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Wang J, Wei J, Li H, Li Y. High-efficiency genome editing of an extreme thermophile Thermus thermophilus using endogenous type I and type III CRISPR-Cas systems. MLIFE 2022; 1:412-427. [PMID: 38818488 PMCID: PMC10989782 DOI: 10.1002/mlf2.12045] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 10/13/2022] [Accepted: 10/15/2022] [Indexed: 06/01/2024]
Abstract
Thermus thermophilus is an attractive species in the bioindustry due to its valuable natural products, abundant thermophilic enzymes, and promising fermentation capacities. However, efficient and versatile genome editing tools are not available for this species. In this study, we developed an efficient genome editing tool for T. thermophilus HB27 based on its endogenous type I-B, I-C, and III-A/B CRISPR-Cas systems. First, we systematically characterized the DNA interference capabilities of the different types of the native CRISPR-Cas systems in T. thermophilus HB27. We found that genomic manipulations such as gene deletion, mutation, and in situ tagging could be easily implemented by a series of genome-editing plasmids carrying an artificial self-targeting mini-CRISPR and a donor DNA responsible for the recombinant recovery. We also compared the genome editing efficiency of different CRISPR-Cas systems and the editing plasmids with donor DNAs of different lengths. Additionally, we developed a reporter gene system for T. thermophilus based on a heat-stable β-galactosidase gene TTP0042, and constructed an engineered strain with a high production capacity of superoxide dismutases by genome modification.
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Affiliation(s)
- Jinting Wang
- State Key Laboratory of Agricultural Microbiology and College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenChina
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
| | - Junwei Wei
- State Key Laboratory of Agricultural Microbiology and College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenChina
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
| | - Haijuan Li
- College of Biological and Environmental EngineeringXi'an UniversityXi'anChina
| | - Yingjun Li
- State Key Laboratory of Agricultural Microbiology and College of Life Science and TechnologyHuazhong Agricultural UniversityWuhanChina
- Shenzhen Institute of Nutrition and HealthHuazhong Agricultural UniversityShenzhenChina
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhenChina
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Efficient genome editing of an extreme thermophile, Thermus thermophilus, using a thermostable Cas9 variant. Sci Rep 2021; 11:9586. [PMID: 33953310 PMCID: PMC8100143 DOI: 10.1038/s41598-021-89029-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/20/2021] [Indexed: 02/03/2023] Open
Abstract
Thermophilic organisms are extensively studied in industrial biotechnology, for exploration of the limits of life, and in other contexts. Their optimal growth at high temperatures presents a challenge for the development of genetic tools for their genome editing, since genetic markers and selection substrates are often thermolabile. We sought to develop a thermostable CRISPR-Cas9 based system for genome editing of thermophiles. We identified CaldoCas9 and designed an associated guide RNA and showed that the pair have targetable nuclease activity in vitro at temperatures up to 65 °C. We performed a detailed characterization of the protospacer adjacent motif specificity of CaldoCas9, which revealed a preference for 5'-NNNNGNMA. We constructed a plasmid vector for the delivery and use of the CaldoCas9 based genome editing system in the extreme thermophile Thermus thermophilus at 65 °C. Using the vector, we generated gene knock-out mutants of T. thermophilus, targeting genes on the bacterial chromosome and megaplasmid. Mutants were obtained at a frequency of about 90%. We demonstrated that the vector can be cured from mutants for a subsequent round of genome editing. CRISPR-Cas9 based genome editing has not been reported previously in the extreme thermophile T. thermophilus. These results may facilitate development of genome editing tools for other extreme thermophiles and to that end, the vector has been made available via the plasmid repository Addgene.
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Fujino Y, Goda S, Suematsu Y, Doi K. Development of a new gene expression vector for Thermus thermophilus using a silica-inducible promoter. Microb Cell Fact 2020; 19:126. [PMID: 32513169 PMCID: PMC7282064 DOI: 10.1186/s12934-020-01385-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/01/2020] [Indexed: 01/30/2023] Open
Abstract
Background Thermostable enzymes are commonly produced in mesophilic hosts for research and bioengineering purposes. However, these hosts do not overexpress the active forms of some biologically functional thermoenzymes. Therefore, an efficient thermophilic expression system is needed. Thermus thermophilus contains an easily manipulable genome and is therefore among the best candidate microbes for a “hot” expression system. We previously identified a strong and inducible promoter that was active in T. thermophilus under supersaturated silica conditions. Here, we report a new heterologous gene expression system based on a silica-inducible promoter in T. thermophilus. Results A Thermus sp. A4 gene encoding thermostable β-galactosidase was cloned as a reporter gene into the expression vector pSix1, which contains a selection marker that confers thermostable resistance to hygromycin and a 600 bp DNA region containing a putative silica-inducible promoter. β-galactosidase activity was 11-fold higher in the presence than in the absence of 10 mM silicic acid. SDS-PAGE revealed a prominent band corresponding to 73 kDa of β-galactosidase, and this enzyme was expressed as an active and soluble protein (yield: 27 mg/L) in Thermus but as an inclusion body in Escherichia coli. Truncation of the putative silica-inducible promoter region in Thermus expression vector improved the yield of the target protein, possibly by avoiding plasmid instability due to homologous recombination. Finally, we developed an expression vector containing the pSix1 backbone and a 100 bp DNA region corresponding to the silica-inducible promoter. We used this vector to successfully express the active form of glutamate dehydrogenase from Pyrobaculum islandicum (PisGDH) without additional treatment (yield: 9.5 mg/L), whereas the expression of active PisGDH in E. coli required heat treatment. Conclusion We successfully expressed the thermostable β-galactosidase and PisGDH in T. thermophilus as active and soluble forms and achieved with our system the highest known protein expression levels in this species. These thermoenzymes were expressed in active and soluble forms. Our results validate the use of our silica-inducible expression system as a novel strategy for the intracellular overexpression of thermostable proteins.
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Affiliation(s)
- Yasuhiro Fujino
- Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Shuichiro Goda
- Graduate School of Science and Engineering, Soka University, 1-236, Tangi-cho, Hachioji-shi, Tokyo, 192-8577, Japan
| | - Yuri Suematsu
- Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Katsumi Doi
- Institute of Genetic Resources, Faculty of Agriculture, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan.
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Li H. Selection-free markerless genome manipulations in the polyploid bacterium Thermus thermophilus. 3 Biotech 2019; 9:148. [PMID: 30944795 DOI: 10.1007/s13205-019-1682-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 03/14/2019] [Indexed: 12/17/2022] Open
Abstract
A genome manipulation approach based on double-crossover homologous recombination was developed in the polyploid model organism Thermus thermophilus HB27 without the use of any selectable marker. The method was established and optimized by targeting the megaplasmid-encoded β-glucosidase gene bgl. When linear and supercoiled forms of marker-free suicide vector were used for transformations, the frequencies of obtaining apparent Bgl- mutant were 10- 5 and 10- 3, respectively; while the frequency could reach 10- 2 when transformation with concatemer form of the same vector. All randomly selected Bgl- colonies from the transformations were found to be true bgl knockout mutants. Thus, markerless gene deletion mutants could be constructed in T. thermophilus by the direct selection-free method. The functionality of this approach was further demonstrated by deletion of one chromosomal locus (TTC_0340-0341) as well as by generation of a reporter strain for the phytoene synthase promoter (PcrtB), homozygous mutants of the both targets could also be detected with a frequency of approximately 10- 2. During the genome modification process, heterozygous cells carrying two different alleles at a same locus (e.g., bgl and pyrE) could also be generated. However, in the absence of selection pressure, these strains could rapidly convert to homozygous strains containing only one of the two alleles. This indicated that allele segregation could occur in the heterozygous T. thermophilus cells, which probably explained the ease of obtaining homozygous gene deletion mutants with high frequency (10- 2) in the polyploid genomic background, as after the mutant allele had been introduced to the target region, allele segregation would lead to homozygous mutant cells. This marker-free genome manipulation approach does not require phenotype-based screens, and is applicable in gene deletion and tagging applications.
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Affiliation(s)
- Haijuan Li
- College of Biological and Environmental Engineering, Xi'an University, No. 168 South Taibai Road, Xi'an, 710065 China
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Development of a new host-vector system for colour selection of cloned DNA inserts using a newly designed β-galactosidase gene containing multiple cloning sites in Thermus thermophilus HB27. Extremophiles 2017; 21:1111-1117. [PMID: 28894938 DOI: 10.1007/s00792-017-0961-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 09/01/2017] [Indexed: 10/18/2022]
Abstract
We constructed a new Thermus thermophilus cloning vector which enables the colour selection of cloned DNA inserts in the T. thermophilus HB27 host strain (β-gal-) on growth plates containing 3,4-cyclohexenoesculetin β-D-galactopyranoside (S-gal) in the medium. This vector harbors a modified β-galactosidase gene (TTP0042 of T. thermophilus HB27) with 12 unique restriction enzyme sites (Acc65I, AvrII, BlpI, BssHII, EcoRI, EcoRV, HindIII, NruI, SalI, SpeI, SphI and XbaI) as multiple cloning sites under the control of the T. thermophilus slpA promoter. This host-vector system facilitates cloning procedures in T. thermophilus HB27.
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Togawa Y, Nunoshiba T, Hiratsu K. Cre/lox-based multiple markerless gene disruption in the genome of the extreme thermophile Thermus thermophilus. Mol Genet Genomics 2017; 293:277-291. [PMID: 28840320 DOI: 10.1007/s00438-017-1361-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/20/2017] [Indexed: 12/01/2022]
Abstract
Markerless gene-disruption technology is particularly useful for effective genetic analyses of Thermus thermophilus (T. thermophilus), which have a limited number of selectable markers. In an attempt to develop a novel system for the markerless disruption of genes in T. thermophilus, we applied a Cre/lox system to construct a triple gene disruptant. To achieve this, we constructed two genetic tools, a loxP-htk-loxP cassette and cre-expressing plasmid, pSH-Cre, for gene disruption and removal of the selectable marker by Cre-mediated recombination. We found that the Cre/lox system was compatible with the proliferation of the T. thermophilus HB27 strain at the lowest growth temperature (50 °C), and thus succeeded in establishing a triple gene disruptant, the (∆TTC1454::loxP, ∆TTC1535KpnI::loxP, ∆TTC1576::loxP) strain, without leaving behind a selectable marker. During the process of the sequential disruption of multiple genes, we observed the undesired deletion and inversion of the chromosomal region between multiple loxP sites that were induced by Cre-mediated recombination. Therefore, we examined the effects of a lox66-htk-lox71 cassette by exploiting the mutant lox sites, lox66 and lox71, instead of native loxP sites. We successfully constructed a (∆TTC1535::lox72, ∆TTC1537::lox72) double gene disruptant without inducing the undesired deletion of the 0.7-kbp region between the two directly oriented lox72 sites created by the Cre-mediated recombination of the lox66-htk-lox71 cassette. This is the first demonstration of a Cre/lox system being applicable to extreme thermophiles in a genetic manipulation. Our results indicate that this system is a powerful tool for multiple markerless gene disruption in T. thermophilus.
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Affiliation(s)
- Yoichiro Togawa
- Department of Applied Chemistry, National Defense Academy, Hashirimizu 1-10-20, Yokosuka, Kanagawa, 239-8686, Japan
| | - Tatsuo Nunoshiba
- College of Liberal Arts, International Christian University, Osawa 3-10-2, Mitaka, Tokyo, 181-8585, Japan
| | - Keiichiro Hiratsu
- Department of Applied Chemistry, National Defense Academy, Hashirimizu 1-10-20, Yokosuka, Kanagawa, 239-8686, Japan.
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Loder AJ, Zeldes BM, Conway JM, Counts JA, Straub CT, Khatibi PA, Lee LL, Vitko NP, Keller MW, Rhaesa AM, Rubinstein GM, Scott IM, Lipscomb GL, Adams MW, Kelly RM. Extreme Thermophiles as Metabolic Engineering Platforms: Strategies and Current Perspective. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1002/9783527807796.ch14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Andrew J. Loder
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Benjamin M. Zeldes
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Jonathan M. Conway
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - James A. Counts
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Christopher T. Straub
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Piyum A. Khatibi
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Laura L. Lee
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Nicholas P. Vitko
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
| | - Matthew W. Keller
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Amanda M. Rhaesa
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Gabe M. Rubinstein
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Israel M. Scott
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Gina L. Lipscomb
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Michael W.W. Adams
- University of Georgia; Department of Biochemistry and Molecular Biology; Life Sciences Bldg., University of Georgia, Athens GA 30602-7229, USA
| | - Robert M. Kelly
- North Carolina State University; Department of Chemical and Biomolecular Engineering; EB-1, 911 Partners Way Raleigh NC 27695-7905 USA
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