1
|
Chai R, Guo J, Geng Y, Huang S, Wang H, Yao X, Li T, Qiu L. The Influence of Homologous Arm Length on Homologous Recombination Gene Editing Efficiency Mediated by SSB/CRISPR-Cas9 in Escherichia coli. Microorganisms 2024; 12:1102. [PMID: 38930484 PMCID: PMC11205466 DOI: 10.3390/microorganisms12061102] [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: 05/19/2024] [Revised: 05/28/2024] [Accepted: 05/28/2024] [Indexed: 06/28/2024] Open
Abstract
The precise editing of genes mediated by CRISPR-Cas9 necessitates the application of donor DNA with appropriate lengths of homologous arms and fragment sizes. Our previous development, SSB/CRISPR-Cas9, has demonstrated high efficiency in homologous recombination and non-homologous end joining gene editing within bacteria. In this study, we optimized the lengths and sizes of homologous arms of the donor DNA within this system. Two sets of donor DNA constructs were generated: one set comprised donors with only 10-100 bp homologous arms, while the other set included donors with homologous arms ranging from 10-100 bp, between which was a tetracycline resistance expression cassette (1439 bp). These donor constructs were transformed into Escherichia coli MG1655 cells alongside pCas-SSB/pTargetF-lacZ. Notably, when the homologous arms ranged from 10 to 70 bp, the transformation efficiency of non-selectable donors was significantly higher than that of selectable donors. However, within the range of 10-100 bp homologous arm lengths, the homologous recombination rate of selectable donors was significantly higher than that of non-selectable donors, with the gap narrowing as the homologous arm length increased. For selectable donor DNA with homologous arm lengths of 10-60 bp, the homologous recombination rate increased linearly, reaching a plateau when the homologous arm length was between 60-100 bp. Conversely, for non-selectable donor DNA, the homologous recombination rate increased linearly with homologous arm lengths of 10-90 bp, plateauing at 90-100 bp. Editing two loci simultaneously with 100 bp homologous arms, whether selectable or non-selectable, showed no difference in transformation or homologous recombination rates. Editing three loci simultaneously with 100 bp non-selectable homologous arms resulted in a 45% homologous recombination rate. These results suggest that efficient homologous recombination gene editing mediated by SSB/CRISPR-Cas9 can be achieved using donor DNA with 90-100 bp non-selectable homologous arms or 60-100 bp selectable homologous arms.
Collapse
Affiliation(s)
- Ran Chai
- School of Environmental Engineering, Yellow River Conservancy Technical Institute, Henan Engineering Technology Research Center of Green Coating Materials, Kaifeng 475004, China; (R.C.)
- College of Life Sciences, Henan Agricultural University, Key Laboratory of Enzyme Engineering of Agricultural Microbiology, Ministry of Agriculture and Rural Affairs, Zhengzhou 450046, China
| | - Jiaxiang Guo
- School of Environmental Engineering, Yellow River Conservancy Technical Institute, Henan Engineering Technology Research Center of Green Coating Materials, Kaifeng 475004, China; (R.C.)
| | - Yue Geng
- School of Environmental Engineering, Yellow River Conservancy Technical Institute, Henan Engineering Technology Research Center of Green Coating Materials, Kaifeng 475004, China; (R.C.)
| | - Shuai Huang
- School of Environmental Engineering, Yellow River Conservancy Technical Institute, Henan Engineering Technology Research Center of Green Coating Materials, Kaifeng 475004, China; (R.C.)
| | - Haifeng Wang
- School of Environmental Engineering, Yellow River Conservancy Technical Institute, Henan Engineering Technology Research Center of Green Coating Materials, Kaifeng 475004, China; (R.C.)
| | - Xinding Yao
- School of Environmental Engineering, Yellow River Conservancy Technical Institute, Henan Engineering Technology Research Center of Green Coating Materials, Kaifeng 475004, China; (R.C.)
| | - Tao Li
- College of Applied Engineering, Henan University of Science and Technology, Sanmenxia 472000, China
| | - Liyou Qiu
- College of Life Sciences, Henan Agricultural University, Key Laboratory of Enzyme Engineering of Agricultural Microbiology, Ministry of Agriculture and Rural Affairs, Zhengzhou 450046, China
| |
Collapse
|
2
|
Chen W, Ji Q. CRISPR/Cas9-based Genome Editing of Pseudomonas aeruginosa. Methods Mol Biol 2024; 2721:3-12. [PMID: 37819511 DOI: 10.1007/978-1-0716-3473-8_1] [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: 10/13/2023]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 system has been developed as a robust genome engineering tool in a variety of organisms attributed to its high efficiency and versatility. In this chapter, we described the detailed procedures of CRISPR-Cas9-based genetic manipulation in Pseudomonas aeruginosa, including precise gene deletion and insertion via Cas9-mediated DNA double-strand break and homologous recombination repair. In addition, we provided a detailed protocol for cytidine base editor, a highly efficient gene inactivation and point mutation tool in Pseudomonas aeruginosa.
Collapse
Affiliation(s)
- Weizhong Chen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Quanjiang Ji
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, China.
| |
Collapse
|
3
|
Enright AL, Banta AB, Ward RD, Rivera Vazquez J, Felczak MM, Wolfe MB, TerAvest MA, Amador-Noguez D, Peters JM. The genetics of aerotolerant growth in an alphaproteobacterium with a naturally reduced genome. mBio 2023; 14:e0148723. [PMID: 37905909 PMCID: PMC10746277 DOI: 10.1128/mbio.01487-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/25/2023] [Indexed: 11/02/2023] Open
Abstract
Reduced genome bacteria are genetically simplified systems that facilitate biological study and industrial use. The free-living alphaproteobacterium Zymomonas mobilis has a naturally reduced genome containing fewer than 2,000 protein-coding genes. Despite its small genome, Z. mobilis thrives in diverse conditions including the presence or absence of atmospheric oxygen. However, insufficient characterization of essential and conditionally essential genes has limited broader adoption of Z. mobilis as a model alphaproteobacterium. Here, we use genome-scale CRISPRi-seq (clustered regularly interspaced short palindromic repeats interference sequencing) to systematically identify and characterize Z. mobilis genes that are conditionally essential for aerotolerant or anaerobic growth or are generally essential across both conditions. Comparative genomics revealed that the essentiality of most "generally essential" genes was shared between Z. mobilis and other Alphaproteobacteria, validating Z. mobilis as a reduced genome model. Among conditionally essential genes, we found that the DNA repair gene, recJ, was critical only for aerobic growth but reduced the mutation rate under both conditions. Further, we show that genes encoding the F1FO ATP synthase and Rhodobacter nitrogen fixation (Rnf) respiratory complex are required for the anaerobic growth of Z. mobilis. Combining CRISPRi partial knockdowns with metabolomics and membrane potential measurements, we determined that the ATP synthase generates membrane potential that is consumed by Rnf to power downstream processes. Rnf knockdown strains accumulated isoprenoid biosynthesis intermediates, suggesting a key role for Rnf in powering essential biosynthetic reactions. Our work establishes Z. mobilis as a streamlined model for alphaproteobacterial genetics, has broad implications in bacterial energy coupling, and informs Z. mobilis genome manipulation for optimized production of valuable isoprenoid-based bioproducts. IMPORTANCE The inherent complexity of biological systems is a major barrier to our understanding of cellular physiology. Bacteria with markedly fewer genes than their close relatives, or reduced genome bacteria, are promising biological models with less complexity. Reduced genome bacteria can also have superior properties for industrial use, provided the reduction does not overly restrict strain robustness. Naturally reduced genome bacteria, such as the alphaproteobacterium Zymomonas mobilis, have fewer genes but remain environmentally robust. In this study, we show that Z. mobilis is a simplified genetic model for Alphaproteobacteria, a class with important impacts on the environment, human health, and industry. We also identify genes that are only required in the absence of atmospheric oxygen, uncovering players that maintain and utilize the cellular energy state. Our findings have broad implications for the genetics of Alphaproteobacteria and industrial use of Z. mobilis to create biofuels and bioproducts.
Collapse
Affiliation(s)
- Amy L. Enright
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Amy B. Banta
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Ryan D. Ward
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Julio Rivera Vazquez
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Magdalena M. Felczak
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Michael B. Wolfe
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Michaela A. TerAvest
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Daniel Amador-Noguez
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Jason M. Peters
- DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, Wisconsin, USA
| |
Collapse
|
4
|
Han Y, Li W, Filko A, Li J, Zhang F. Genome-wide promoter responses to CRISPR perturbations of regulators reveal regulatory networks in Escherichia coli. Nat Commun 2023; 14:5757. [PMID: 37717013 PMCID: PMC10505187 DOI: 10.1038/s41467-023-41572-4] [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: 12/07/2022] [Accepted: 09/08/2023] [Indexed: 09/18/2023] Open
Abstract
Elucidating genome-scale regulatory networks requires a comprehensive collection of gene expression profiles, yet measuring gene expression responses for every transcription factor (TF)-gene pair in living prokaryotic cells remains challenging. Here, we develop pooled promoter responses to TF perturbation sequencing (PPTP-seq) via CRISPR interference to address this challenge. Using PPTP-seq, we systematically measure the activity of 1372 Escherichia coli promoters under single knockdown of 183 TF genes, illustrating more than 200,000 possible TF-gene responses in one experiment. We perform PPTP-seq for E. coli growing in three different media. The PPTP-seq data reveal robust steady-state promoter activities under most single TF knockdown conditions. PPTP-seq also enables identifications of, to the best of our knowledge, previously unknown TF autoregulatory responses and complex transcriptional control on one-carbon metabolism. We further find context-dependent promoter regulation by multiple TFs whose relative binding strengths determined promoter activities. Additionally, PPTP-seq reveals different promoter responses in different growth media, suggesting condition-specific gene regulation. Overall, PPTP-seq provides a powerful method to examine genome-wide transcriptional regulatory networks and can be potentially expanded to reveal gene expression responses to other genetic elements.
Collapse
Affiliation(s)
- Yichao Han
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missouri, USA
| | - Wanji Li
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missouri, USA
| | - Alden Filko
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missouri, USA
| | - Jingyao Li
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missouri, USA
| | - Fuzhong Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, Missouri, USA.
- Division of Biological and Biomedical Sciences, Washington University in St. Louis, Saint Louis, Missouri, USA.
- Institute of Materials Science and Engineering, Washington University in St. Louis, Saint Louis, Missouri, USA.
| |
Collapse
|
5
|
Ham DT, Browne TS, Banglorewala PN, Wilson TL, Michael RK, Gloor GB, Edgell DR. A generalizable Cas9/sgRNA prediction model using machine transfer learning with small high-quality datasets. Nat Commun 2023; 14:5514. [PMID: 37679324 PMCID: PMC10485023 DOI: 10.1038/s41467-023-41143-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 08/24/2023] [Indexed: 09/09/2023] Open
Abstract
The CRISPR/Cas9 nuclease from Streptococcus pyogenes (SpCas9) can be used with single guide RNAs (sgRNAs) as a sequence-specific antimicrobial agent and as a genome-engineering tool. However, current bacterial sgRNA activity models struggle with accurate predictions and do not generalize well, possibly because the underlying datasets used to train the models do not accurately measure SpCas9/sgRNA activity and cannot distinguish on-target cleavage from toxicity. Here, we solve this problem by using a two-plasmid positive selection system to generate high-quality data that more accurately reports on SpCas9/sgRNA cleavage and that separates activity from toxicity. We develop a machine learning architecture (crisprHAL) that can be trained on existing datasets, that shows marked improvements in sgRNA activity prediction accuracy when transfer learning is used with small amounts of high-quality data, and that can generalize predictions to different bacteria. The crisprHAL model recapitulates known SpCas9/sgRNA-target DNA interactions and provides a pathway to a generalizable sgRNA bacterial activity prediction tool that will enable accurate antimicrobial and genome engineering applications.
Collapse
Affiliation(s)
- Dalton T Ham
- Department of Biochemistry, Schulich School of Medicine and Dentistry, London, ON, N6A5C1, Canada
| | - Tyler S Browne
- Department of Biochemistry, Schulich School of Medicine and Dentistry, London, ON, N6A5C1, Canada
| | - Pooja N Banglorewala
- Department of Biochemistry, Schulich School of Medicine and Dentistry, London, ON, N6A5C1, Canada
| | | | | | - Gregory B Gloor
- Department of Biochemistry, Schulich School of Medicine and Dentistry, London, ON, N6A5C1, Canada.
| | - David R Edgell
- Department of Biochemistry, Schulich School of Medicine and Dentistry, London, ON, N6A5C1, Canada.
| |
Collapse
|
6
|
Bailey TS, Hittmeyer P, Zhang Y, Kubiak AM. Streamlined assembly of cloning and genome editing vectors for genus Clostridium. iScience 2023; 26:107484. [PMID: 37599836 PMCID: PMC10432817 DOI: 10.1016/j.isci.2023.107484] [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: 12/06/2022] [Revised: 03/27/2023] [Accepted: 07/24/2023] [Indexed: 08/22/2023] Open
Abstract
Reported herein is a new set of vectors designed to streamline molecular cloning and genome editing by exploiting modern cloning methods. The new vectors build on the existing pMTL8000 vectors that have been a staple of Clostridium research for more than a decade. The introduction of two pairs of type IIS restriction sites flanking an insulated multiple cloning site in both a cloning vector and a CRISPR-Cas9 gene editing vector enables plasmid construction in a "one-pot" reaction, avoiding the more laborious steps of conventional cloning. A synthetic lacZα expression cassette introduced between the cloning sites enables visual detection of background colonies. In addition, distinct selection markers on each vector permit selection of the desired clones according to antibiotic resistance. An example of strain development using the new vectors is demonstrated.
Collapse
Affiliation(s)
- Tom S. Bailey
- GROW - School for Oncology and Reproduction, Faculty of Health and Medical Life Sciences, Maastricht University, Maastricht, Limburg, the Netherlands
| | - Philip Hittmeyer
- GROW - School for Oncology and Reproduction, Faculty of Health and Medical Life Sciences, Maastricht University, Maastricht, Limburg, the Netherlands
| | - Yanchao Zhang
- GROW - School for Oncology and Reproduction, Faculty of Health and Medical Life Sciences, Maastricht University, Maastricht, Limburg, the Netherlands
| | | |
Collapse
|
7
|
Sufyan M, Daraz U, Hyder S, Zulfiqar U, Iqbal R, Eldin SM, Rafiq F, Mahmood N, Shahzad K, Uzair M, Fiaz S, Ali I. An overview of genome engineering in plants, including its scope, technologies, progress and grand challenges. Funct Integr Genomics 2023; 23:119. [PMID: 37022538 DOI: 10.1007/s10142-023-01036-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 04/07/2023]
Abstract
Genome editing is a useful, adaptable, and favored technique for both functional genomics and crop enhancement. Over the years, rapidly evolving genome editing technologies, including clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas), transcription activator-like effector nucleases (TALENs), and zinc finger nucleases (ZFNs), have shown broad application prospects in gene function research and improvement of critical agronomic traits in many crops. These technologies have also opened up opportunities for plant breeding. These techniques provide excellent chances for the quick modification of crops and the advancement of plant science in the future. The current review describes various genome editing techniques and how they function, particularly CRISPR/Cas9 systems, which can contribute significantly to the most accurate characterization of genomic rearrangement and plant gene functions as well as the enhancement of critical traits in field crops. To accelerate the use of gene-editing technologies for crop enhancement, the speed editing strategy of gene-family members was designed. As it permits genome editing in numerous biological systems, the CRISPR technology provides a valuable edge in this regard that particularly captures the attention of scientists.
Collapse
Affiliation(s)
- Muhammad Sufyan
- College of Biological Sciences, China Agricultural University, Beijing, 100083, China
| | - Umar Daraz
- State Key Laboratory of Grassland Agro-Ecosystems, Center for Grassland Microbiome, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Sajjad Hyder
- Department of Botant, Government College Women University, Sialkot, Pakistan
| | - Usman Zulfiqar
- Department of Agronomy, Faculty of Agriculture and Environment, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan
| | - Rashid Iqbal
- Department of Agronomy, Faculty of Agriculture and Environment, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan.
| | - Sayed M Eldin
- Center of Research, Faculty of Engineering, Future University in Egypt, New Cairo, 11835, Egypt
| | - Farzana Rafiq
- School of Environmental Sciences and Engineering, NCEPU, Beijing, China
| | - Naveed Mahmood
- College of Biological Sciences, China Agricultural University, Beijing, 100083, China
| | - Khurram Shahzad
- Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing, China
| | - Muhammad Uzair
- National Institute for Genomics and Advanced Biotechnology, Park Road, Islamabad, Pakistan
| | - Sajid Fiaz
- Department of Plant Breeding and Genetics, The University of Haripur, Haripur, 22620, Pakistan
| | - Iftikhar Ali
- Center for Plant Sciences and Biodiversity, University of Swat, Charbagh, 19120, Pakistan.
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, 10032, USA.
| |
Collapse
|
8
|
Dallo T, Krishnakumar R, Kolker SD, Ruffing AM. High-Density Guide RNA Tiling and Machine Learning for Designing CRISPR Interference in Synechococcus sp. PCC 7002. ACS Synth Biol 2023; 12:1175-1186. [PMID: 36893454 DOI: 10.1021/acssynbio.2c00653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
While CRISPRi was previously established in Synechococcus sp. PCC 7002 (hereafter 7002), the design principles for guide RNA (gRNA) effectiveness remain largely unknown. Here, 76 strains of 7002 were constructed with gRNAs targeting three reporter systems to evaluate features that impact gRNA efficiency. Correlation analysis of the data revealed that important features of gRNA design include the position relative to the start codon, GC content, protospacer adjacent motif (PAM) site, minimum free energy, and targeted DNA strand. Unexpectedly, some gRNAs targeting upstream of the promoter region showed small but significant increases in reporter expression, and gRNAs targeting the terminator region showed greater repression than gRNAs targeting the 3' end of the coding sequence. Machine learning algorithms enabled prediction of gRNA effectiveness, with Random Forest having the best performance across all training sets. This study demonstrates that high-density gRNA data and machine learning can improve gRNA design for tuning gene expression in 7002.
Collapse
Affiliation(s)
- Tessa Dallo
- Molecular and Microbiology, Sandia National Laboratories, P.O. Box 5800, MS 1413, Albuquerque, New Mexico 87185, United States
| | - Raga Krishnakumar
- Systems Biology, Sandia National Laboratories, P.O. Box 969, MS 9292, Livermore, California 94551, United States
| | - Stephanie D Kolker
- Molecular and Microbiology, Sandia National Laboratories, P.O. Box 5800, MS 1413, Albuquerque, New Mexico 87185, United States
| | - Anne M Ruffing
- Molecular and Microbiology, Sandia National Laboratories, P.O. Box 5800, MS 1413, Albuquerque, New Mexico 87185, United States
| |
Collapse
|
9
|
Gervais NC, La Bella AA, Wensing LF, Sharma J, Acquaviva V, Best M, Cadena López RO, Fogal M, Uthayakumar D, Chavez A, Santiago-Tirado F, Flores-Mireles AL, Shapiro RS. Development and applications of a CRISPR activation system for facile genetic overexpression in Candida albicans. G3 (BETHESDA, MD.) 2023; 13:jkac301. [PMID: 36450451 PMCID: PMC9911074 DOI: 10.1093/g3journal/jkac301] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/02/2021] [Accepted: 11/04/2022] [Indexed: 12/02/2022]
Abstract
For the fungal pathogen Candida albicans, genetic overexpression readily occurs via a diversity of genomic alterations, such as aneuploidy and gain-of-function mutations, with important consequences for host adaptation, virulence, and evolution of antifungal drug resistance. Given the important role of overexpression on C. albicans biology, it is critical to develop and harness tools that enable the analysis of genes expressed at high levels in the fungal cell. Here, we describe the development, optimization, and application of a novel, single-plasmid-based CRISPR activation (CRISPRa) platform for targeted genetic overexpression in C. albicans, which employs a guide RNA to target an activator complex to the promoter region of a gene of interest, thus driving transcriptional expression of that gene. Using this system, we demonstrate the ability of CRISPRa to drive high levels of gene expression in C. albicans, and we assess optimal guide RNA targeting for robust and constitutive overexpression. We further demonstrate the specificity of the system via RNA sequencing. We highlight the application of CRISPR activation to overexpress genes involved in pathogenesis and drug susceptibility, and contribute toward the identification of novel phenotypes. Consequently, this tool will facilitate a broad range of applications for the study of C. albicans genetic overexpression.
Collapse
Affiliation(s)
- Nicholas C Gervais
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1H 5N4, Canada
| | - Alyssa A La Bella
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Lauren F Wensing
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1H 5N4, Canada
| | - Jehoshua Sharma
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1H 5N4, Canada
| | - Victoria Acquaviva
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1H 5N4, Canada
| | - Madison Best
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1H 5N4, Canada
| | | | - Meea Fogal
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1H 5N4, Canada
| | - Deeva Uthayakumar
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1H 5N4, Canada
- Present address: Department of Immunology, University of Toronto, Toronto, ON, Canada
| | - Alejandro Chavez
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | | | - Ana L Flores-Mireles
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Rebecca S Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1H 5N4, Canada
| |
Collapse
|
10
|
Song Y, He S, Jopkiewicz A, Setroikromo R, van Merkerk R, Quax WJ. Development and application of CRISPR-based genetic tools in Bacillus species and Bacillus phages. J Appl Microbiol 2022; 133:2280-2298. [PMID: 35797344 PMCID: PMC9796756 DOI: 10.1111/jam.15704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/02/2022] [Accepted: 07/06/2022] [Indexed: 01/07/2023]
Abstract
Recently, the clustered regularly interspaced short palindromic repeats (CRISPR) system has been developed into a precise and efficient genome editing tool. Since its discovery as an adaptive immune system in prokaryotes, it has been applied in many different research fields including biotechnology and medical sciences. The high demand for rapid, highly efficient and versatile genetic tools to thrive in bacteria-based cell factories accelerates this process. This review mainly focuses on significant advancements of the CRISPR system in Bacillus subtilis, including the achievements in gene editing, and on problems still remaining. Next, we comprehensively summarize this genetic tool's up-to-date development and utilization in other Bacillus species, including B. licheniformis, B. methanolicus, B. anthracis, B. cereus, B. smithii and B. thuringiensis. Furthermore, we describe the current application of CRISPR tools in phages to increase Bacillus hosts' resistance to virulent phages and phage genetic modification. Finally, we suggest potential strategies to further improve this advanced technique and provide insights into future directions of CRISPR technologies for rendering Bacillus species cell factories more effective and more powerful.
Collapse
Affiliation(s)
- Yafeng Song
- Department of Chemical and Pharmaceutical BiologyGroningen Research Institute of Pharmacy, University of GroningenGroningenThe Netherlands,Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern ChinaInstitute of Microbiology, Guangdong Acadamy of SciencesGuangzhouChina
| | - Siqi He
- Department of Chemical and Pharmaceutical BiologyGroningen Research Institute of Pharmacy, University of GroningenGroningenThe Netherlands
| | - Anita Jopkiewicz
- Department of Chemical and Pharmaceutical BiologyGroningen Research Institute of Pharmacy, University of GroningenGroningenThe Netherlands
| | - Rita Setroikromo
- Department of Chemical and Pharmaceutical BiologyGroningen Research Institute of Pharmacy, University of GroningenGroningenThe Netherlands
| | - Ronald van Merkerk
- Department of Chemical and Pharmaceutical BiologyGroningen Research Institute of Pharmacy, University of GroningenGroningenThe Netherlands
| | - Wim J. Quax
- Department of Chemical and Pharmaceutical BiologyGroningen Research Institute of Pharmacy, University of GroningenGroningenThe Netherlands
| |
Collapse
|
11
|
Khurana A, Sayed N, Singh V, Khurana I, Allawadhi P, Rawat PS, Navik U, Pasumarthi SK, Bharani KK, Weiskirchen R. A comprehensive overview of CRISPR/Cas 9 technology and application thereof in drug discovery. J Cell Biochem 2022; 123:1674-1698. [PMID: 36128934 DOI: 10.1002/jcb.30329] [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: 04/24/2022] [Revised: 08/13/2022] [Accepted: 09/01/2022] [Indexed: 11/07/2022]
Abstract
Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-Cas technology possesses revolutionary potential to positively affect various domains of drug discovery. It has initiated a rise in the area of genetic engineering and its advantages range from classical science to translational medicine. These genome editing systems have given a new dimension to our capabilities to alter, detect and annotate specified gene sequences. Moreover, the ease, robustness and adaptability of the CRISPR/Cas9 technology have led to its extensive utilization in research areas in such a short period of time. The applications include the development of model cell lines, understanding disease mechanisms, discovering disease targets, developing transgenic animals and plants, and transcriptional modulation. Further, the technology is rapidly growing; hence, an overlook of progressive success is crucial. This review presents the current status of the CRISPR-Cas technology in a tailor-made format from its discovery to several advancements for drug discovery alongwith future trends associated with possibilities and hurdles including ethical concerns.
Collapse
Affiliation(s)
- Amit Khurana
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH Aachen University Hospital, Aachen, Germany
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Science (CVSc), PVNRTVU, Hyderabad, Telangana, India
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Science (CVSc), PVNRTVU, Mamnoor, Warangal, Telangana, India
| | - Nilofer Sayed
- Department of Pharmacy, Pravara Rural Education Society's (P.R.E.S.'s) College of Pharmacy, Shreemati Nathibai Damodar Thackersey (SNDT) Women's University, Nashik, Maharashtra, India
| | - Vishakha Singh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
| | - Isha Khurana
- Department of Pharmaceutical Chemistry, University Institute of Pharmaceutical Sciences (UIPS), Panjab University, Chandigarh, India
| | - Prince Allawadhi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
| | - Pushkar Singh Rawat
- Department of Pharmacology, Central University of Punjab, Ghudda, Bathinda, Punjab, India
| | - Umashanker Navik
- Department of Pharmacology, Central University of Punjab, Ghudda, Bathinda, Punjab, India
| | | | - Kala Kumar Bharani
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary Science (CVSc), PVNRTVU, Mamnoor, Warangal, Telangana, India
| | - Ralf Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH Aachen University Hospital, Aachen, Germany
| |
Collapse
|
12
|
A New Class of Cell Wall-Recycling l,d-Carboxypeptidase Determines β-Lactam Susceptibility and Morphogenesis in Acinetobacter baumannii. mBio 2021; 12:e0278621. [PMID: 34872350 PMCID: PMC8649774 DOI: 10.1128/mbio.02786-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The hospital-acquired pathogen Acinetobacter baumannii possesses a complex cell envelope that is key to its multidrug resistance and virulence. The bacterium, however, lacks many canonical enzymes that build the envelope in model organisms. Instead, A. baumannii contains a number of poorly annotated proteins that may allow alternative mechanisms of envelope biogenesis. We demonstrated previously that one of these unusual proteins, ElsL, is required for maintaining a characteristic short rod shape and for withstanding antibiotics that attack the septal cell wall. Curiously, ElsL is composed of a leaderless YkuD-family domain usually found in secreted, cell wall-modifying l,d-transpeptidases (LDTs). Here, we show that, rather than being an LDT, ElsL is actually a new class of cytoplasmic l,d-carboxypeptidase (LDC) that provides a critical step in cell wall recycling previously thought to be missing from A. baumannii. Absence of ElsL impairs cell wall integrity, morphology, and intrinsic resistance due to buildup of murein tetrapeptide precursors, toxicity of which is bypassed by preventing muropeptide recycling. Multiple pathways in the cell become sites of vulnerability when ElsL is inactivated, including l,d-cross-link formation, cell division, and outer membrane lipid homoeostasis, reflecting its pleiotropic influence on envelope physiology. We thus reveal a novel class of cell wall-recycling LDC critical to growth and homeostasis of A. baumannii and likely many other bacteria.
Collapse
|
13
|
Yamada S, Suzuki Y, Kouzuma A, Watanabe K. Development of a CRISPR interference system for selective gene knockdown in Acidithiobacillus ferrooxidans. J Biosci Bioeng 2021; 133:105-109. [PMID: 34865958 DOI: 10.1016/j.jbiosc.2021.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/18/2021] [Accepted: 10/29/2021] [Indexed: 11/26/2022]
Abstract
Acidithiobacillus ferrooxidans is an iron-oxidizing chemolithotroph used for bioleaching of precious metals and is also regarded as a potential host for bioelectrochemical production of value-added chemicals. Despite its industrial utility, however, it is difficult to genetically engineer A. ferrooxidans due to low transformation and recombination efficiencies. Here, we developed a clustered regularly interspaced short palindromic repeats interference (CRISPRi) system that can selectively repress the expression of a target gene in A. ferrooxidans. The mutated gene encoding a nuclease-deactivated Cas9 protein was cloned into the broad-host-range plasmid pBBR1-MCS2, and the applicability of the CRISPRi system was examined using the nitrogenase nifH gene as a knockdown target. Introduction of the CRISPRi plasmid into A. ferrooxidans resulted in decreased nifH transcription and retarded cell growth in the absence of nitrogen sources, demonstrating that the CRISPRi system altered the phenotype of this bacterium via selective gene knockdown. We suggest that the CRISPRi system developed in this study provides an efficient technique for constructing A. ferrooxidans knockdown mutants that are useful for the genetic dissection of this bacterium.
Collapse
Affiliation(s)
- Shohei Yamada
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Yusuke Suzuki
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| | - Atsushi Kouzuma
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
| | - Kazuya Watanabe
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan
| |
Collapse
|
14
|
Silvis MR, Rajendram M, Shi H, Osadnik H, Gray AN, Cesar S, Peters JM, Hearne CC, Kumar P, Todor H, Huang KC, Gross CA. Morphological and Transcriptional Responses to CRISPRi Knockdown of Essential Genes in Escherichia coli. mBio 2021; 12:e0256121. [PMID: 34634934 PMCID: PMC8510551 DOI: 10.1128/mbio.02561-21] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 09/09/2021] [Indexed: 01/03/2023] Open
Abstract
CRISPR interference (CRISPRi) has facilitated the study of essential genes in diverse organisms using both high-throughput and targeted approaches. Despite the promise of this technique, no comprehensive arrayed CRISPRi library targeting essential genes exists for the model bacterium Escherichia coli, or for any Gram-negative species. Here, we built and characterized such a library. Each of the ∼500 strains in our E. coli library contains an inducible, chromosomally integrated single guide RNA (sgRNA) targeting an essential (or selected nonessential) gene and can be mated with a pseudo-Hfr donor strain carrying a dcas9 cassette to create a CRISPRi knockdown strain. Using this system, we built an arrayed library of CRISPRi strains and performed population and single-cell growth and morphology measurements as well as targeted follow-up experiments. These studies found that inhibiting translation causes an extended lag phase, identified new modulators of cell morphology, and revealed that the morphogene mreB is subject to transcriptional feedback regulation, which is critical for the maintenance of morphology. Our findings highlight canonical and noncanonical roles for essential genes in numerous aspects of cellular homeostasis. IMPORTANCE Essential genes make up only ∼5 to 10% of the genetic complement in most organisms but occupy much of their protein synthesis and account for almost all antibiotic targets. Despite the importance of essential genes, their intractability has, until recently, hampered efforts to study them. CRISPRi has facilitated the study of essential genes by allowing inducible and titratable depletion. However, all large-scale CRISPRi studies in Gram-negative bacteria thus far have used plasmids to express CRISPRi components and have been constructed in pools, limiting their utility for targeted assays and complicating the determination of antibiotic effects. Here, we use a modular method to construct an arrayed library of chromosomally integrated CRISPRi strains targeting the essential genes of the model bacterium Escherichia coli. This library enables targeted studies of essential gene depletions and high-throughput determination of antibiotic targets and facilitates studies targeting the outer membrane, an essential component that serves as the major barrier to antibiotics.
Collapse
Affiliation(s)
- Melanie R. Silvis
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Manohary Rajendram
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Handuo Shi
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Hendrik Osadnik
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Andrew N. Gray
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Spencer Cesar
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Jason M. Peters
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Cameron C. Hearne
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Parth Kumar
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Horia Todor
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
| | - Carol A. Gross
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| |
Collapse
|
15
|
Abstract
CRISPR interference is an increasingly popular method for perturbing gene expression. Guided by single-guide RNAs (sgRNAs), nuclease-deficient Cas9 proteins bind to specific DNA sequences and hinder transcription. Specificity is achieved through complementarity of the sgRNAs to the DNA. Changing complementarity by introducing single-nucleotide mismatches can be exploited to tune knockdown. Here, we present a computational pipeline to identify sgRNAs targeting specific genes in a bacterial genome, filter them, and titrate their activity by introducing mismatches. For complete details on the use and execution of this protocol, please refer to Hawkins et al. (2020).
Collapse
Affiliation(s)
- Jordi van Gestel
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - John S. Hawkins
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Horia Todor
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Carol A. Gross
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94158, USA
- California Institute of Quantitative Biology, University of California, San Francisco, San Francisco 94158, CA, USA
| |
Collapse
|
16
|
Nguyen KT, Sugie J, Khanna K, Egan ME, Birkholz EA, Lee J, Beierschmitt C, Villa E, Pogliano J. Selective transport of fluorescent proteins into the phage nucleus. PLoS One 2021; 16:e0251429. [PMID: 34111132 PMCID: PMC8191949 DOI: 10.1371/journal.pone.0251429] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 04/26/2021] [Indexed: 11/18/2022] Open
Abstract
Upon infection of Pseudomonas cells, jumbo phages 201Φ2-1, ΦPA3, and ΦKZ assemble a phage nucleus. Viral DNA is enclosed within the phage-encoded proteinaceous shell along with proteins associated with DNA replication, recombination and transcription. Ribosomes and proteins involved in metabolic processes are excluded from the nucleus. RNA synthesis occurs inside the phage nucleus and messenger RNA is presumably transported into the cytoplasm to be translated. Newly synthesized proteins either remain in the cytoplasm or specifically translocate into the nucleus. The molecular mechanisms governing selective protein sorting and nuclear import in these phage infection systems are currently unclear. To gain insight into this process, we studied the localization of five reporter fluorescent proteins (GFP+, sfGFP, GFPmut1, mCherry, CFP). During infection with ΦPA3 or 201Φ2-1, all five fluorescent proteins were excluded from the nucleus as expected; however, we have discovered an anomaly with the ΦKZ nuclear transport system. The fluorescent protein GFPmut1, expressed by itself, was transported into the ΦKZ phage nucleus. We identified the amino acid residues on the surface of GFPmut1 required for nuclear targeting. Fusing GFPmut1 to any protein, including proteins that normally reside in the cytoplasm, resulted in transport of the fusion into the nucleus. Although the mechanism of transport is still unknown, we demonstrate that GFPmut1 is a useful tool that can be used for fluorescent labelling and targeting of proteins into the ΦKZ phage nucleus.
Collapse
Affiliation(s)
- Katrina T Nguyen
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Joseph Sugie
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Kanika Khanna
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - MacKennon E Egan
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Erica A Birkholz
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Jina Lee
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Christopher Beierschmitt
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Elizabeth Villa
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Joe Pogliano
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| |
Collapse
|
17
|
Essential gene analysis in Acinetobacter baumannii by high-density transposon mutagenesis and CRISPR interference. J Bacteriol 2021; 203:e0056520. [PMID: 33782056 DOI: 10.1128/jb.00565-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Acinetobacter baumannii is a poorly understood bacterium capable of life-threatening infections in hospitals. Few antibiotics remain effective against this highly resistant pathogen. Developing rationally-designed antimicrobials that can target A. baumannii requires improved knowledge of the proteins that carry out essential processes allowing growth of the organism. Unfortunately, studying essential genes has been challenging using traditional techniques, which usually require time-consuming recombination-based genetic manipulations. Here, we performed saturating mutagenesis with dual transposon systems to identify essential genes in A. baumannii and we developed a CRISPR-interference (CRISPRi) system for facile analysis of these genes. We show that the CRISPRi system enables efficient transcriptional silencing in A. baumannii Using these tools, we confirmed the essentiality of the novel cell division protein AdvA and discovered a previously uncharacterized AraC-family transcription factor (ACX60_RS03245) that is necessary for growth. In addition, we show that capsule biosynthesis is a conditionally essential process, with mutations in late-acting steps causing toxicity in strain ATCC 17978 that can be bypassed by blocking early-acting steps or activating the BfmRS stress response. These results open new avenues for analysis of essential pathways in A. baumannii ImportanceNew approaches are urgently needed to control A. baumannii, one of the most drug resistant pathogens known. To facilitate the development of novel targets that allow inhibition of the pathogen, we performed a large-scale identification of genes whose products the bacterium needs for growth. We also developed a CRISPR-based gene knockdown tool that operates efficiently in A. baumannii, allowing rapid analysis of these essential genes. We used these methods to define multiple processes vital to the bacterium, including a previously uncharacterized gene-regulatory factor and export of a protective polymeric capsule. These tools will enhance our ability to investigate processes critical for the essential biology of this challenging hospital-acquired pathogen.
Collapse
|
18
|
Dailey KM, Allgood JE, Johnson PR, Ostlie MA, Schaner KC, Brooks BD, Brooks AE. The next frontier of oncotherapy: accomplishing clinical translation of oncolytic bacteria through genetic engineering. Future Microbiol 2021; 16:341-368. [PMID: 33754804 DOI: 10.2217/fmb-2020-0245] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The development of a 'smart' drug capable of distinguishing tumor from host cells has been sought for centuries, but the microenvironment of solid tumors continues to confound therapeutics. Solid tumors present several challenges for current oncotherapeutics, including aberrant vascularization, hypoxia, necrosis, abnormally high pH and local immune suppression. While traditional chemotherapeutics are limited by such an environment, oncolytic microbes are drawn to it - having an innate ability to selectively infect, colonize and eradicate solid tumors. Development of an oncolytic species would represent a shift in the cancer therapeutic paradigm, with ramifications reaching from the medical into the socio-economic. Modern genetic engineering techniques could be implemented to customize 'Frankenstein' bacteria with advantageous characteristics from several species.
Collapse
Affiliation(s)
- Kaitlin M Dailey
- Cellular & Molecular Biology Program, North Dakota State University, Fargo, ND 58103, USA.,Pharmaceutical Sciences Department, North Dakota State University, Fargo, ND 58103, USA
| | - JuliAnne E Allgood
- Department of Neuroscience, University of Wyoming, Laramie, WY 82071, USA
| | - Paige R Johnson
- Pharmaceutical Sciences Department, North Dakota State University, Fargo, ND 58103, USA
| | - Mackenzie A Ostlie
- Pharmaceutical Sciences Department, North Dakota State University, Fargo, ND 58103, USA
| | - Kambri C Schaner
- Pharmaceutical Sciences Department, North Dakota State University, Fargo, ND 58103, USA
| | | | - Amanda E Brooks
- Cellular & Molecular Biology Program, North Dakota State University, Fargo, ND 58103, USA.,Pharmaceutical Sciences Department, North Dakota State University, Fargo, ND 58103, USA.,Office of Research & Scholarly Activity. Rocky Vista University, Ivins, UT 84738, USA
| |
Collapse
|
19
|
Todor H, Silvis MR, Osadnik H, Gross CA. Bacterial CRISPR screens for gene function. Curr Opin Microbiol 2020; 59:102-109. [PMID: 33285498 DOI: 10.1016/j.mib.2020.11.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/03/2020] [Accepted: 11/04/2020] [Indexed: 12/16/2022]
Abstract
In this review we describe the application of CRISPR tools for functional genomics screens in bacteria, with a focus on the use of interference (CRISPRi) approaches. We review recent developments in CRISPRi titration, which has enabled essential gene functional screens, and genome-scale pooled CRISPRi screens. We summarize progress toward enabling CRISPRi screens in non-model and pathogenic bacteria, including the development of new dCas9 variants. Taking into account the current state of the field, we provide a forward-looking analysis of CRISPRi strategies for determining gene function in bacteria.
Collapse
Affiliation(s)
- Horia Todor
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Melanie R Silvis
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hendrik Osadnik
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Carol A Gross
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94158, USA; California Institute of Quantitative Biology, University of California, San Francisco, San Francisco 94158 CA, USA.
| |
Collapse
|
20
|
Abdullah, Jiang Z, Hong X, Zhang S, Yao R, Xiao Y. CRISPR base editing and prime editing: DSB and template-free editing systems for bacteria and plants. Synth Syst Biotechnol 2020; 5:277-292. [PMID: 32954022 PMCID: PMC7481536 DOI: 10.1016/j.synbio.2020.08.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/14/2020] [Accepted: 08/25/2020] [Indexed: 12/20/2022] Open
Abstract
CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated) has been extensively exploited as a genetic tool for genome editing. The RNA guided Cas nucleases generate DNA double-strand break (DSB), triggering cellular repair systems mainly Non-homologous end-joining (NHEJ, imprecise repair) or Homology-directed repair (HDR, precise repair). However, DSB typically leads to unexpected DNA changes and lethality in some organisms. The establishment of bacteria and plants into major bio-production platforms require efficient and precise editing tools. Hence, in this review, we focus on the non-DSB and template-free genome editing, i.e., base editing (BE) and prime editing (PE) in bacteria and plants. We first highlight the development of base and prime editors and summarize their studies in bacteria and plants. We then discuss current and future applications of BE/PE in synthetic biology, crop improvement, evolutionary engineering, and metabolic engineering. Lastly, we critically consider the challenges and prospects of BE/PE in PAM specificity, editing efficiency, off-targeting, sequence specification, and editing window.
Collapse
Affiliation(s)
- Abdullah
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhengzheng Jiang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Xulin Hong
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Shun Zhang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ruilian Yao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yi Xiao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
- Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China
| |
Collapse
|
21
|
Caenepeel C, Sadat Seyed Tabib N, Vieira-Silva S, Vermeire S. Review article: how the intestinal microbiota may reflect disease activity and influence therapeutic outcome in inflammatory bowel disease. Aliment Pharmacol Ther 2020; 52:1453-1468. [PMID: 32969507 DOI: 10.1111/apt.16096] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/08/2020] [Accepted: 09/03/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Intestinal bacteria produce metabolites and by-products necessary for homeostasis. Imbalance in this equilibrium is linked to multiple pathologies including inflammatory bowel disease (IBD). The role of the gut microbiota in determining treatment response is becoming apparent, and may act as biomarker for efficacy. AIM To describe knowledge about the intestinal microbiota on disease severity and treatment outcomes in IBD METHODS: Descriptive review using PubMed to identify literature on the intestinal microbiota in IBD RESULTS: Severe IBD has a less diverse microbiota with fewer commensal microbiota communities and more opportunistic pathogenic bacteria originating from the oral cavity or respiratory tract. IBD treatments can alter gut microbiota composition, but in vitro/in vivo studies are needed to prove causation. A diversification of the microbiota is observed during remission. Patients with a more diverse baseline microbiome and higher microbial diversity show better response to anti-tumour necrosis factor-α, vedolizumab and ustekinumab therapy. Higher abundance of short chain fatty acid-producing bacteria, fewer mucus-colonising bacteria and lower abundance of pro-inflammatory bacteria have also been associated with a favourable outcome. Predictive models, based on a combination of microbiota, clinical data and serological markers, have good accuracy for treatment outcome and disease severity. CONCLUSION The intestinal microbiota in IBD carries a set of promising biomarkers of disease activity and prediction of therapeutic outcome. Current insights may also help in designing microbiota modulation strategies to improve outcomes in IBD.
Collapse
Affiliation(s)
| | | | - Sara Vieira-Silva
- Department of Microbiology and Immunology, Laboratory of Molecular Bacteriology, Rega Institute for Medical Research, VIB, KU Leuven, Leuven, Belgium
| | - Séverine Vermeire
- Department of Chronic Diseases & Metabolism, Translational Research Center for Gastrointestinal Disorders, KU Leuven, Leuven, Belgium.,Department of Gastroenterology and Hepatology, University Hospitals Leuven, Leuven, Belgium
| |
Collapse
|
22
|
Kerry RG, Das G, Golla U, Del Pilar Rodriguez-Torres M, Shin H, Patra JK. Engineered probiotic and prebiotic nutraceutical supplementations in combating non-communicable disorders: A review. Curr Pharm Biotechnol 2020; 23:72-97. [PMID: 33050862 DOI: 10.2174/1389201021666201013153142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/15/2020] [Accepted: 09/18/2020] [Indexed: 11/22/2022]
Abstract
Nutritional supplementations are a form of nutrition sources that may help in improving health complexities throughout the life span of a person. Under the umbrella of food supplementations, nutraceuticals are products extracted from edible sources that provide medical benefits along with primary nutritional value, these can be considered as functional foods. These nutraceutical supplementations are also evidenced in altering the commensal gut microbiota and help to prevent or fight against chronic non-communicable degenerative diseases in adults including neurological disorders (Autism Spectrum Disorder [ASD], Parkinson's disease [PD] and Multiple sclerosis [MS]) and metabolic disorder (Type-II Diabetes, Obesity and non-alcoholic fatty liver disease). Even the complexities of preterm babies like extra-uterine growth restriction, necrotizing enterocolitis, infant eczema and allergy (during pregnancy) and bronchopulmonary dysplasia, etc. could also be lessened up by providing proper nutrition. Molecular perceptive of inflammatory and apoptotic modulators regulating the pathogenesis of these health risks, their control and management by probiotics and prebiotics could further emphasize the scientific overview of their utility. The pivotal role of nutraceutical supplementations in regulating or modulating molecular pathways coupled with the above mentioned non-communicable diseases are briefly described. Lastly, an overall introduction to the sophisticated genome-editing techniques and advanced delivery systems in therapeutic activities applicable under these health risks are also emphasized in this paper.
Collapse
Affiliation(s)
| | - Gitishree Das
- Research Institute of Biotechnology & Medical Converged Science, Dongguk University-Seoul, Goyangsi 10326. Korea
| | - Upendarrao Golla
- Division of Hematology and Oncology, Penn State College of Medicine, Hershey, PA 17033. United States
| | - Maria Del Pilar Rodriguez-Torres
- Laboratorio de Ondas de Choque (LOCH), Centro de Física Aplicada y Tecnología Avanzada (CFATA), Universidad Nacional Autónoma de México, Campus UNAM Juriquilla Boulevard Juriquilla no. 3001, Santiago de Querétaro, Qro., C.P. 76230. Mexico
| | - HanSeung Shin
- Department of Food Science and Biotechnology, Dongguk University-Seoul, Goyangsi 10326. Korea
| | - Jayanta Kumar Patra
- Research Institute of Biotechnology & Medical Converged Science, Dongguk University-Seoul, Goyangsi 10326. Korea
| |
Collapse
|
23
|
Song CW, Rathnasingh C, Park JM, Kwon M, Song H. CRISPR-Cas9 mediated engineering of Bacillus licheniformis for industrial production of (2R,3S)-butanediol. Biotechnol Prog 2020; 37:e3072. [PMID: 32964665 DOI: 10.1002/btpr.3072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/13/2020] [Accepted: 08/21/2020] [Indexed: 12/26/2022]
Abstract
Bacillus lichenformis is an industrially promising generally recognized as safe (GRAS) strain that can be used for the production of a valuable chemical, 2,3-butanediol (BDO). Conventional gene deletion vectors and/or methods are time-consuming and have poor efficiency. Therefore, clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 mediated homologous recombination was used to engineer a newly isolated and UV-mutagenized B. licheniformis 4071-15 strain. With the help of a CRISPR-Cas9 system, this one-step process could be used for the deletion of ldh gene within 4 days with high-efficiency exceeding 60%. In addition, the sequential deletion of target genes for engineering studies was evaluated, and it was confirmed that a triple mutant strain (ldh, dgp, and acoR) could be obtained by repeated one-step cycles. Furthermore, a practical metabolic engineering study was carried out using a CRISPR-Cas9 system for the stereospecific production of (2R,3S)-BDO. The predicted (2R,3R)-butanediol dehydrogenase encoded by the gdh gene was selected as a target for the production of (2R,3S)-BDO, and the mutant was successfully obtained. The results show that the stereospecific production of (2R,3S)-BDO was possible with the gdh deletion mutant, while the 4071-15 host strain still generated 26% of (2R,3R)-BDO. It was also shown that the 4071-15 Δgdh mutant could produce 115 g/L of (2R,3S)-BDO in 64 hr by two-stage fed-batch fermentation. This study has shown the efficient development of a (2R,3S)-BDO producing B. licheniformis strain based on CRISPR-Cas9 and fermentation technologies.
Collapse
Affiliation(s)
- Chan Woo Song
- Research and Development Center, GS Caltex Corporation, Daejeon, Republic of Korea
| | | | - Jong Myoung Park
- Research and Development Center, GS Caltex Corporation, Daejeon, Republic of Korea
| | - Mina Kwon
- Research and Development Center, GS Caltex Corporation, Daejeon, Republic of Korea
| | - Hyohak Song
- Research and Development Center, GS Caltex Corporation, Daejeon, Republic of Korea
| |
Collapse
|
24
|
Challenges of in vitro genome editing with CRISPR/Cas9 and possible solutions: A review. Gene 2020; 753:144813. [DOI: 10.1016/j.gene.2020.144813] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 04/26/2020] [Accepted: 05/23/2020] [Indexed: 12/20/2022]
|
25
|
Liu D, Huang C, Guo J, Zhang P, Chen T, Wang Z, Zhao X. Development and characterization of a CRISPR/Cas9n-based multiplex genome editing system for Bacillus subtilis. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:197. [PMID: 31572493 PMCID: PMC6764132 DOI: 10.1186/s13068-019-1537-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 08/04/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Metabolic engineering has expanded from a focus on designs requiring a small number of genetic modifications to increasingly complex designs driven by advances in multiplex genome editing technologies. However, simultaneously modulating multiple genes on the chromosome remains challenging in Bacillus subtilis. Thus, developing an efficient and convenient method for B. subtilis multiplex genome editing is imperative. RESULTS Here, we developed a CRISPR/Cas9n-based multiplex genome editing system for iterative genome editing in B. subtilis. This system enabled us to introduce various types of genomic modifications with more satisfying efficiency than using CRISPR/Cas9, especially in multiplex gene editing. Our system achieved at least 80% efficiency for 1-8 kb gene deletions, at least 90% efficiency for 1-2 kb gene insertions, near 100% efficiency for site-directed mutagenesis, 23.6% efficiency for large DNA fragment deletion and near 50% efficiency for three simultaneous point mutations. The efficiency for multiplex gene editing was further improved by regulating the nick repair mechanism mediated by ligD gene, which finally led to roughly 65% efficiency for introducing three point mutations on the chromosome. To demonstrate its potential, we applied our system to simultaneously fine-tune three genes in the riboflavin operon and significantly improved the production of riboflavin in a single cycle. CONCLUSIONS We present not only the iterative CRISPR/Cas9n system for B. subtilis but also the highest efficiency for simultaneous modulation of multiple genes on the chromosome in B. subtilis reported to date. We anticipate this CRISPR/Cas9n mediated system to greatly enhance the optimization of diverse biological systems via metabolic engineering and synthetic biology.
Collapse
Affiliation(s)
- Dingyu Liu
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Can Huang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Jiaxin Guo
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Peiji Zhang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Tao Chen
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Zhiwen Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Xueming Zhao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| |
Collapse
|
26
|
Wang Y, Wang Z, Chen Y, Hua X, Yu Y, Ji Q. A Highly Efficient CRISPR-Cas9-Based Genome Engineering Platform in Acinetobacter baumannii to Understand the H 2O 2-Sensing Mechanism of OxyR. Cell Chem Biol 2019; 26:1732-1742.e5. [PMID: 31548010 DOI: 10.1016/j.chembiol.2019.09.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 07/25/2019] [Accepted: 09/03/2019] [Indexed: 12/18/2022]
Abstract
The rapid emergence of extensively drug-resistant A. baumannii has posed a major threat to global public health, emphasizing the desperate need for novel therapeutic strategies. We report the development of a highly efficient genome-engineering platform in A. baumannii by coupling a Cas9 nuclease-mediated genome cleavage system with the RecAb recombination system. We applied the CRISPR-Cas9/RecAb system to dissect the oxidative stress-sensing mechanism of OxyR by performing alanine scanning mutagenesis of 13 residues residing in the H2O2-sensing pocket, pinpointing new vital factors for H2O2 sensing. Moreover, we developed a cytidine base-editing system, enabling programmed C to T conversions. Exploiting this powerful technique, we systematically investigated the drug-resistant mechanisms in a clinically isolated multidrug-resistant A. baumannii strain by generating premature stop codons in the possible resistance genes, unveiling distinct roles of these genes in drug resistance. The development of these genome-engineering methods will facilitate new therapeutic-means development in A. baumannii and related organisms.
Collapse
Affiliation(s)
- Yu Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Zhipeng Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yan Chen
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou 310016, China
| | - Xiaoting Hua
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou 310016, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310016, China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou 310016, China
| | - Quanjiang Ji
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China.
| |
Collapse
|
27
|
|
28
|
Corts AD, Thomason LC, Gill RT, Gralnick JA. Efficient and Precise Genome Editing in Shewanella with Recombineering and CRISPR/Cas9-Mediated Counter-Selection. ACS Synth Biol 2019; 8:1877-1889. [PMID: 31277550 DOI: 10.1021/acssynbio.9b00188] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Dissimilatory metal-reducing bacteria, particularly those from the genus Shewanella, are of importance for bioremediation of metal contaminated sites and sustainable energy production. However, studies on this species have suffered from a lack of effective genetic tools for precise and high throughput genome manipulation. Here we report the development of a highly efficient system based on single-stranded DNA oligonucleotide recombineering coupled with CRISPR/Cas9-mediated counter-selection. Our system uses two plasmids: a sgRNA targeting vector and an editing vector, the latter harboring both Cas9 and the phage recombinase W3 Beta. Following the experimental analysis of Cas9 activity, we demonstrate the ability of this system to efficiently and precisely engineer different Shewanella strains with an average efficiency of >90% among total transformed cells, compared to ≃5% by recombineering alone, and regardless of the gene modified. We also show that different genetic changes can be introduced: mismatches, deletions, and small insertions. Surprisingly, we found that use of CRISPR/Cas9 alone allows selection of recombinase-independent S. oneidensis mutations, albeit at lower efficiency and frequency. With synthesized single-stranded DNA as substrates for homologous recombination and Cas9 as a counter-selectable marker, this new system provides a rapid, scalable, versatile, and scarless tool that will accelerate progress in Shewanella genomic engineering.
Collapse
Affiliation(s)
- Anna D. Corts
- BioTechnology Institute and Department of Plant and Microbial Biology, University of Minnesota−Twin Cities, St. Paul, Minnesota 55108, United States
| | - Lynn C. Thomason
- Basic Science Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Ryan T. Gill
- DTU BIOSUSTAIN, Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Jeffrey A. Gralnick
- BioTechnology Institute and Department of Plant and Microbial Biology, University of Minnesota−Twin Cities, St. Paul, Minnesota 55108, United States
| |
Collapse
|
29
|
Streamlined Genetic Manipulation of Diverse Bacteroides and Parabacteroides Isolates from the Human Gut Microbiota. mBio 2019; 10:mBio.01762-19. [PMID: 31409684 PMCID: PMC6692515 DOI: 10.1128/mbio.01762-19] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
We have entered an era when studies of the gut microbiota are transitioning from basic questions of composition and host effects to understanding the microbial molecules that underlie compositional shifts and mediate health and disease processes. The importance of the gut Bacteroidales to human health and disease and their potential as a source of engineered live biotherapeutics make these bacteria of particular interest for in-depth mechanistic study. However, there are still barriers to the genetic analysis of diverse Bacteroidales strains, limiting our ability to study important host and community phenotypes identified in these strains. Here, we have overcome many of these obstacles by constructing a series of vectors that allow easy genetic manipulation in diverse gut Bacteroides and Parabacteroides strains. These constructs fill a critical need and allow streamlined allelic replacement in diverse gut Bacteroidales, including the growing number of multiantibiotic-resistant strains present in the modern-day human intestine. Studies of the gut microbiota have dramatically increased in recent years as the importance of this microbial ecosystem to human health and disease is better appreciated. The Bacteroidales are the most abundant order of bacteria in the healthy human gut and induce both health-promoting and disease-promoting effects. There are more than 55 species of gut Bacteroidales with extensive intraspecies genetic diversity, especially in regions involved in the synthesis of molecules that interact with other bacteria, the host, and the diet. This property necessitates the study of diverse species and strains. In recent years, the genetic toolkit to study these bacteria has greatly expanded, but we still lack a facile system for creating deletion mutants and allelic replacements in diverse strains, especially with the rapid increase in resistance to the two antibiotics used for genetic manipulation. Here, we present a new versatile and highly efficient vector suite that allows the creation of allelic deletions and replacements in multiresistant strains of Bacteroides and Parabacteroides using a gain-of-function system based on polysaccharide utilization. These vectors also allow for easy counterselection independent of creating a mutant background strain, using a toxin from a type VI secretion system of Bacteroides fragilis. Toxin production during counterselection is induced with one of two different molecules, providing flexibility based on strain phenotypes. This family of vectors greatly facilitates functional genetic analyses and extends the range of gut Bacteroidales strains that can be genetically modified to include multiresistant strains that are currently genetically intractable with existing genetic tools.
Collapse
|
30
|
Abstract
Genes necessary for the survival or reproduction of a cell are an attractive class of antibiotic targets. Studying essential genes by classical genetics, however, is inherently problematic because it is impossible to knock them out. Here, we screened a set of predicted essential genes for growth inhibition using CRISPR-interference (CRISPRi) knockdown in the human pathogen Vibrio cholerae We demonstrate that CRISPRi knockdown of 37 predicted essential genes inhibits V. cholerae viability, thus validating the products of these genes as potential drug target candidates. V. cholerae was particularly vulnerable to lethal inhibition of the system for lipoprotein transport (Lol), a central hub for directing lipoproteins from the inner to the outer membrane (OM), with many of these lipoproteins coordinating their own essential processes. Lol depletion makes cells prone to plasmolysis and elaborate membrane reorganization, during which the periplasm extrudes into a mega outer membrane vesicle or "MOMV" encased by OM which dynamically emerges specifically at plasmolysis sites. Our work identifies the Lol system as an ideal drug target, whose inhibition could deplete gram-negative bacteria of numerous proteins that reside in the periplasm.
Collapse
|
31
|
Pena SA, Iyengar R, Eshraghi RS, Bencie N, Mittal J, Aljohani A, Mittal R, Eshraghi AA. Gene therapy for neurological disorders: challenges and recent advancements. J Drug Target 2019; 28:111-128. [DOI: 10.1080/1061186x.2019.1630415] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Stefanie A. Pena
- Department of Otolaryngology, Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Rahul Iyengar
- Department of Otolaryngology, Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Rebecca S. Eshraghi
- Department of Otolaryngology, Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Nicole Bencie
- Department of Otolaryngology, Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jeenu Mittal
- Department of Otolaryngology, Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Abdulrahman Aljohani
- Department of Otolaryngology, Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Rahul Mittal
- Department of Otolaryngology, Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Adrien A. Eshraghi
- Department of Otolaryngology, Hearing Research Laboratory, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Biomedical Engineering, University of Miami Miller School of Medicine, Miami, FL, USA
| |
Collapse
|
32
|
Cañadas IC, Groothuis D, Zygouropoulou M, Rodrigues R, Minton NP. RiboCas: A Universal CRISPR-Based Editing Tool for Clostridium. ACS Synth Biol 2019; 8:1379-1390. [PMID: 31181894 DOI: 10.1021/acssynbio.9b00075] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Members of the genus Clostridium represent a diverse assemblage of species exhibiting both medical and industrial importance. Deriving both a greater understanding of their biology, while at the same time enhancing their exploitable properties, requires effective genome editing tools. Here, we demonstrate the first implementation in the genus of theophylline-dependent, synthetic riboswitches exhibiting a full set of dynamic ranges, also suitable for applications where tight control of gene expression is required. Their utility was highlighted by generating a novel riboswitch-based editing tool-RiboCas-that overcomes the main obstacles associated with CRISPR/Cas9 systems, including low transformation efficiencies and excessive Cas9 toxicity. The universal nature of the tool was established by obtaining chromosomal modifications in C. pasteurianum, C. difficile, and C. sporogenes, as well as by carrying out the first reported example of CRISPR-targeted gene disruption in C. botulinum. The high efficiency (100% mutant generation) and ease of application of RiboCas make it suitable for use in a diverse range of microorganisms.
Collapse
Affiliation(s)
- Inés C. Cañadas
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Centre for Biomolecular Sciences, The University of Nottingham, Nottingham NG7 2RD, U.K
| | - Daphne Groothuis
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Centre for Biomolecular Sciences, The University of Nottingham, Nottingham NG7 2RD, U.K
| | - Maria Zygouropoulou
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Centre for Biomolecular Sciences, The University of Nottingham, Nottingham NG7 2RD, U.K
| | - Raquel Rodrigues
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Centre for Biomolecular Sciences, The University of Nottingham, Nottingham NG7 2RD, U.K
| | - Nigel P. Minton
- Clostridia Research Group, BBSRC/EPSRC Synthetic Biology Research Centre (SBRC), School of Life Sciences, Centre for Biomolecular Sciences, The University of Nottingham, Nottingham NG7 2RD, U.K
- NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and the University of Nottingham, Nottingham NG7 2RD, U.K
| |
Collapse
|
33
|
Transcriptional noise and exaptation as sources for bacterial sRNAs. Biochem Soc Trans 2019; 47:527-539. [PMID: 30837318 DOI: 10.1042/bst20180171] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/01/2019] [Accepted: 02/01/2019] [Indexed: 11/17/2022]
Abstract
Understanding how new genes originate and integrate into cellular networks is key to understanding evolution. Bacteria present unique opportunities for both the natural history and experimental study of gene origins, due to their large effective population sizes, rapid generation times, and ease of genetic manipulation. Bacterial small non-coding RNAs (sRNAs), in particular, many of which operate through a simple antisense regulatory logic, may serve as tractable models for exploring processes of gene origin and adaptation. Understanding how and on what timescales these regulatory molecules arise has important implications for understanding the evolution of bacterial regulatory networks, in particular, for the design of comparative studies of sRNA function. Here, we introduce relevant concepts from evolutionary biology and review recent work that has begun to shed light on the timescales and processes through which non-functional transcriptional noise is co-opted to provide regulatory functions. We explore possible scenarios for sRNA origin, focusing on the co-option, or exaptation, of existing genomic structures which may provide protected spaces for sRNA evolution.
Collapse
|
34
|
Nayak DD, Metcalf WW. Genetic techniques for studies of methyl-coenzyme M reductase from Methanosarcina acetivorans C2A. Methods Enzymol 2018; 613:325-347. [PMID: 30509472 DOI: 10.1016/bs.mie.2018.10.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methanogenic archaea generate methane as a by-product of anaerobic respiration using CO2, C1 compounds (like methanol or methylated amines), or acetate as terminal electron acceptors. Methanogens are an untapped resource for biotechnological advances related to methane production as well as methane consumption. However, key biological features of these organisms remain poorly understood. One such feature is the enzyme methyl-coenzyme M reductase (referred to as MCR), which catalyzes the last step in the methanogenic pathway and results in methane formation. Gene essentiality has limited genetic analyses of MCR thus far. Therefore, studies of this important enzyme have been limited to biochemical and biophysical techniques that are especially laborious and often reliant on sophisticated instrumentation that is not commonly available. In this chapter, we outline our recently developed CRISPR-Cas9-based genome editing tools and describe how these tools have been used for the introduction of a tandem affinity purification tag at the chromosomal mcr locus in the model methanogen, Methanosarcina acetivorans C2A. We also report a protocol for rapid affinity purification of MCR from M. acetivorans C2A that will enable high-throughput studies of this enzyme in the future.
Collapse
Affiliation(s)
- Dipti D Nayak
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, United States; Department of Microbiology, University of Illinois, Urbana, IL, United States
| | - William W Metcalf
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, IL, United States; Department of Microbiology, University of Illinois, Urbana, IL, United States.
| |
Collapse
|
35
|
Zhang S, Voigt CA. Engineered dCas9 with reduced toxicity in bacteria: implications for genetic circuit design. Nucleic Acids Res 2018; 46:11115-11125. [PMID: 30289463 PMCID: PMC6237744 DOI: 10.1093/nar/gky884] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 12/26/2022] Open
Abstract
Large synthetic genetic circuits require the simultaneous expression of many regulators. Deactivated Cas9 (dCas9) can serve as a repressor by having a small guide RNA (sgRNA) direct it to bind a promoter. The programmability and specificity of RNA:DNA basepairing simplifies the generation of many orthogonal sgRNAs that, in theory, could serve as a large set of regulators in a circuit. However, dCas9 is toxic in many bacteria, thus limiting how high it can be expressed, and low concentrations are quickly sequestered by multiple sgRNAs. Here, we construct a non-toxic version of dCas9 by eliminating PAM (protospacer adjacent motif) binding with a R1335K mutation (dCas9*) and recovering DNA binding by fusing it to the PhlF repressor (dCas9*_PhlF). Both the 30 bp PhlF operator and 20 bp sgRNA binding site are required to repress a promoter. The larger region required for recognition mitigates toxicity in Escherichia coli, allowing up to 9600 ± 800 molecules of dCas9*_PhlF per cell before growth or morphology are impacted, as compared to 530 ± 40 molecules of dCas9. Further, PhlF multimerization leads to an increase in average cooperativity from n = 0.9 (dCas9) to 1.6 (dCas9*_PhlF). A set of 30 orthogonal sgRNA-promoter pairs are characterized as NOT gates; however, the simultaneous use of multiple sgRNAs leads to a monotonic decline in repression and after 15 are co-expressed the dynamic range is <10-fold. This work introduces a non-toxic variant of dCas9, critical for its use in applications in metabolic engineering and synthetic biology, and exposes a limitation in the number of regulators that can be used in one cell when they rely on a shared resource.
Collapse
Affiliation(s)
- Shuyi Zhang
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Christopher A Voigt
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| |
Collapse
|
36
|
Buckner MMC, Ciusa ML, Piddock LJV. Strategies to combat antimicrobial resistance: anti-plasmid and plasmid curing. FEMS Microbiol Rev 2018; 42:781-804. [PMID: 30085063 PMCID: PMC6199537 DOI: 10.1093/femsre/fuy031] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 07/25/2018] [Indexed: 12/17/2022] Open
Abstract
Antimicrobial resistance (AMR) is a global problem hindering treatment of bacterial infections, rendering many aspects of modern medicine less effective. AMR genes (ARGs) are frequently located on plasmids, which are self-replicating elements of DNA. They are often transmissible between bacteria, and some have spread globally. Novel strategies to combat AMR are needed, and plasmid curing and anti-plasmid approaches could reduce ARG prevalence, and sensitise bacteria to antibiotics. We discuss the use of curing agents as laboratory tools including chemicals (e.g. detergents and intercalating agents), drugs used in medicine including ascorbic acid, psychotropic drugs (e.g. chlorpromazine), antibiotics (e.g. aminocoumarins, quinolones and rifampicin) and plant-derived compounds. Novel strategies are examined; these include conjugation inhibitors (e.g. TraE inhibitors, linoleic, oleic, 2-hexadecynoic and tanzawaic acids), systems designed around plasmid incompatibility, phages and CRISPR/Cas-based approaches. Currently, there is a general lack of in vivo curing options. This review highlights this important shortfall, which if filled could provide a promising mechanism to reduce ARG prevalence in humans and animals. Plasmid curing mechanisms which are not suitable for in vivo use could still prove important for reducing the global burden of AMR, as high levels of ARGs exist in the environment.
Collapse
Affiliation(s)
- Michelle M C Buckner
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, The University of Birmingham B15 2TT, UK
| | - Maria Laura Ciusa
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, The University of Birmingham B15 2TT, UK
| | - Laura J V Piddock
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, The University of Birmingham B15 2TT, UK
| |
Collapse
|
37
|
Synthetic CRISPR-Cas gene activators for transcriptional reprogramming in bacteria. Nat Commun 2018; 9:2489. [PMID: 29950558 PMCID: PMC6021436 DOI: 10.1038/s41467-018-04901-6] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 06/01/2018] [Indexed: 02/06/2023] Open
Abstract
Methods to regulate gene expression programs in bacterial cells are limited by the absence of effective gene activators. To address this challenge, we have developed synthetic bacterial transcriptional activators in E. coli by linking activation domains to programmable CRISPR-Cas DNA binding domains. Effective gene activation requires target sites situated in a narrow region just upstream of the transcription start site, in sharp contrast to the relatively flexible target site requirements for gene activation in eukaryotic cells. Together with existing tools for CRISPRi gene repression, these bacterial activators enable programmable control over multiple genes with simultaneous activation and repression. Further, the entire gene expression program can be switched on by inducing expression of the CRISPR-Cas system. This work will provide a foundation for engineering synthetic bacterial cellular devices with applications including diagnostics, therapeutics, and industrial biosynthesis. The absence of effective gene activators in bacteria limits regulated expression programs. Here the authors design synthetic bacterial CRISPR-Cas transcriptional activators that can be used to construct multi-gene programs of activation and repression.
Collapse
|
38
|
Woolston BM, Emerson DF, Currie DH, Stephanopoulos G. Rediverting carbon flux in Clostridium ljungdahlii using CRISPR interference (CRISPRi). Metab Eng 2018; 48:243-253. [PMID: 29906505 DOI: 10.1016/j.ymben.2018.06.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 06/10/2018] [Indexed: 12/28/2022]
Abstract
Clostridium ljungdahlii has emerged as an attractive candidate for the bioconversion of synthesis gas (CO, CO2, H2) to a variety of fuels and chemicals through the Wood-Ljungdahl pathway. However, metabolic engineering and pathway elucidation in this microbe is limited by the lack of genetic tools to downregulate target genes. To overcome this obstacle, here we developed an inducible CRISPR interference (CRISPRi) system for C. ljungdahlii that enables efficient (> 94%) transcriptional repression of several target genes, both individually and in tandem. We then applied CRISPRi in a strain engineered for 3-hydroxybutyrate (3HB) production to examine targets for increasing carbon flux toward the desired product. Downregulating phosphotransacetylase (pta) with a single sgRNA led to a 97% decrease in enzyme activity and a 2.3-fold increase in titer during heterotrophic growth. However, acetate production still accounted for 40% of the carbon flux. Repression of aldehyde:ferredoxin oxidoreductase (aor2), another potential route for acetate production, led to a 5% reduction in acetate flux, whereas using an additional sgRNA targeted to pta reduced the enzyme activity to 0.7% of the wild-type level, and further reduced acetate production to 25% of the carbon flux with an accompanying increase in 3HB titer and yield. These results demonstrate the utility of CRISPRi for elucidating and controlling carbon flow in C. ljungdahlii.
Collapse
Affiliation(s)
- Benjamin M Woolston
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames Street, MIT 56-469 C, Cambridge, MA 02139, United States
| | - David F Emerson
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames Street, MIT 56-469 C, Cambridge, MA 02139, United States
| | - Devin H Currie
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames Street, MIT 56-469 C, Cambridge, MA 02139, United States
| | - Gregory Stephanopoulos
- Department of Chemical Engineering, Massachusetts Institute of Technology, 25 Ames Street, MIT 56-469 C, Cambridge, MA 02139, United States.
| |
Collapse
|
39
|
Barquist L, Westermann AJ, Vogel J. Molecular phenotyping of infection-associated small non-coding RNAs. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2016.0081. [PMID: 27672158 DOI: 10.1098/rstb.2016.0081] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2016] [Indexed: 02/07/2023] Open
Abstract
Infection is a complicated balance, with both pathogen and host struggling to tilt the result in their favour. Bacterial infection biology has relied on forward genetics for many of its advances, defining phenotype in terms of replication in model systems. However, many known virulence factors fail to produce robust phenotypes, particularly in the systems most amenable to genetic manipulation, such as cell-culture models. This has particularly been limiting for the study of the bacterial regulatory small RNAs (sRNAs) in infection. We argue that new sequencing-based technologies can work around this problem by providing a 'molecular phenotype', defined in terms of the specific transcriptional dysregulation in the infection system induced by gene deletion. We illustrate this using the example of our recent study of the PinT sRNA using dual RNA-seq, that is, simultaneous RNA sequencing of host and pathogen during infection. We additionally discuss how other high-throughput technologies, in particular genetic interaction mapping using transposon insertion sequencing, may be used to further dissect molecular phenotypes. We propose a strategy for how high-throughput technologies can be integrated in the study of non-coding regulators as well as bacterial virulence factors, enhancing our ability to rapidly generate hypotheses with regards to their function.This article is part of the themed issue 'The new bacteriology'.
Collapse
Affiliation(s)
- Lars Barquist
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2/D15, 97080 Würzburg, Germany
| | - Alexander J Westermann
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2/D15, 97080 Würzburg, Germany
| | - Jörg Vogel
- RNA Biology Group, Institute for Molecular Infection Biology, University of Würzburg, Josef-Schneider-Straße 2/D15, 97080 Würzburg, Germany Research Centre for Infectious Diseases (ZINF), University of Würzburg, 97070 Würzburg, Germany
| |
Collapse
|
40
|
French S, Ellis MJ, Coutts BE, Brown ED. Chemical genomics reveals mechanistic hypotheses for uncharacterized bioactive molecules in bacteria. Curr Opin Microbiol 2017; 39:42-47. [PMID: 28957731 DOI: 10.1016/j.mib.2017.09.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/06/2017] [Indexed: 01/24/2023]
Abstract
In an effort to combat the perpetual emergence of new antibiotic-resistant human pathogens, research in industry and academe aims to find new means of controlling infection. The discovery of new antimicrobial chemicals is not the bottleneck in an era where high-throughput screening rapidly uncovers new bioactive compounds. Rather, the rate-limiting step in antimicrobial discovery pipelines is identifying mechanisms of action (MOA) of bioactive molecules produced by these increasingly large-scale efforts. Chemical genomics has proven to be of high value in providing mechanistic hypotheses for novel bioactive chemical matter. Several techniques fall under this blanket term, including interactions with deletion or transposon libraries, fluorescent or luminescent reporter library profiles, or deep sequencing approaches. Each of these provide unique and complementary outputs, and have high value in generating target lists for chemical screens, or assisting in downstream MOA discovery. We review here the broad usefulness of this technique to aid in MOA determination, to identify targets for new lead molecules, and to expand our mechanistic understanding of existing drugs.
Collapse
Affiliation(s)
- Shawn French
- Department of Biochemistry and Biomedical Sciences and Michael G DeGroote Institute for Infectious Disease Research, McMaster University, Canada
| | - Michael J Ellis
- Department of Biochemistry and Biomedical Sciences and Michael G DeGroote Institute for Infectious Disease Research, McMaster University, Canada
| | - Brittney E Coutts
- Department of Biochemistry and Biomedical Sciences and Michael G DeGroote Institute for Infectious Disease Research, McMaster University, Canada
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences and Michael G DeGroote Institute for Infectious Disease Research, McMaster University, Canada.
| |
Collapse
|
41
|
Abstract
Descriptions of the changeable, striking colors associated with secreted natural products date back well over a century. These molecules can serve as extracellular electron shuttles (EESs) that permit microbes to access substrates at a distance. In this review, we argue that the colorful world of EESs has been too long neglected. Rather than simply serving as a diagnostic attribute of a particular microbial strain, redox-active natural products likely play fundamental, underappreciated roles in the biology of their producers, particularly those that inhabit biofilms. Here, we describe the chemical diversity and potential distribution of EES producers and users, discuss the costs associated with their biosynthesis, and critically evaluate strategies for their economical usage. We hope this review will inspire efforts to identify and explore the importance of EES cycling by a wide range of microorganisms so that their contributions to shaping microbial communities can be better assessed and exploited.
Collapse
Affiliation(s)
- Nathaniel R Glasser
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125; , ,
| | - Scott H Saunders
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125; , ,
| | - Dianne K Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125; , , .,Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125
| |
Collapse
|
42
|
The dev Operon Regulates the Timing of Sporulation during Myxococcus xanthus Development. J Bacteriol 2017; 199:JB.00788-16. [PMID: 28264995 DOI: 10.1128/jb.00788-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/28/2017] [Indexed: 02/06/2023] Open
Abstract
Myxococcus xanthus undergoes multicellular development when starved. Thousands of rod-shaped cells coordinate their movements and aggregate into mounds in which cells differentiate into spores. Mutations in the dev operon impair development. The dev operon encompasses a clustered regularly interspaced short palindromic repeat-associated (CRISPR-Cas) system. Null mutations in devI, a small gene at the beginning of the dev operon, suppress the developmental defects caused by null mutations in the downstream devR and devS genes but failed to suppress defects caused by a small in-frame deletion in devT We provide evidence that the original mutant has a second-site mutation. We show that devT null mutants exhibit developmental defects indistinguishable from devR and devS null mutants, and a null mutation in devI suppresses the defects of a devT null mutation. The similarity of DevTRS proteins to components of the CRISPR-associated complex for antiviral defense (Cascade), together with our molecular characterization of dev mutants, support a model in which DevTRS form a Cascade-like subcomplex that negatively autoregulates dev transcript accumulation and prevents DevI overproduction that would strongly inhibit sporulation. Our results also suggest that DevI transiently inhibits sporulation when regulated normally. The mechanism of transient inhibition may involve MrpC, a key transcription factor, whose translation appears to be weakly inhibited by DevI. Finally, our characterization of a devI devS mutant indicates that very little exo transcript is required for sporulation, which is surprising since Exo proteins help form the polysaccharide spore coat.IMPORTANCE CRISPR-Cas systems typically function as adaptive immune systems in bacteria. The dev CRISPR-Cas system of M. xanthus has been proposed to prevent bacteriophage infection during development, but how dev controls sporulation has been elusive. Recent evidence supported a model in which DevR and DevS prevent overproduction of DevI, a predicted 40-residue inhibitor of sporulation. We provide genetic evidence that DevT functions together with DevR and DevS to prevent DevI overproduction. We also show that spores form about 6 h earlier in mutants lacking devI than in the wild type. Only a minority of natural isolates appear to have a functional dev promoter and devI, suggesting that a functional dev CRISPR-Cas system evolved recently in niches where delayed sporulation and/or protection from bacteriophage infection proved advantageous.
Collapse
|
43
|
Abdurashitov MA, Degtyarev SK. Use of site-specific DNA endonucleases in genome-wide studies of human DNA. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417010021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
44
|
Li XT, Jun Y, Erickstad MJ, Brown SD, Parks A, Court DL, Jun S. tCRISPRi: tunable and reversible, one-step control of gene expression. Sci Rep 2016; 6:39076. [PMID: 27996021 PMCID: PMC5171832 DOI: 10.1038/srep39076] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/17/2016] [Indexed: 02/06/2023] Open
Abstract
The ability to control the level of gene expression is a major quest in biology. A widely used approach employs deletion of a nonessential gene of interest (knockout), or multi-step recombineering to move a gene of interest under a repressible promoter (knockdown). However, these genetic methods are laborious, and limited for quantitative study. Here, we report a tunable CRISPR-cas system, "tCRISPRi", for precise and continuous titration of gene expression by more than 30-fold. Our tCRISPRi system employs various previous advancements into a single strain: (1) We constructed a new strain containing a tunable arabinose operon promoter PBAD to quantitatively control the expression of CRISPR-(d)Cas protein over two orders of magnitude in a plasmid-free system. (2) tCRISPRi is reversible, and gene expression is repressed under knockdown conditions. (3) tCRISPRi shows significantly less than 10% leaky expression. (4) Most important from a practical perspective, construction of tCRISPRi to target a new gene requires only one-step of oligo recombineering. Our results show that tCRISPRi, in combination with recombineering, provides a simple and easy-to-implement tool for gene expression control, and is ideally suited for construction of both individual strains and high-throughput tunable knockdown libraries.
Collapse
Affiliation(s)
- Xin-tian Li
- Section of Molecular Biology, Division of Biological Sciences and Department of Physics, UC San Diego, La Jolla, CA 92093, USA
| | - Yonggun Jun
- Section of Molecular Biology, Division of Biological Sciences and Department of Physics, UC San Diego, La Jolla, CA 92093, USA
| | - Michael J. Erickstad
- Section of Molecular Biology, Division of Biological Sciences and Department of Physics, UC San Diego, La Jolla, CA 92093, USA
| | - Steven D. Brown
- Section of Molecular Biology, Division of Biological Sciences and Department of Physics, UC San Diego, La Jolla, CA 92093, USA
| | - Adam Parks
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, USA
| | - Donald L. Court
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, USA
| | - Suckjoon Jun
- Section of Molecular Biology, Division of Biological Sciences and Department of Physics, UC San Diego, La Jolla, CA 92093, USA
| |
Collapse
|
45
|
A CRISPR-Cas9 Assisted Non-Homologous End-Joining Strategy for One-step Engineering of Bacterial Genome. Sci Rep 2016; 6:37895. [PMID: 27883076 PMCID: PMC5121644 DOI: 10.1038/srep37895] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 11/01/2016] [Indexed: 11/08/2022] Open
Abstract
Homologous recombination-mediated genome engineering has been broadly applied in prokaryotes with high efficiency and accuracy. However, this method is limited in realizing larger-scale genome editing with numerous genes or large DNA fragments because of the relatively complicated procedure for DNA editing template construction. Here, we describe a CRISPR-Cas9 assisted non-homologous end-joining (CA-NHEJ) strategy for the rapid and efficient inactivation of bacterial gene (s) in a homologous recombination-independent manner and without the use of selective marker. Our study show that CA-NHEJ can be used to delete large chromosomal DNA fragments in a single step that does not require homologous DNA template. It is thus a novel and powerful tool for bacterial genomes reducing and possesses the potential for accelerating the genome evolution.
Collapse
|
46
|
Holowko MB, Wang H, Jayaraman P, Poh CL. Biosensing Vibrio cholerae with Genetically Engineered Escherichia coli. ACS Synth Biol 2016; 5:1275-1283. [PMID: 27529184 DOI: 10.1021/acssynbio.6b00079] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cholera is a potentially mortal, infectious disease caused by Vibrio cholerae bacterium. Current treatment methods of cholera still have limitations. Beneficial microbes that could sense and kill the V. cholerae could offer potential alternative to preventing and treating cholera. However, such V. cholerae targeting microbe is still not available. This microbe requires a sensing system to be able to detect the presence of V. cholera bacterium. To this end, we designed and created a synthetic genetic sensing system using nonpathogenic Escherichia coli as the host. To achieve the system, we have moved proteins used by V. cholerae for quorum sensing into E. coli. These sensor proteins have been further layered with a genetic inverter based on CRISPRi technology. Our design process was aided by computer models simulating in vivo behavior of the system. Our sensor shows high sensitivity to presence of V. cholerae supernatant with tight control of expression of output GFP protein.
Collapse
Affiliation(s)
- Maciej B. Holowko
- School of Chemical and Biomedical
Engineering, Nanyang Technological University, Singapore 639798
| | - Huijuan Wang
- School of Chemical and Biomedical
Engineering, Nanyang Technological University, Singapore 639798
| | - Premkumar Jayaraman
- School of Chemical and Biomedical
Engineering, Nanyang Technological University, Singapore 639798
| | - Chueh Loo Poh
- School of Chemical and Biomedical
Engineering, Nanyang Technological University, Singapore 639798
| |
Collapse
|
47
|
Richter F, Fonfara I, Bouazza B, Schumacher CH, Bratovič M, Charpentier E, Möglich A. Engineering of temperature- and light-switchable Cas9 variants. Nucleic Acids Res 2016; 44:10003-10014. [PMID: 27744350 PMCID: PMC5175372 DOI: 10.1093/nar/gkw930] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/05/2016] [Accepted: 10/06/2016] [Indexed: 01/18/2023] Open
Abstract
Sensory photoreceptors have enabled non-invasive and spatiotemporal control of numerous biological processes. Photoreceptor engineering has expanded the repertoire beyond natural receptors, but to date no generally applicable strategy exists towards constructing light-regulated protein actuators of arbitrary function. We hence explored whether the homodimeric Rhodobacter sphaeroides light-oxygen-voltage (LOV) domain (RsLOV) that dissociates upon blue-light exposure can confer light sensitivity onto effector proteins, via a mechanism of light-induced functional site release. We chose the RNA-guided programmable DNA endonuclease Cas9 as proof-of-principle effector, and constructed a comprehensive library of RsLOV inserted throughout the Cas9 protein. Screening with a high-throughput assay based on transcriptional repression in Escherichia coli yielded paRC9, a moderately light-activatable variant. As domain insertion can lead to protein destabilization, we also screened the library for temperature-sensitive variants and isolated tsRC9, a variant with robust activity at 29°C but negligible activity at 37°C. Biochemical assays confirmed temperature-dependent DNA cleavage and binding for tsRC9, but indicated that the light sensitivity of paRC9 is specific to the cellular setting. Using tsRC9, the first temperature-sensitive Cas9 variant, we demonstrate temperature-dependent transcriptional control over ectopic and endogenous genetic loci. Taken together, RsLOV can confer light sensitivity onto an unrelated effector; unexpectedly, the same LOV domain can also impart strong temperature sensitivity.
Collapse
Affiliation(s)
- Florian Richter
- Biophysikalische Chemie, Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | - Ines Fonfara
- Max-Planck-Institute for Infection Biology, 10117 Berlin, Germany.,The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umeå 90187, Sweden
| | - Boris Bouazza
- Biophysikalische Chemie, Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
| | | | - Majda Bratovič
- Max-Planck-Institute for Infection Biology, 10117 Berlin, Germany
| | - Emmanuelle Charpentier
- Max-Planck-Institute for Infection Biology, 10117 Berlin, Germany.,The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Department of Molecular Biology, Umeå University, Umeå 90187, Sweden
| | - Andreas Möglich
- Biophysikalische Chemie, Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany .,Lehrstuhl für Biochemie, Universität Bayreuth, 95447 Bayreuth, Germany
| |
Collapse
|
48
|
Depletion of Undecaprenyl Pyrophosphate Phosphatases Disrupts Cell Envelope Biogenesis in Bacillus subtilis. J Bacteriol 2016; 198:2925-2935. [PMID: 27528508 DOI: 10.1128/jb.00507-16] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 08/02/2016] [Indexed: 11/20/2022] Open
Abstract
The integrity of the bacterial cell envelope is essential to sustain life by countering the high turgor pressure of the cell and providing a barrier against chemical insults. In Bacillus subtilis, synthesis of both peptidoglycan and wall teichoic acids requires a common C55 lipid carrier, undecaprenyl-pyrophosphate (UPP), to ferry precursors across the cytoplasmic membrane. The synthesis and recycling of UPP requires a phosphatase to generate the monophosphate form Und-P, which is the substrate for peptidoglycan and wall teichoic acid synthases. Using an optimized clustered regularly interspaced short palindromic repeat (CRISPR) system with catalytically inactive ("dead") CRISPR-associated protein 9 (dCas9)-based transcriptional repression system (CRISPR interference [CRISPRi]), we demonstrate that B. subtilis requires either of two UPP phosphatases, UppP or BcrC, for viability. We show that a third predicted lipid phosphatase (YodM), with homology to diacylglycerol pyrophosphatases, can also support growth when overexpressed. Depletion of UPP phosphatase activity leads to morphological defects consistent with a failure of cell envelope synthesis and strongly activates the σM-dependent cell envelope stress response, including bcrC, which encodes one of the two UPP phosphatases. These results highlight the utility of an optimized CRISPRi system for the investigation of synthetic lethal gene pairs, clarify the nature of the B. subtilis UPP-Pase enzymes, and provide further evidence linking the σM regulon to cell envelope homeostasis pathways. IMPORTANCE The emergence of antibiotic resistance among bacterial pathogens is of critical concern and motivates efforts to develop new therapeutics and increase the utility of those already in use. The lipid II cycle is one of the most frequently targeted processes for antibiotics and has been intensively studied. Despite these efforts, some steps have remained poorly defined, partly due to genetic redundancy. CRISPRi provides a powerful tool to investigate the functions of essential genes and sets of genes. Here, we used an optimized CRISPRi system to demonstrate functional redundancy of two UPP phosphatases that are required for the conversion of the initially synthesized UPP lipid carrier to Und-P, the substrate for the synthesis of the initial lipid-linked precursors in peptidoglycan and wall teichoic acid synthesis.
Collapse
|
49
|
Csörgő B, Nyerges Á, Pósfai G, Fehér T. System-level genome editing in microbes. Curr Opin Microbiol 2016; 33:113-122. [PMID: 27472027 DOI: 10.1016/j.mib.2016.07.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/09/2016] [Accepted: 07/06/2016] [Indexed: 11/16/2022]
Abstract
The release of the first complete microbial genome sequences at the end of the past century opened the way for functional genomics and systems-biology to uncover the genetic basis of various phenotypes. The surge of available sequence data facilitated the development of novel genome editing techniques for system-level analytical studies. Recombineering allowed unprecedented throughput and efficiency in microbial genome editing and the recent discovery and widespread use of RNA-guided endonucleases offered several further perspectives: (i) previously recalcitrant species became editable, (ii) the efficiency of recombineering could be elevated, and as a result (iii) diverse genomic libraries could be generated more effectively. Supporting recombineering by RNA-guided endonucleases has led to success stories in metabolic engineering, but their use for system-level analysis is mostly unexplored. For the full exploitation of opportunities that are offered by the genome editing proficiency, future development of large scale analytical procedures is also vitally needed.
Collapse
Affiliation(s)
- Bálint Csörgő
- Systems and Synthetic Biology Unit, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - Ákos Nyerges
- Systems and Synthetic Biology Unit, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| | - György Pósfai
- Systems and Synthetic Biology Unit, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary.
| | - Tamás Fehér
- Systems and Synthetic Biology Unit, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
| |
Collapse
|
50
|
Rütering M, Schmid J, Rühmann B, Schilling M, Sieber V. Controlled production of polysaccharides–exploiting nutrient supply for levan and heteropolysaccharide formation in Paenibacillus sp. Carbohydr Polym 2016; 148:326-34. [DOI: 10.1016/j.carbpol.2016.04.074] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/15/2016] [Accepted: 04/16/2016] [Indexed: 12/31/2022]
|