1
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Zahradka K, Zahradka D, Repar J. Structural Differences between the Genomes of Deinococcus radiodurans Strains from Different Laboratories. Genes (Basel) 2024; 15:847. [PMID: 39062626 PMCID: PMC11276467 DOI: 10.3390/genes15070847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/28/2024] Open
Abstract
The bacterium Deinococcus radiodurans is known to efficiently and accurately reassemble its genome after hundreds of DNA double-strand breaks (DSBs). Only at very large amounts of radiation-induced DSBs is this accuracy affected in the wild-type D. radiodurans, causing rearrangements in its genome structure. However, changes in its genome structure may also be possible during the propagation and storage of cell cultures. We investigate this possibility by listing structural differences between three completely sequenced genomes of D. radiodurans strains with a recent common ancestor-the type strain stored and sequenced in two different laboratories (of the ATCC 13939 lineage) and the first sequenced strain historically used as the reference (ATCC BAA-816). We detected a number of structural differences and found the most likely mechanisms behind them: (i) transposition/copy number change in mobile interspersed repeats-insertion sequences and small non-coding repeats, (ii) variable number of monomers within tandem repeats, (iii) deletions between long direct DNA repeats, and (iv) deletions between short (4-10 bp) direct DNA repeats. The most surprising finding was the deletions between short repeats because it indicates the utilization of a less accurate DSB repair mechanism in conditions in which a more accurate one should be both available and preferred. The detected structural differences, as well as SNPs and short indels, while being important footprints of deinococcal DNA metabolism and repair, are also a valuable resource for researchers using these D. radiodurans strains.
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Affiliation(s)
| | | | - Jelena Repar
- Division of Molecular Biology, Ruđer Bošković Institute, 10000 Zagreb, Croatia; (K.Z.); (D.Z.)
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2
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Łazowski K, Woodgate R, Fijalkowska IJ. Escherichia coli DNA replication: the old model organism still holds many surprises. FEMS Microbiol Rev 2024; 48:fuae018. [PMID: 38982189 PMCID: PMC11253446 DOI: 10.1093/femsre/fuae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 06/26/2024] [Accepted: 07/08/2024] [Indexed: 07/11/2024] Open
Abstract
Research on Escherichia coli DNA replication paved the groundwork for many breakthrough discoveries with important implications for our understanding of human molecular biology, due to the high level of conservation of key molecular processes involved. To this day, it attracts a lot of attention, partially by virtue of being an important model organism, but also because the understanding of factors influencing replication fidelity might be important for studies on the emergence of antibiotic resistance. Importantly, the wide access to high-resolution single-molecule and live-cell imaging, whole genome sequencing, and cryo-electron microscopy techniques, which were greatly popularized in the last decade, allows us to revisit certain assumptions about the replisomes and offers very detailed insight into how they work. For many parts of the replisome, step-by-step mechanisms have been reconstituted, and some new players identified. This review summarizes the latest developments in the area, focusing on (a) the structure of the replisome and mechanisms of action of its components, (b) organization of replisome transactions and repair, (c) replisome dynamics, and (d) factors influencing the base and sugar fidelity of DNA synthesis.
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Affiliation(s)
- Krystian Łazowski
- Laboratory of DNA Replication and Genome Stability, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Roger Woodgate
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-3371, United States
| | - Iwona J Fijalkowska
- Laboratory of DNA Replication and Genome Stability, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
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3
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Dagva O, Thibessard A, Lorenzi JN, Labat V, Piotrowski E, Rouhier N, Myllykallio H, Leblond P, Bertrand C. Correction of non-random mutational biases along a linear bacterial chromosome by the mismatch repair endonuclease NucS. Nucleic Acids Res 2024; 52:5033-5047. [PMID: 38444149 PMCID: PMC11109965 DOI: 10.1093/nar/gkae132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/19/2024] [Accepted: 02/09/2024] [Indexed: 03/07/2024] Open
Abstract
The linear chromosome of Streptomyces exhibits a highly compartmentalized structure with a conserved central region flanked by variable arms. As double strand break (DSB) repair mechanisms play a crucial role in shaping the genome plasticity of Streptomyces, we investigated the role of EndoMS/NucS, a recently characterized endonuclease involved in a non-canonical mismatch repair (MMR) mechanism in archaea and actinobacteria, that singularly corrects mismatches by creating a DSB. We showed that Streptomyces mutants lacking NucS display a marked colonial phenotype and a drastic increase in spontaneous mutation rate. In vitro biochemical assays revealed that NucS cooperates with the replication clamp to efficiently cleave G/T, G/G and T/T mismatched DNA by producing DSBs. These findings are consistent with the transition-shifted mutational spectrum observed in the mutant strains and reveal that NucS-dependent MMR specific task is to eliminate G/T mismatches generated by the DNA polymerase during replication. Interestingly, our data unveil a crescent-shaped distribution of the transition frequency from the replication origin towards the chromosomal ends, shedding light on a possible link between NucS-mediated DSBs and Streptomyces genome evolution.
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Affiliation(s)
- Oyut Dagva
- Université de Lorraine, INRAE, UMR 1128 DynAMic, 54000 Nancy, France
| | | | | | - Victor Labat
- Université de Lorraine, INRAE, UMR 1128 DynAMic, 54000 Nancy, France
| | - Emilie Piotrowski
- Université de Lorraine, INRAE, UMR 1128 DynAMic, 54000 Nancy, France
| | - Nicolas Rouhier
- Université de Lorraine, INRAE, UMR 1136 IAM, 54000 Nancy, France
| | - Hannu Myllykallio
- Ecole Polytechnique, INSERM U696-CNRS UMR 7645 LOB, 91128 Palaiseau, France
| | - Pierre Leblond
- Université de Lorraine, INRAE, UMR 1128 DynAMic, 54000 Nancy, France
| | - Claire Bertrand
- Université de Lorraine, INRAE, UMR 1128 DynAMic, 54000 Nancy, France
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4
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Pham P, Wood EA, Cox MM, Goodman MF. RecA and SSB genome-wide distribution in ssDNA gaps and ends in Escherichia coli. Nucleic Acids Res 2023; 51:5527-5546. [PMID: 37070184 PMCID: PMC10287960 DOI: 10.1093/nar/gkad263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 04/19/2023] Open
Abstract
Single-stranded DNA (ssDNA) gapped regions are common intermediates in DNA transactions. Using a new non-denaturing bisulfite treatment combined with ChIP-seq, abbreviated 'ssGap-seq', we explore RecA and SSB binding to ssDNA on a genomic scale in E. coli in a wide range of genetic backgrounds. Some results are expected. During log phase growth, RecA and SSB assembly profiles coincide globally, concentrated on the lagging strand and enhanced after UV irradiation. Unexpected results also abound. Near the terminus, RecA binding is favored over SSB, binding patterns change in the absence of RecG, and the absence of XerD results in massive RecA assembly. RecA may substitute for the absence of XerCD to resolve chromosome dimers. A RecA loading pathway may exist that is independent of RecBCD and RecFOR. Two prominent and focused peaks of RecA binding revealed a pair of 222 bp and GC-rich repeats, equidistant from dif and flanking the Ter domain. The repeats, here named RRS for replication risk sequence, trigger a genomically programmed generation of post-replication gaps that may play a special role in relieving topological stress during replication termination and chromosome segregation. As demonstrated here, ssGap-seq provides a new window on previously inaccessible aspects of ssDNA metabolism.
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Affiliation(s)
- Phuong Pham
- Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089-2910, USA
| | - Elizabeth A Wood
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
| | - Michael M Cox
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706-1544, USA
| | - Myron F Goodman
- Departments of Biological Sciences and Chemistry, University of Southern California, Los Angeles, CA 90089-2910, USA
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5
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Mre11-Rad50: the DNA end game. Biochem Soc Trans 2023; 51:527-538. [PMID: 36892213 DOI: 10.1042/bst20220754] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/09/2023] [Accepted: 02/17/2023] [Indexed: 03/10/2023]
Abstract
The Mre11-Rad50-(Nbs1/Xrs2) complex is an evolutionarily conserved factor for the repair of DNA double-strand breaks and other DNA termini in all kingdoms of life. It is an intricate DNA associated molecular machine that cuts, among other functions, a large variety of free and obstructed DNA termini for DNA repair by end joining or homologous recombination, yet leaves undamaged DNA intact. Recent years have brought progress in both the structural and functional analyses of Mre11-Rad50 orthologs, revealing mechanisms of DNA end recognition, endo/exonuclease activities, nuclease regulation and DNA scaffolding. Here, I review our current understanding and recent progress on the functional architecture Mre11-Rad50 and how this chromosome associated coiled-coil ABC ATPase acts as DNA topology specific endo-/exonuclease.
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6
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Colizzi ES, van Dijk B, Merks RMH, Rozen DE, Vroomans RMA. Evolution of genome fragility enables microbial division of labor. Mol Syst Biol 2023; 19:e11353. [PMID: 36727665 PMCID: PMC9996244 DOI: 10.15252/msb.202211353] [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: 09/14/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 02/03/2023] Open
Abstract
Division of labor can evolve when social groups benefit from the functional specialization of its members. Recently, a novel means of coordinating the division of labor was found in the antibiotic-producing bacterium Streptomyces coelicolor, where specialized cells are generated through large-scale genomic re-organization. We investigate how the evolution of a genome architecture enables such mutation-driven division of labor, using a multiscale computational model of bacterial evolution. In this model, bacterial behavior-antibiotic production or replication-is determined by the structure and composition of their genome, which encodes antibiotics, growth-promoting genes, and fragile genomic loci that can induce chromosomal deletions. We find that a genomic organization evolves, which partitions growth-promoting genes and antibiotic-coding genes into distinct parts of the genome, separated by fragile genomic loci. Mutations caused by these fragile sites mostly delete growth-promoting genes, generating sterile, and antibiotic-producing mutants from weakly-producing progenitors, in agreement with experimental observations. This division of labor enhances the competition between colonies by promoting antibiotic diversity. These results show that genomic organization can co-evolve with genomic instabilities to enable reproductive division of labor.
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Affiliation(s)
- Enrico Sandro Colizzi
- Mathematical Institute, Leiden University, Leiden, The Netherlands.,Origins Center, Leiden, The Netherlands.,Sainsbury Laboratory, Cambridge University, Cambridge, UK
| | - Bram van Dijk
- Department of Microbial Population Biology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Roeland M H Merks
- Mathematical Institute, Leiden University, Leiden, The Netherlands.,Origins Center, Leiden, The Netherlands.,Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Daniel E Rozen
- Institute of Biology, Leiden University, Leiden, The Netherlands
| | - Renske M A Vroomans
- Origins Center, Leiden, The Netherlands.,Sainsbury Laboratory, Cambridge University, Cambridge, UK.,Informatic Institute, University of Amsterdam, Amsterdam, The Netherlands
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7
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Chen PJ, McMullin AB, Visser BJ, Mei Q, Rosenberg SM, Bates D. Interdependent progression of bidirectional sister replisomes in E. coli. eLife 2023; 12:e82241. [PMID: 36621919 PMCID: PMC9859026 DOI: 10.7554/elife.82241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 01/05/2023] [Indexed: 01/10/2023] Open
Abstract
Bidirectional DNA replication complexes initiated from the same origin remain colocalized in a factory configuration for part or all their lifetimes. However, there is little evidence that sister replisomes are functionally interdependent, and the consequence of factory replication is unknown. Here, we investigated the functional relationship between sister replisomes in Escherichia coli, which naturally exhibits both factory and solitary configurations in the same replication cycle. Using an inducible transcription factor roadblocking system, we found that blocking one replisome caused a significant decrease in overall progression and velocity of the sister replisome. Remarkably, progression was impaired only if the block occurred while sister replisomes were still in a factory configuration - blocking one fork had no significant effect on the other replisome when sister replisomes were physically separate. Disruption of factory replication also led to increased fork stalling and requirement of fork restart mechanisms. These results suggest that physical association between sister replisomes is important for establishing an efficient and uninterrupted replication program. We discuss the implications of our findings on mechanisms of replication factory structure and function, and cellular strategies of replicating problematic DNA such as highly transcribed segments.
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Affiliation(s)
- Po Jui Chen
- Molecular Virology and Microbiology, Baylor College of MedicineHoustonUnited States
| | - Anna B McMullin
- Molecular Virology and Microbiology, Baylor College of MedicineHoustonUnited States
| | - Bryan J Visser
- Graduate Program in Integrative Molecular and Biomedical Sciences, Baylor College of MedicineHoustonUnited States
| | - Qian Mei
- Systems, Synthetic, and Physical Biology Program, Rice UniversityHoustonUnited States
| | - Susan M Rosenberg
- Molecular Virology and Microbiology, Baylor College of MedicineHoustonUnited States
- Graduate Program in Integrative Molecular and Biomedical Sciences, Baylor College of MedicineHoustonUnited States
- Systems, Synthetic, and Physical Biology Program, Rice UniversityHoustonUnited States
- Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Dan L Duncan Comprehensive Cancer Center, Baylor College of MedicineHoustonUnited States
| | - David Bates
- Molecular Virology and Microbiology, Baylor College of MedicineHoustonUnited States
- Graduate Program in Integrative Molecular and Biomedical Sciences, Baylor College of MedicineHoustonUnited States
- Molecular and Human Genetics, Baylor College of MedicineHoustonUnited States
- Dan L Duncan Comprehensive Cancer Center, Baylor College of MedicineHoustonUnited States
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8
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Shiriaeva AA, Kuznedelov K, Fedorov I, Musharova O, Khvostikov T, Tsoy Y, Kurilovich E, Smith GR, Semenova E, Severinov K. Host nucleases generate prespacers for primed adaptation in the E. coli type I-E CRISPR-Cas system. SCIENCE ADVANCES 2022; 8:eabn8650. [PMID: 36427302 PMCID: PMC9699676 DOI: 10.1126/sciadv.abn8650] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
CRISPR-Cas systems provide prokaryotes with adaptive immunity against foreign nucleic acids. In Escherichia coli, immunity is acquired upon integration of 33-bp spacers into CRISPR arrays. DNA targets complementary to spacers get degraded and serve as a source of new spacers during a process called primed adaptation. Precursors of such spacers, prespacers, are ~33-bp double-stranded DNA fragments with a ~4-nt 3' overhang. The mechanism of prespacer generation is not clear. Here, we use FragSeq and biochemical approaches to determine enzymes involved in generation of defined prespacer ends. We demonstrate that RecJ is the main exonuclease trimming 5' ends of prespacer precursors, although its activity can be partially substituted by ExoVII. The RecBCD complex allows single strand-specific RecJ to process double-stranded regions flanking prespacers. Our results reveal intricate functional interactions of genome maintenance proteins with CRISPR interference and adaptation machineries during generation of prespacers capable of integration into CRISPR arrays.
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Affiliation(s)
- Anna A. Shiriaeva
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
- Saint Petersburg State University, Saint Petersburg 199034, Russia
- Peter the Great St. Petersburg Polytechnic University, Saint Petersburg 195251, Russia
- Waksman Institute, Rutgers, State University of New Jersey, Piscataway, NJ 08854, USA
| | - Konstantin Kuznedelov
- Waksman Institute, Rutgers, State University of New Jersey, Piscataway, NJ 08854, USA
| | - Ivan Fedorov
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
- Institute of Gene Biology, Russian Academy of Science, Moscow 119334, Russia
| | - Olga Musharova
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
- Institute of Molecular Genetics, National Research Center Kurchatov Institute, Moscow 123182, Russia
| | - Timofey Khvostikov
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Yuliya Tsoy
- Peter the Great St. Petersburg Polytechnic University, Saint Petersburg 195251, Russia
| | - Elena Kurilovich
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Moscow 121205, Russia
| | - Gerald R. Smith
- Division of Basic Sciences, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Ekaterina Semenova
- Waksman Institute, Rutgers, State University of New Jersey, Piscataway, NJ 08854, USA
| | - Konstantin Severinov
- Waksman Institute, Rutgers, State University of New Jersey, Piscataway, NJ 08854, USA
- Institute of Molecular Genetics, National Research Center Kurchatov Institute, Moscow 123182, Russia
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9
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Abstract
Mechanisms of evolution and evolution of antibiotic resistance are both fundamental and world health problems. Stress-induced mutagenesis defines mechanisms of mutagenesis upregulated by stress responses, which drive adaptation when cells are maladapted to their environments—when stressed. Work in mutagenesis induced by antibiotics had produced tantalizing clues but not coherent mechanisms. We review recent advances in antibiotic-induced mutagenesis that integrate how reactive oxygen species (ROS), the SOS and general stress responses, and multichromosome cells orchestrate a stress response-induced switch from high-fidelity to mutagenic repair of DNA breaks. Moreover, while sibling cells stay stable, a mutable “gambler” cell subpopulation is induced by differentially generated ROS, which signal the general stress response. We discuss other evolvable subpopulations and consider diverse evolution-promoting molecules as potential targets for drugs to slow evolution of antibiotic resistance, cross-resistance, and immune evasion. An FDA-approved drug exemplifies “stealth” evolution-slowing drugs that avoid selecting resistance to themselves or antibiotics.
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10
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Chromosome organization affects genome evolution in Sulfolobus archaea. Nat Microbiol 2022; 7:820-830. [PMID: 35618771 DOI: 10.1038/s41564-022-01127-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 04/21/2022] [Indexed: 12/16/2022]
Abstract
In all organisms, the DNA sequence and the structural organization of chromosomes affect gene expression. The extremely thermophilic crenarchaeon Sulfolobus has one circular chromosome with three origins of replication. We previously revealed that this chromosome has defined A and B compartments that have high and low gene expression, respectively. As well as higher levels of gene expression, the A compartment contains the origins of replication. To evaluate the impact of three-dimensional organization on genome evolution, we characterized the effect of replication origins and compartmentalization on primary sequence evolution in eleven Sulfolobus species. Using single-nucleotide polymorphism analyses, we found that distance from an origin of replication was associated with increased mutation rates in the B but not in the A compartment. The enhanced polymorphisms distal to replication origins suggest that replication termination may have a causal role in their generation. Further mutational analyses revealed that the sequences in the A compartment are less likely to be mutated, and that there is stronger purifying selection than in the B compartment. Finally, we applied the Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) to show that the B compartment is less accessible than the A compartment. Taken together, our data suggest that compartmentalization of chromosomal DNA can influence chromosome evolution in Sulfolobus. We propose that the A compartment serves as a haven for stable maintenance of gene sequences, while sequences in the B compartment can be diversified.
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11
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Mori JF, Kanaly RA. Natural Chromosome-Chromid Fusion across rRNA Operons in a Burkholderiaceae Bacterium. Microbiol Spectr 2022; 10:e0222521. [PMID: 34985328 PMCID: PMC8729776 DOI: 10.1128/spectrum.02225-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 12/07/2021] [Indexed: 12/31/2022] Open
Abstract
Chromids (secondary chromosomes) in bacterial genomes that are present in addition to the main chromosome appear to be evolutionarily conserved in some specific bacterial groups. In rare cases among these groups, a small number of strains from Rhizobiales and Vibrionales were shown to possess a naturally fused single chromosome that was reported to have been generated through intragenomic homologous recombination between repeated sequences on the chromosome and chromid. Similar examples have never been reported in the family Burkholderiaceae, a well-documented group that conserves chromids. Here, an in-depth genomic characterization was performed on a Burkholderiaceae bacterium that was isolated from a soil bacterial consortium maintained on diesel fuel and mutagenic benzo[a]pyrene. This organism, Cupriavidus necator strain KK10, was revealed to carry a single chromosome with unexpectedly large size (>6.6 Mb), and results of comparative genomics with the genome of C. necator N-1T indicated that the single chromosome of KK10 was generated through fusion of the prototypical chromosome and chromid at the rRNA operons. This fusion hypothetically occurred through homologous recombination with a crossover between repeated rRNA operons on the chromosome and chromid. Some metabolic functions that were likely expressed from genes on the prototypical chromid region were indicated to be retained. If this phenomenon-the bacterial chromosome-chromid fusion across the rRNA operons through homologous recombination-occurs universally in prokaryotes, the multiple rRNA operons in bacterial genomes may not only contribute to the robustness of ribosome function, but also provide more opportunities for genomic rearrangements through frequent recombination. IMPORTANCE A bacterial chromosome that was naturally fused with the secondary chromosome, or "chromid," and presented as an unexpectedly large single replicon was discovered in the genome of Cupriavidus necator strain KK10, a biotechnologically useful member of the family Burkholderiaceae. Although Burkholderiaceae is a well-documented group that conserves chromids in their genomes, this chromosomal fusion event has not been previously reported for this family. This fusion has hypothetically occurred through intragenomic homologous recombination between repeated rRNA operons and, if so, provides novel insight into the potential of multiple rRNA operons in bacterial genomes to lead to chromosome-chromid fusion. The harsh conditions under which strain KK10 was maintained-a genotoxic hydrocarbon-enriched milieu-may have provided this genotype with a niche in which to survive.
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Affiliation(s)
- Jiro F. Mori
- Graduate School of Nanobiosicences, Yokohama City University, Yokohama, Japan
| | - Robert A. Kanaly
- Graduate School of Nanobiosicences, Yokohama City University, Yokohama, Japan
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12
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Toft CJ, Moreau MJJ, Perutka J, Mandapati S, Enyeart P, Sorenson AE, Ellington AD, Schaeffer PM. Delineation of the Ancestral Tus-Dependent Replication Fork Trap. Int J Mol Sci 2021; 22:ijms222413533. [PMID: 34948327 PMCID: PMC8707476 DOI: 10.3390/ijms222413533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/10/2021] [Accepted: 12/15/2021] [Indexed: 12/28/2022] Open
Abstract
In Escherichia coli, DNA replication termination is orchestrated by two clusters of Ter sites forming a DNA replication fork trap when bound by Tus proteins. The formation of a ‘locked’ Tus–Ter complex is essential for halting incoming DNA replication forks. However, the absence of replication fork arrest at some Ter sites raised questions about their significance. In this study, we examined the genome-wide distribution of Tus and found that only the six innermost Ter sites (TerA–E and G) were significantly bound by Tus. We also found that a single ectopic insertion of TerB in its non-permissive orientation could not be achieved, advocating against a need for ‘back-up’ Ter sites. Finally, examination of the genomes of a variety of Enterobacterales revealed a new replication fork trap architecture mostly found outside the Enterobacteriaceae family. Taken together, our data enabled the delineation of a narrow ancestral Tus-dependent DNA replication fork trap consisting of only two Ter sites.
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Affiliation(s)
- Casey J. Toft
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia; (C.J.T.); (M.J.J.M.); (A.E.S.)
- Centre of Tropical Bioinformatics and Molecular Biology, James Cook University, Douglas, QLD 4811, Australia
| | - Morgane J. J. Moreau
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia; (C.J.T.); (M.J.J.M.); (A.E.S.)
| | - Jiri Perutka
- Institute for Cell and Molecular Biology, University of Texas, Austin, TX 78712, USA; (J.P.); (S.M.); (P.E.); (A.D.E.)
| | - Savitri Mandapati
- Institute for Cell and Molecular Biology, University of Texas, Austin, TX 78712, USA; (J.P.); (S.M.); (P.E.); (A.D.E.)
| | - Peter Enyeart
- Institute for Cell and Molecular Biology, University of Texas, Austin, TX 78712, USA; (J.P.); (S.M.); (P.E.); (A.D.E.)
| | - Alanna E. Sorenson
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia; (C.J.T.); (M.J.J.M.); (A.E.S.)
| | - Andrew D. Ellington
- Institute for Cell and Molecular Biology, University of Texas, Austin, TX 78712, USA; (J.P.); (S.M.); (P.E.); (A.D.E.)
| | - Patrick M. Schaeffer
- Molecular and Cell Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Douglas, QLD 4811, Australia; (C.J.T.); (M.J.J.M.); (A.E.S.)
- Centre of Tropical Bioinformatics and Molecular Biology, James Cook University, Douglas, QLD 4811, Australia
- Correspondence: ; Tel.: +61-(0)-7-4781-4448; Fax: +61-(0)-7-4781-6078
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13
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Liu J, Mei Q, Nimer S, Fitzgerald DM, Rosenberg SM. Genomic mapping of DNA-repair reaction intermediates in living cells with engineered DNA structure-trap proteins. Methods Enzymol 2021; 661:155-181. [PMID: 34776211 DOI: 10.1016/bs.mie.2021.09.015] [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: 01/04/2023]
Abstract
Diverse DNA structures occur as reaction intermediates in various DNA-damage and -repair mechanisms, most of which results from replication stress. We harness the power of proteins evolutionarily optimized to bind and "trap" specific DNA reaction-intermediate structures, to quantify the structures, and discern the mechanisms of their occurrence in cells. The engineered proteins also allow genomic mapping of sites at which specific DNA structures occur preferentially, using a structure-trapping protein and ChIP-seq- or Cut-and-Tag-like methods. Genome-wide identification of sites with recurrent DNA-damage intermediates has illuminated mechanisms implicated in genome instability, replication stress, and chromosome fragility. Here, we describe X-seq, for identifying sites of recurrent four-way DNA junctions or Holliday-junctions (HJs). X-seq uses an engineered, catalysis-defective mutant of Escherichia coli RuvC HJ-specific endonuclease, RuvCDefGFP. X-seq signal indicates sites of recombinational DNA repair or replication-fork stalling and reversal. We also describe methods for genomic mapping of 3'-single-stranded DNA ends with SsEND-seq, in E. coli. Both methods allow genomic profiling of DNA-damage and -repair intermediates, which can precede genome instability, and are expected to have many additional applications including in other cells and organisms.
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Affiliation(s)
- Jingjing Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Qian Mei
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States; Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, United States; Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States; Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, United States; Systems, Synthetic, and Physical Biology Program, Rice University, Houston, TX, United States
| | - Sadeieh Nimer
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States; Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, United States; Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States; Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, United States
| | - Devon M Fitzgerald
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States; Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, United States; Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States; Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, United States
| | - Susan M Rosenberg
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States; Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, United States; Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States; Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, United States; Systems, Synthetic, and Physical Biology Program, Rice University, Houston, TX, United States.
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Fitzgerald DM, Rosenberg SM. Biology before the SOS Response-DNA Damage Mechanisms at Chromosome Fragile Sites. Cells 2021; 10:2275. [PMID: 34571923 PMCID: PMC8465572 DOI: 10.3390/cells10092275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/13/2021] [Accepted: 08/13/2021] [Indexed: 01/03/2023] Open
Abstract
The Escherichia coli SOS response to DNA damage, discovered and conceptualized by Evelyn Witkin and Miroslav Radman, is the prototypic DNA-damage stress response that upregulates proteins of DNA protection and repair, a radical idea when formulated in the late 1960s and early 1970s. SOS-like responses are now described across the tree of life, and similar mechanisms of DNA-damage tolerance and repair underlie the genome instability that drives human cancer and aging. The DNA damage that precedes damage responses constitutes upstream threats to genome integrity and arises mostly from endogenous biology. Radman's vision and work on SOS, mismatch repair, and their regulation of genome and species evolution, were extrapolated directly from bacteria to humans, at a conceptual level, by Radman, then many others. We follow his lead in exploring bacterial molecular genomic mechanisms to illuminate universal biology, including in human disease, and focus here on some events upstream of SOS: the origins of DNA damage, specifically at chromosome fragile sites, and the engineered proteins that allow us to identify mechanisms. Two fragility mechanisms dominate: one at replication barriers and another associated with the decatenation of sister chromosomes following replication. DNA structures in E. coli, additionally, suggest new interpretations of pathways in cancer evolution, and that Holliday junctions may be universal molecular markers of chromosome fragility.
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Affiliation(s)
- Devon M. Fitzgerald
- Departments of Molecular and Human Genetics, Biochemistry and Molecular Biology, Molecular Virology and Microbiology, and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Susan M. Rosenberg
- Departments of Molecular and Human Genetics, Biochemistry and Molecular Biology, Molecular Virology and Microbiology, and Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
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