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Ajay A, Begum T, Arya A, Kumar K, Ahmad S. Global and local genomic features together modulate the spontaneous single nucleotide mutation rate. Comput Biol Chem 2024; 112:108107. [PMID: 38875896 DOI: 10.1016/j.compbiolchem.2024.108107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 04/23/2024] [Accepted: 05/17/2024] [Indexed: 06/16/2024]
Abstract
Spontaneous mutations are evolutionary engines as they generate variants for the evolutionary downstream processes that give rise to speciation and adaptation. Single nucleotide mutations (SNM) are the most abundant type of mutations among them. Here, we perform a meta-analysis to quantify the influence of selected global genomic parameters (genome size, genomic GC content, genomic repeat fraction, number of coding genes, gene count, and strand bias in prokaryotes) and local genomic features (local GC content, repeat content, CpG content and the number of SNM at CpG islands) on spontaneous SNM rates across the tree of life (prokaryotes, unicellular eukaryotes, multicellular eukaryotes) using wild-type sequence data in two different taxon classification systems. We find that the spontaneous SNM rates in our data are correlated with many genomic features in prokaryotes and unicellular eukaryotes irrespective of their sample sizes. On the other hand, only the number of coding genes was correlated with the spontaneous SNM rates in multicellular eukaryotes primarily contributed by vertebrates data. Considering local features, we notice that local GC content and CpG content significantly were correlated with the spontaneous SNM rates in the unicellular eukaryotes, while local repeat fraction is an important feature in prokaryotes and certain specific uni- and multi-cellular eukaryotes. Such predictive features of the spontaneous SNM rates often support non-linear models as the best fit compared to the linear model. We also observe that the strand asymmetry in prokaryotes plays an important role in determining the spontaneous SNM rates but the SNM spectrum does not.
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Affiliation(s)
- Akash Ajay
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India; School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Tina Begum
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
| | - Ajay Arya
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Krishan Kumar
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Shandar Ahmad
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
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2
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Worthan SB, McCarthy RDP, Delaleau M, Stikeleather R, Bratton BP, Boudvillain M, Behringer MG. Evolution of pH-sensitive transcription termination in Escherichia coli during adaptation to repeated long-term starvation. Proc Natl Acad Sci U S A 2024; 121:e2405546121. [PMID: 39298488 DOI: 10.1073/pnas.2405546121] [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: 03/17/2024] [Accepted: 08/19/2024] [Indexed: 09/21/2024] Open
Abstract
Fluctuating environments that consist of regular cycles of co-occurring stress are a common challenge faced by cellular populations. For a population to thrive in constantly changing conditions, an ability to coordinate a rapid cellular response is essential. Here, we identify a mutation conferring an arginine-to-histidine (Arg to His) substitution in the transcription terminator Rho. The rho R109H mutation frequently arose in Escherichia coli populations experimentally evolved under repeated long-term starvation conditions, during which the accumulation of metabolic waste followed by transfer into fresh media results in drastic environmental pH fluctuations associated with feast and famine. Metagenomic sequencing revealed that populations containing the rho mutation also possess putative loss-of-function mutations in ydcI, which encodes a recently characterized transcription factor associated with pH homeostasis. Genetic reconstructions of these mutations show that the rho allele confers plasticity via an alkaline-induced reduction of Rho function that, when found in tandem with a ΔydcI allele, leads to intracellular alkalization and genetic assimilation of Rho mutant function. We further identify Arg to His substitutions at analogous sites in rho alleles from species that regularly experience neutral to alkaline pH fluctuations in their environments. Our results suggest that Arg to His substitutions in Rho may serve to rapidly coordinate complex physiological responses through pH sensing and shed light on how cellular populations use environmental cues to coordinate rapid responses to complex, fluctuating environments.
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Affiliation(s)
- Sarah B Worthan
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN 37232
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN 37232
| | - Robert D P McCarthy
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
| | - Mildred Delaleau
- Centre de Biophysique Moléculaire, CNRS UPR4301, affiliated with Université d'Orléans, Orléans Cedex 2 45071, France
| | - Ryan Stikeleather
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85281
| | - Benjamin P Bratton
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN 37232
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN 37232
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232
| | - Marc Boudvillain
- Centre de Biophysique Moléculaire, CNRS UPR4301, affiliated with Université d'Orléans, Orléans Cedex 2 45071, France
| | - Megan G Behringer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN 37232
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN 37232
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232
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3
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Pal A, Ghosh D, Thakur P, Nagpal P, Irulappan M, Maruthan K, Mukherjee S, Patil N, Dutta T, Veeraraghavan B, Vivekanandan P. Clinically relevant mutations in regulatory regions of metabolic genes facilitate early adaptation to ciprofloxacin in Escherichia coli. Nucleic Acids Res 2024; 52:10385-10399. [PMID: 39180403 PMCID: PMC11417348 DOI: 10.1093/nar/gkae719] [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: 12/04/2023] [Revised: 07/31/2024] [Accepted: 08/09/2024] [Indexed: 08/26/2024] Open
Abstract
The genomic landscape associated with early adaptation to ciprofloxacin is poorly understood. Although the interplay between core metabolism and antimicrobial resistance is being increasingly recognized, mutations in metabolic genes and their biological role remain elusive. Here, we exposed Escherichia coli to increasing gradients of ciprofloxacin with intermittent transfer-bottlenecking and identified mutations in three non-canonical targets linked to metabolism including a deletion (tRNA-ArgΔ414-bp) and point mutations in the regulatory regions of argI (ARG box) and narU. Our findings suggest that these mutations modulate arginine and carbohydrate metabolism, facilitate anaerobiosis and increased ATP production during ciprofloxacin stress. Furthermore, mutations in the regulatory regions of argI and narU were detected in over 70% of sequences from clinical E. coli isolates and were overrepresented among ciprofloxacin-resistant isolates. In sum, we have identified clinically relevant mutations in the regulatory regions of metabolic genes as a central theme that drives physiological changes necessary for adaptation to ciprofloxacin stress.
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Affiliation(s)
- Arijit Pal
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
- Department of Zoology, Raiganj Surendranath Mahavidyalaya, Sudarshanpur, Raiganj, Uttar Dinajpur, West Bengal733134, India
| | - Dipannita Ghosh
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Pratyusha Thakur
- RNA Biology Laboratory, Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Priya Nagpal
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Madhumathi Irulappan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Karthik Maruthan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Sanket Mukherjee
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Nikita G Patil
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
- Amity Institute of Virology and Immunology, Amity University, Noida, Uttar Pradesh, India
| | - Tanmay Dutta
- RNA Biology Laboratory, Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Perumal Vivekanandan
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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4
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Stemwedel K, Haase N, Christ S, Bogdanova N, Rudorf S. Synonymous rpsH variants: the common denominator in Escherichia coli adapting to ionizing radiation. NAR Genom Bioinform 2024; 6:lqae110. [PMID: 39184377 PMCID: PMC11344242 DOI: 10.1093/nargab/lqae110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 07/18/2024] [Accepted: 08/08/2024] [Indexed: 08/27/2024] Open
Abstract
Ionizing radiation (IR) in high doses is generally lethal to most organisms. Investigating mechanisms of radiation resistance is crucial for gaining insights into the underlying cellular responses and understanding the damaging effects of IR. In this study, we conducted a comprehensive analysis of sequencing data from an evolutionary experiment aimed at understanding the genetic adaptations to ionizing radiation in Escherichia coli. By including previously neglected synonymous mutations, we identified the rpsH c.294T > G variant, which emerged in all 17 examined isolates across four subpopulations. The identified variant is a synonymous mutation affecting the 30S ribosomal protein S8, and consistently exhibited high detection and low allele frequencies in all subpopulations. This variant, along with two additional rpsH variants, potentially influences translational control of the ribosomal spc operon. The early emergence and stability of these variants suggest their role in adapting to environmental stress, possibly contributing to radiation resistance. Our findings shed light on the dynamics of ribosomal variants during the evolutionary process and their potential role in stress adaptation, providing valuable implications for understanding clinical radiation sensitivity and improving radiotherapy.
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Affiliation(s)
- Katharina Stemwedel
- Leibniz University Hannover, Institute of Cell Biology and Biophysics, Hannover, 30167, Germany
| | - Nadin Haase
- Leibniz University Hannover, Institute of Cell Biology and Biophysics, Hannover, 30167, Germany
| | - Simon Christ
- Leibniz University Hannover, Institute of Cell Biology and Biophysics, Hannover, 30167, Germany
| | | | - Sophia Rudorf
- Leibniz University Hannover, Institute of Cell Biology and Biophysics, Hannover, 30167, Germany
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Clavier T, Pinel C, de Jong H, Geiselmann J. Improving the genetic stability of bacterial growth control for long-term bioproduction. Biotechnol Bioeng 2024; 121:2808-2819. [PMID: 38877869 DOI: 10.1002/bit.28756] [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: 02/14/2024] [Revised: 04/23/2024] [Accepted: 05/11/2024] [Indexed: 08/15/2024]
Abstract
Using microorganisms for bioproduction requires the reorientation of metabolic fluxes from biomass synthesis to the production of compounds of interest. We previously engineered a synthetic growth switch in Escherichia coli based on inducible expression of the β- and β'-subunits of RNA polymerase. Depending on the level of induction, the cells stop growing or grow at a rate close to that of the wild-type strain. This strategy has been successful in transforming growth-arrested bacteria into biofactories with a high production yield, releasing cellular resources from growth towards biosynthesis. However, high selection pressure is placed on a growth-arrested population, favoring mutations that allow cells to escape from growth control. Accordingly, we made the design of the growth switch more robust by building in genetic redundancy. More specifically, we added the rpoA gene, encoding for the α-subunit of RNA polymerase, under the control of a copy of the same inducible promoter used for expression control of ββ'. The improved growth switch is much more stable (escape frequency <10-9), while preserving the capacity to improve production yields. Moreover, after a long period of growth inhibition the population can be regenerated within a few generations. This opens up the possibility to alternate biomass accumulation and product synthesis over a longer period of time and is an additional step towards the dynamical control of bioproduction.
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Affiliation(s)
- Thibault Clavier
- Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France
- Université Grenoble Alpes, Inria, Grenoble, France
| | - Corinne Pinel
- Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France
- Université Grenoble Alpes, Inria, Grenoble, France
| | - Hidde de Jong
- Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France
- Université Grenoble Alpes, Inria, Grenoble, France
| | - Johannes Geiselmann
- Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France
- Université Grenoble Alpes, Inria, Grenoble, France
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Hemez C, Mohler K, Radford F, Moen J, Rinehart J, Isaacs FJ. Genomically recoded Escherichia coli with optimized functional phenotypes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.29.610322. [PMID: 39257802 PMCID: PMC11383693 DOI: 10.1101/2024.08.29.610322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
Genomically recoded organisms hold promise for many biotechnological applications, but they may exhibit substantial fitness defects relative to their non-recoded counterparts. We used targeted metabolic screens, genetic analysis, and proteomics to identify the origins of fitness impairment in a model recoded organism, Escherichia coli C321.∆A. We found that defects in isoleucine biosynthesis and release factor activity, caused by mutations extant in all K-12 lineage strains, elicited profound fitness impairments in C321.∆A, suggesting that genome recoding exacerbates suboptimal traits present in precursor strains. By correcting these and other C321.∆A-specific mutations, we engineered C321.∆A strains with doubling time reductions of 17% and 42% in rich and minimal medium, respectively, compared to ancestral C321. Strains with improved growth kinetics also demonstrated enhanced ribosomal non-standard amino acid incorporation capabilities. Proteomic analysis indicated that C321.∆A lacks the ability to regulate essential amino acid and nucleotide biosynthesis pathways, and that targeted mutation reversion restored regulatory capabilities. Our work outlines a strategy for the rapid and precise phenotypic optimization of genomically recoded organisms and other engineered microbes.
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Affiliation(s)
- Colin Hemez
- Systems Biology Institute, Yale University, West Haven, CT 06516
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520
- Department of Biomedical Engineering, Yale University, New Haven CT 06520
| | - Kyle Mohler
- Systems Biology Institute, Yale University, West Haven, CT 06516
- Department of Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520
| | - Felix Radford
- Systems Biology Institute, Yale University, West Haven, CT 06516
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520
| | - Jack Moen
- Systems Biology Institute, Yale University, West Haven, CT 06516
- Department of Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520
| | - Jesse Rinehart
- Systems Biology Institute, Yale University, West Haven, CT 06516
- Department of Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520
| | - Farren J Isaacs
- Systems Biology Institute, Yale University, West Haven, CT 06516
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520
- Department of Biomedical Engineering, Yale University, New Haven CT 06520
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7
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Deng MZ, Liu Q, Cui SJ, Wang YX, Zhu G, Fu H, Gan M, Xu YY, Cai X, Wang S, Sha W, Zhao GP, Fortune SM, Lyu LD. An additional proofreader contributes to DNA replication fidelity in mycobacteria. Proc Natl Acad Sci U S A 2024; 121:e2322938121. [PMID: 39141351 PMCID: PMC11348249 DOI: 10.1073/pnas.2322938121] [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: 01/02/2024] [Accepted: 07/08/2024] [Indexed: 08/15/2024] Open
Abstract
The removal of mis-incorporated nucleotides by proofreading activity ensures DNA replication fidelity. Whereas the ε-exonuclease DnaQ is a well-established proofreader in the model organism Escherichia coli, it has been shown that proofreading in a majority of bacteria relies on the polymerase and histidinol phosphatase (PHP) domain of replicative polymerase, despite the presence of a DnaQ homolog that is structurally and functionally distinct from E. coli DnaQ. However, the biological functions of this type of noncanonical DnaQ remain unclear. Here, we provide independent evidence that noncanonical DnaQ functions as an additional proofreader for mycobacteria. Using the mutation accumulation assay in combination with whole-genome sequencing, we showed that depletion of DnaQ in Mycolicibacterium smegmatis leads to an increased mutation rate, resulting in AT-biased mutagenesis and increased insertions/deletions in the homopolymer tract. Our results showed that mycobacterial DnaQ binds to the β clamp and functions synergistically with the PHP domain proofreader to correct replication errors. Furthermore, the loss of dnaQ results in replication fork dysfunction, leading to attenuated growth and increased mutagenesis on subinhibitory fluoroquinolones potentially due to increased vulnerability to fork collapse. By analyzing the sequence polymorphism of dnaQ in clinical isolates of Mycobacterium tuberculosis (Mtb), we demonstrated that a naturally evolved DnaQ variant prevalent in Mtb lineage 4.3 may enable hypermutability and is associated with drug resistance. These results establish a coproofreading model and suggest a division of labor between DnaQ and PHP domain proofreader. This study also provides real-world evidence that a mutator-driven evolutionary pathway may exist during the adaptation of Mtb.
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Affiliation(s)
- Ming-Zhi Deng
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai200032, China
| | - Qingyun Liu
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA02115
| | - Shu-Jun Cui
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai200032, China
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai200433, China
| | - Yi-Xin Wang
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai200032, China
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai200433, China
| | - Guoliang Zhu
- Shanghai Zelixir Biotech Company Ltd., Shanghai200030, China
| | - Han Fu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai200032, China
- Chinese Academy of Sciences Key Laboratory of Synthetic Biology, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai200032, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Mingyu Gan
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai201102, China
| | - Yuan-Yuan Xu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai200032, China
| | - Xia Cai
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai200032, China
| | - Sheng Wang
- Shanghai Zelixir Biotech Company Ltd., Shanghai200030, China
| | - Wei Sha
- Shanghai Clinical Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Shanghai200433, China
| | - Guo-Ping Zhao
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai200433, China
- Chinese Academy of Sciences Key Laboratory of Synthetic Biology, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai200032, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Sarah M. Fortune
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA02115
| | - Liang-Dong Lyu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health, Department of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Fudan University, Shanghai200032, China
- Shanghai Clinical Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Shanghai200433, China
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8
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Chuang YC, Behringer MG, Patton G, Bird JT, Love CE, Dalia A, McKinlay JB. Bacterial cross-feeding can promote gene retention by lowering gene expression costs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.19.608702. [PMID: 39229193 PMCID: PMC11370488 DOI: 10.1101/2024.08.19.608702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Gene loss is expected in microbial communities when the benefit of obtaining a biosynthetic precursor from a neighbor via cross-feeding outweighs the cost of retaining a biosynthetic gene. However, gene cost primarily comes from expression, and many biosynthetic genes are only expressed when needed. Thus, one can conversely expect cross-feeding to repress biosynthetic gene expression and promote gene retention by lowering gene cost. Here we examined long-term bacterial cocultures pairing Escherichia coli and Rhodopseudomonas palustris for evidence of gene loss or retention in response to cross-feeding of non-essential adenine. Although R. palustris continued to externalize adenine in long-term cultures, E. coli did not accumulate mutations in purine synthesis genes, even after 700 generations. E. coli purine synthesis gene expression was low in coculture, suggesting that gene repression removed selective pressure for gene loss. In support of this explanation, R. palustris also had low transcript levels for iron-scavenging siderophore genes in coculture, likely because E. coli facilitated iron acquisition by R. palustris. R. palustris siderophore gene mutations were correspondingly rare in long-term cocultures but were prevalent in monocultures where transcript levels were high. Our data suggests that cross-feeding does not always drive gene loss, but can instead promote gene retention by repressing costly expression.
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Affiliation(s)
- Ying-Chih Chuang
- Department of Biology, Indiana University, Bloomington, IN, USA
- Biochemistry Program, Indiana University, Bloomington, IN, USA
| | - Megan G Behringer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Gillian Patton
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | | | - Crystal E Love
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Ankur Dalia
- Department of Biology, Indiana University, Bloomington, IN, USA
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9
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Delgado S, Armijo Á, Bravo V, Orellana O, Salazar JC, Katz A. Impact of the chemical modification of tRNAs anticodon loop on the variability and evolution of codon usage in proteobacteria. Front Microbiol 2024; 15:1412318. [PMID: 39161601 PMCID: PMC11332805 DOI: 10.3389/fmicb.2024.1412318] [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: 04/04/2024] [Accepted: 05/27/2024] [Indexed: 08/21/2024] Open
Abstract
Despite the highly conserved nature of the genetic code, the frequency of usage of each codon can vary significantly. The evolution of codon usage is shaped by two main evolutionary forces: mutational bias and selection pressures. These pressures can be driven by environmental factors, but also by the need for efficient translation, which depends heavily on the concentration of transfer RNAs (tRNAs) within the cell. The data presented here supports the proposal that tRNA modifications play a key role in shaping the overall preference of codon usage in proteobacteria. Interestingly, some codons, such as CGA and AGG (encoding arginine), exhibit a surprisingly low level of variation in their frequency of usage, even across genomes with differing GC content. These findings suggest that the evolution of GC content in proteobacterial genomes might be primarily driven by changes in the usage of a specific subset of codons, whose usage is itself influenced by tRNA modifications.
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Affiliation(s)
| | - Álvaro Armijo
- Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Verónica Bravo
- Programa Centro de Investigacion Biomédica y Aplicada, Escuela de Medicina, Facultad de Ciencias Médicas, Universidad de Santiago de Chile, Santiago, Chile
| | - Omar Orellana
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Juan Carlos Salazar
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Assaf Katz
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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10
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López-Cortegano E, Chebib J, Jonas A, Vock A, Künzel S, Tautz D, Keightley PD. Variation in the Spectrum of New Mutations among Inbred Strains of Mice. Mol Biol Evol 2024; 41:msae163. [PMID: 39101589 PMCID: PMC11327921 DOI: 10.1093/molbev/msae163] [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: 03/27/2024] [Revised: 07/06/2024] [Accepted: 07/31/2024] [Indexed: 08/06/2024] Open
Abstract
The mouse serves as a mammalian model for understanding the nature of variation from new mutations, a question that has both evolutionary and medical significance. Previous studies suggest that the rate of single-nucleotide mutations (SNMs) in mice is ∼50% of that in humans. However, information largely comes from studies involving the C57BL/6 strain, and there is little information from other mouse strains. Here, we study the mutations that accumulated in 59 mouse lines derived from four inbred strains that are commonly used in genetics and clinical research (BALB/cAnNRj, C57BL/6JRj, C3H/HeNRj, and FVB/NRj), maintained for eight to nine generations by brother-sister mating. By analyzing Illumina whole-genome sequencing data, we estimate that the average rate of new SNMs in mice is ∼μ = 6.7 × 10-9. However, there is substantial variation in the spectrum of SNMs among strains, so the burden from new mutations also varies among strains. For example, the FVB strain has a spectrum that is markedly skewed toward C→A transversions and is likely to experience a higher deleterious load than other strains, due to an increased frequency of nonsense mutations in glutamic acid codons. Finally, we observe substantial variation in the rate of new SNMs among DNA sequence contexts, CpG sites, and their adjacent nucleotides playing an important role.
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Affiliation(s)
| | - Jobran Chebib
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Anika Jonas
- Department for Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
| | - Anastasia Vock
- Department for Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
| | - Sven Künzel
- Department for Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
| | - Diethard Tautz
- Department for Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany
| | - Peter D Keightley
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh, EH9 3FL, UK
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11
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Radde N, Mortensen GA, Bhat D, Shah S, Clements JJ, Leonard SP, McGuffie MJ, Mishler DM, Barrick JE. Measuring the burden of hundreds of BioBricks defines an evolutionary limit on constructability in synthetic biology. Nat Commun 2024; 15:6242. [PMID: 39048554 PMCID: PMC11269670 DOI: 10.1038/s41467-024-50639-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 07/18/2024] [Indexed: 07/27/2024] Open
Abstract
Engineered DNA will slow the growth of a host cell if it redirects limiting resources or otherwise interferes with homeostasis. Escape mutants that alleviate this burden can rapidly evolve and take over cell populations, making genetic engineering less reliable and predictable. Synthetic biologists often use genetic parts encoded on plasmids, but their burden is rarely characterized. We measured how 301 BioBrick plasmids affected Escherichia coli growth and found that 59 (19.6%) were burdensome, primarily because they depleted the limited gene expression resources of host cells. Overall, no BioBricks reduced the growth rate of E. coli by >45%, which agreed with a population genetic model that predicts such plasmids should be unclonable. We made this model available online for education ( https://barricklab.org/burden-model ) and added our burden measurements to the iGEM Registry. Our results establish a fundamental limit on what DNA constructs and genetic modifications can be successfully engineered into cells.
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Affiliation(s)
- Noor Radde
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Genevieve A Mortensen
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Diya Bhat
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Shireen Shah
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Joseph J Clements
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Sean P Leonard
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Matthew J McGuffie
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Dennis M Mishler
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
- The Freshman Research Initiative, College of Natural Sciences, The University of Texas at Austin, Austin, TX, USA
| | - Jeffrey E Barrick
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA.
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12
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Sass TH, Lovett ST. The DNA damage response of Escherichia coli, revisited: Differential gene expression after replication inhibition. Proc Natl Acad Sci U S A 2024; 121:e2407832121. [PMID: 38935560 PMCID: PMC11228462 DOI: 10.1073/pnas.2407832121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 05/29/2024] [Indexed: 06/29/2024] Open
Abstract
In 1967, in this journal, Evelyn Witkin proposed the existence of a coordinated DNA damage response in Escherichia coli, which later came to be called the "SOS response." We revisited this response using the replication inhibitor azidothymidine (AZT) and RNA-Seq analysis and identified several features. We confirm the induction of classic Save our ship (SOS) loci and identify several genes, including many of the pyrimidine pathway, that have not been previously demonstrated to be DNA damage-inducible. Despite a strong dependence on LexA, these genes lack LexA boxes and their regulation by LexA is likely to be indirect via unknown factors. We show that the transcription factor "stringent starvation protein" SspA is as important as LexA in the regulation of AZT-induced genes and that the genes activated by SspA change dramatically after AZT exposure. Our experiments identify additional LexA-independent DNA damage inducible genes, including 22 small RNA genes, some of which appear to activated by SspA. Motility and chemotaxis genes are strongly down-regulated by AZT, possibly as a result of one of more of the small RNAs or other transcription factors such as AppY and GadE, whose expression is elevated by AZT. Genes controlling the iron siderophore, enterobactin, and iron homeostasis are also strongly induced, independent of LexA. We confirm that IraD antiadaptor protein is induced independent of LexA and that a second antiadaptor, IraM is likewise strongly AZT-inducible, independent of LexA, suggesting that RpoS stabilization via these antiadaptor proteins is an integral part of replication stress tolerance.
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Affiliation(s)
- Thalia H Sass
- Department of Biology, Brandeis University, Waltham, MA 02454-9110
- Rosenstiel Basic Medical Sciences Research Center MS029, Brandeis University, Waltham, MA 02454-9110
| | - Susan T Lovett
- Department of Biology, Brandeis University, Waltham, MA 02454-9110
- Rosenstiel Basic Medical Sciences Research Center MS029, Brandeis University, Waltham, MA 02454-9110
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13
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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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14
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Nyerges A, Chiappino-Pepe A, Budnik B, Baas-Thomas M, Flynn R, Yan S, Ostrov N, Liu M, Wang M, Zheng Q, Hu F, Chen K, Rudolph A, Chen D, Ahn J, Spencer O, Ayalavarapu V, Tarver A, Harmon-Smith M, Hamilton M, Blaby I, Yoshikuni Y, Hajian B, Jin A, Kintses B, Szamel M, Seregi V, Shen Y, Li Z, Church GM. Synthetic genomes unveil the effects of synonymous recoding. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.16.599206. [PMID: 38915524 PMCID: PMC11195188 DOI: 10.1101/2024.06.16.599206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Engineering the genetic code of an organism provides the basis for (i) making any organism safely resistant to natural viruses and (ii) preventing genetic information flow into and out of genetically modified organisms while (iii) allowing the biosynthesis of genetically encoded unnatural polymers1-4. Achieving these three goals requires the reassignment of multiple of the 64 codons nature uses to encode proteins. However, synonymous codon replacement-recoding-is frequently lethal, and how recoding impacts fitness remains poorly explored. Here, we explore these effects using whole-genome synthesis, multiplexed directed evolution, and genome-transcriptome-translatome-proteome co-profiling on multiple recoded genomes. Using this information, we assemble a synthetic Escherichia coli genome in seven sections using only 57 codons to encode proteins. By discovering the rules responsible for the lethality of synonymous recoding and developing a data-driven multi-omics-based genome construction workflow that troubleshoots synthetic genomes, we overcome the lethal effects of 62,007 synonymous codon swaps and 11,108 additional genomic edits. We show that synonymous recoding induces transcriptional noise including new antisense RNAs, leading to drastic transcriptome and proteome perturbation. As the elimination of select codons from an organism's genetic code results in the widespread appearance of cryptic promoters, we show that synonymous codon choice may naturally evolve to minimize transcriptional noise. Our work provides the first genome-scale description of how synonymous codon changes influence organismal fitness and paves the way for the construction of functional genomes that provide genetic firewalls from natural ecosystems and safely produce biopolymers, drugs, and enzymes with an expanded chemistry.
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Affiliation(s)
- Akos Nyerges
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | | | - Bogdan Budnik
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
| | | | - Regan Flynn
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Shirui Yan
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
- BGI Research, Shenzhen 518083, China
| | - Nili Ostrov
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Min Liu
- GenScript USA Inc., Piscataway, NJ 08854, USA
| | | | | | | | | | - Alexandra Rudolph
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Dawn Chen
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Jenny Ahn
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Owen Spencer
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | | | - Angela Tarver
- DOE Joint Genome Institute (JGI), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Miranda Harmon-Smith
- DOE Joint Genome Institute (JGI), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Matthew Hamilton
- DOE Joint Genome Institute (JGI), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ian Blaby
- DOE Joint Genome Institute (JGI), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yasuo Yoshikuni
- DOE Joint Genome Institute (JGI), Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Behnoush Hajian
- Center for the Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Adeline Jin
- GenScript USA Inc., Piscataway, NJ 08854, USA
| | - Balint Kintses
- Institute of Biochemistry, HUN-REN Biological Research Centre, Szeged, 6726, Hungary
| | - Monika Szamel
- Institute of Biochemistry, HUN-REN Biological Research Centre, Szeged, 6726, Hungary
| | - Viktoria Seregi
- Institute of Biochemistry, HUN-REN Biological Research Centre, Szeged, 6726, Hungary
| | - Yue Shen
- BGI Research, Shenzhen 518083, China
- BGI Research, Changzhou 213299, China
- Guangdong Provincial Key Laboratory of Genome Read and Write, BGI Research, Shenzhen 518083, China
| | - Zilong Li
- GenScript USA Inc., Piscataway, NJ 08854, USA
| | - George M. Church
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
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15
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Hersch SJ, Chandrasekaran S, Lam J, Nafissi N, Slavcev RA. Manufacturing DNA in E. coli yields higher-fidelity DNA than in vitro enzymatic synthesis. Mol Ther Methods Clin Dev 2024; 32:101227. [PMID: 38516691 PMCID: PMC10951457 DOI: 10.1016/j.omtm.2024.101227] [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: 09/18/2023] [Accepted: 02/26/2024] [Indexed: 03/23/2024]
Abstract
Biotechnologies such as gene therapy have brought DNA vectors to the forefront of pharmaceuticals. The quality of starting material plays a pivotal role in determining final product quality. Here, we examined the fidelity of DNA replication using enzymatic methods (in vitro) compared to plasmid DNA produced in vivo in E. coli. Next-generation sequencing approaches rely on in vitro polymerases, which have inherent limitations in sensitivity. To address this challenge, we introduce a novel assay based on loss-of-function (LOF) mutations in the conditionally toxic sacB gene. Our findings show that DNA production in E. coli results in significantly fewer LOF mutations (80- to 3,000-fold less) compared to enzymatic DNA replication methods such as polymerase chain reaction (PCR) and rolling circle amplification (RCA). These results suggest that using DNA produced by PCR or RCA may introduce a substantial number of mutation impurities, potentially affecting the quality and yield of final pharmaceutical products. Our study underscores that DNA synthesized in vitro has a significantly higher mutation rate than DNA produced traditionally in E. coli. Therefore, utilizing in vitro enzymatically produced DNA in biotechnology and biomanufacturing may entail considerable fidelity-related risks, while using DNA starting material derived from E. coli substantially mitigates this risk.
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Affiliation(s)
| | | | - Jamie Lam
- Mediphage Bioceuticals, Inc, Toronto, ON, Canada
| | - Nafiseh Nafissi
- Mediphage Bioceuticals, Inc, Toronto, ON, Canada
- School of Pharmacy, University of Waterloo, Waterloo, ON, Canada
| | - Roderick A. Slavcev
- Mediphage Bioceuticals, Inc, Toronto, ON, Canada
- School of Pharmacy, University of Waterloo, Waterloo, ON, Canada
- Centre for Eye and Vision Research, HKSTP, Ma Liu Shui, Hong Kong
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16
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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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17
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Prax M, McDonald CP, Bekeredjian-Ding I, Cloutier M, Gravemann U, Grothaus A, Krut O, Mpumlwana X, O'Flaherty N, Satake M, Stafford B, Suessner S, Vollmer T, Ramirez-Arcos S. Characterization of transfusion-relevant bacteria reference strains in a lyophilized format. Vox Sang 2024. [PMID: 38754952 DOI: 10.1111/vox.13654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/29/2024] [Accepted: 04/29/2024] [Indexed: 05/18/2024]
Abstract
BACKGROUND AND OBJECTIVES Blood safety measures used by blood establishments to increase blood component safety can be validated using Transfusion-Relevant Bacterial Reference Strains (TRBRS). Ultra-cold storage conditions and manual preparation of the current TRBRS may restrict their practical use. To address this issue, the ISBT Transfusion-Transmitted Infectious Diseases Working Party's Bacterial Subgroup organized an international study to validate TRBRS in a user-friendly, lyophilised format. MATERIALS AND METHODS Two bacterial strains Klebsiella pneumoniae PEI-B-P-08 and Staphylococcus aureus PEI-B-P-63 were manufactured as lyophilised material. The lyophilised bacteria were distributed to 11 different labs worldwide to assess the robustness for enumeration, identification and determination of growth kinetics in platelet concentrates (PCs). RESULTS Production of lyophilised TRBRS had no impact on the growth properties compared with the traditional format. The new format allows a direct low-quantity spiking of approximately 30 bacteria in PCs for transfusion-relevant experiments. In addition, the lyophilised bacteria exhibit long-term stability across a broad temperature range and can even be directly rehydrated in PCs without losing viability. Interlaboratory comparative study demonstrated the robustness of the new format as 100% of spiked PC exhibited growth. CONCLUSION Lyophilised TRBRS provide a user-friendly material for transfusion-related studies. TRBRS in the new format have improved features that may lead to a more frequent use in the quality control of transfusion-related safety measures in the future.
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Affiliation(s)
| | | | | | | | - Ute Gravemann
- German Red Cross Blood Service NSTOB, Springe, Germany
| | | | - Oleg Krut
- Paul-Ehrlich-Institut, Langen, Germany
| | - Xoliswa Mpumlwana
- Constantia Kloof, South African National Blood Service, Johannesburg, South Africa
| | | | | | | | - Susanne Suessner
- Red Cross Transfusion Service of Upper Austria, Austrian Red Cross, Linz, Austria
| | - Tanja Vollmer
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum NRW, Universitätsklinik der Ruhr-Universität Bochum, Bad Oeynhausen, Germany
| | - Sandra Ramirez-Arcos
- Innovation & Portfolio Management, Canadian Blood Services, Ottawa, Ontario, Canada
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
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18
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Wielgoss S, Van Dyken JD, Velicer GJ. Mutation Rate and Effective Population Size of the Model Cooperative Bacterium Myxococcus xanthus. Genome Biol Evol 2024; 16:evae066. [PMID: 38526062 PMCID: PMC11069108 DOI: 10.1093/gbe/evae066] [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: 10/17/2023] [Revised: 03/18/2024] [Accepted: 03/21/2024] [Indexed: 03/26/2024] Open
Abstract
Intrinsic rates of genetic mutation have diverged greatly across taxa and exhibit statistical associations with several other parameters and features. These include effective population size (Ne), genome size, and gametic multicellularity, with the latter being associated with both increased mutation rates and decreased effective population sizes. However, data sufficient to test for possible relationships between microbial multicellularity and mutation rate (µ) are lacking. Here, we report estimates of two key population-genetic parameters, Ne and µ, for Myxococcus xanthus, a bacterial model organism for the study of aggregative multicellular development, predation, and social swarming. To estimate µ, we conducted an ∼400-day mutation accumulation experiment with 46 lineages subjected to regular single colony bottlenecks prior to clonal regrowth. Upon conclusion, we sequenced one clonal-isolate genome per lineage. Given collective evolution for 85,323 generations across all lines, we calculate a per base-pair mutation rate of ∼5.5 × 10-10 per site per generation, one of the highest mutation rates among free-living eubacteria. Given our estimate of µ, we derived Ne at ∼107 from neutral diversity at four-fold degenerate sites across two dozen M. xanthus natural isolates. This estimate is below average for eubacteria and strengthens an already clear negative correlation between µ and Ne in prokaryotes. The higher and lower than average mutation rate and Ne for M. xanthus, respectively, amplify the question of whether any features of its multicellular life cycle-such as group-size reduction during fruiting-body development-or its highly structured spatial distribution have significantly influenced how these parameters have evolved.
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Affiliation(s)
- Sébastien Wielgoss
- Department of Environmental Systems Science, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland
| | - James David Van Dyken
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
- Department of Biology, University of Miami, Coral Gables, FL 33146, USA
| | - Gregory J Velicer
- Department of Environmental Systems Science, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
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19
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Bradley CC, Wang C, Gordon AJE, Wen AX, Luna PN, Cooke MB, Kohrn BF, Kennedy SR, Avadhanula V, Piedra PA, Lichtarge O, Shaw CA, Ronca SE, Herman C. Targeted accurate RNA consensus sequencing (tARC-seq) reveals mechanisms of replication error affecting SARS-CoV-2 divergence. Nat Microbiol 2024; 9:1382-1392. [PMID: 38649410 PMCID: PMC11384275 DOI: 10.1038/s41564-024-01655-4] [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: 12/04/2023] [Accepted: 02/28/2024] [Indexed: 04/25/2024]
Abstract
RNA viruses, like SARS-CoV-2, depend on their RNA-dependent RNA polymerases (RdRp) for replication, which is error prone. Monitoring replication errors is crucial for understanding the virus's evolution. Current methods lack the precision to detect rare de novo RNA mutations, particularly in low-input samples such as those from patients. Here we introduce a targeted accurate RNA consensus sequencing method (tARC-seq) to accurately determine the mutation frequency and types in SARS-CoV-2, both in cell culture and clinical samples. Our findings show an average of 2.68 × 10-5 de novo errors per cycle with a C > T bias that cannot be solely attributed to APOBEC editing. We identified hotspots and cold spots throughout the genome, correlating with high or low GC content, and pinpointed transcription regulatory sites as regions more susceptible to errors. tARC-seq captured template switching events including insertions, deletions and complex mutations. These insights shed light on the genetic diversity generation and evolutionary dynamics of SARS-CoV-2.
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Affiliation(s)
- Catherine C Bradley
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Baylor College of Medicine Medical Scientist Training Program, Houston, TX, USA
- Robert and Janice McNair Foundation/ McNair Medical Institute M.D./Ph.D. Scholars program, Houston, TX, USA
| | - Chen Wang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Alasdair J E Gordon
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Alice X Wen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Baylor College of Medicine Medical Scientist Training Program, Houston, TX, USA
- Robert and Janice McNair Foundation/ McNair Medical Institute M.D./Ph.D. Scholars program, Houston, TX, USA
| | - Pamela N Luna
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Matthew B Cooke
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Brendan F Kohrn
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - Scott R Kennedy
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - Vasanthi Avadhanula
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Pedro A Piedra
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Olivier Lichtarge
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Chad A Shaw
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Shannon E Ronca
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
- Feigin Biosafety Level 3 Facility, Texas Children's Hospital, Houston, TX, USA
- National School of Tropical Medicine, Department of Pediatrics Tropical Medicine, Texas Children's Hospital and Baylor College of Medicine, Houston, TX, USA
| | - Christophe Herman
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA.
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX, USA.
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20
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Jiang W, Lin T, Pan J, Rivera CE, Tincher C, Wang Y, Zhang Y, Gao X, Wang Y, Tsui HCT, Winkler ME, Lynch M, Long H. Spontaneous mutations and mutational responses to penicillin treatment in the bacterial pathogen Streptococcus pneumoniae D39. MARINE LIFE SCIENCE & TECHNOLOGY 2024; 6:198-211. [PMID: 38827133 PMCID: PMC11136922 DOI: 10.1007/s42995-024-00220-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 03/04/2024] [Indexed: 06/04/2024]
Abstract
Bacteria with functional DNA repair systems are expected to have low mutation rates due to strong natural selection for genomic stability. However, our study of the wild-type Streptococcus pneumoniae D39, a pathogen responsible for many common diseases, revealed a high spontaneous mutation rate of 0.02 per genome per cell division in mutation-accumulation (MA) lines. This rate is orders of magnitude higher than that of other non-mutator bacteria and is characterized by a high mutation bias in the A/T direction. The high mutation rate may have resulted from a reduction in the overall efficiency of selection, conferred by the tiny effective population size in nature. In line with this, S. pneumoniae D39 also exhibited the lowest DNA mismatch-repair (MMR) efficiency among bacteria. Treatment with the antibiotic penicillin did not elevate the mutation rate, as penicillin did not induce DNA damage and S. pneumoniae lacks a stress response pathway. Our findings suggested that the MA results are applicable to within-host scenarios and provide insights into pathogen evolution. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-024-00220-6.
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Affiliation(s)
- Wanyue Jiang
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao, 266237 China
| | - Tongtong Lin
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Jiao Pan
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Caitlyn E. Rivera
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | - Clayton Tincher
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | - Yaohai Wang
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Yu Zhang
- School of Mathematics Science, Ocean University of China, Qingdao, 266000 China
| | - Xiang Gao
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, School of Life Science, Shandong University, Qingdao, 266237 China
| | - Yan Wang
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
| | - Ho-Ching T. Tsui
- Department of Biology, Indiana University, Bloomington, IN 47405 USA
| | | | - Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85281 USA
| | - Hongan Long
- Institute of Evolution and Marine Biodiversity, KLMME, Ocean University of China, Qingdao, 266003 China
- Laboratory for Marine Biology and Biotechnology, Laoshan Laboratory, Qingdao, 266237 China
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21
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Atre M, Joshi B, Babu J, Sawant S, Sharma S, Sankar TS. Origin, evolution, and maintenance of gene-strand bias in bacteria. Nucleic Acids Res 2024; 52:3493-3509. [PMID: 38442257 DOI: 10.1093/nar/gkae155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 02/06/2024] [Accepted: 02/19/2024] [Indexed: 03/07/2024] Open
Abstract
Gene-strand bias is a characteristic feature of bacterial genome organization wherein genes are preferentially encoded on the leading strand of replication, promoting co-orientation of replication and transcription. This co-orientation bias has evolved to protect gene essentiality, expression, and genomic stability from the harmful effects of head-on replication-transcription collisions. However, the origin, variation, and maintenance of gene-strand bias remain elusive. Here, we reveal that the frequency of inversions that alter gene orientation exhibits large variation across bacterial populations and negatively correlates with gene-strand bias. The density, distance, and distribution of inverted repeats show a similar negative relationship with gene-strand bias explaining the heterogeneity in inversions. Importantly, these observations are broadly evident across the entire bacterial kingdom uncovering inversions and inverted repeats as primary factors underlying the variation in gene-strand bias and its maintenance. The distinct catalytic subunits of replicative DNA polymerase have co-evolved with gene-strand bias, suggesting a close link between replication and the origin of gene-strand bias. Congruently, inversion frequencies and inverted repeats vary among bacteria with different DNA polymerases. In summary, we propose that the nature of replication determines the fitness cost of replication-transcription collisions, establishing a selection gradient on gene-strand bias by fine-tuning DNA sequence repeats and, thereby, gene inversions.
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Affiliation(s)
- Malhar Atre
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
| | - Bharat Joshi
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
| | - Jebin Babu
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
| | - Shabduli Sawant
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
| | - Shreya Sharma
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
| | - T Sabari Sankar
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala 695551, India
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22
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Behringer MG, Ho WC, Miller SF, Worthan SB, Cen Z, Stikeleather R, Lynch M. Trade-offs, trade-ups, and high mutational parallelism underlie microbial adaptation during extreme cycles of feast and famine. Curr Biol 2024; 34:1403-1413.e5. [PMID: 38460514 PMCID: PMC11066936 DOI: 10.1016/j.cub.2024.02.040] [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: 10/04/2023] [Revised: 12/12/2023] [Accepted: 02/16/2024] [Indexed: 03/11/2024]
Abstract
Microbes are evolutionarily robust organisms capable of rapid adaptation to complex stress, which enables them to colonize harsh environments. In nature, microbes are regularly challenged by starvation, which is a particularly complex stress because resource limitation often co-occurs with changes in pH, osmolarity, and toxin accumulation created by metabolic waste. Often overlooked are the additional complications introduced by eventual resource replenishment, as successful microbes must withstand rapid environmental shifts before swiftly capitalizing on replenished resources to avoid invasion by competing species. To understand how microbes navigate trade-offs between growth and survival, ultimately adapting to thrive in environments with extreme fluctuations, we experimentally evolved 16 Escherichia coli populations for 900 days in repeated feast/famine conditions with cycles of 100-day starvation before resource replenishment. Using longitudinal population-genomic analysis, we found that evolution in response to extreme feast/famine is characterized by narrow adaptive trajectories with high mutational parallelism and notable mutational order. Genetic reconstructions reveal that early mutations result in trade-offs for biofilm and motility but trade-ups for growth and survival, as these mutations conferred positively correlated advantages during both short-term and long-term culture. Our results demonstrate how microbes can navigate the adaptive landscapes of regularly fluctuating conditions and ultimately follow mutational trajectories that confer benefits across diverse environments.
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Affiliation(s)
- Megan G Behringer
- Department of Biological Sciences, Vanderbilt University, 21st Avenue S, Nashville, TN 37232, USA; Department of Pathology Microbiology and Immunology, Vanderbilt University Medical Center, 21st Avenue S, Nashville, TN 37232, USA.
| | - Wei-Chin Ho
- Biodesign Center for Mechanisms of Evolution, Arizona State University, S McAllister Ave., Tempe, AZ 85281, USA; Department of Biology, University of Texas at Tyler, University Blvd., Tyler, TX 75799, USA.
| | - Samuel F Miller
- Biodesign Center for Mechanisms of Evolution, Arizona State University, S McAllister Ave., Tempe, AZ 85281, USA
| | - Sarah B Worthan
- Department of Biological Sciences, Vanderbilt University, 21st Avenue S, Nashville, TN 37232, USA
| | - Zeer Cen
- Department of Biological Sciences, Vanderbilt University, 21st Avenue S, Nashville, TN 37232, USA
| | - Ryan Stikeleather
- Biodesign Center for Mechanisms of Evolution, Arizona State University, S McAllister Ave., Tempe, AZ 85281, USA
| | - Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State University, S McAllister Ave., Tempe, AZ 85281, USA
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23
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Radde N, Mortensen GA, Bhat D, Shah S, Clements JJ, Leonard SP, McGuffie MJ, Mishler DM, Barrick JE. Measuring the burden of hundreds of BioBricks defines an evolutionary limit on constructability in synthetic biology. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.08.588465. [PMID: 38645188 PMCID: PMC11030366 DOI: 10.1101/2024.04.08.588465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Engineered DNA will slow the growth of a host cell if it redirects limiting resources or otherwise interferes with homeostasis. Populations of engineered cells can rapidly become dominated by "escape mutants" that evolve to alleviate this burden by inactivating the intended function. Synthetic biologists working with bacteria rely on genetic parts and devices encoded on plasmids, but the burden of different engineered DNA sequences is rarely characterized. We measured how 301 BioBricks on high-copy plasmids affected the growth rate of Escherichia coli. Of these, 59 (19.6%) negatively impacted growth. The burden imposed by engineered DNA is commonly associated with diverting ribosomes or other gene expression factors away from producing endogenous genes that are essential for cellular replication. In line with this expectation, BioBricks exhibiting burden were more likely to contain highly active constitutive promoters and strong ribosome binding sites. By monitoring how much each BioBrick reduced expression of a chromosomal GFP reporter, we found that the burden of most, but not all, BioBricks could be wholly explained by diversion of gene expression resources. Overall, no BioBricks reduced the growth rate of E. coli by >45%, which agreed with a population genetic model that predicts such plasmids should be "unclonable" because escape mutants will take over during growth of a bacterial colony or small laboratory culture from a transformed cell. We made this model available as an interactive web tool for synthetic biology education and added our burden measurements to the iGEM Registry descriptions of each BioBrick.
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Affiliation(s)
- Noor Radde
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Genevieve A. Mortensen
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Diya Bhat
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Shireen Shah
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Joseph J. Clements
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Sean P. Leonard
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Matthew J. McGuffie
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Dennis M. Mishler
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
- The Freshman Research Initiative, College of Natural Sciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Jeffrey E. Barrick
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX 78712, USA
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24
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Garushyants SK, Sane M, Selifanova MV, Agashe D, Bazykin GA, Gelfand MS. Mutational Signatures in Wild Type Escherichia coli Strains Reveal Predominance of DNA Polymerase Errors. Genome Biol Evol 2024; 16:evae035. [PMID: 38401265 PMCID: PMC10995721 DOI: 10.1093/gbe/evae035] [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: 12/06/2023] [Revised: 02/13/2024] [Accepted: 02/17/2024] [Indexed: 02/26/2024] Open
Abstract
While mutational processes operating in the Escherichia coli genome have been revealed by multiple laboratory experiments, the contribution of these processes to accumulation of bacterial polymorphism and evolution in natural environments is unknown. To address this question, we reconstruct signatures of distinct mutational processes from experimental data on E. coli hypermutators, and ask how these processes contribute to differences between naturally occurring E. coli strains. We show that both mutations accumulated in the course of evolution of wild-type strains in nature and in the lab-grown nonmutator laboratory strains are explained predominantly by the low fidelity of DNA polymerases II and III. By contrast, contributions specific to disruption of DNA repair systems cannot be detected, suggesting that temporary accelerations of mutagenesis associated with such disruptions are unimportant for within-species evolution. These observations demonstrate that accumulation of diversity in bacterial strains in nature is predominantly associated with errors of DNA polymerases.
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Affiliation(s)
- Sofya K Garushyants
- A.A. Kharkevich Institute for Information Transmission Problems, RAS, Moscow, Russia
| | - Mrudula Sane
- National Centre for Biological Sciences, Bengaluru, India
| | - Maria V Selifanova
- Faculty of Bioengineering and Bioinformatics, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Deepa Agashe
- National Centre for Biological Sciences, Bengaluru, India
| | - Georgii A Bazykin
- A.A. Kharkevich Institute for Information Transmission Problems, RAS, Moscow, Russia
| | - Mikhail S Gelfand
- A.A. Kharkevich Institute for Information Transmission Problems, RAS, Moscow, Russia
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology (Skoltech), Moscow, Russia
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25
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Gifford DR, Bhattacharyya A, Geim A, Marshall E, Krašovec R, Knight CG. Environmental and genetic influence on the rate and spectrum of spontaneous mutations in Escherichia coli. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001452. [PMID: 38687010 PMCID: PMC11084559 DOI: 10.1099/mic.0.001452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 03/19/2024] [Indexed: 05/02/2024]
Abstract
Spontaneous mutations are the ultimate source of novel genetic variation on which evolution operates. Although mutation rate is often discussed as a single parameter in evolution, it comprises multiple distinct types of changes at the level of DNA. Moreover, the rates of these distinct changes can be independently influenced by genomic background and environmental conditions. Using fluctuation tests, we characterized the spectrum of spontaneous mutations in Escherichia coli grown in low and high glucose environments. These conditions are known to affect the rate of spontaneous mutation in wild-type MG1655, but not in a ΔluxS deletant strain - a gene with roles in both quorum sensing and the recycling of methylation products used in E. coli's DNA repair process. We find an increase in AT>GC transitions in the low glucose environment, suggesting that processes relating to the production or repair of this mutation could drive the response of overall mutation rate to glucose concentration. Interestingly, this increase in AT>GC transitions is maintained by the glucose non-responsive ΔluxS deletant. Instead, an elevated rate of GC>TA transversions, more common in a high glucose environment, leads to a net non-responsiveness of overall mutation rate for this strain. Our results show how relatively subtle changes, such as the concentration of a carbon substrate or loss of a regulatory gene, can substantially influence the amount and nature of genetic variation available to selection.
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Affiliation(s)
- Danna R. Gifford
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Anish Bhattacharyya
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Alexandra Geim
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
- Pembroke College, University of Cambridge, Cambridge, UK
| | - Eleanor Marshall
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Rok Krašovec
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Christopher G. Knight
- Department of Earth and Environmental Sciences, School of Natural Sciences, Faculty of Science and Engineering, The University of Manchester, Manchester, UK
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26
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Widney KA, Yang DD, Rusch LM, Copley SD. CRISPR-Cas9-assisted genome editing in E. coli elevates the frequency of unintended mutations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.19.584922. [PMID: 38562785 PMCID: PMC10983943 DOI: 10.1101/2024.03.19.584922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Cas-assisted lambda Red recombineering techniques have rapidly become a mainstay of bacterial genome editing. Such techniques have been used to construct both individual mutants and massive libraries to assess the effects of genomic changes. We have found that a commonly used Cas9-assisted editing method results in unintended mutations elsewhere in the genome in 26% of edited clones. The unintended mutations are frequently found over 200 kb from the intended edit site and even over 10 kb from potential off-target sites. We attribute the high frequency of unintended mutations to error-prone polymerases expressed in response to dsDNA breaks introduced at the edit site. Most unintended mutations occur in regulatory or coding regions and thus may have phenotypic effects. Our findings highlight the risks associated with genome editing techniques involving dsDNA breaks in E. coli and likely other bacteria and emphasize the importance of sequencing the genomes of edited cells to ensure the absence of unintended mutations.
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Affiliation(s)
- Karl A. Widney
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, 80309, USA
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, 80309, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, 80205, USA
| | - Dong-Dong Yang
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, 80309, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, 80205, USA
| | - Leo M. Rusch
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, 80309, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, 80205, USA
| | - Shelley D. Copley
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, CO, 80309, USA
- Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, 80205, USA
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27
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Lagerstrom KM, Scales NC, Hadly EA. Impressive pan-genomic diversity of E. coli from a wild animal community near urban development reflects human impacts. iScience 2024; 27:109072. [PMID: 38375235 PMCID: PMC10875580 DOI: 10.1016/j.isci.2024.109072] [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: 08/28/2023] [Revised: 11/22/2023] [Accepted: 01/26/2024] [Indexed: 02/21/2024] Open
Abstract
Human and domesticated animal waste infiltrates global freshwater, terrestrial, and marine environments, widely disseminating fecal microbes, antibiotics, and other chemical pollutants. Emerging evidence suggests that guts of wild animals are being invaded by our microbes, including Escherichia coli, which face anthropogenic selective pressures to gain antimicrobial resistance (AMR) and increase virulence. However, wild animal sources remain starkly under-represented among genomic sequence repositories. We sequenced whole genomes of 145 E. coli isolates from 55 wild and 13 domestic animal fecal samples, averaging 2 (ranging 1-7) isolates per sample, on a preserve imbedded in a human-dominated landscape in California Bay Area, USA, to assess AMR, virulence, and pan-genomic diversity. With single nucleotide polymorphism analyses we predict potential transmission routes. We illustrate the usefulness of E. coli to aid our understanding of and ability to surveil the emergence of zoonotic pathogens created by the mixing of human and wild bacteria in the environment.
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Affiliation(s)
| | - Nicholas C. Scales
- Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, CA, USA
| | - Elizabeth A. Hadly
- Department of Biology, Stanford University, Stanford, CA, USA
- Stanford Woods Institute for the Environment, Stanford University, Stanford, CA, USA
- Center for Innovation in Global Health, Stanford University, Stanford, CA, USA
- Department of Earth Systems Science, Stanford University, Stanford, CA, USA
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28
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Worthan SB, McCarthy RDP, Delaleau M, Stikeleather R, Bratton BP, Boudvillain M, Behringer MG. Evolution of pH-sensitive transcription termination during adaptation to repeated long-term starvation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.01.582989. [PMID: 38464051 PMCID: PMC10925284 DOI: 10.1101/2024.03.01.582989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Fluctuating environments that consist of regular cycles of co-occurring stress are a common challenge faced by cellular populations. For a population to thrive in constantly changing conditions, an ability to coordinate a rapid cellular response is essential. Here, we identify a mutation conferring an arginine-to-histidine (Arg to His) substitution in the transcription terminator Rho. The rho R109H mutation frequently arose in E. coli populations experimentally evolved under repeated long-term starvation conditions, during which feast and famine result in drastic environmental pH fluctuations. Metagenomic sequencing revealed that populations containing the rho mutation also possess putative loss-of-function mutations in ydcI, which encodes a recently characterized transcription factor associated with pH homeostasis. Genetic reconstructions of these mutations show that the rho allele confers a plastic alkaline-induced reduction of Rho function that, when found in tandem with a ΔydcI allele, leads to intracellular alkalinization and genetic assimilation of Rho mutant function. We further identify Arg to His substitutions at analogous sites in rho alleles from species originating from fluctuating alkaline environments. Our results suggest that Arg to His substitutions in global regulators of gene expression can serve to rapidly coordinate complex responses through pH sensing and shed light on how cellular populations across the tree of life use environmental cues to coordinate rapid responses to complex, fluctuating environments.
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Affiliation(s)
- Sarah B Worthan
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN
| | | | - Mildred Delaleau
- Centre de Biophysique Moléculaire, CNRS UPR4301, affiliated with Université d'Orléans, rue Charles Sadron, 45071 Orléans cedex 2, France
| | - Ryan Stikeleather
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ
| | - Benjamin P Bratton
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | - Marc Boudvillain
- Centre de Biophysique Moléculaire, CNRS UPR4301, affiliated with Université d'Orléans, rue Charles Sadron, 45071 Orléans cedex 2, France
| | - Megan G Behringer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN
- Evolutionary Studies Initiative, Vanderbilt University, Nashville, TN
- Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, TN
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ
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29
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Reichert F, Brinkwirth S, Pfennigwerth N, Haller S, Fritsch LS, Eckmanns T, Werner G, Gatermann S, Hans JB. Prolonged carriage of OXA-244-carbapenemase-producing Escherichia coli complicates epidemiological investigations. Int J Med Microbiol 2024; 314:151595. [PMID: 38159514 DOI: 10.1016/j.ijmm.2023.151595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/14/2023] [Accepted: 12/14/2023] [Indexed: 01/03/2024] Open
Abstract
The rapid increase of OXA-244-producing Escherichia coli, predominantly driven by genetically clustered isolates of sequence type (ST)38, has been observed in at least nine European countries, including Germany. However, the reasons for the spread of OXA-244-producing E. coli remain unclear. Here, we aim to evaluate the possibility of prolonged carriage. We identified a total of six different patients with repeated detection of OXA-244-producing E. coli isolates, which were subjected to both short and long-read whole-genome sequencing (WGS). Besides allelic differences using core genome multilocus sequence typing (cgMLST) analyses, we obtained numbers of single-nucleotide polymorphisms (SNPs) to calculate individual base-pair substitution (BPS) rates. To assess possible re-exposure and risk factors for prolonged carriage, case interviews were conducted. The time between detections ranged from eleven months to more than three years. Initial isolates originated in three+ out of six cases from clinical samples, whereas remaining samples were from screening, mostly in the inpatient setting. As expected, cgMLST analyses showed low numbers of allelic differences between isolates of each case ranging from 1 to 4, whereas numbers of SNPs were between 2 and 99 (mean = 36), thus clearly highlighting the discrepancy between these different bacterial typing approaches. For five out of six cases, observed BPS rates suggest that patients can be colonized with OXA-244-producing E. coli, including ST38 cluster isolates, for extensively long times. Thus, we may have previously missed the epidemiological link between cases because exposure to OXA-244-producing E. coli could have occurred in a time frame, which has not been evaluated in previous investigations. Our results may help to guide future epidemiological investigations as well as to support the interpretation of genetic diversity of OXA-244-producing E. coli, particularly among ST38 cluster isolates.
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Affiliation(s)
- Felix Reichert
- Robert Koch Institute, Department of Infectious Disease Epidemiology, Unit 37: Healthcare-Associated Infections, Surveillance of Antibiotic Resistance and Consumption, Berlin, Germany
| | - Simon Brinkwirth
- Robert Koch Institute, Department of Infectious Disease Epidemiology, Unit 37: Healthcare-Associated Infections, Surveillance of Antibiotic Resistance and Consumption, Berlin, Germany; Postgraduate Training for Applied Epidemiology (PAE), Robert Koch-Institute, Berlin, Germany; ECDC Fellowship Programme, Field Epidemiology path (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
| | - Niels Pfennigwerth
- National Reference Centre for multidrug-resistant Gram-negative bacteria, Department of Medical Microbiology, Ruhr-University Bochum, Bochum, Germany
| | - Sebastian Haller
- Robert Koch Institute, Department of Infectious Disease Epidemiology, Unit 37: Healthcare-Associated Infections, Surveillance of Antibiotic Resistance and Consumption, Berlin, Germany
| | - Lena Sophie Fritsch
- National Reference Centre for multidrug-resistant Gram-negative bacteria, Department of Medical Microbiology, Ruhr-University Bochum, Bochum, Germany
| | - Tim Eckmanns
- Robert Koch Institute, Department of Infectious Disease Epidemiology, Unit 37: Healthcare-Associated Infections, Surveillance of Antibiotic Resistance and Consumption, Berlin, Germany
| | - Guido Werner
- Robert Koch Institute, Division of Nosocomial Pathogens and Antibiotic Resistances, Wernigerode Branch, Germany
| | - Sören Gatermann
- National Reference Centre for multidrug-resistant Gram-negative bacteria, Department of Medical Microbiology, Ruhr-University Bochum, Bochum, Germany
| | - Jörg B Hans
- National Reference Centre for multidrug-resistant Gram-negative bacteria, Department of Medical Microbiology, Ruhr-University Bochum, Bochum, Germany.
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30
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Tsukimi T, Obana N, Shigemori S, Arakawa K, Miyauchi E, Yang J, Song I, Ashino Y, Wakayama M, Soga T, Tomita M, Ohno H, Mori H, Fukuda S. Genetic mutation in Escherichia coli genome during adaptation to the murine intestine is optimized for the host diet. mSystems 2024; 9:e0112323. [PMID: 38205998 PMCID: PMC10878103 DOI: 10.1128/msystems.01123-23] [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: 10/23/2023] [Accepted: 11/15/2023] [Indexed: 01/12/2024] Open
Abstract
Mammalian gut microbes colonize the intestinal tract of their host and adapt to establish a microbial ecosystem. The host diet changes the nutrient profile of the intestine and has a high impact on microbiota composition. Genetic mutations in Escherichia coli, a prevalent species in the human gut, allow for adaptation to the mammalian intestine, as reported in previous studies. However, the extent of colonization fitness in the intestine elevated by genetic mutation and the effects of diet change on these mutations in E. coli are still poorly known. Here, we show that notable mutations in sugar metabolism-related genes (gatC, araC, and malI) were detected in the E. coli K-12 genome just 2 weeks after colonization in the germ-free mouse intestine. In addition to elevated fitness by deletion of gatC, as previously reported, deletion of araC and malI also elevated E. coli fitness in the murine intestine in a host diet-dependent manner. In vitro cultures of medium containing nutrients abundant in the intestine (e.g., galactose, N-acetylglucosamine, and asparagine) also showed increased E. coli fitness after deletion of the genes-of-interest associated with their metabolism. Furthermore, the host diet was found to influence the developmental trajectory of gene mutations in E. coli. Taken together, we suggest that genetic mutations in E. coli are selected in response to the intestinal environment, which facilitates efficient utilization of nutrients abundant in the intestine under laboratory conditions. Our study offers some insight into the possible adaptation mechanisms of gut microbes.IMPORTANCEThe gut microbiota is closely associated with human health and is greatly impacted by the host diet. Bacteria such as Escherichia coli live in the gut all throughout the life of a human host and adapt to the intestinal environment. Adaptive mutations in E. coli are reported to enhance fitness in the mammalian intestine, but to what extent is still poorly known. It is also unknown whether the host diet affects what genes are mutated and to what extent fitness is affected. This study suggests that genetic mutations in the E. coli K-12 strain are selected in response to the intestinal environment and facilitate efficient utilization of abundant nutrients in the germ-free mouse intestine. Our study provides a better understanding of these intestinal adaptation mechanisms of gut microbes.
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Affiliation(s)
- Tomoya Tsukimi
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Nozomu Obana
- Transborder Medical Research Center, Institute of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Suguru Shigemori
- Transborder Medical Research Center, Institute of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Kazuharu Arakawa
- 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
| | - Eiji Miyauchi
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
- Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Jiayue Yang
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Isaiah Song
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Yujin Ashino
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
| | - Masataka Wakayama
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
| | - Tomoyoshi Soga
- 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
| | - Masaru Tomita
- 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
| | - Hiroshi Ohno
- RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Hirotada Mori
- Graduate School of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
- Institute of Animal Sciences, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, China
| | - Shinji Fukuda
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Japan
- Transborder Medical Research Center, Institute of Medicine, University of Tsukuba, Tsukuba, Japan
- Gut Environmental Design Group, Kanagawa Institute of Industrial Science and Technology, Kawasaki, Japan
- Laboratory for Regenerative Microbiology, Juntendo University Graduate School of Medicine, Tokyo, Japan
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31
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Höhmann S, Briol TA, Ihle N, Frick O, Schmid A, Bühler B. Glycolate as alternative carbon source for Escherichia coli. J Biotechnol 2024; 381:76-85. [PMID: 38190849 DOI: 10.1016/j.jbiotec.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/20/2023] [Accepted: 01/01/2024] [Indexed: 01/10/2024]
Abstract
The physiology of different Escherichia coli stains was analyzed for growth with glycolate as a potentially promising sustainable sole source of carbon and energy. Different E. coli strains showed large differences regarding lag phases after provision of glycolate. Whereas E. coli W showed fast adaptation, E. coli BW25113, JM101, and BL21 (DE3) needed extensive time for adaption (up to 30 generations) until the attainable µmax was reached, which, at 30 °C, amounted to 0.20-0.25 h-1 for all strains. The overexpression of genes encoding glycolate degradation did neither overcome the need for adaptation of E. coli BL21 (DE3) nor improve growth of E. coli W. Rather, high level expression of proteins involved in uptake and initial degradation steps had an adverse effect on growth. Overall, the results show a promising capacity of E. coli strains for growth on glycolate.
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Affiliation(s)
- Sonja Höhmann
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany; Department of Microbial Biotechnology, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany
| | - Tim Arik Briol
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany; Department of Microbial Biotechnology, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany
| | - Nadine Ihle
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany
| | - Oliver Frick
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany
| | - Andreas Schmid
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany
| | - Bruno Bühler
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany; Department of Microbial Biotechnology, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany.
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32
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Aduru SV, Szenkiel K, Rahman A, Ahmad M, Fabozzi M, Smith RP, Lopatkin AJ. Sub-inhibitory antibiotic treatment selects for enhanced metabolic efficiency. Microbiol Spectr 2024; 12:e0324123. [PMID: 38226801 PMCID: PMC10846238 DOI: 10.1128/spectrum.03241-23] [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: 08/30/2023] [Accepted: 12/05/2023] [Indexed: 01/17/2024] Open
Abstract
Bacterial growth and metabolic rates are often closely related. However, under antibiotic selection, a paradox in this relationship arises: antibiotic efficacy decreases when bacteria are metabolically dormant, yet antibiotics select for resistant cells that grow fastest during treatment. That is, antibiotic selection counterintuitively favors bacteria with fast growth but slow metabolism. Despite this apparent contradiction, antibiotic resistant cells have historically been characterized primarily in the context of growth, whereas the extent of analogous changes in metabolism is comparatively unknown. Here, we observed that previously evolved antibiotic-resistant strains exhibited a unique relationship between growth and metabolism whereby nutrient utilization became more efficient, regardless of the growth rate. To better understand this unexpected phenomenon, we used a simplified model to simulate bacterial populations adapting to sub-inhibitory antibiotic selection through successive bottlenecking events. Simulations predicted that sub-inhibitory bactericidal antibiotic concentrations could select for enhanced metabolic efficiency, defined based on nutrient utilization: drug-adapted cells are able to achieve the same biomass while utilizing less substrate, even in the absence of treatment. Moreover, simulations predicted that restoring metabolic efficiency would re-sensitize resistant bacteria exhibiting metabolic-dependent resistance; we confirmed this result using adaptive laboratory evolutions of Escherichia coli under carbenicillin treatment. Overall, these results indicate that metabolic efficiency is under direct selective pressure during antibiotic treatment and that differences in evolutionary context may determine both the efficacy of different antibiotics and corresponding re-sensitization approaches.IMPORTANCEThe sustained emergence of antibiotic-resistant pathogens combined with the stalled drug discovery pipelines highlights the critical need to better understand the underlying evolution mechanisms of antibiotic resistance. To this end, bacterial growth and metabolic rates are often closely related, and resistant cells have historically been characterized exclusively in the context of growth. However, under antibiotic selection, antibiotics counterintuitively favor cells with fast growth, and slow metabolism. Through an integrated approach of mathematical modeling and experiments, this study thereby addresses the significant knowledge gap of whether antibiotic selection drives changes in metabolism that complement, and/or act independently, of antibiotic resistance phenotypes.
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Affiliation(s)
- Sai Varun Aduru
- Department of Chemical Engineering, University of Rochester, Rochester, New York, USA
| | | | - Anika Rahman
- Department of Biology, Barnard College, New York, New York, USA
| | - Mehrose Ahmad
- Department of Biology, Barnard College, New York, New York, USA
| | - Maya Fabozzi
- Department of Biology, Barnard College, New York, New York, USA
| | - Robert P. Smith
- Cell Therapy Institute, Kiran Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, Florida, USA
| | - Allison J. Lopatkin
- Department of Chemical Engineering, University of Rochester, Rochester, New York, USA
- Department of Biology, Barnard College, New York, New York, USA
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, New York, USA
- Data Science Institute, Columbia University, New York, New York, USA
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
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33
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Sharma A, Timilsina S, Abrahamian P, Minsavage GV, Jones JB, Vallad GE, Goss EM. Bacterial Mutation During Seasonal Epidemics. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2024; 37:93-97. [PMID: 38105425 DOI: 10.1094/mpmi-10-23-0164-sc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Rapidly evolving bacterial pathogens pose a unique challenge for long-term plant disease management. In this study, we investigated the types and rate of mutations in bacterial populations during seasonal disease epidemics. Two phylogenetically distinct strains of the bacterial spot pathogen, Xanthomonas perforans, were marked, released in tomato fields, and recaptured at several time points during the growing season. Genomic variations in recaptured isolates were identified by comparative analysis of their whole-genome sequences. In total, 180 unique variations (116 substitutions, 57 insertions/deletions, and 7 structural variations) were identified from 300 genomes, resulting in the overall host-associated mutation rate of ∼0.3 to 0.9/genome/week. This result serves as a benchmark for bacterial mutation during epidemics in similar pathosystems. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Anuj Sharma
- Department of Plant Pathology, University of Florida, Gainesville, FL, U.S.A
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL, U.S.A
| | - Sujan Timilsina
- Department of Plant Pathology, University of Florida, Gainesville, FL, U.S.A
| | - Peter Abrahamian
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL, U.S.A
| | - Gerald V Minsavage
- Department of Plant Pathology, University of Florida, Gainesville, FL, U.S.A
| | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL, U.S.A
| | - Gary E Vallad
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL, U.S.A
| | - Erica M Goss
- Department of Plant Pathology, University of Florida, Gainesville, FL, U.S.A
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, U.S.A
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34
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Tian R, Rehm FBH, Czernecki D, Gu Y, Zürcher JF, Liu KC, Chin JW. Establishing a synthetic orthogonal replication system enables accelerated evolution in E. coli. Science 2024; 383:421-426. [PMID: 38271510 DOI: 10.1126/science.adk1281] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 11/28/2023] [Indexed: 01/27/2024]
Abstract
The evolution of new function in living organisms is slow and fundamentally limited by their critical mutation rate. Here, we established a stable orthogonal replication system in Escherichia coli. The orthogonal replicon can carry diverse cargos of at least 16.5 kilobases and is not copied by host polymerases but is selectively copied by an orthogonal DNA polymerase (O-DNAP), which does not copy the genome. We designed mutant O-DNAPs that selectively increase the mutation rate of the orthogonal replicon by two to four orders of magnitude. We demonstrate the utility of our system for accelerated continuous evolution by evolving a 150-fold increase in resistance to tigecycline in 12 days. And, starting from a GFP variant, we evolved a 1000-fold increase in cellular fluorescence in 5 days.
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Affiliation(s)
- Rongzhen Tian
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Fabian B H Rehm
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Dariusz Czernecki
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Yangqi Gu
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Jérôme F Zürcher
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Kim C Liu
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Jason W Chin
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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35
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Chen S, Yang Z, Zhong Z, Yu S, Zhou J, Li J, Du G, Zhang G. Ultrahigh-throughput screening-assisted in vivo directed evolution for enzyme engineering. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:9. [PMID: 38254175 PMCID: PMC10804518 DOI: 10.1186/s13068-024-02457-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 01/05/2024] [Indexed: 01/24/2024]
Abstract
BACKGROUND Classical directed evolution is a powerful approach for engineering biomolecules with improved or novel functions. However, it traditionally relies on labour- and time-intensive iterative cycles, due in part to the need for multiple molecular biology steps, including DNA transformation, and limited screening throughput. RESULTS In this study, we present an ultrahigh throughput in vivo continuous directed evolution system with thermosensitive inducible tunability, which is based on error-prone DNA polymerase expression modulated by engineered thermal-responsive repressor cI857, and genomic MutS mutant with temperature-sensitive defect for fixation of mutations in Escherichia coli. We demonstrated the success of the in vivo evolution platform with β-lactamase as a model, with an approximately 600-fold increase in the targeted mutation rate. Furthermore, the platform was combined with ultrahigh-throughput screening methods and employed to evolve α-amylase and the resveratrol biosynthetic pathway. After iterative rounds of enrichment, a mutant with a 48.3% improvement in α-amylase activity was identified via microfluidic droplet screening. In addition, when coupled with an in vivo biosensor in the resveratrol biosynthetic pathway, a variant with 1.7-fold higher resveratrol production was selected by fluorescence-activated cell sorting. CONCLUSIONS In this study, thermal-responsive targeted mutagenesis coupled with ultrahigh-throughput screening was developed for the rapid evolution of enzymes and biosynthetic pathways.
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Affiliation(s)
- Shuaili Chen
- Science Center for Future Foods, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
| | - Zhanhao Yang
- Science Center for Future Foods, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
| | - Ze Zhong
- Science Center for Future Foods, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
| | - Shiqin Yu
- Science Center for Future Foods, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
| | - Jingwen Zhou
- Science Center for Future Foods, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- Engineering Research Center of Ministry of Education On Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
| | - Jianghua Li
- Science Center for Future Foods, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- Engineering Research Center of Ministry of Education On Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China
| | - Guocheng Du
- Science Center for Future Foods, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China.
- Engineering Research Center of Ministry of Education On Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China.
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China.
| | - Guoqiang Zhang
- Science Center for Future Foods, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China.
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China.
- Engineering Research Center of Ministry of Education On Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China.
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, Jiangsu, China.
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36
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Plum-Jensen LE, Schramm A, Marshall IPG. First single-strain enrichments of Electrothrix cable bacteria, description of E. aestuarii sp. nov. and E. rattekaaiensis sp. nov., and proposal of a cable bacteria taxonomy following the rules of the SeqCode. Syst Appl Microbiol 2024; 47:126487. [PMID: 38295603 DOI: 10.1016/j.syapm.2024.126487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 12/23/2023] [Accepted: 01/15/2024] [Indexed: 02/02/2024]
Abstract
Cable bacteria are electrically conductive, filamentous Desulfobulbaceae, which are morphologically, functionally, and phylogenetically distinct from the other members of this family. Cable bacteria have not been obtained in pure culture and were therefore previously described as candidate genera, Candidatus Electrothrix and Ca. Electronema; a representative of the latter is available as single-strain sediment enrichment. Here we present an improved workflow to obtain the first single-strain enrichments of Ca. Electrothrix and report their metagenome-assembled genomes (MAGs) and morphology. Based on these results and on previously published high-quality MAGs and morphological data of cable bacteria from both candidate genera, we propose to adopt the genus names Electrothrix and Electronema following the rules of the Code of Nomenclature of Prokaryotes Described from Sequence Data (SeqCode), with Electrothrix communis RBTS and Electronema aureum GSTS, respectively, as the nomenclatural types of the genera. Furthermore, based on average nucleotide identity (ANI) values < 95 % with any described species, we propose two of our three single-strain enrichment cultures as novel species of the genus Electrothrix, with the names E. aestuarii sp. nov. and E. rattekaaiensis sp. nov., according to the SeqCode.
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Affiliation(s)
- Lea E Plum-Jensen
- Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark.
| | - Andreas Schramm
- Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark.
| | - Ian P G Marshall
- Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark.
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37
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Arbel-Groissman M, Menuhin-Gruman I, Yehezkeli H, Naki D, Bergman S, Udi Y, Tuller T. The Causes for Genomic Instability and How to Try and Reduce Them Through Rational Design of Synthetic DNA. Methods Mol Biol 2024; 2760:371-392. [PMID: 38468099 DOI: 10.1007/978-1-0716-3658-9_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
Genetic engineering has revolutionized our ability to manipulate DNA and engineer organisms for various applications. However, this approach can lead to genomic instability, which can result in unwanted effects such as toxicity, mutagenesis, and reduced productivity. To overcome these challenges, smart design of synthetic DNA has emerged as a promising solution. By taking into consideration the intricate relationships between gene expression and cellular metabolism, researchers can design synthetic constructs that minimize metabolic stress on the host cell, reduce mutagenesis, and increase protein yield. In this chapter, we summarize the main challenges of genomic instability in genetic engineering and address the dangers of unknowingly incorporating genomically unstable sequences in synthetic DNA. We also demonstrate the instability of those sequences by the fact that they are selected against conserved sequences in nature. We highlight the benefits of using ESO, a tool for the rational design of DNA for avoiding genetically unstable sequences, and also summarize the main principles and working parameters of the software that allow maximizing its benefits and impact.
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Affiliation(s)
- Matan Arbel-Groissman
- Shmunis School of Biomedicine and Cancer Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Itamar Menuhin-Gruman
- School of Mathematical Sciences, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Hader Yehezkeli
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Doron Naki
- Shmunis School of Biomedicine and Cancer Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Shaked Bergman
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Yarin Udi
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Tamir Tuller
- Department of Biomedical Engineering, Tel Aviv University, Tel Aviv, Israel.
- The Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel.
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38
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MacGillivray KA, Ng SL, Wiesenfeld S, Guest RL, Jubery T, Silhavy TJ, Ratcliff WC, Hammer BK. Trade-offs constrain adaptive pathways to the type VI secretion system survival. iScience 2023; 26:108332. [PMID: 38025790 PMCID: PMC10679819 DOI: 10.1016/j.isci.2023.108332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 08/25/2023] [Accepted: 10/22/2023] [Indexed: 12/01/2023] Open
Abstract
The Type VI Secretion System (T6SS) is a nano-harpoon used by many bacteria to inject toxins into neighboring cells. While much is understood about mechanisms of T6SS-mediated toxicity, less is known about the ways that competitors can defend themselves against this attack, especially in the absence of their own T6SS. Here we subjected eight replicate populations of Escherichia coli to T6SS attack by Vibrio cholerae. Over ∼500 generations of competition, isolates of the E. coli populations evolved to survive T6SS attack an average of 27-fold better, through two convergently evolved pathways: apaH was mutated in six of the eight replicate populations, while the other two populations each had mutations in both yejM and yjeP. However, the mutations we identified are pleiotropic, reducing cellular growth rates, and increasing susceptibility to antibiotics and elevated pH. These trade-offs help us understand how the T6SS shapes the evolution of bacterial interactions.
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Affiliation(s)
- Kathryn A. MacGillivray
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Siu Lung Ng
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Sophia Wiesenfeld
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Randi L. Guest
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Tahrima Jubery
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Thomas J. Silhavy
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - William C. Ratcliff
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
| | - Brian K. Hammer
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, GA, USA
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39
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Gyorgy A. Competition and evolutionary selection among core regulatory motifs in gene expression control. Nat Commun 2023; 14:8266. [PMID: 38092759 PMCID: PMC10719253 DOI: 10.1038/s41467-023-43327-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 11/07/2023] [Indexed: 12/17/2023] Open
Abstract
Gene products that are beneficial in one environment may become burdensome in another, prompting the emergence of diverse regulatory schemes that carry their own bioenergetic cost. By ensuring that regulators are only expressed when needed, we demonstrate that autoregulation generally offers an advantage in an environment combining mutation and time-varying selection. Whether positive or negative feedback emerges as dominant depends primarily on the demand for the target gene product, typically to ensure that the detrimental impact of inevitable mutations is minimized. While self-repression of the regulator curbs the spread of these loss-of-function mutations, self-activation instead facilitates their propagation. By analyzing the transcription network of multiple model organisms, we reveal that reduced bioenergetic cost may contribute to the preferential selection of autoregulation among transcription factors. Our results not only uncover how seemingly equivalent regulatory motifs have fundamentally different impact on population structure, growth dynamics, and evolutionary outcomes, but they can also be leveraged to promote the design of evolutionarily robust synthetic gene circuits.
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Affiliation(s)
- Andras Gyorgy
- Division of Engineering, New York University Abu Dhabi, Abu Dhabi, UAE.
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40
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Xu X, Chen M, Chen T, Ni X, Fang Z, Fang Y, Zhang L, Zhang X, Huang J. Ultra-high static magnetic field induces a change in the spectrum but not frequency of DNA spontaneous mutations in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2023; 14:1305069. [PMID: 38126008 PMCID: PMC10731980 DOI: 10.3389/fpls.2023.1305069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023]
Abstract
Biological effects of magnetic fields have been extensively studied in plants, microorganisms and animals, and applications of magnetic fields in regulation of plant growth and phytoprotection is a promising field in sustainable agriculture. However, the effect of magnetic fields especially ultra-high static magnetic field (UHSMF) on genomic stability is largely unclear. Here, we investigated the mutagenicity of 24.5, 30.5 and 33.0 T UHSMFs with the gradient of 150, 95 and 0 T/m, respectively, via whole genome sequencing. Our results showed that 1 h exposure of Arabidopsis dried seeds to UHSMFs has no significant effect on the average rate of DNA mutations including single nucleotide variations and InDels (insertions and deletions) in comparison with the control, but 33.0 T and 24.5 T treatments lead to a significant change in the rate of nucleotide transitions and InDels longer than 3 bp, respectively, suggesting that both strength and gradient of UHSMF impact molecular spectrum of DNA mutations. We also found that the decreased transition rate in UHSMF groups is correlated with the upstream flanking sequences of G and C mutation sites. Furthermore, the germination rate of seeds exposed to 24.5 T SMF with -150 T/m gradient showed a significant decrease at 24 hours after sowing. Overall, our data lay a basis for precisely assessing the potential risk of UHSMF on DNA stability, and for elucidating molecular mechanism underlying gradient SMF-regulated biological processes in the future.
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Affiliation(s)
- Xiang Xu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Mengjiao Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Tianli Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Xinda Ni
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Zhicai Fang
- Heye Health Industrial Research Institute of Heye Health Technology Co., Ltd., Huzhou, China
| | - Yanwen Fang
- Heye Health Industrial Research Institute of Heye Health Technology Co., Ltd., Huzhou, China
| | - Lei Zhang
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Xin Zhang
- High Magnetic Field Laboratory, Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Jirong Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
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41
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Papkou A, Garcia-Pastor L, Escudero JA, Wagner A. A rugged yet easily navigable fitness landscape. Science 2023; 382:eadh3860. [PMID: 37995212 DOI: 10.1126/science.adh3860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 09/29/2023] [Indexed: 11/25/2023]
Abstract
Fitness landscape theory predicts that rugged landscapes with multiple peaks impair Darwinian evolution, but experimental evidence is limited. In this study, we used genome editing to map the fitness of >260,000 genotypes of the key metabolic enzyme dihydrofolate reductase in the presence of the antibiotic trimethoprim, which targets this enzyme. The resulting landscape is highly rugged and harbors 514 fitness peaks. However, its highest peaks are accessible to evolving populations via abundant fitness-increasing paths. Different peaks share large basins of attraction that render the outcome of adaptive evolution highly contingent on chance events. Our work shows that ruggedness need not be an obstacle to Darwinian evolution but can reduce its predictability. If true in general, the complexity of optimization problems on realistic landscapes may require reappraisal.
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Affiliation(s)
- Andrei Papkou
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Lucia Garcia-Pastor
- Departamento de Sanidad Animal and VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, Madrid, Spain
| | - José Antonio Escudero
- Departamento de Sanidad Animal and VISAVET Health Surveillance Centre, Universidad Complutense de Madrid, Madrid, Spain
| | - Andreas Wagner
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
- The Santa Fe Institute, Santa Fe, NM, USA
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42
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Mani S, Tlusty T. Gene birth in a model of non-genic adaptation. BMC Biol 2023; 21:257. [PMID: 37957718 PMCID: PMC10644530 DOI: 10.1186/s12915-023-01745-5] [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: 09/18/2022] [Accepted: 10/24/2023] [Indexed: 11/15/2023] Open
Abstract
BACKGROUND Over evolutionary timescales, genomic loci can switch between functional and non-functional states through processes such as pseudogenization and de novo gene birth. Particularly, de novo gene birth is a widespread process, and many examples continue to be discovered across diverse evolutionary lineages. However, the general mechanisms that lead to functionalization are poorly understood, and estimated rates of de novo gene birth remain contentious. Here, we address this problem within a model that takes into account mutations and structural variation, allowing us to estimate the likelihood of emergence of new functions at non-functional loci. RESULTS Assuming biologically reasonable mutation rates and mutational effects, we find that functionalization of non-genic loci requires the realization of strict conditions. This is in line with the observation that most de novo genes are localized to the vicinity of established genes. Our model also provides an explanation for the empirical observation that emerging proto-genes are often lost despite showing signs of adaptation. CONCLUSIONS Our work elucidates the properties of non-genic loci that make them fertile for adaptation, and our results offer mechanistic insights into the process of de novo gene birth.
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Affiliation(s)
- Somya Mani
- Center for Soft and Living Matter, Institute for Basic Science, Ulsan 44919, Republic of Korea.
| | - Tsvi Tlusty
- Center for Soft and Living Matter, Institute for Basic Science, Ulsan 44919, Republic of Korea
- Departments of Physics and Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
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43
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Crockford PW, Bar On YM, Ward LM, Milo R, Halevy I. The geologic history of primary productivity. Curr Biol 2023; 33:4741-4750.e5. [PMID: 37827153 DOI: 10.1016/j.cub.2023.09.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/11/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023]
Abstract
The rate of primary productivity is a keystone variable in driving biogeochemical cycles today and has been throughout Earth's past.1 For example, it plays a critical role in determining nutrient stoichiometry in the oceans,2 the amount of global biomass,3 and the composition of Earth's atmosphere.4 Modern estimates suggest that terrestrial and marine realms contribute near-equal amounts to global gross primary productivity (GPP).5 However, this productivity balance has shifted significantly in both recent times6 and through deep time.7,8 Combining the marine and terrestrial components, modern GPP fixes ≈250 billion tonnes of carbon per year (Gt C year-1).5,9,10,11 A grand challenge in the study of the history of life on Earth has been to constrain the trajectory that connects present-day productivity to the origin of life. Here, we address this gap by piecing together estimates of primary productivity from the origin of life to the present day. We estimate that ∼1011-1012 Gt C has cumulatively been fixed through GPP (≈100 times greater than Earth's entire carbon stock). We further estimate that 1039-1040 cells have occupied the Earth to date, that more autotrophs than heterotrophs have ever existed, and that cyanobacteria likely account for a larger proportion than any other group in terms of the number of cells. We discuss implications for evolutionary trajectories and highlight the early Proterozoic, which encompasses the Great Oxidation Event (GOE), as the time where most uncertainty exists regarding the quantitative census presented here.
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Affiliation(s)
- Peter W Crockford
- Department of Earth Sciences, Carleton University, Ottawa, ON K1S 5B6, Canada; Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel; Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
| | - Yinon M Bar On
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel; Division of Geological Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Luce M Ward
- Department of Geosciences, Smith College, Northampton, MA 01063, USA
| | - Ron Milo
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Itay Halevy
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
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44
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Ruis C, Weimann A, Tonkin-Hill G, Pandurangan AP, Matuszewska M, Murray GGR, Lévesque RC, Blundell TL, Floto RA, Parkhill J. Mutational spectra are associated with bacterial niche. Nat Commun 2023; 14:7091. [PMID: 37925514 PMCID: PMC10625568 DOI: 10.1038/s41467-023-42916-w] [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: 08/03/2023] [Accepted: 10/25/2023] [Indexed: 11/06/2023] Open
Abstract
As observed in cancers, individual mutagens and defects in DNA repair create distinctive mutational signatures that combine to form context-specific spectra within cells. We reasoned that similar processes must occur in bacterial lineages, potentially allowing decomposition analysis to detect both disruption of DNA repair processes and exposure to niche-specific mutagens. Here we reconstruct mutational spectra for 84 clades from 31 diverse bacterial species and find distinct mutational patterns. We extract signatures driven by specific DNA repair defects using hypermutator lineages, and further deconvolute the spectra into multiple signatures operating within different clades. We show that these signatures are explained by both bacterial phylogeny and replication niche. By comparing mutational spectra of clades from different environmental and biological locations, we identify niche-associated mutational signatures, and then employ these signatures to infer the predominant replication niches for several clades where this was previously obscure. Our results show that mutational spectra may be associated with sites of bacterial replication when mutagen exposures differ, and can be used in these cases to infer transmission routes for established and emergent human bacterial pathogens.
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Affiliation(s)
- Christopher Ruis
- Molecular Immunity Unit, University of Cambridge Department of Medicine, MRC-Laboratory of Molecular Biology, Cambridge, UK
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
- Cambridge Centre for AI in Medicine, University of Cambridge, Cambridge, UK
| | - Aaron Weimann
- Molecular Immunity Unit, University of Cambridge Department of Medicine, MRC-Laboratory of Molecular Biology, Cambridge, UK
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
- Cambridge Centre for AI in Medicine, University of Cambridge, Cambridge, UK
| | | | | | - Marta Matuszewska
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Gemma G R Murray
- Parasites and Microbes Programme, Wellcome Sanger Institute; Wellcome Genome Campus, Cambridge, UK
| | - Roger C Lévesque
- Institut de biologie intégrative et des systèmes (IBIS), Université Laval, Québec City, Québec, Canada
| | - Tom L Blundell
- Department of Biochemistry, Sanger Building, University of Cambridge, Cambridge, UK
| | - R Andres Floto
- Molecular Immunity Unit, University of Cambridge Department of Medicine, MRC-Laboratory of Molecular Biology, Cambridge, UK.
- Cambridge Centre for AI in Medicine, University of Cambridge, Cambridge, UK.
- Cambridge Centre for Lung Infection, Papworth Hospital, Cambridge, UK.
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK.
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45
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On YY, Figueroa W, Fan C, Ho PM, Bényei ÉB, Weimann A, Ruis C, Floto AR, Welch M. Impact of transient acquired hypermutability on the inter- and intra-species competitiveness of Pseudomonas aeruginosa. THE ISME JOURNAL 2023; 17:1931-1939. [PMID: 37666975 PMCID: PMC10579334 DOI: 10.1038/s41396-023-01503-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/22/2023] [Accepted: 08/24/2023] [Indexed: 09/06/2023]
Abstract
Once acquired, hypermutation is unrelenting, and in the long-term, leads to impaired fitness due to its cumulative impact on the genome. This raises the question of why hypermutators arise so frequently in microbial ecosystems. In this work, we explore this problem by examining how the transient acquisition of hypermutability affects inter- and intra-species competitiveness, and the response to environmental insults such as antibiotic challenge. We do this by engineering Pseudomonas aeruginosa to allow the expression of an important mismatch repair gene, mutS, to be experimentally controlled over a wide dynamic range. We show that high levels of mutS expression induce genomic stasis (hypomutation), whereas lower levels of induction lead to progressively higher rates of mutation. Whole-genome sequence analyses confirmed that the mutational spectrum of the inducible hypermutator is similar to the distinctive profile associated with mutS mutants obtained from the airways of people with cystic fibrosis (CF). The acquisition of hypermutability conferred a distinct temporal fitness advantage over the wild-type P. aeruginosa progenitor strain, in both the presence and the absence of an antibiotic selection pressure. However, over a similar time-scale, acquisition of hypermutability had little impact on the population dynamics of P. aeruginosa when grown in the presence of a competing species (Staphylococcus aureus). These data indicate that in the short term, acquired hypermutability primarily confers a competitive intra-species fitness advantage.
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Affiliation(s)
- Yue Yuan On
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Wendy Figueroa
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | - Catherine Fan
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
- Currently based at Epoch Biodesign, Oxford, UK
| | - Pok-Man Ho
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK
| | | | - Aaron Weimann
- Heart Lung Research Institute, University of Cambridge, Cambridge, UK
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
- Cambridge Centre for AI in Medicine, University of Cambridge, Cambridge, UK
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Christopher Ruis
- Heart Lung Research Institute, University of Cambridge, Cambridge, UK
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
- Cambridge Centre for AI in Medicine, University of Cambridge, Cambridge, UK
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Andres R Floto
- Heart Lung Research Institute, University of Cambridge, Cambridge, UK
- University of Cambridge Molecular Immunity Unit, MRC Laboratory of Molecular Biology, Cambridge, UK
- Cambridge Centre for AI in Medicine, University of Cambridge, Cambridge, UK
- Cambridge Centre for Lung Infection, Royal Papworth Hospital, Cambridge, UK
- Cambridge University Hospitals Trust, Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - Martin Welch
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK.
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46
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Liu Y, Zhang Y, Kang C, Tian D, Lu H, Xu B, Xia Y, Kashiwagi A, Westermann M, Hoischen C, Xu J, Yomo T. Comparative genomics hints at dispensability of multiple essential genes in two Escherichia coli L-form strains. Biosci Rep 2023; 43:BSR20231227. [PMID: 37819245 PMCID: PMC10600066 DOI: 10.1042/bsr20231227] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/09/2023] [Accepted: 10/11/2023] [Indexed: 10/13/2023] Open
Abstract
Despite the critical role of bacterial cell walls in maintaining cell shapes, certain environmental stressors can induce the transition of many bacterial species into a wall-deficient state called L-form. Long-term induced Escherichia coli L-forms lose their rod shape and usually hold significant mutations that affect cell division and growth. Besides this, the genetic background of L-form bacteria is still poorly understood. In the present study, the genomes of two stable L-form strains of E. coli (NC-7 and LWF+) were sequenced and their gene mutation status was determined and compared with their parental strains. Comparative genomic analysis between two L-forms reveals both unique adaptions and common mutated genes, many of which belong to essential gene categories not involved in cell wall biosynthesis, indicating that L-form genetic adaptation impacts crucial metabolic pathways. Missense variants from L-forms and Lenski's long-term evolution experiment (LTEE) were analyzed in parallel using an optimized DeepSequence pipeline to investigate predicted mutation effects (α) on protein functions. We report that the two L-form strains analyzed display a frequency of 6-10% (0% for LTEE) in mutated essential genes where the missense variants have substantial impact on protein functions (α<0.5). This indicates the emergence of different survival strategies in L-forms through changes in essential genes during adaptions to cell wall deficiency. Collectively, our results shed light on the detailed genetic background of two E. coli L-forms and pave the way for further investigations of the gene functions in L-form bacterial models.
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Affiliation(s)
- Yunfei Liu
- Laboratory of Biology and Information Science, School of Life Sciences, East China Normal University, Shanghai 200062, PR China
| | - Yueyue Zhang
- Laboratory of Biology and Information Science, School of Life Sciences, East China Normal University, Shanghai 200062, PR China
| | - Chen Kang
- School of Software Engineering, East China Normal University, Shanghai 200062, PR China
| | - Di Tian
- Laboratory of Biology and Information Science, School of Life Sciences, East China Normal University, Shanghai 200062, PR China
| | - Hui Lu
- Laboratory of Biology and Information Science, School of Life Sciences, East China Normal University, Shanghai 200062, PR China
| | - Boying Xu
- Laboratory of Biology and Information Science, School of Life Sciences, East China Normal University, Shanghai 200062, PR China
- Tongji University Cancer Center, Shanghai Tenth People’s Hospital, School of Medicine, Tongji University, Shanghai 200072, China
| | - Yang Xia
- Laboratory of Biology and Information Science, School of Life Sciences, East China Normal University, Shanghai 200062, PR China
| | - Akiko Kashiwagi
- Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki 036-8561, Japan
| | - Martin Westermann
- Center for Electron Microscopy, Medical Faculty, Friedrich–Schiller–University Jena, Ziegelmühlenweg 1, D-07743 Jena, Germany
| | - Christian Hoischen
- CF Imaging, Leibniz Institute On Aging, Fritz–Lipmann–Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Jian Xu
- Laboratory of Biology and Information Science, School of Life Sciences, East China Normal University, Shanghai 200062, PR China
| | - Tetsuya Yomo
- Laboratory of Biology and Information Science, School of Life Sciences, East China Normal University, Shanghai 200062, PR China
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47
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Stone CJ, Boyer GF, Behringer MG. Differential adenine methylation analysis reveals increased variability in 6mA in the absence of methyl-directed mismatch repair. mBio 2023; 14:e0128923. [PMID: 37796009 PMCID: PMC10653831 DOI: 10.1128/mbio.01289-23] [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: 05/30/2023] [Accepted: 08/22/2023] [Indexed: 10/06/2023] Open
Abstract
IMPORTANCE Methylation greatly influences the bacterial genome by guiding DNA repair and regulating pathogenic and stress-response phenotypes. But, the rate of epigenetic changes and their consequences on molecular phenotypes are underexplored. Through a detailed characterization of genome-wide adenine methylation in a commonly used laboratory strain of Escherichia coli, we reveal that mismatch repair deficient populations experience an increase in epimutations resulting in a genome-wide reduction of 6mA methylation in a manner consistent with genetic drift. Our findings highlight how methylation patterns evolve and the constraints on epigenetic evolution due to post-replicative DNA repair, contributing to a deeper understanding of bacterial genome evolution and how epimutations may introduce semi-permanent variation that can influence adaptation.
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Affiliation(s)
- Carl J. Stone
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Gwyneth F. Boyer
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, Arizona, USA
| | - Megan G. Behringer
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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48
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Deng MZ, Liu Q, Cui SJ, Fu H, Gan M, Xu YY, Cai X, Sha W, Zhao GP, Fortune SM, Lyu LD. Mycobacterial DnaQ is an Alternative Proofreader Ensuring DNA Replication Fidelity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.24.563508. [PMID: 37961690 PMCID: PMC10634781 DOI: 10.1101/2023.10.24.563508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Remove of mis-incorporated nucleotides ensures replicative fidelity. Although the ε-exonuclease DnaQ is a well-established proofreader in the model organism Escherichia coli, proofreading in mycobacteria relies on the polymerase and histidinol phosphatase (PHP) domain of replicative polymerase despite the presence of an alternative DnaQ homolog. Here, we show that depletion of DnaQ in Mycolicibacterium smegmatis results in increased mutation rate, leading to AT-biased mutagenesis and elevated insertions/deletions in homopolymer tract. We demonstrated that mycobacterial DnaQ binds to the b-clamp and functions synergistically with the PHP domain to correct replication errors. Further, we found that the mycobacterial DnaQ sustains replicative fidelity upon chromosome topological stress. Intriguingly, we showed that a naturally evolved DnaQ variant prevalent in clinical Mycobacterium tuberculosis isolates enables hypermutability and is associated with extensive drug resistance. These results collectively establish that the alternative DnaQ functions in proofreading, and thus reveal that mycobacteria deploy two proofreaders to maintain replicative fidelity.
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Affiliation(s)
- Ming-Zhi Deng
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health (MOE/NHC), School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R.China
- These authors contributed equally
| | - Qingyun Liu
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA 02115
- These authors contributed equally
| | - Shu-Jun Cui
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health (MOE/NHC), School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R.China
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai, 200433, P.R.China
| | - Han Fu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health (MOE/NHC), School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R.China
- CAS Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai 200032, P.R.China
- University of Chinese Academy of Sciences, Beijing 100049, P.R.China
| | - Mingyu Gan
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, 201102, P.R.China
| | - Yuan-Yuan Xu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health (MOE/NHC), School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R.China
| | - Xia Cai
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health (MOE/NHC), School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R.China
| | - Wei Sha
- Shanghai Clinical Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Shanghai 200433, P.R.China
| | - Guo-Ping Zhao
- Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai, 200433, P.R.China
- CAS Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai 200032, P.R.China
- University of Chinese Academy of Sciences, Beijing 100049, P.R.China
| | - Sarah M. Fortune
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA 02115
| | - Liang-Dong Lyu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education/Ministry of Health (MOE/NHC), School of Basic Medical Sciences, Fudan University, Shanghai 200032, P.R.China
- Shanghai Clinical Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital, Shanghai 200433, P.R.China
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49
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Tuffaha MZ, Varakunan S, Castellano D, Gutenkunst RN, Wahl LM. Shifts in Mutation Bias Promote Mutators by Altering the Distribution of Fitness Effects. Am Nat 2023; 202:503-518. [PMID: 37792927 DOI: 10.1086/726010] [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] [Indexed: 10/06/2023]
Abstract
AbstractRecent experimental evidence demonstrates that shifts in mutational biases-for example, increases in transversion frequency-can change the distribution of fitness effects of mutations (DFE). In particular, reducing or reversing a prevailing bias can increase the probability that a de novo mutation is beneficial. It has also been shown that mutator bacteria are more likely to emerge if the beneficial mutations they generate have a larger effect size than observed in the wild type. Here, we connect these two results, demonstrating that mutator strains that reduce or reverse a prevailing bias have a positively shifted DFE, which in turn can dramatically increase their emergence probability. Since changes in mutation rate and bias are often coupled through the gain and loss of DNA repair enzymes, our results predict that the invasion of mutator strains will be facilitated by shifts in mutation bias that offer improved access to previously undersampled beneficial mutations.
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50
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Abstract
AbstractEvolutionary biologists have thought about the role of genetic variation during adaptation for a very long time-before we understood the organization of the genetic code, the provenance of genetic variation, and how such variation influenced the phenotypes on which natural selection acts. Half a century after the discovery of the structure of DNA and the unraveling of the genetic code, we have a rich understanding of these problems and the means to both delve deeper and widen our perspective across organisms and natural populations. The 2022 Vice Presidential Symposium of the American Society of Naturalists highlighted examples of recent insights into the role of genetic variation in adaptive processes, which are compiled in this special section. The work was conducted in different parts of the world, included theoretical and empirical studies with diverse organisms, and addressed distinct aspects of how genetic variation influences adaptation. In our introductory article to the special section, we discuss some important recent insights about the generation and maintenance of genetic variation, its impacts on phenotype and fitness, its fate in natural populations, and its role in driving adaptation. By placing the special section articles in the broader context of recent developments, we hope that this overview will also serve as a useful introduction to the field.
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