic pathogens promotes host susceptibility by targeting nuclear DNA and inducing DDR.
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Affiliation(s)
- Diana Ramirez-Garcés
- Laboratoire de Recherche en Sciences Végétales, UPS, Université Toulouse 3, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- Laboratoire de Recherche en Sciences Végétales, CNRS, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
| | - Laurent Camborde
- Laboratoire de Recherche en Sciences Végétales, UPS, Université Toulouse 3, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- Laboratoire de Recherche en Sciences Végétales, CNRS, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
| | - Michiel J C Pel
- Laboratoire de Recherche en Sciences Végétales, UPS, Université Toulouse 3, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- Laboratoire de Recherche en Sciences Végétales, CNRS, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
| | - Alain Jauneau
- CNRS, Plateforme Imagerie-Microscopie Plateforme Imagerie-Microscopie, F-31326, Castanet-Tolosan, France
| | - Yves Martinez
- CNRS, Plateforme Imagerie-Microscopie Plateforme Imagerie-Microscopie, F-31326, Castanet-Tolosan, France
| | - Isabelle Néant
- Centre de Biologie du Développement, Université Toulouse 3, Toulouse, F31062, France
- CNRS UMR5547, Toulouse, F31062, France
| | - Catherine Leclerc
- Centre de Biologie du Développement, Université Toulouse 3, Toulouse, F31062, France
- CNRS UMR5547, Toulouse, F31062, France
| | - Marc Moreau
- Centre de Biologie du Développement, Université Toulouse 3, Toulouse, F31062, France
- CNRS UMR5547, Toulouse, F31062, France
| | - Bernard Dumas
- Laboratoire de Recherche en Sciences Végétales, UPS, Université Toulouse 3, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- Laboratoire de Recherche en Sciences Végétales, CNRS, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
| | - Elodie Gaulin
- Laboratoire de Recherche en Sciences Végétales, UPS, Université Toulouse 3, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
- Laboratoire de Recherche en Sciences Végétales, CNRS, 24 chemin de Borde Rouge, BP42617, Auzeville, F-31326, Castanet-Tolosan, France
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18
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c-di-GMP signalling and the regulation of developmental transitions in streptomycetes. Nat Rev Microbiol 2015; 13:749-60. [PMID: 26499894 DOI: 10.1038/nrmicro3546] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The complex life cycle of streptomycetes involves two distinct filamentous cell forms: the growing (or vegetative) hyphae and the reproductive (or aerial) hyphae, which differentiate into long chains of spores. Until recently, little was known about the signalling pathways that regulate the developmental transitions leading to sporulation. In this Review, we discuss important new insights into these pathways that have led to the emergence of a coherent regulatory network, focusing on the erection of aerial hyphae and the synchronous cell division event that produces dozens of unigenomic spores. In particular, we highlight the role of cyclic di-GMP (c-di-GMP) in controlling the initiation of development, and the role of the master regulator BldD in mediating c-di-GMP signalling.
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Venken KJT, Sarrion-Perdigones A, Vandeventer PJ, Abel NS, Christiansen AE, Hoffman KL. Genome engineering: Drosophila melanogaster and beyond. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2015; 5:233-67. [PMID: 26447401 DOI: 10.1002/wdev.214] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 08/03/2015] [Accepted: 08/20/2015] [Indexed: 12/26/2022]
Abstract
A central challenge in investigating biological phenomena is the development of techniques to modify genomic DNA with nucleotide precision that can be transmitted through the germ line. Recent years have brought a boon in these technologies, now collectively known as genome engineering. Defined genomic manipulations at the nucleotide level enable a variety of reverse engineering paradigms, providing new opportunities to interrogate diverse biological functions. These genetic modifications include controlled removal, insertion, and substitution of genetic fragments, both small and large. Small fragments up to a few kilobases (e.g., single nucleotide mutations, small deletions, or gene tagging at single or multiple gene loci) to large fragments up to megabase resolution can be manipulated at single loci to create deletions, duplications, inversions, or translocations of substantial sections of whole chromosome arms. A specialized substitution of chromosomal portions that presumably are functionally orthologous between different organisms through syntenic replacement, can provide proof of evolutionary conservation between regulatory sequences. Large transgenes containing endogenous or synthetic DNA can be integrated at defined genomic locations, permitting an alternative proof of evolutionary conservation, and sophisticated transgenes can be used to interrogate biological phenomena. Precision engineering can additionally be used to manipulate the genomes of organelles (e.g., mitochondria). Novel genome engineering paradigms are often accelerated in existing, easily genetically tractable model organisms, primarily because these paradigms can be integrated in a rigorous, existing technology foundation. The Drosophila melanogaster fly model is ideal for these types of studies. Due to its small genome size, having just four chromosomes, the vast amount of cutting-edge genetic technologies, and its short life-cycle and inexpensive maintenance requirements, the fly is exceptionally amenable to complex genetic analysis using advanced genome engineering. Thus, highly sophisticated methods developed in the fly model can be used in nearly any sequenced organism. Here, we summarize different ways to perform precise inheritable genome engineering using integrases, recombinases, and DNA nucleases in the D. melanogaster. For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Koen J T Venken
- Department of Biochemistry and Molecular Biology, Verna and Marrs McLean, Houston, TX, USA.,Department of Pharmacology, Baylor College of Medicine, Houston, TX, USA.,Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA.,Program in Integrative Molecular and Biomedical Sciences, Baylor College of Medicine, Houston, TX, USA
| | | | - Paul J Vandeventer
- Department of Biochemistry and Molecular Biology, Verna and Marrs McLean, Houston, TX, USA
| | - Nicholas S Abel
- Department of Pharmacology, Baylor College of Medicine, Houston, TX, USA
| | - Audrey E Christiansen
- Department of Biochemistry and Molecular Biology, Verna and Marrs McLean, Houston, TX, USA
| | - Kristi L Hoffman
- Department of Biochemistry and Molecular Biology, Verna and Marrs McLean, Houston, TX, USA
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20
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Salavirta H, Oksanen I, Kuuskeri J, Mäkelä M, Laine P, Paulin L, Lundell T. Mitochondrial genome of Phlebia radiata is the second largest (156 kbp) among fungi and features signs of genome flexibility and recent recombination events. PLoS One 2014; 9:e97141. [PMID: 24824642 PMCID: PMC4019555 DOI: 10.1371/journal.pone.0097141] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 04/15/2014] [Indexed: 01/28/2023] Open
Abstract
Mitochondria are eukaryotic organelles supporting individual life-style via generation of proton motive force and cellular energy, and indispensable metabolic pathways. As part of genome sequencing of the white rot Basidiomycota species Phlebia radiata, we first assembled its mitochondrial genome (mtDNA). So far, the 156 348 bp mtDNA is the second largest described for fungi, and of considerable size among eukaryotes. The P. radiata mtDNA assembled as single circular dsDNA molecule containing genes for the large and small ribosomal RNAs, 28 transfer RNAs, and over 100 open reading frames encoding the 14 fungal conserved protein subunits of the mitochondrial complexes I, III, IV, and V. Two genes (atp6 and tRNA-IleGAU) were duplicated within 6.1 kbp inverted region, which is a unique feature of the genome. The large mtDNA size, however, is explained by the dominance of intronic and intergenic regions (sum 80% of mtDNA sequence). The intergenic DNA stretches harness short (≤ 200 nt) repetitive, dispersed and overlapping sequence elements in abundance. Long self-splicing introns of types I and II interrupt eleven of the conserved genes (cox1,2,3; cob; nad1,2,4,4L,5; rnl; rns). The introns embrace a total of 57 homing endonucleases with LAGLIDADGD and GYI-YIG core motifs, which makes P. radiata mtDNA to one of the largest known reservoirs of intron-homing endonucleases. The inverted duplication, intergenic stretches, and intronic features are indications of dynamics and genetic flexibility of the mtDNA, not fully recognized to this extent in fungal mitochondrial genomes previously, thus giving new insights for the evolution of organelle genomes in eukaryotes.
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Affiliation(s)
- Heikki Salavirta
- Microbiology and Biotechnology, Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Ilona Oksanen
- Microbiology and Biotechnology, Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Jaana Kuuskeri
- Microbiology and Biotechnology, Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Miia Mäkelä
- Microbiology and Biotechnology, Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Pia Laine
- Institute of Biotechnology, DNA Sequencing and Genomics Laboratory, University of Helsinki, Helsinki, Finland
| | - Lars Paulin
- Institute of Biotechnology, DNA Sequencing and Genomics Laboratory, University of Helsinki, Helsinki, Finland
| | - Taina Lundell
- Microbiology and Biotechnology, Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland
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Hausner G, Hafez M, Edgell DR. Bacterial group I introns: mobile RNA catalysts. Mob DNA 2014; 5:8. [PMID: 24612670 PMCID: PMC3984707 DOI: 10.1186/1759-8753-5-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 02/24/2014] [Indexed: 12/02/2022] Open
Abstract
Group I introns are intervening sequences that have invaded tRNA, rRNA and protein coding genes in bacteria and their phages. The ability of group I introns to self-splice from their host transcripts, by acting as ribozymes, potentially renders their insertion into genes phenotypically neutral. Some group I introns are mobile genetic elements due to encoded homing endonuclease genes that function in DNA-based mobility pathways to promote spread to intronless alleles. Group I introns have a limited distribution among bacteria and the current assumption is that they are benign selfish elements, although some introns and homing endonucleases are a source of genetic novelty as they have been co-opted by host genomes to provide regulatory functions. Questions regarding the origin and maintenance of group I introns among the bacteria and phages are also addressed.
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Affiliation(s)
- Georg Hausner
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2 N2, Canada
| | - Mohamed Hafez
- Department of Biochemistry, Faculty of Medicine, University of Montreal, Montréal, QC H3C 3 J7, Canada
- Department of Botany, Faculty of Science, Suez University, Suez, Egypt
| | - David R Edgell
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5C1, Canada
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Stoddard BL. Homing endonucleases from mobile group I introns: discovery to genome engineering. Mob DNA 2014; 5:7. [PMID: 24589358 PMCID: PMC3943268 DOI: 10.1186/1759-8753-5-7] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/13/2014] [Indexed: 12/20/2022] Open
Abstract
Homing endonucleases are highly specific DNA cleaving enzymes that are encoded within genomes of all forms of microbial life including phage and eukaryotic organelles. These proteins drive the mobility and persistence of their own reading frames. The genes that encode homing endonucleases are often embedded within self-splicing elements such as group I introns, group II introns and inteins. This combination of molecular functions is mutually advantageous: the endonuclease activity allows surrounding introns and inteins to act as invasive DNA elements, while the splicing activity allows the endonuclease gene to invade a coding sequence without disrupting its product. Crystallographic analyses of representatives from all known homing endonuclease families have illustrated both their mechanisms of action and their evolutionary relationships to a wide range of host proteins. Several homing endonucleases have been completely redesigned and used for a variety of genome engineering applications. Recent efforts to augment homing endonucleases with auxiliary DNA recognition elements and/or nucleic acid processing factors has further accelerated their use for applications that demand exceptionally high specificity and activity.
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Affiliation(s)
- Barry L Stoddard
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave, N, A3-025, Seattle, WA 98109, USA.
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23
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Horstman A, Willemsen V, Boutilier K, Heidstra R. AINTEGUMENTA-LIKE proteins: hubs in a plethora of networks. TRENDS IN PLANT SCIENCE 2014; 19:146-57. [PMID: 24280109 DOI: 10.1016/j.tplants.2013.10.010] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 10/24/2013] [Accepted: 10/27/2013] [Indexed: 05/18/2023]
Abstract
Members of the AINTEGUMENTA-LIKE (AIL) family of APETALA 2/ETHYLENE RESPONSE FACTOR (AP2/ERF) domain transcription factors are expressed in all dividing tissues in the plant, where they have central roles in developmental processes such as embryogenesis, stem cell niche specification, meristem maintenance, organ positioning, and growth. When overexpressed, AIL proteins induce adventitious growth, including somatic embryogenesis and ectopic organ formation. The Arabidopsis (Arabidopsis thaliana) genome contains eight AIL genes, including AINTEGUMENTA, BABY BOOM, and the PLETHORA genes. Studies on these transcription factors have revealed their intricate relationship with auxin as well as their involvement in an increasing number of gene regulatory networks, in which extensive crosstalk and feedback loops have a major role.
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Affiliation(s)
- Anneke Horstman
- Plant Research International, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Viola Willemsen
- Plant Developmental Biology, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Kim Boutilier
- Plant Research International, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Renze Heidstra
- Plant Developmental Biology, Wageningen University and Research Centre, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands.
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Abstract
Bacterial genomes are remarkably stable from one generation to the next but are plastic on an evolutionary time scale, substantially shaped by horizontal gene transfer, genome rearrangement, and the activities of mobile DNA elements. This implies the existence of a delicate balance between the maintenance of genome stability and the tolerance of genome instability. In this review, we describe the specialized genetic elements and the endogenous processes that contribute to genome instability. We then discuss the consequences of genome instability at the physiological level, where cells have harnessed instability to mediate phase and antigenic variation, and at the evolutionary level, where horizontal gene transfer has played an important role. Indeed, this ability to share DNA sequences has played a major part in the evolution of life on Earth. The evolutionary plasticity of bacterial genomes, coupled with the vast numbers of bacteria on the planet, substantially limits our ability to control disease.
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Epinat JC. A yeast-based recombination assay for homing endonuclease activity. Methods Mol Biol 2014; 1123:105-26. [PMID: 24510264 DOI: 10.1007/978-1-62703-968-0_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Homing endonucleases (HEs) are natural enzymes that cleave long DNA target with a high specificity and trigger homologous recombination at the exact site of the break. Such mechanisms can thus be used for all the applications covered today by the generic name of "genome engineering": targeted sequence insertion, removal, or editing. However, before being able to address those applications, the engineering of HEs must be mastered so that any potential target would be efficiently and specifically recognized and cleaved. Working on the I-CreI model, we have developed a very powerful platform to generate HEs with new tailored specificity. We have put in place the first in vivo, functional, high throughput assay to generate I-CreI variants and measure their activity. We use semi-rational design combined with proprietary in silico predictions to design and synthesize I-CreI mutants that are tested for their capacity to induce homologous recombination in a yeast cell. The process has been standardized and robotized so that we can generate thousands of I-CreI derivatives, characterize their cleavage profile, and deliver them for further applications in the research, therapeutic, or agrobusiness fields.
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Hafez M, Guha TK, Shen C, Sethuraman J, Hausner G. PCR-based bioprospecting for homing endonucleases in fungal mitochondrial rRNA genes. Methods Mol Biol 2014; 1123:37-53. [PMID: 24510258 DOI: 10.1007/978-1-62703-968-0_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fungal mitochondrial genomes act as "reservoirs" for homing endonucleases. These enzymes with their DNA site-specific cleavage activities are attractive tools for genome editing and gene therapy applications. Bioprospecting and characterization of naturally occurring homing endonucleases offers an alternative to synthesizing artificial endonucleases. Here, we describe methods for PCR-based screening of fungal mitochondrial rRNA genes for homing endonuclease encoding sequences, and we also provide protocols for the purification and biochemical characterization of putative native homing endonucleases.
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Affiliation(s)
- Mohamed Hafez
- Department of Biochemistry, Université de Montréal, Montréal, QC, Canada
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27
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Abstract
Homing endonucleases are strong drivers of genetic exchange and horizontal transfer of both their own genes and their local genetic environment. The mechanisms that govern the function and evolution of these genetic oddities have been well documented over the past few decades at the genetic, biochemical, and structural levels. This wealth of information has led to the manipulation and reprogramming of the endonucleases and to their exploitation in genome editing for use as therapeutic agents, for insect vector control and in agriculture. In this chapter we summarize the molecular properties of homing endonucleases and discuss their strengths and weaknesses in genome editing as compared to other site-specific nucleases such as zinc finger endonucleases, TALEN, and CRISPR-derived endonucleases.
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Lamont EA, Xu WW, Sreevatsan S. Host-Mycobacterium avium subsp. paratuberculosis interactome reveals a novel iron assimilation mechanism linked to nitric oxide stress during early infection. BMC Genomics 2013; 14:694. [PMID: 24112552 PMCID: PMC3832399 DOI: 10.1186/1471-2164-14-694] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Accepted: 10/02/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The initial interaction between host cell and pathogen sets the stage for the ensuing infection and ultimately determine the course of disease. However, there is limited knowledge of the transcripts utilized by host and pathogen and how they may impact one another during this critical step. The purpose of this study was to create a host-Mycobacterium avium subsp. paratuberculosis (MAP) interactome for early infection in an epithelium-macrophage co-culture system using RNA-seq. RESULTS Establishment of the host-MAP interactome revealed a novel iron assimilation system for carboxymycobactin. Iron assimilation is linked to nitric oxide synthase-2 production by the host and subsequent nitric oxide buildup. Iron limitation as well as nitric oxide is a prompt for MAP to enter into an iron sequestration program. This new iron sequestration program provides an explanation for mycobactin independence in some MAP strains grown in vitro as well as during infection within the host cell. Utilization of such a pathway is likely to aid MAP establishment and long-term survival within the host. CONCLUSIONS The host-MAP interactome identified a number of metabolic, DNA repair and virulence genes worthy for consideration as novel drug targets as well as future pathogenesis studies. Reported interactome data may also be utilized to conduct focused, hypothesis-driven research. Co-culture of uninfected bovine epithelial cells (MAC-T) and primary bovine macrophages creates a tolerant genotype as demonstrated by downregulation of inflammatory pathways. This co-culture system may serve as a model to investigate other bovine enteric pathogens.
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Affiliation(s)
- Elise A Lamont
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, 1971 Commonwealth Avenue, Saint Paul, MN 55108, USA
| | - Wayne W Xu
- Minnesota Supercomputing Institute, University of Minnesota, Saint Paul, MN 55108, USA
| | - Srinand Sreevatsan
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, 1971 Commonwealth Avenue, Saint Paul, MN 55108, USA
- Department of Veterinary Biomedical Sciences, University of Minnesota, Saint Paul, MN 55108, USA
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Abstract
The abundance of group I introns, intragenic RNA sequences capable of self-splicing, in Gram-positive bacteriophage genomes, is illustrated by various new group I introns recently described in Staphylococcus phage genomes. These introns were found to interrupt DNA metabolism genes as well as late genes. These group I introns often code for homing endonucleases, which promote lateral transfer of group I introns, thereby enabling spread through a population. Homing endonucleases encoded by group I introns in Staphylococcus phage genomes were predicted to belong to the GIY-YIG, LAGLIDADG, HNH or EDxHD family of endonucleases. The group I intron distribution in Staphylococcus phage genomes exemplifies the homology between these introns as well as the encoded endonucleases. Despite several suggested functions, the role of group I introns in bacteriophages remains unclear or might be nonexistent. However, transcriptome analysis might provide additional information to elucidate the possible purpose of group I introns in phage genomes.
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Affiliation(s)
- Rob Lavigne
- Katholieke Universiteit Leuven, Department of Biosystems, Kasteelpark Arenberg 21, Bus 2462, Leuven, Belgium
| | - Katrien Vandersteegen
- Katholieke Universiteit Leuven, Department of Biosystems, Kasteelpark Arenberg 21, Bus 2462, Leuven, Belgium
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Bush MJ, Bibb MJ, Chandra G, Findlay KC, Buttner MJ. Genes required for aerial growth, cell division, and chromosome segregation are targets of WhiA before sporulation in Streptomyces venezuelae. mBio 2013; 4:e00684-13. [PMID: 24065632 PMCID: PMC3781837 DOI: 10.1128/mbio.00684-13] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 08/23/2013] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED WhiA is a highly unusual transcriptional regulator related to a family of eukaryotic homing endonucleases. WhiA is required for sporulation in the filamentous bacterium Streptomyces, but WhiA homologues of unknown function are also found throughout the Gram-positive bacteria. To better understand the role of WhiA in Streptomyces development and its function as a transcription factor, we identified the WhiA regulon through a combination of chromatin immunoprecipitation-sequencing (ChIP-seq) and microarray transcriptional profiling, exploiting a new model organism for the genus, Streptomyces venezuelae, which sporulates in liquid culture. The regulon encompasses ~240 transcription units, and WhiA appears to function almost equally as an activator and as a repressor. Bioinformatic analysis of the upstream regions of the complete regulon, combined with DNase I footprinting, identified a short but highly conserved asymmetric sequence, GACAC, associated with the majority of WhiA targets. Construction of a null mutant showed that whiA is required for the initiation of sporulation septation and chromosome segregation in S. venezuelae, and several genes encoding key proteins of the Streptomyces cell division machinery, such as ftsZ, ftsW, and ftsK, were found to be directly activated by WhiA during development. Several other genes encoding proteins with important roles in development were also identified as WhiA targets, including the sporulation-specific sigma factor σ(WhiG) and the diguanylate cyclase CdgB. Cell division is tightly coordinated with the orderly arrest of apical growth in the sporogenic cell, and filP, encoding a key component of the polarisome that directs apical growth, is a direct target for WhiA-mediated repression during sporulation. IMPORTANCE Since the initial identification of the genetic loci required for Streptomyces development, all of the bld and whi developmental master regulators have been cloned and characterized, and significant progress has been made toward understanding the cell biological processes that drive morphogenesis. A major challenge now is to connect the cell biological processes and the developmental master regulators by dissecting the regulatory networks that link the two. Studies of these regulatory networks have been greatly facilitated by the recent introduction of Streptomyces venezuelae as a new model system for the genus, a species that sporulates in liquid culture. Taking advantage of S. venezuelae, we have characterized the regulon of genes directly under the control of one of these master regulators, WhiA. Our results implicate WhiA in the direct regulation of key steps in sporulation, including the cessation of aerial growth, the initiation of cell division, and chromosome segregation.
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Affiliation(s)
- Matthew J Bush
- Department of Molecular Microbiology, John Innes Centre, Norwich, United Kingdom.
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31
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North A, Burt A, Godfray HCJ. Modelling the spatial spread of a homing endonuclease gene in a mosquito population. J Appl Ecol 2013; 50:1216-1225. [PMID: 25558082 PMCID: PMC4277857 DOI: 10.1111/1365-2664.12133] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 06/12/2013] [Indexed: 01/19/2023]
Abstract
Homing endonuclease genes (HEGs) exist naturally in many single‐celled organisms and can show extremely strong genetic drive allowing them to spread through populations into which they are introduced. They are being investigated as tools to manipulate the populations of important vectors of human disease, in particular the mosquitoes that transmit malaria. Before HEGs can be deployed, it is important to study their spatial spread in order to design efficient release strategies. A spatially explicit model is developed to study the spread of a HEG through a landscape whose structure is defined by the distribution of mosquito breeding and feeding sites. The model is motivated by the biology of the major vectors of malaria in Africa. The conditions for spread, fixation and loss of two major types of HEG are explored in different landscapes. In landscapes where mosquito resources are abundant, the conditions for spread are well approximated by a mean‐field model. Where a HEG imposes a genetic load, it can cause population extinction, though spatial models more often predict population suppression. In certain types of landscapes where mosquito resources are rare, an introduced HEG may be prevented from moving between local mosquito populations and so a simple release strategy is unlikely to be effective, yet if the HEG succeeds in spreading population extinction is a feasible outcome. Increasing the number of release sites at the expense of releasing fewer mosquitoes per site reduces the probability that a HEG will fail. Synthesis and applications. The model presented asks for the first time how the spatial structure of mosquito populations will influence the effectiveness of a technology that is being rapidly developed for vector control. If homing endonuclease genes (HEGs) are to be used in this way, we have qualified the importance of accounting for landscape characteristics in both the execution and the expectation of their application. The next stage is to use the model to study the spread of HEGs through real landscapes where releases may take place, something that will be facilitated by the results of the present study.
The model presented asks for the first time how the spatial structure of mosquito populations will influence the effectiveness of a technology that is being rapidly developed for vector control. If homing endonuclease genes (HEGs) are to be used in this way, we have qualified the importance of accounting for landscape characteristics in both the execution and the expectation of their application. The next stage is to use the model to study the spread of HEGs through real landscapes where releases may take place, something that will be facilitated by the results of the present study.
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Affiliation(s)
- Ace North
- Department of Zoology, University of Oxford South Parks Road, Oxford, OX1 3PS, UK
| | - Austin Burt
- Department of Biology, Imperial College London Silwood Park, Ascot, Berks, SL5 7PY, UK
| | - H Charles J Godfray
- Department of Zoology, University of Oxford South Parks Road, Oxford, OX1 3PS, UK
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Yamasaki K, Kigawa T, Seki M, Shinozaki K, Yokoyama S. DNA-binding domains of plant-specific transcription factors: structure, function, and evolution. TRENDS IN PLANT SCIENCE 2013; 18:267-76. [PMID: 23040085 DOI: 10.1016/j.tplants.2012.09.001] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 08/10/2012] [Accepted: 09/04/2012] [Indexed: 05/02/2023]
Abstract
The families of the plant-specific transcription factors (TFs) are defined by their characteristic DNA-binding domains (DBDs), such as AP2/ERF, B3, NAC, SBP, and WRKY. Recently, three-dimensional structures of the DBDs, including those in complexes with DNA, were determined by NMR spectroscopy and X-ray crystallography. In this review we summarize the functional and evolutionary implications arising from structure analyses. The unexpected structural similarity between B3 and the noncatalytic DBD of the restriction endonuclease EcoRII allowed us to build structural models of the B3/DNA complex. Most of the DBDs of plant-specific TFs are likely to have originated from endonucleases associated with transposable elements. After the DBDs have been established in unicellular eukaryotes, they experienced extensive plant-specific expansion, by acquiring new functions.
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Affiliation(s)
- Kazuhiko Yamasaki
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology-AIST, 1-1-1 Higashi, Tsukuba 305-8566, Japan.
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Kleinstiver BP, Wolfs JM, Edgell DR. The monomeric GIY-YIG homing endonuclease I-BmoI uses a molecular anchor and a flexible tether to sequentially nick DNA. Nucleic Acids Res 2013; 41:5413-27. [PMID: 23558745 PMCID: PMC3664794 DOI: 10.1093/nar/gkt186] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The GIY-YIG nuclease domain is found within protein scaffolds that participate in diverse cellular pathways and contains a single active site that hydrolyzes DNA by a one-metal ion mechanism. GIY-YIG homing endonucleases (GIY-HEs) are two-domain proteins with N-terminal GIY-YIG nuclease domains connected to C-terminal DNA-binding and they are thought to function as monomers. Using I-BmoI as a model GIY-HE, we test mechanisms by which the single active site is used to generate a double-strand break. We show that I-BmoI is partially disordered in the absence of substrate, and that the GIY-YIG domain alone has weak affinity for DNA. Significantly, we show that I-BmoI functions as a monomer at all steps of the reaction pathway and does not transiently dimerize or use sequential transesterification reactions to cleave substrate. Our results are consistent with the I-BmoI DNA-binding domain acting as a molecular anchor to tether the GIY-YIG domain to substrate, permitting rotation of the GIY-YIG domain to sequentially nick each DNA strand. These data highlight the mechanistic differences between monomeric GIY-HEs and dimeric or tetrameric GIY-YIG restriction enzymes, and they have implications for the use of the GIY-YIG domain in genome-editing applications.
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Affiliation(s)
- Benjamin P Kleinstiver
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada
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Godfray HCJ. Mosquito ecology and control of malaria. J Anim Ecol 2012; 82:15-25. [DOI: 10.1111/1365-2656.12003] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 09/01/2012] [Indexed: 11/30/2022]
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Xu SY, Gupta YK. Natural zinc ribbon HNH endonucleases and engineered zinc finger nicking endonuclease. Nucleic Acids Res 2012; 41:378-90. [PMID: 23125367 PMCID: PMC3592412 DOI: 10.1093/nar/gks1043] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Many bacteriophage and prophage genomes encode an HNH endonuclease (HNHE) next to their cohesive end site and terminase genes. The HNH catalytic domain contains the conserved catalytic residues His-Asn-His and a zinc-binding site [CxxC]2. An additional zinc ribbon (ZR) domain with one to two zinc-binding sites ([CxxxxC], [CxxxxH], [CxxxC], [HxxxH], [CxxC] or [CxxH]) is frequently found at the N-terminus or C-terminus of the HNHE or a ZR domain protein (ZRP) located adjacent to the HNHE. We expressed and purified 10 such HNHEs and characterized their cleavage sites. These HNHEs are site-specific and strand-specific nicking endonucleases (NEase or nickase) with 3- to 7-bp specificities. A minimal HNH nicking domain of 76 amino acid residues was identified from Bacillus phage γ HNHE and subsequently fused to a zinc finger protein to generate a chimeric NEase with a new specificity (12–13 bp). The identification of a large pool of previously unknown natural NEases and engineered NEases provides more ‘tools’ for DNA manipulation and molecular diagnostics. The small modular HNH nicking domain can be used to generate rare NEases applicable to targeted genome editing. In addition, the engineered ZF nickase is useful for evaluation of off-target sites in vitro before performing cell-based gene modification.
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Affiliation(s)
- Shuang-yong Xu
- New England Biolabs, Inc, Research Department, 240 County Road, Ipswich, MA 01938, USA.
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36
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Abstract
Buried within the genomes of many microorganisms are genetic elements that encode rare-cutting homing endonucleases that assist in the mobility of the elements that encode them, such as the self-splicing group I and II introns and in some cases inteins. There are several different families of homing endonucleases and their ability to initiate and target specific sequences for lateral transfers makes them attractive reagents for gene targeting. Homing endonucleases have been applied in promoting DNA modification or genome editing such as gene repair or "gene knockouts". This review examines the categories of homing endonucleases that have been described so far and their possible applications to biotechnology. Strategies to engineer homing endonucleases to alter target site specificities will also be addressed. Alternatives to homing endonucleases such as zinc finger nucleases, transcription activator-like effector nucleases, triplex forming oligonucleotide nucleases, and targetrons are also briefly discussed.
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Affiliation(s)
- Mohamed Hafez
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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