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Liang K, Zhan X, Li Y, Yang Y, Xie Y, Jin Z, Xu X, Zhang W, Lu Y, Zhang S, Zou Y, Feng S, Wu J, Yan Z. Conservation and specialization of the Ycf2-FtsHi chloroplast protein import motor in green algae. Cell 2024:S0092-8674(24)00893-6. [PMID: 39197449 DOI: 10.1016/j.cell.2024.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 05/31/2024] [Accepted: 08/05/2024] [Indexed: 09/01/2024]
Abstract
The protein import motor in chloroplasts plays a pivotal role in their biogenesis and homeostasis by driving the translocation of preproteins into chloroplasts. While the Ycf2-FtsHi complex serves as the import motor in land plants, its evolutionary conservation, specialization, and mechanisms across photosynthetic organisms are largely unexplored. Here, we isolated and determined the cryogenic electron microscopy (cryo-EM) structures of the native Ycf2-FtsHi complex from Chlamydomonas reinhardtii, uncovering a complex composed of up to 19 subunits, including multiple green-algae-specific components. The heterohexameric AAA+ ATPase motor module is tilted, potentially facilitating preprotein handover from the translocon at the inner chloroplast membrane (TIC) complex. Preprotein interacts with Ycf2-FtsHi and enhances its ATPase activity in vitro. Integrating Ycf2-FtsHi and translocon at the outer chloroplast membrane (TOC)-TIC supercomplex structures reveals insights into their physical and functional interplay during preprotein translocation. By comparing these findings with those from land plants, our study establishes a structural foundation for understanding the assembly, function, evolutionary conservation, and diversity of chloroplast protein import motors.
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Affiliation(s)
- Ke Liang
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310024, China; Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Xiechao Zhan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yuxin Li
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310024, China; Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yi Yang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Yanqiu Xie
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Zeyu Jin
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Xiaoyan Xu
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Mass Spectrometry & Metabolomics Core Facility, The Biomedical Research Core Facility, Westlake University, Hangzhou, Zhejiang 310024, China
| | - Wenwen Zhang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Mass Spectrometry & Metabolomics Core Facility, The Biomedical Research Core Facility, Westlake University, Hangzhou, Zhejiang 310024, China
| | - Yang Lu
- Westlake Four-Dimensional Dynamic Metabolomics (Meta4D) Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Research Center for the Industries of the Future, Westlake University, Hangzhou, Zhejiang, China
| | - Sheng Zhang
- Westlake Four-Dimensional Dynamic Metabolomics (Meta4D) Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Research Center for the Industries of the Future, Westlake University, Hangzhou, Zhejiang, China
| | - Yilong Zou
- Westlake Four-Dimensional Dynamic Metabolomics (Meta4D) Lab, Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Research Center for the Industries of the Future, Westlake University, Hangzhou, Zhejiang, China
| | - Shan Feng
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Mass Spectrometry & Metabolomics Core Facility, The Biomedical Research Core Facility, Westlake University, Hangzhou, Zhejiang 310024, China
| | - Jianping Wu
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China
| | - Zhen Yan
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang 310024, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang 310024, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang 310024, China.
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2
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Li X, Zhang Y, Wen X, Pan J. Utilizing codon degeneracy in the design of donor DNA for CRISPR/Cas9-mediated gene editing to streamline the screening process for single amino acid mutations. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 119:2133-2143. [PMID: 38963727 DOI: 10.1111/tpj.16903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 06/07/2024] [Accepted: 06/17/2024] [Indexed: 07/06/2024]
Abstract
Chlamydomonas reinhardtii, a unicellular green alga, has been widely used as a model organism for studies of algal, plant and ciliary biology. The generation of targeted amino acid mutations is often necessary, and this can be achieved using CRISPR/Cas9 induced homology-directed repair to install genomic modifications from exogenous donor DNA. Due to the low gene editing efficiency, the technical challenge lies in identifying the mutant cells. Direct sequencing is not practical, and pre-screening is required. Here, we report a strategy for generating and screening for amino acid point mutations using the CRISPR/Cas9 gene editing system. The strategy is based on designing donor DNA using codon degeneracy, which enables the design of specific primers to facilitate mutant screening by PCR. An in vitro assembled RNP complex, along with a dsDNA donor and an antibiotic resistance marker, was electroporated into wild-type cells, followed by PCR screening. To demonstrate this principle, we have generated the E102K mutation in centrin and the K40R mutation in α-tubulin. The editing efficiencies at the target sites for Centrin, TUA1, TUA2 were 4, 24 and 8% respectively, based on PCR screening. More than 80% of the mutants with the expected size of PCR products were precisely edited, as revealed by DNA sequencing. Subsequently, the precision-edited mutants were biochemically verified. The introduction of codon degeneracy did not affect the gene expression of centrin and α-tubulins. Thus, this approach can be used to facilitate the identification of point mutations, especially in genes with low editing rates.
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Affiliation(s)
- Xuecheng Li
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yongli Zhang
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xin Wen
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Junmin Pan
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, Shandong Province, 266000, China
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Lihanova Y, Nagel R, Jakob T, Sasso S. Characterization of activating cis-regulatory elements from the histone genes of Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 119:525-539. [PMID: 38693717 DOI: 10.1111/tpj.16781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 04/08/2024] [Accepted: 04/12/2024] [Indexed: 05/03/2024]
Abstract
Regulation of gene expression in eukaryotes is controlled by cis-regulatory modules (CRMs). A major class of CRMs are enhancers which are composed of activating cis-regulatory elements (CREs) responsible for upregulating transcription. To date, most enhancers and activating CREs have been studied in angiosperms; in contrast, our knowledge about these key regulators of gene expression in green algae is limited. In this study, we aimed at characterizing putative activating CREs/CRMs from the histone genes of the unicellular model alga Chlamydomonas reinhardtii. To test the activity of four candidates, reporter constructs consisting of a tetramerized CRE, an established promoter, and a gene for the mCerulean3 fluorescent protein were incorporated into the nuclear genome of C. reinhardtii, and their activity was quantified by flow cytometry. Two tested candidates, Eupstr and Ehist cons, significantly upregulated gene expression and were characterized in detail. Eupstr, which originates from highly expressed genes of C. reinhardtii, is an orientation-independent CRE capable of activating both the RBCS2 and β2-tubulin promoters. Ehist cons, which is a CRM from histone genes of angiosperms, upregulates the β2-tubulin promoter in C. reinhardtii over a distance of at least 1.5 kb. The octamer motif present in Ehist cons was identified in C. reinhardtii and the related green algae Chlamydomonas incerta, Chlamydomonas schloesseri, and Edaphochlamys debaryana, demonstrating its high evolutionary conservation. The results of this investigation expand our knowledge about the regulation of gene expression in green algae. Furthermore, the characterized activating CREs/CRMs can be applied as valuable genetic tools.
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Affiliation(s)
- Yuliia Lihanova
- Department of Plant Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Raimund Nagel
- Department of Plant Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Torsten Jakob
- Department of Plant Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
| | - Severin Sasso
- Department of Plant Physiology, Institute of Biology, Leipzig University, Leipzig, Germany
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4
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Einhaus A, Baier T, Kruse O. Molecular design of microalgae as sustainable cell factories. Trends Biotechnol 2024; 42:728-738. [PMID: 38092627 DOI: 10.1016/j.tibtech.2023.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 11/17/2023] [Accepted: 11/17/2023] [Indexed: 06/09/2024]
Abstract
Microalgae are regarded as sustainable and potent chassis for biotechnology. Their capacity for efficient photosynthesis fuels dynamic growth independent from organic carbon sources and converts atmospheric CO2 directly into various valuable hydrocarbon-based metabolites. However, approaches to gene expression and metabolic regulation have been inferior to those in more established heterotrophs (e.g., prokaryotes or yeast) since the genetic tools and insights in expression regulation have been distinctly less advanced. In recent years, however, these tools and their efficiency have dramatically improved. Various examples have demonstrated new trends in microalgal biotechnology and the potential of microalgae for the transition towards a sustainable bioeconomy.
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Affiliation(s)
- Alexander Einhaus
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Thomas Baier
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Olaf Kruse
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany.
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5
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Kneip JS, Kniepkamp N, Jang J, Mortaro MG, Jin E, Kruse O, Baier T. CRISPR/Cas9-Mediated Knockout of the Lycopene ε-Cyclase for Efficient Astaxanthin Production in the Green Microalga Chlamydomonas reinhardtii. PLANTS (BASEL, SWITZERLAND) 2024; 13:1393. [PMID: 38794462 PMCID: PMC11125023 DOI: 10.3390/plants13101393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/09/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024]
Abstract
Carotenoids are valuable pigments naturally occurring in all photosynthetic plants and microalgae as well as in selected fungi, bacteria, and archaea. Green microalgae developed a complex carotenoid profile suitable for efficient light harvesting and light protection and harbor great capacity for carotenoid production through the substantial power of the endogenous 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. Previous works established successful genome editing and induced significant changes in the cellular carotenoid content in Chlamydomonas reinhardtii. This study employs a tailored carotenoid pathway for engineered bioproduction of the valuable ketocarotenoid astaxanthin. Functional knockout of lycopene ε-cyclase (LCYE) and non-homologous end joining (NHEJ)-based integration of donor DNA at the target site inhibit the accumulation of α-carotene and consequently lutein and loroxanthin, abundant carotenoids in C. reinhardtii without changes in cellular fitness. PCR-based screening indicated that 4 of 96 regenerated candidate lines carried (partial) integrations of donor DNA and increased ß-carotene as well as derived carotenoid contents. Iterative overexpression of CrBKT, PacrtB, and CrCHYB resulted in a 2.3-fold increase in astaxanthin accumulation in mutant ΔLCYE#3 (1.8 mg/L) compared to the parental strain UVM4, which demonstrates the potential of genome editing for the design of a green cell factory for astaxanthin bioproduction.
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Affiliation(s)
- Jacob Sebastian Kneip
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
| | - Niklas Kniepkamp
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
| | - Junhwan Jang
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Maria Grazia Mortaro
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
| | - EonSeon Jin
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Olaf Kruse
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
| | - Thomas Baier
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, 33615 Bielefeld, Germany
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6
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Zaman QU, Raza A, Lozano-Juste J, Chao L, Jones MGK, Wang HF, Varshney RK. Engineering plants using diverse CRISPR-associated proteins and deregulation of genome-edited crops. Trends Biotechnol 2024; 42:560-574. [PMID: 37993299 DOI: 10.1016/j.tibtech.2023.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/18/2023] [Accepted: 10/18/2023] [Indexed: 11/24/2023]
Abstract
The CRISPR/Cas system comprises RNA-guided nucleases, the target specificity of which is directed by Watson-Crick base pairing of target loci with single guide (sg)RNA to induce the desired edits. CRISPR-associated proteins and other engineered nucleases are opening new avenues of research in crops to induce heritable mutations. Here, we review the diversity of CRISPR-associated proteins and strategies to deregulate genome-edited (GEd) crops by considering them to be close to natural processes. This technology ensures yield without penalties, advances plant breeding, and guarantees manipulation of the genome for desirable traits. DNA-free and off-target-free GEd crops with defined characteristics can help to achieve sustainable global food security under a changing climate, but need alignment of international regulations to operate in existing supply chains.
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Affiliation(s)
- Qamar U Zaman
- School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan Yazhou-Bay Seed Laboratory, Hainan University, Sanya, 572025, China; Collaborative Innovation Center of Nanfan and High-Efficiency Tropical Agriculture, School of Tropical Crops, Hainan University, Haikou 570228, China; Key Laboratory for Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Xudong 2nd Road, Wuhan 430062, China
| | - Ali Raza
- Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Jorge Lozano-Juste
- Instituto de Biología Molecular y Celular de Plantas, Universitat Politècnica de València, Consejo Superior de Investigaciones Científicas, Valencia 46022, Spain
| | - Li Chao
- Key Laboratory for Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Xudong 2nd Road, Wuhan 430062, China
| | - Michael G K Jones
- Centre for Crop and Food Innovation, State Agricultural Biotechnology Centre, Murdoch University, Perth, WA 6150, Australia
| | - Hua-Feng Wang
- School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan Yazhou-Bay Seed Laboratory, Hainan University, Sanya, 572025, China; Collaborative Innovation Center of Nanfan and High-Efficiency Tropical Agriculture, School of Tropical Crops, Hainan University, Haikou 570228, China.
| | - Rajeev K Varshney
- Centre for Crop and Food Innovation, State Agricultural Biotechnology Centre, Murdoch University, Perth, WA 6150, Australia.
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7
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Strenkert D, Schmollinger S, Paruthiyil S, Brown BC, Green S, Shafer CM, Salomé P, Nelson H, Blaby-Haas CE, Moseley JL, Merchant SS. Distinct function of Chlamydomonas CTRA-CTR transporters in Cu assimilation and intracellular mobilization. Metallomics 2024; 16:mfae013. [PMID: 38439674 PMCID: PMC10959442 DOI: 10.1093/mtomcs/mfae013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 03/02/2024] [Indexed: 03/06/2024]
Abstract
Successful acclimation to copper (Cu) deficiency involves a fine balance between Cu import and export. In the green alga Chlamydomonas reinhardtii, Cu import is dependent on a transcription factor, Copper Response Regulator 1 (CRR1), responsible for activating genes in Cu-deficient cells. Among CRR1 target genes are two Cu transporters belonging to the CTR/COPT gene family (CTR1 and CTR2) and a related soluble protein (CTR3). The ancestor of these green algal proteins was likely acquired from an ancient chytrid and contained conserved cysteine-rich domains (named the CTR-associated domains, CTRA) that are predicted to be involved in Cu acquisition. We show by reverse genetics that Chlamydomonas CTR1 and CTR2 are canonical Cu importers albeit with distinct affinities, while loss of CTR3 did not result in an observable phenotype under the conditions tested. Mutation of CTR1, but not CTR2, recapitulates the poor growth of crr1 in Cu-deficient medium, consistent with a dominant role for CTR1 in high-affinity Cu(I) uptake. On the other hand, the overaccumulation of Cu(I) (20 times the quota) in zinc (Zn) deficiency depends on CRR1 and both CTR1 and CTR2. CRR1-dependent activation of CTR gene expression needed for Cu over-accumulation can be bypassed by the provision of excess Cu in the growth medium. Over-accumulated Cu is sequestered into the acidocalcisome but can become remobilized by restoring Zn nutrition. This mobilization is also CRR1-dependent, and requires activation of CTR2 expression, again distinguishing CTR2 from CTR1 and consistent with the lower substrate affinity of CTR2. ONE SENTENCE SUMMARY Regulation of Cu uptake and sequestration by members of the CTR family of proteins in Chlamydomonas.
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Affiliation(s)
- Daniela Strenkert
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Stefan Schmollinger
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Srinand Paruthiyil
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Bonnie C Brown
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Sydnee Green
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Catherine M Shafer
- Molecular Toxicology Inter-departmental Ph.D. program, University of California, Los Angeles, CA 90095, USA
| | - Patrice Salomé
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095, USA
| | - Hosea Nelson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Crysten E Blaby-Haas
- Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jeffrey L Moseley
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - Sabeeha S Merchant
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
- Institute for Genomics and Proteomics, University of California, Los Angeles, CA 90095, USA
- Department of Molecular and Cell Biology and Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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8
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Tóth D, Kuntam S, Ferenczi Á, Vidal-Meireles A, Kovács L, Wang L, Sarkadi Z, Migh E, Szentmihályi K, Tengölics R, Neupert J, Bock R, Jonikas MC, Molnar A, Tóth SZ. Chloroplast phosphate transporter CrPHT4-7 regulates phosphate homeostasis and photosynthesis in Chlamydomonas. PLANT PHYSIOLOGY 2024; 194:1646-1661. [PMID: 37962583 PMCID: PMC10904345 DOI: 10.1093/plphys/kiad607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/18/2023] [Accepted: 10/19/2023] [Indexed: 11/15/2023]
Abstract
In eukaryotic cells, phosphorus is assimilated and utilized primarily as phosphate (Pi). Pi homeostasis is mediated by transporters that have not yet been adequately characterized in green algae. This study reports on PHOSPHATE TRANSPORTER 4-7 (CrPHT4-7) from Chlamydomonas reinhardtii, a member of the PHT4 transporter family, which exhibits remarkable similarity to AtPHT4;4 from Arabidopsis (Arabidopsis thaliana), a chloroplastic ascorbate transporter. Using fluorescent protein tagging, we show that CrPHT4-7 resides in the chloroplast envelope membrane. Crpht4-7 mutants, generated by the CRISPR/Cas12a-mediated single-strand templated repair, show retarded growth, especially in high light, reduced ATP level, strong ascorbate accumulation, and diminished non-photochemical quenching in high light. On the other hand, total cellular phosphorous content was unaffected, and the phenotype of the Crpht4-7 mutants could not be alleviated by ample Pi supply. CrPHT4-7-overexpressing lines exhibit enhanced biomass accumulation under high light conditions in comparison with the wild-type strain. Expressing CrPHT4-7 in a yeast (Saccharomyces cerevisiae) strain lacking Pi transporters substantially recovered its slow growth phenotype, demonstrating that CrPHT4-7 transports Pi. Even though CrPHT4-7 shows a high degree of similarity to AtPHT4;4, it does not display any substantial ascorbate transport activity in yeast or intact algal cells. Thus, the results demonstrate that CrPHT4-7 functions as a chloroplastic Pi transporter essential for maintaining Pi homeostasis and photosynthesis in C. reinhardtii.
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Affiliation(s)
- Dávid Tóth
- Institute of Plant Biology, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
- Doctoral School of Biology, University of Szeged, H-6722 Szeged, Hungary
| | - Soujanya Kuntam
- Institute of Plant Biology, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
| | - Áron Ferenczi
- Institute of Molecular Plant Sciences, School of Biological Sciences, King's Buildings, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - André Vidal-Meireles
- Institute of Plant Biology, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
| | - László Kovács
- Institute of Plant Biology, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
| | - Lianyong Wang
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Princeton, NJ 08544, USA
| | - Zsuzsa Sarkadi
- Institute of Biochemistry, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
- Hungarian Centre of Excellence for Molecular Medicine—Biological Research Centre Metabolic Systems Biology Research Group, H-6726 Szeged, Hungary
| | - Ede Migh
- Institute of Biochemistry, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
| | - Klára Szentmihályi
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, H-1117 Budapest, Hungary
| | - Roland Tengölics
- Hungarian Centre of Excellence for Molecular Medicine—Biological Research Centre Metabolic Systems Biology Research Group, H-6726 Szeged, Hungary
- Metabolomics Lab, Core Facilities, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
| | - Juliane Neupert
- Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany
| | - Martin C Jonikas
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Princeton, NJ 08544, USA
- Howard Hughes Medical Institute, Princeton University, Lewis Thomas Laboratory, Princeton, NJ 08544, USA
| | - Attila Molnar
- Institute of Molecular Plant Sciences, School of Biological Sciences, King's Buildings, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Szilvia Z Tóth
- Institute of Plant Biology, HUN-REN Biological Research Centre, H-6726 Szeged, Hungary
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9
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Nomura T, Kim J, Ishikawa M, Suzuki K, Mochida K. High-efficiency genome editing by Cas12a ribonucleoprotein complex in Euglena gracilis. Microb Biotechnol 2024; 17:e14393. [PMID: 38332568 PMCID: PMC10884871 DOI: 10.1111/1751-7915.14393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 11/18/2023] [Accepted: 12/19/2023] [Indexed: 02/10/2024] Open
Abstract
Transgene-free genome editing based on clustered regularly interspaced short palindromic repeats (CRISPR) technology is key to achieving genetic engineering in microalgae for basic research and industrial applications. Euglena gracilis, a unicellular phytoflagellate microalga, is a promising biomaterial for foods, feeds, cosmetics and biofuels. However, methods for the genetic manipulation of E. gracilis are still limited. Here, we developed a high-efficiency, transgene-free genome editing method for E. gracilis using Lachnospiraceae bacterium CRISPR-associated protein 12a (LbCas12a) ribonucleoprotein (RNP) complex, which complements the previously established Cas9 RNP-based method. Through the direct delivery of LbCas12a-containing RNPs, our method reached mutagenesis rates of approximately 77.2-94.5% at two different E. gracilis target genes, Glucan synthase-like 2 (EgGSL2) and a phytoene synthase gene (EgcrtB). Moreover, in addition to targeted mutagenesis, we demonstrated efficient knock-in and base editing at the target site using LbCas12a-based RNPs with a single-stranded DNA donor template in E. gracilis. This study extends the genetic engineering capabilities of Euglena to accelerate its basic use for research and engineering for bioproduction.
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Affiliation(s)
- Toshihisa Nomura
- RIKEN Center for Sustainable Resource ScienceYokohamaJapan
- RIKEN Baton Zone ProgramYokohamaJapan
- Faculty of AgricultureYamagata UniversityTsuruokaJapan
| | - June‐Silk Kim
- RIKEN Center for Sustainable Resource ScienceYokohamaJapan
- Institute of Plant Science and ResourcesOkayama UniversityOkayamaJapan
| | - Marumi Ishikawa
- RIKEN Baton Zone ProgramYokohamaJapan
- Euglena Co., Ltd.TokyoJapan
| | - Kengo Suzuki
- RIKEN Baton Zone ProgramYokohamaJapan
- Euglena Co., Ltd.TokyoJapan
| | - Keiichi Mochida
- RIKEN Center for Sustainable Resource ScienceYokohamaJapan
- RIKEN Baton Zone ProgramYokohamaJapan
- Kihara Institute for Biological ResearchYokohama City UniversityYokohamaKanagawaJapan
- Graduate School of NanobioscienceYokohama City UniversityYokohamaKanagawaJapan
- School of Information and Data SciencesNagasaki UniversityNagasakiJapan
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10
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Knoshaug EP, Sun P, Nag A, Nguyen H, Mattoon EM, Zhang N, Liu J, Chen C, Cheng J, Zhang R, St. John P, Umen J. Identification and preliminary characterization of conserved uncharacterized proteins from Chlamydomonas reinhardtii, Arabidopsis thaliana, and Setaria viridis. PLANT DIRECT 2023; 7:e527. [PMID: 38044962 PMCID: PMC10690477 DOI: 10.1002/pld3.527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/03/2023] [Accepted: 08/11/2023] [Indexed: 12/05/2023]
Abstract
The rapid accumulation of sequenced plant genomes in the past decade has outpaced the still difficult problem of genome-wide protein-coding gene annotation. A substantial fraction of protein-coding genes in all plant genomes are poorly annotated or unannotated and remain functionally uncharacterized. We identified unannotated proteins in three model organisms representing distinct branches of the green lineage (Viridiplantae): Arabidopsis thaliana (eudicot), Setaria viridis (monocot), and Chlamydomonas reinhardtii (Chlorophyte alga). Using similarity searching, we identified a subset of unannotated proteins that were conserved between these species and defined them as Deep Green proteins. Bioinformatic, genomic, and structural predictions were performed to begin classifying Deep Green genes and proteins. Compared to whole proteomes for each species, the Deep Green set was enriched for proteins with predicted chloroplast targeting signals predictive of photosynthetic or plastid functions, a result that was consistent with enrichment for daylight phase diurnal expression patterning. Structural predictions using AlphaFold and comparisons to known structures showed that a significant proportion of Deep Green proteins may possess novel folds. Though only available for three organisms, the Deep Green genes and proteins provide a starting resource of high-value targets for further investigation of potentially new protein structures and functions conserved across the green lineage.
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Affiliation(s)
- Eric P. Knoshaug
- Biosciences CenterNational Renewable Energy LaboratoryGoldenColoradoUSA
| | - Peipei Sun
- Donald Danforth Plant Science CenterSt. LouisMOUSA
| | - Ambarish Nag
- Computational Sciences CenterNational Renewable Energy LaboratoryGoldenColoradoUSA
| | - Huong Nguyen
- Donald Danforth Plant Science CenterSt. LouisMOUSA
- Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil ScienceTexas Tech UniversityLubbockTexasUSA
| | - Erin M. Mattoon
- Donald Danforth Plant Science CenterSt. LouisMOUSA
- Plant and Microbial Biosciences Program, Division of Biology and Biomedical SciencesWashington University in Saint LouisSt. LouisMissouriUSA
| | | | - Jian Liu
- Department of Electrical Engineering and Computer ScienceUniversity of MissouriColumbiaMissouriUSA
| | - Chen Chen
- Department of Electrical Engineering and Computer ScienceUniversity of MissouriColumbiaMissouriUSA
| | - Jianlin Cheng
- Department of Electrical Engineering and Computer ScienceUniversity of MissouriColumbiaMissouriUSA
| | - Ru Zhang
- Donald Danforth Plant Science CenterSt. LouisMOUSA
| | - Peter St. John
- Biosciences CenterNational Renewable Energy LaboratoryGoldenColoradoUSA
| | - James Umen
- Donald Danforth Plant Science CenterSt. LouisMOUSA
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11
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Chaux F, Jarrige D, Rodrigues-Azevedo M, Bujaldon S, Caspari OD, Ozawa SI, Drapier D, Vallon O, Choquet Y, de Vitry C. Chloroplast ATP synthase biogenesis requires peripheral stalk subunits AtpF and ATPG and stabilization of atpE mRNA by OPR protein MDE1. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:1582-1599. [PMID: 37824282 DOI: 10.1111/tpj.16448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/15/2023] [Accepted: 08/21/2023] [Indexed: 10/14/2023]
Abstract
Chloroplast ATP synthase contains subunits of plastid and nuclear genetic origin. To investigate the coordinated biogenesis of this complex, we isolated novel ATP synthase mutants in the green alga Chlamydomonas reinhardtii by screening for high light sensitivity. We report here the characterization of mutants affecting the two peripheral stalk subunits b and b', encoded respectively by the atpF and ATPG genes, and of three independent mutants which identify the nuclear factor MDE1, required to stabilize the chloroplast-encoded atpE mRNA. Whole-genome sequencing revealed a transposon insertion in the 3'UTR of ATPG while mass spectrometry shows a small accumulation of functional ATP synthase in this knock-down ATPG mutant. In contrast, knock-out ATPG mutants, obtained by CRISPR-Cas9 gene editing, fully prevent ATP synthase function and accumulation, as also observed in an atpF frame-shift mutant. Crossing ATP synthase mutants with the ftsh1-1 mutant of the major thylakoid protease identifies AtpH as an FTSH substrate, and shows that FTSH significantly contributes to the concerted accumulation of ATP synthase subunits. In mde1 mutants, the absence of atpE transcript fully prevents ATP synthase biogenesis and photosynthesis. Using chimeric atpE genes to rescue atpE transcript accumulation, we demonstrate that MDE1, a novel octotricopeptide repeat (OPR) protein, genetically targets the atpE 5'UTR. In the perspective of the primary endosymbiosis (~1.5 Gy), the recruitment of MDE1 to its atpE target exemplifies a nucleus/chloroplast interplay that evolved rather recently, in the ancestor of the CS clade of Chlorophyceae, ~300 My ago.
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Affiliation(s)
- Frédéric Chaux
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Domitille Jarrige
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Marcio Rodrigues-Azevedo
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Sandrine Bujaldon
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Oliver D Caspari
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Shin-Ichiro Ozawa
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Dominique Drapier
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Olivier Vallon
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Yves Choquet
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
| | - Catherine de Vitry
- Unité Mixte de Recherche (UMR) 7141, Centre National de la Recherche Scientifique (CNRS) and Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, F-75005, Paris, France
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12
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Strenkert D, Schmollinger S, Paruthiyil S, Brown BC, Green S, Shafer CM, Salomé P, Nelson H, Blaby-Haas CE, Moseley JL, Merchant SS. Distinct function of Chlamydomonas CTRA-CTR transporters in Cu assimilation and intracellular mobilization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.19.563170. [PMID: 37905083 PMCID: PMC10614975 DOI: 10.1101/2023.10.19.563170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Successful acclimation to copper (Cu) deficiency involves a fine balance between Cu import and export. In the unicellular green alga Chlamydomonas reinhardtii , Cu import is dependent on C opper R esponse R egulator 1 (CRR1), the master regulator of Cu homeostasis. Among CRR1 target genes are two Cu transporters belonging to the CTR/COPT gene family ( CTR1 and CTR2 ) and a related soluble cysteine-rich protein (CTR3). The ancestor of these green algal proteins was likely acquired from an ancient chytrid and contained conserved cysteine-rich domains (named the CTR-associated domains, CTRA) that are predicted to be involved in Cu acquisition. We show by reverse genetics that Chlamydomonas CTR1 and CTR2 are canonical Cu importers albeit with distinct affinities, while loss of CTR3 did not result in an observable phenotype under the conditions tested. Mutation of CTR1 , but not CTR2 , recapitulate the poor growth of crr1 in Cu-deficient medium, consistent with a dominant role for CTR1 in high affinity Cu(I) uptake. Notably, the over-accumulation of Cu(I) in Zinc (Zn)-deficiency (20 times the quota) depends on CRR1 and both CTR1 and CTR2. CRR1-dependent activation of CTR gene expression needed for Cu over-accumulation can be bypassed by the provision of excess Cu in the growth medium. Over-accumulated Cu is sequestered into the acidocalcisome but can become remobilized by restoring Zn nutrition. This mobilization is also CRR1-dependent, and requires activation of CTR2 expression, again distinguishing CTR2 from CTR1 and is consistent with the lower substrate affinity of CTR2.
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13
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Ding L, Xu X, Wang X, Chen X, Lu Y, Xu J, Peng C. Qualitative and Quantitative Detection of CRISPR-Associated Cas Gene in Gene-Edited Foods. Foods 2023; 12:3681. [PMID: 37835336 PMCID: PMC10572612 DOI: 10.3390/foods12193681] [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: 08/22/2023] [Revised: 09/14/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023] Open
Abstract
Effective regulation of gene-edited products and resolution of public concerns are the prerequisites for the industrialization of gene-edited crops and their derived foods. CRISPR-associated protein, the core element of the CRISPR system, requires to be regulated. Thus, there is an urgent need to establish qualitative and quantitative detection methods for the Cas gene. In the present study, the primers and probes were designed and screened for Cas12a (Cpf1), which is the most commonly used target site in gene editing; we performed PCR system optimization, determined the optimal primer concentration and annealing temperature, and established qualitative PCR and quantitative PCR (qPCR) assays for detecting Cpf1 in gene editing by specificity and sensitivity tests. In specificity testing, qualitative PCR and qPCR methods could 100% detect samples containing Cpf1 DNA, while the detection rate of other samples without Cpf1 was 0%. In the assay sensitivity test, the limit of detection of qualitative PCR was 0.1% (approximately 44 copies), and the limit of detection of the qPCR method was 14 copies. In the stability test, both the qualitative PCR and qPCR methods were repeated 60 times at their corresponding lowest detection limit concentrations, and the results were positive. Thus, the qualitative and quantitative assays for Cpf1 are specific, sensitive, and stable. The method provides technical support for the effective monitoring of gene-edited products and their derived foods in the future.
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Affiliation(s)
- Lin Ding
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Traceability for Agricultural Genetically Modified Organisms, Ministry of Agriculture and Rural Affairs, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Xiaoli Xu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Traceability for Agricultural Genetically Modified Organisms, Ministry of Agriculture and Rural Affairs, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Xiaofu Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Traceability for Agricultural Genetically Modified Organisms, Ministry of Agriculture and Rural Affairs, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Xiaoyun Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Traceability for Agricultural Genetically Modified Organisms, Ministry of Agriculture and Rural Affairs, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Yuwen Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
| | - Junfeng Xu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Traceability for Agricultural Genetically Modified Organisms, Ministry of Agriculture and Rural Affairs, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Cheng Peng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Traceability for Agricultural Genetically Modified Organisms, Ministry of Agriculture and Rural Affairs, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
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14
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Gu X, Huang L, Lian J. Biomanufacturing of γ-linolenic acid-enriched galactosyldiacylglycerols: Challenges in microalgae and potential in oleaginous yeasts. Synth Syst Biotechnol 2023; 8:469-478. [PMID: 37692201 PMCID: PMC10485790 DOI: 10.1016/j.synbio.2023.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/20/2023] [Accepted: 06/25/2023] [Indexed: 09/12/2023] Open
Abstract
γ-Linolenic acid-enriched galactosyldiacylglycerols (GDGs-GLA), as the natural form of γ-linolenic acid in microalgae, have a range of functional activities, including anti-inflammatory, antioxidant, and anti-allergic properties. The low abundance of microalgae and the structural stereoselectivity complexity impede microalgae extraction or chemical synthesis, resulting in a lack of supply of GDGs-GLA with a growing demand. At present, there is a growing interest in engineering oleaginous yeasts for mass production of GDGs-GLA based on their ability to utilize a variety of hydrophobic substrates and a high metabolic flux toward fatty acid and lipid (triacylglycerol, TAG) production. Here, we first introduce the GDGs-GLA biosynthetic pathway in microalgae and challenges in the engineering of the native host. Subsequently, we describe in detail the applications of oleaginous yeasts with Yarrowia lipolytica as the representative for GDGs-GLA biosynthesis, including the development of synthetic biology parts, gene editing tools, and metabolic engineering of lipid biosynthesis. Finally, we discuss the development trend of GDGs-GLA biosynthesis in Y. lipolytica.
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Affiliation(s)
- Xiaosong Gu
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311215, China
| | - Lei Huang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311215, China
| | - Jiazhang Lian
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China
- ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, 311215, China
- Zhejiang Key Laboratory of Smart Biomaterials, Zhejiang University, Hangzhou, 310027, China
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15
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Boisset ND, Favoino G, Meloni M, Jomat L, Cassier-Chauvat C, Zaffagnini M, Lemaire SD, Crozet P. Phosphoribulokinase abundance is not limiting the Calvin-Benson-Bassham cycle in Chlamydomonas reinhardtii. FRONTIERS IN PLANT SCIENCE 2023; 14:1230723. [PMID: 37719215 PMCID: PMC10501310 DOI: 10.3389/fpls.2023.1230723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 07/21/2023] [Indexed: 09/19/2023]
Abstract
Improving photosynthetic efficiency in plants and microalgae is of utmost importance to support the growing world population and to enable the bioproduction of energy and chemicals. Limitations in photosynthetic light conversion efficiency can be directly attributed to kinetic bottlenecks within the Calvin-Benson-Bassham cycle (CBBC) responsible for carbon fixation. A better understanding of these bottlenecks in vivo is crucial to overcome these limiting factors through bio-engineering. The present study is focused on the analysis of phosphoribulokinase (PRK) in the unicellular green alga Chlamydomonas reinhardtii. We have characterized a PRK knock-out mutant strain and showed that in the absence of PRK, Chlamydomonas cannot grow photoautotrophically while functional complementation with a synthetic construct allowed restoration of photoautotrophy. Nevertheless, using standard genetic elements, the expression of PRK was limited to 40% of the reference level in complemented strains and could not restore normal growth in photoautotrophic conditions suggesting that the CBBC is limited. We were subsequently able to overcome this initial limitation by improving the design of the transcriptional unit expressing PRK using diverse combinations of DNA parts including PRK endogenous promoter and introns. This enabled us to obtain strains with PRK levels comparable to the reference strain and even overexpressing strains. A collection of strains with PRK levels between 16% and 250% of WT PRK levels was generated and characterized. Immunoblot and growth assays revealed that a PRK content of ≈86% is sufficient to fully restore photoautotrophic growth. This result suggests that PRK is present in moderate excess in Chlamydomonas. Consistently, the overexpression of PRK did not increase photosynthetic growth indicating that that the endogenous level of PRK in Chlamydomonas is not limiting the Calvin-Benson-Bassham cycle under optimal conditions.
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Affiliation(s)
- Nicolas D. Boisset
- Laboratoire de Biologie Computationnelle et Quantitative, Institut de Biologie Parie-Seine, Sorbonne Université, CNRS, UMR 7238, Paris, France
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Sorbonne Université, CNRS, UMR 8226, Paris, France
- Doctoral School of Plant Sciences, Université Paris-Saclay, Saint-Aubin, France
| | - Giusi Favoino
- Laboratoire de Biologie Computationnelle et Quantitative, Institut de Biologie Parie-Seine, Sorbonne Université, CNRS, UMR 7238, Paris, France
| | - Maria Meloni
- Department of Pharmacy and Biotechnologies, University of Bologna, Bologna, Italy
| | - Lucile Jomat
- Laboratoire de Biologie Computationnelle et Quantitative, Institut de Biologie Parie-Seine, Sorbonne Université, CNRS, UMR 7238, Paris, France
| | - Corinne Cassier-Chauvat
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), UMR 9198, Gif-sur-Yvette, France
| | - Mirko Zaffagnini
- Department of Pharmacy and Biotechnologies, University of Bologna, Bologna, Italy
| | - Stéphane D. Lemaire
- Laboratoire de Biologie Computationnelle et Quantitative, Institut de Biologie Parie-Seine, Sorbonne Université, CNRS, UMR 7238, Paris, France
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Sorbonne Université, CNRS, UMR 8226, Paris, France
| | - Pierre Crozet
- Laboratoire de Biologie Computationnelle et Quantitative, Institut de Biologie Parie-Seine, Sorbonne Université, CNRS, UMR 7238, Paris, France
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Sorbonne Université, CNRS, UMR 8226, Paris, France
- Polytech-Sorbonne, Sorbonne Université, Paris, France
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16
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Nievergelt AP, Diener DR, Bogdanova A, Brown T, Pigino G. Efficient precision editing of endogenous Chlamydomonas reinhardtii genes with CRISPR-Cas. CELL REPORTS METHODS 2023; 3:100562. [PMID: 37671018 PMCID: PMC10475843 DOI: 10.1016/j.crmeth.2023.100562] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/11/2022] [Accepted: 07/28/2023] [Indexed: 09/07/2023]
Abstract
CRISPR-Cas genome engineering in the unicellular green algal model Chlamydomonas reinhardtii has until now been primarily applied to targeted gene disruption, whereas scarless knockin transgenesis has generally been considered difficult in practice. We have developed an efficient homology-directed method for knockin mutagenesis in Chlamydomonas by delivering CRISPR-Cas ribonucleoproteins and a linear double-stranded DNA (dsDNA) donor into cells by electroporation. Our method allows scarless integration of fusion tags and sequence modifications of proteins without the need for a preceding mutant line. We also present methods for high-throughput crossing of transformants and a custom quantitative PCR (qPCR)-based high-throughput screening of mutants as well as meiotic progeny. We demonstrate how to use this pipeline to facilitate the generation of mutant lines without residual selectable markers by co-targeted insertion. Finally, we describe how insertional cassettes can be erroneously mutated during insertion and suggest strategies to select for lines that are modified as designed.
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Affiliation(s)
- Adrian Pascal Nievergelt
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Dennis Ray Diener
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Aliona Bogdanova
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Thomas Brown
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
- DRESDEN-concept Genome Center (DcGC), Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Dresden, Germany
| | - Gaia Pigino
- Human Technopole, V.le Rita Levi-Montalcini, 1, 20017 Milan, Italy
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17
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Zadabbas Shahabadi H, Akbarzadeh A, Ofoghi H, Kadkhodaei S. Site-specific gene knock-in and bacterial phytase gene expression in Chlamydomonas reinhardtii via Cas9 RNP-mediated HDR. FRONTIERS IN PLANT SCIENCE 2023; 14:1150436. [PMID: 37275253 PMCID: PMC10235511 DOI: 10.3389/fpls.2023.1150436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 03/28/2023] [Indexed: 06/07/2023]
Abstract
In the present study, we applied the HDR (homology-directed DNA repair) CRISPR-Cas9-mediated knock-in system to accurately insert an optimized foreign bacterial phytase gene at a specific site of the nitrate reductase (NR) gene (exon 2) to achieve homologous recombination with the stability of the transgene and reduce insertion site effects or gene silencing. To this end, we successfully knocked-in the targeted NR gene of Chlamydomonas reinhardtii using the bacterial phytase gene cassette through direct delivery of the CRISPR/Cas9 system as the ribonucleoprotein (RNP) complex consisting of Cas9 protein and the specific single guide RNAs (sgRNAs). The NR insertion site editing was confirmed by PCR and sequencing of the transgene positive clones. Moreover, 24 clones with correct editing were obtained, where the phytase gene cassette was located in exon 2 of the NR gene, and the editing efficiency was determined to be 14.81%. Additionally, site-specific gene expression was analyzed and confirmed using RT-qPCR. Cultivation of the positive knocked-in colonies on the selective media during 10 generations indicated the stability of the correct editing without gene silencing or negative insertion site effects. Our results demonstrated that CRISPR-Cas9-mediated knock-in could be applied for nuclear expression of the heterologous gene of interest, and also confirmed its efficacy as an effective tool for site-specific gene knock-in, avoiding nuclear positional effects and gene silencing in C. reinhardtii. These findings could also provide a new perspective on the advantageous application of RNP-CRISPR/Cas9 gene-editing to accelerate the commercial production of complex recombinant proteins in the food-grade organism "C. reinhardtii".
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Affiliation(s)
- Hassan Zadabbas Shahabadi
- Department of Fisheries, Faculty of Marine Science and Technology, University of Hormozgan, Bandar Abbas, Iran
- Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran
- Agricultural Biotechnology Research Institute of Iran (ABRII), Isfahan Branch, Agricultural Research, Education and Extension Organization (AREEO), Isfahan, Iran
| | - Arash Akbarzadeh
- Department of Fisheries, Faculty of Marine Science and Technology, University of Hormozgan, Bandar Abbas, Iran
| | - Hamideh Ofoghi
- Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran
| | - Saeid Kadkhodaei
- Agricultural Biotechnology Research Institute of Iran (ABRII), Isfahan Branch, Agricultural Research, Education and Extension Organization (AREEO), Isfahan, Iran
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18
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Kolackova M, Janova A, Dobesova M, Zvalova M, Chaloupsky P, Krystofova O, Adam V, Huska D. Role of secondary metabolites in distressed microalgae. ENVIRONMENTAL RESEARCH 2023; 224:115392. [PMID: 36746204 DOI: 10.1016/j.envres.2023.115392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/09/2023] [Accepted: 01/28/2023] [Indexed: 06/18/2023]
Abstract
Proficient photosynthetic microalgae/cyanobacteria produce a remarkable amount of various biomolecules. Secondary metabolites (SM) represent high value products for global biotrend application. Production improvement can be achieved by nutritional, environmental, and physiological stress as a first line tools for their stimulation. In recent decade, an increasing interest in algal stress biology and omics techniques have deepened knowledge in this area. However, deep understanding and connection of specific stress elucidator are missing. Hence, the present review summarizes recent evidence with an emphasis on the carotenoids, phenolic, and less-discussed compounds (glycerol, proline, mycosporins-like amino acids). Even when they are synthesized at very low concentrations, it highlights the need to expand knowledge in this area using genome-editing tools and omics approaches.
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Affiliation(s)
- Martina Kolackova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Anna Janova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Marketa Dobesova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Monika Zvalova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Pavel Chaloupsky
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Olga Krystofova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Vojtech Adam
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic
| | - Dalibor Huska
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, 613 00, Brno, Czech Republic.
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19
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Chen H, Yang QL, Xu JX, Deng X, Zhang YJ, Liu T, Rots MG, Xu GL, Huang KY. Efficient methods for multiple types of precise gene-editing in Chlamydomonas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023. [PMID: 37310200 DOI: 10.1111/tpj.16265] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 04/20/2023] [Accepted: 04/26/2023] [Indexed: 06/14/2023]
Abstract
Precise gene-editing using CRISPR/Cas9 technology remains a long-standing challenge, especially for genes with low expression and no selectable phenotypes in Chlamydomonas reinhardtii, a classic model for photosynthesis and cilia research. Here, we developed a multi-type and precise genetic manipulation method in which a DNA break was generated by Cas9 nuclease and the repair was mediated using a homologous DNA template. The efficacy of this method was demonstrated for several types of gene editing, including inactivation of two low-expression genes (CrTET1 and CrKU80), the introduction of a FLAG-HA epitope tag into VIPP1, IFT46, CrTET1 and CrKU80 genes, and placing a YFP tag into VIPP1 and IFT46 for live-cell imaging. We also successfully performed a single amino acid substitution for the FLA3, FLA10 and FTSY genes, and documented the attainment of the anticipated phenotypes. Lastly, we demonstrated that precise fragment deletion from the 3'-UTR of MAA7 and VIPP1 resulted in a stable knock-down effect. Overall, our study has established efficient methods for multiple types of precise gene editing in Chlamydomonas, enabling substitution, insertion and deletion at the base resolution, thus improving the potential of this alga in both basic research and industrial applications.
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Affiliation(s)
- Hui Chen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Qing-Lin Yang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Jia-Xi Xu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xuan Deng
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Yun-Jie Zhang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Ting Liu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Marianne G Rots
- Department of Pathology and Medical Biology, University of Groningen, University Medical Center Groningen, 9713 GZ, Groningen, The Netherlands
| | - Guo-Liang Xu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
- Shanghai Key Laboratory of Medical Epigenetics, Laboratory of Cancer Epigenetics, Institutes of Biomedical Sciences, Medical College of Fudan University, Chinese Academy of Medical Sciences (RU069), Shanghai, China
| | - Kai-Yao Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
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20
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Jeong BR, Jang J, Jin E. Genome engineering via gene editing technologies in microalgae. BIORESOURCE TECHNOLOGY 2023; 373:128701. [PMID: 36746216 DOI: 10.1016/j.biortech.2023.128701] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 01/27/2023] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
CRISPR-Cas has revolutionized genetic modification with its comparative simplicity and accuracy, and it can be used even at the genomic level. Microalgae are excellent feedstocks for biofuels and nutraceuticals because they contain high levels of fatty acids, carotenoids, and other metabolites; however, genome engineering for microalgae is not yet as developed as for other model organisms. Microalgal engineering at the genetic and metabolic levels is relatively well established, and a few genomic resources are available. Their genomic information was used for a "safe harbor" site for stable transgene expression in microalgae. This review proposes further genome engineering schemes including the construction of sgRNA libraries, pan-genomic and epigenomic resources, and mini-genomes, which can together be developed into synthetic biology for carbon-based engineering in microalgae. Acetyl-CoA is at the center of carbon metabolic pathways and is further reviewed for the production of molecules including terpenoids in microalgae.
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Affiliation(s)
- Byeong-Ryool Jeong
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - Junhwan Jang
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea
| | - EonSeon Jin
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea; Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Seoul 04763, Korea.
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21
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Belshaw N, Grouneva I, Aram L, Gal A, Hopes A, Mock T. Efficient gene replacement by CRISPR/Cas-mediated homologous recombination in the model diatom Thalassiosira pseudonana. THE NEW PHYTOLOGIST 2023; 238:438-452. [PMID: 36307966 DOI: 10.1111/nph.18587] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
CRISPR/Cas enables targeted genome editing in many different plant and algal species including the model diatom Thalassiosira pseudonana. However, efficient gene targeting by homologous recombination (HR) to date is only reported for photosynthetic organisms in their haploid life-cycle phase. Here, a CRISPR/Cas construct, assembled using Golden Gate cloning, enabled highly efficient HR in a diploid photosynthetic organism. Homologous recombination was induced in T. pseudonana using sequence-specific CRISPR/Cas, paired with a dsDNA donor matrix, generating substitution of the silacidin, nitrate reductase and urease genes by a resistance cassette (FCP:NAT). Up to c. 85% of NAT-resistant T. pseudonana colonies screened positive for HR by nested PCR. Precise integration of FCP:NAT at each locus was confirmed using an inverse PCR approach. The knockout of the nitrate reductase and urease genes impacted growth on nitrate and urea, respectively, while the knockout of the silacidin gene in T. pseudonana caused a significant increase in cell size, confirming the role of this gene for cell-size regulation in centric diatoms. Highly efficient gene targeting by HR makes T. pseudonana as genetically tractable as Nannochloropsis and Physcomitrella, hence rapidly advancing functional diatom biology, bionanotechnology and biotechnological applications targeted on harnessing the metabolic potential of diatoms.
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Affiliation(s)
- Nigel Belshaw
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Irina Grouneva
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Lior Aram
- Department of Plant and Environmental Sciences, Faculty of Biochemistry, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Assaf Gal
- Department of Plant and Environmental Sciences, Faculty of Biochemistry, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Amanda Hopes
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
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22
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Payne ZL, Penny GM, Turner TN, Dutcher SK. A gap-free genome assembly of Chlamydomonas reinhardtii and detection of translocations induced by CRISPR-mediated mutagenesis. PLANT COMMUNICATIONS 2023; 4:100493. [PMID: 36397679 PMCID: PMC10030371 DOI: 10.1016/j.xplc.2022.100493] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/26/2022] [Accepted: 11/15/2022] [Indexed: 05/04/2023]
Abstract
Genomic assemblies of the unicellular green alga Chlamydomonas reinhardtii have provided important resources for researchers. However, assembly errors, large gaps, and unplaced scaffolds as well as strain-specific variants currently impede many types of analysis. By combining PacBio HiFi and Oxford Nanopore long-read technologies, we generated a de novo genome assembly for strain CC-5816, derived from crosses of strains CC-125 and CC-124. Multiple methods of evaluating genome completeness and base-pair error rate suggest that the final telomere-to-telomere assembly is highly accurate. The CC-5816 assembly enabled previously difficult analyses that include characterization of the 17 centromeres, rDNA arrays on three chromosomes, and 56 insertions of organellar DNA into the nuclear genome. Using Nanopore sequencing, we identified sites of cytosine (CpG) methylation, which are enriched at centromeres. We analyzed CRISPR-Cas9 insertional mutants in the PF23 gene. Two of the three alleles produced progeny that displayed patterns of meiotic inviability that suggested the presence of a chromosomal aberration. Mapping Nanopore reads from pf23-2 and pf23-3 onto the CC-5816 genome showed that these two strains each carry a translocation that was initiated at the PF23 gene locus on chromosome 11 and joined with chromosomes 5 or 3, respectively. The translocations were verified by demonstrating linkage between loci on the two translocated chromosomes in meiotic progeny. The three pf23 alleles display the expected short-cilia phenotype, and immunoblotting showed that pf23-2 lacks the PF23 protein. Our CC-5816 genome assembly will undoubtedly provide an important tool for the Chlamydomonas research community.
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Affiliation(s)
- Zachary L Payne
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Gervette M Penny
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Tychele N Turner
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Susan K Dutcher
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA.
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23
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Patel VK, Das A, Kumari R, Kajla S. Recent progress and challenges in CRISPR-Cas9 engineered algae and cyanobacteria. ALGAL RES 2023. [DOI: 10.1016/j.algal.2023.103068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
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24
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Zakrzewska M, Burmistrz M. Mechanisms regulating the CRISPR-Cas systems. Front Microbiol 2023; 14:1060337. [PMID: 36925473 PMCID: PMC10013973 DOI: 10.3389/fmicb.2023.1060337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 02/10/2023] [Indexed: 03/08/2023] Open
Abstract
The CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats- CRISPR associated proteins) is a prokaryotic system that enables sequence specific recognition and cleavage of nucleic acids. This is possible due to cooperation between CRISPR array which contains short fragments of DNA called spacers that are complimentary to the targeted nucleic acid and Cas proteins, which take part in processes of: acquisition of new spacers, processing them into their functional form as well as recognition and cleavage of targeted nucleic acids. The primary role of CRISPR-Cas systems is to provide their host with an adaptive and hereditary immunity against exogenous nucleic acids. This system is present in many variants in both Bacteria and Archea. Due to its modular structure, and programmability CRISPR-Cas system become attractive tool for modern molecular biology. Since their discovery and implementation, the CRISPR-Cas systems revolutionized areas of gene editing and regulation of gene expression. Although our knowledge on how CRISPR-Cas systems work has increased rapidly in recent years, there is still little information on how these systems are controlled and how they interact with other cellular mechanisms. Such regulation can be the result of both auto-regulatory mechanisms as well as exogenous proteins of phage origin. Better understanding of these interaction networks would be beneficial for optimization of current and development of new CRISPR-Cas-based tools. In this review we summarize current knowledge on the various molecular mechanisms that affect activity of CRISPR-Cas systems.
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Affiliation(s)
- Marta Zakrzewska
- Department of Environmental Microbiology and Biotechnology, Faculty of Biology, Institute of Microbiology, University of Warsaw, Warsaw, Poland.,Department of Molecular Microbiology, Biological and Chemical Research Centre, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Michal Burmistrz
- Department of Molecular Microbiology, Biological and Chemical Research Centre, Faculty of Biology, University of Warsaw, Warsaw, Poland.,Centre of New Technologies, University of Warsaw, Warsaw, Poland
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25
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Hou Y, Cheng X, Witman GB. Direct in situ protein tagging in Chlamydomonas reinhardtii utilizing TIM, a method for CRISPR/Cas9-based targeted insertional mutagenesis. PLoS One 2022; 17:e0278972. [PMID: 36490276 PMCID: PMC9733891 DOI: 10.1371/journal.pone.0278972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022] Open
Abstract
Chlamydomonas reinhardtii is an important model organism for the study of many cellular processes, and protein tagging is an increasingly indispensable tool for these studies. To circumvent the disadvantages of conventional approaches in creating a tagged cell line, which involve transforming either a wild-type or null-mutant cell line with an exogenous DNA construct that inserts randomly into the genome, we developed a strategy to tag the endogenous gene in situ. The strategy utilizes TIM, a CRISPR/Cas9-based method for targeted insertional mutagenesis in C. reinhardtii. We have tested the strategy on two genes: LF5/CDKL5, lack of which causes a long-flagella phenotype, and Cre09.g416350/NAP1L1, which has not been studied previously in C. reinhardtii. We successfully tagged the C-terminus of wild-type LF5 with the hemagglutinin (HA) tag with an efficiency of 7.4%. Sequencing confirmed that these strains are correctly edited. Western blotting confirmed the expression of HA-tagged LF5, and immunofluorescence microscopy showed that LF5-HA is localized normally. These strains have normal length flagella and appear wild type. We successfully tagged the N-terminus of Cre09.g416350 with mNeonGreen-3xFLAG with an efficiency of 9%. Sequencing showed that the tag region in these strains is as expected. Western blotting confirmed the expression of tagged protein of the expected size in these strains, which appeared to have normal cell size, growth rate, and swimming speed. This is the first time that C. reinhardtii endogenous genes have been edited in situ to express a wild-type tagged protein. This effective, efficient, and convenient TIM-tagging strategy promises to be a useful tool for the study of nuclear genes, including essential genes, in C. reinhardtii.
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Affiliation(s)
- Yuqing Hou
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Xi Cheng
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - George B. Witman
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
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26
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Structure of a TOC-TIC supercomplex spanning two chloroplast envelope membranes. Cell 2022; 185:4788-4800.e13. [PMID: 36413996 DOI: 10.1016/j.cell.2022.10.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 09/07/2022] [Accepted: 10/28/2022] [Indexed: 11/23/2022]
Abstract
The TOC and TIC complexes are essential translocons that facilitate the import of the nuclear genome-encoded preproteins across the two envelope membranes of chloroplast, but their exact molecular identities and assembly remain unclear. Here, we report a cryoelectron microscopy structure of TOC-TIC supercomplex from Chlamydomonas, containing a total of 14 identified components. The preprotein-conducting pore of TOC is a hybrid β-barrel co-assembled by Toc120 and Toc75, while the potential translocation path of TIC is formed by transmembrane helices from Tic20 and YlmG, rather than a classic model of Tic110. A rigid intermembrane space (IMS) scaffold bridges two chloroplast membranes, and a large hydrophilic cleft on the IMS scaffold connects TOC and TIC, forming a pathway for preprotein translocation. Our study provides structural insights into the TOC-TIC supercomplex composition, assembly, and preprotein translocation mechanism, and lays a foundation to interpret the evolutionary conservation and diversity of this fundamental translocon machinery.
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27
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CRISPR-Cas12a induced DNA double-strand breaks are repaired by multiple pathways with different mutation profiles in Magnaporthe oryzae. Nat Commun 2022; 13:7168. [PMID: 36418866 PMCID: PMC9684475 DOI: 10.1038/s41467-022-34736-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 11/01/2022] [Indexed: 11/24/2022] Open
Abstract
CRISPR-Cas mediated genome engineering has revolutionized functional genomics. However, understanding of DNA repair following Cas-mediated DNA cleavage remains incomplete. Using Cas12a ribonucleoprotein genome editing in the fungal pathogen, Magnaporthe oryzae, we detail non-canonical DNA repair outcomes from hundreds of transformants. Sanger and nanopore sequencing analysis reveals significant variation in DNA repair profiles, ranging from small INDELs to kilobase size deletions and insertions. Furthermore, we find the frequency of DNA repair outcomes varies between loci. The results are not specific to the Cas-nuclease or selection procedure. Through Ku80 deletion analysis, a key protein required for canonical non-homologous end joining, we demonstrate activity of an alternative end joining mechanism that creates larger DNA deletions, and uses longer microhomology compared to C-NHEJ. Together, our results suggest preferential DNA repair pathway activity in the genome that can create different mutation profiles following repair, which could create biased genome variation and impact genome engineering and genome evolution.
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28
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Torriano S, Baulier E, Garcia Diaz A, Corneo B, Farber DB. CRISPR-AsCas12a Efficiently Corrects a GPR143 Intronic Mutation in Induced Pluripotent Stem Cells from an Ocular Albinism Patient. CRISPR J 2022; 5:457-471. [PMID: 35686978 PMCID: PMC9233509 DOI: 10.1089/crispr.2021.0110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Mutations in the GPR143 gene cause X-linked ocular albinism type 1 (OA1), a disease that severely impairs vision. We recently generated induced pluripotent stem cells (iPSCs) from skin fibroblasts of an OA1 patient carrying a point mutation in intron 7 of GPR143. This mutation activates a new splice site causing the incorporation of a pseudoexon. In this study, we present a high-performance CRISPR-Cas ribonucleoprotein strategy to permanently correct the GPR143 mutation in these patient-derived iPSCs. Interestingly, the two single-guide RNAs available for SpCas9 did not allow the cleavage of the target region. In contrast, the cleavage achieved with the CRISPR-AsCas12a system promoted homology-directed repair at a high rate. The CRISPR-AsCas12a-mediated correction did not alter iPSC pluripotency or genetic stability, nor did it result in off-target events. Moreover, we highlight that the disruption of the pathological splice site caused by CRISPR-AsCas12a-mediated insertions/deletions also rescued the normal splicing of GPR143 and its expression level.
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Affiliation(s)
- Simona Torriano
- Department of Ophthalmology, UCLA School of Medicine, Jules Stein Eye Institute, Los Angeles, California, USA
| | - Edouard Baulier
- Department of Ophthalmology, UCLA School of Medicine, Jules Stein Eye Institute, Los Angeles, California, USA
| | - Alejandro Garcia Diaz
- Stem Cell Core, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, New York, New York, USA
| | - Barbara Corneo
- Stem Cell Core, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, New York, New York, USA
| | - Debora B Farber
- Department of Ophthalmology, UCLA School of Medicine, Jules Stein Eye Institute, Los Angeles, California, USA.,Molecular Biology Institute and UCLA, Los Angeles, California, USA.,Brain Research Institute, UCLA, Los Angeles, California, USA
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29
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Ali A, Xiao W, Babar ME, Bi Y. Double-Stranded Break Repair in Mammalian Cells and Precise Genome Editing. Genes (Basel) 2022; 13:genes13050737. [PMID: 35627122 PMCID: PMC9142082 DOI: 10.3390/genes13050737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 12/16/2022] Open
Abstract
In mammalian cells, double-strand breaks (DSBs) are repaired predominantly by error-prone non-homologous end joining (NHEJ), but less prevalently by error-free template-dependent homologous recombination (HR). DSB repair pathway selection is the bedrock for genome editing. NHEJ results in random mutations when repairing DSB, while HR induces high-fidelity sequence-specific variations, but with an undesirable low efficiency. In this review, we first discuss the latest insights into the action mode of NHEJ and HR in a panoramic view. We then propose the future direction of genome editing by virtue of these advancements. We suggest that by switching NHEJ to HR, full fidelity genome editing and robust gene knock-in could be enabled. We also envision that RNA molecules could be repurposed by RNA-templated DSB repair to mediate precise genetic editing.
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Affiliation(s)
- Akhtar Ali
- Key Laboratory of Animal Embryo and Molecular Breeding of Hubei Province, Institute of Animal Science and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (A.A.); (W.X.)
- Department of Biotechnology, Virtual University of Pakistan, Lahore 54000, Pakistan
| | - Wei Xiao
- Key Laboratory of Animal Embryo and Molecular Breeding of Hubei Province, Institute of Animal Science and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (A.A.); (W.X.)
| | - Masroor Ellahi Babar
- The University of Agriculture Dera Ismail Khan, Dera Ismail Khan 29220, Pakistan;
| | - Yanzhen Bi
- Key Laboratory of Animal Embryo and Molecular Breeding of Hubei Province, Institute of Animal Science and Veterinary Medicine, Hubei Academy of Agricultural Sciences, Wuhan 430064, China; (A.A.); (W.X.)
- Correspondence: ; Tel.: +86-151-0714-8708
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30
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The Spermidine Synthase Gene SPD1: A Novel Auxotrophic Marker for Chlamydomonas reinhardtii Designed by Enhanced CRISPR/Cas9 Gene Editing. Cells 2022; 11:cells11050837. [PMID: 35269459 PMCID: PMC8909627 DOI: 10.3390/cells11050837] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/15/2022] [Accepted: 02/24/2022] [Indexed: 01/09/2023] Open
Abstract
Biotechnological application of the green microalga Chlamydomonas reinhardtii hinges on the availability of selectable markers for effective expression of multiple transgenes. However, biological safety concerns limit the establishment of new antibiotic resistance genes and until today, only a few auxotrophic markers exist for C. reinhardtii. The recent improvements in gene editing via CRISPR/Cas allow directed exploration of new endogenous selectable markers. Since editing frequencies remain comparably low, a Cas9-sgRNA ribonucleoprotein (RNP) delivery protocol was strategically optimized by applying nitrogen starvation to the pre-culture, which improved successful gene edits from 10% to 66% after pre-selection. Probing the essential polyamine biosynthesis pathway, the spermidine synthase gene (SPD1) is shown to be a potent selectable marker with versatile biotechnological applicability. Very low levels of spermidine (0.75 mg/L) were required to maintain normal mixotrophic and phototrophic growth in newly designed spermidine auxotrophic strains. Complementation of these strains with a synthetic SPD1 gene was achieved when the mature protein was expressed in the cytosol or targeted to the chloroplast. This work highlights the potential of new selectable markers for biotechnology as well as basic research and proposes an effective pipeline for the identification of new auxotrophies in C. reinhardtii.
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31
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Kelterborn S, Boehning F, Sizova I, Baidukova O, Evers H, Hegemann P. Gene Editing in Green Alga Chlamydomonas reinhardtii via CRISPR-Cas9 Ribonucleoproteins. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2379:45-65. [PMID: 35188655 DOI: 10.1007/978-1-0716-1791-5_3] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
With the establishment of the CRISPR-Cas9 molecular tool as a DNA editing system in 2012, the handling of gene editing experiments was strongly facilitated pushing reverse genetics approaches forward in many organisms. These new gene editing technologies also drastically increased the possibilities for design-driven synthetic biology. Here, we describe a protocol for gene editing in the green algae Chlamydomonas reinhardtii using preassembled CRISPR-Cas9 ribonucleoproteins.The three sections of the protocol guide through a complete gene editing experiment, starting with the experimental design and the choice of suitable CRISPR target sites and how to perform a Cas9 in vitro test digestion. The second part covers the transformation of algal cells with Cas9 RNPs using electroporation. In the last part, the PCR-based screening for mutants and isolation of clones is explained.
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Affiliation(s)
- Simon Kelterborn
- Institute of Biology, Experimental Biophysics, Humboldt University of Berlin, Berlin, Germany. .,Charité - Universitätsmedizin Berlin, Institute of Translational Physiology, Charitéplatz 1, Berlin, Germany.
| | - Francisca Boehning
- Institute of Biology, Experimental Biophysics, Humboldt University of Berlin, Berlin, Germany
| | - Irina Sizova
- Institute of Biology, Experimental Biophysics, Humboldt University of Berlin, Berlin, Germany.,Petersburg Nuclear Physics Institute - NRC Kurchatov Institute, St. Petersburg, Russia.,Kurchatov Genome Center - PNPI, Gatchina, Russia
| | - Olga Baidukova
- Institute of Biology, Experimental Biophysics, Humboldt University of Berlin, Berlin, Germany
| | - Heide Evers
- Institute of Biology, Experimental Biophysics, Humboldt University of Berlin, Berlin, Germany
| | - Peter Hegemann
- Institute of Biology, Experimental Biophysics, Humboldt University of Berlin, Berlin, Germany
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Pham KLJ, Schmollinger S, Merchant SS, Strenkert D. Chlamydomonas ATX1 is essential for Cu distribution to multiple cupro-enzymes and maintenance of biomass in conditions demanding cupro-enzyme-dependent metabolic pathways. PLANT DIRECT 2022; 6:e383. [PMID: 35141461 PMCID: PMC8814560 DOI: 10.1002/pld3.383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 12/13/2021] [Accepted: 01/10/2022] [Indexed: 06/01/2023]
Abstract
Copper (Cu) chaperones, of which yeast ATX1 is a prototype, are small proteins with a Cu(I) binding MxCxxC motif and are responsible for directing intracellular Cu toward specific client protein targets that use Cu as a cofactor. The Chlamydomonas reinhardtii ATX1 (CrATX1) was identified by its high sequence similarity with yeast ATX1. Like the yeast homologue, CrATX1 accumulates in iron-deficient cells (but is not impacted by other metal-deficiencies). N- and C-terminally YFP-ATX1 fusion proteins are distributed in the cytoplasm. Reverse genetic analysis using artificial microRNA (amiRNA) to generate lines with reduced CrATX1 abundance and CRISPR/Cpf1 to generate atx1 knockout lines validated a function for ATX1 in iron-poor cells, again reminiscent of yeast ATX1, most likely because of an impact on metalation of the multicopper oxidase FOX1, which is an important component in high-affinity iron uptake. We further identify other candidate ATX1 targets owing to reduced growth of atx1 mutant lines on guanine as a sole nitrogen source, which we attribute to loss of function of UOX1, encoding a urate oxidase, a cupro-enzyme involved in guanine assimilation. An impact of ATX1 on Cu distribution in atx1 mutants is strikingly evident by a reduced amount of intracellular Cu in all conditions probed in this work.
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Affiliation(s)
- Keegan L. J. Pham
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Stefan Schmollinger
- California Institute for Quantitative BiosciencesUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Sabeeha S. Merchant
- Department of Plant and Microbial BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
- California Institute for Quantitative BiosciencesUniversity of CaliforniaBerkeleyCaliforniaUSA
- Department of Molecular & Cell BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
| | - Daniela Strenkert
- California Institute for Quantitative BiosciencesUniversity of CaliforniaBerkeleyCaliforniaUSA
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Tulin F. Two stones, one bird: co-targeting facilitates precise gene editing of non-selectable genes in Chlamydomonas. PLANT PHYSIOLOGY 2022; 188:16-18. [PMID: 35051288 PMCID: PMC8774741 DOI: 10.1093/plphys/kiab515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 10/18/2021] [Indexed: 06/14/2023]
Affiliation(s)
- Frej Tulin
- Plant Science Department, Botany, Technische Universität München, 85354 Freising, Germany
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34
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Biswas P, Anand U, Ghorai M, Pandey DK, Jha NK, Behl T, Kumar M, Kumar R, Shekhawat MS, Dey A. Unravelling the promise and limitations of CRISPR/Cas system in natural product research: Approaches and challenges. Biotechnol J 2021; 17:e2100507. [PMID: 34882991 DOI: 10.1002/biot.202100507] [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: 09/16/2021] [Revised: 11/30/2021] [Accepted: 12/07/2021] [Indexed: 11/12/2022]
Abstract
An incredible array of natural products are produced by plants that serve several ecological functions, including protecting them from herbivores and microbes, attracting pollinators, and dispersing seeds. In addition to their obvious medical applications, natural products serve as flavouring agents, fragrances and many other uses by humans. With the increasing demand for natural products and the development of various gene engineering systems, researchers are trying to modify the plant genome to increase the biosynthetic pathway of the compound of interest or blocking the pathway of unwanted compound synthesis. The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 has had widespread success in genome editing due to the system's high efficiency, ease of use, and accuracy which revolutionized the genome editing system in living organisms. This article highlights the method of the CRISPR/Cas system, its application in different organisms including microbes, algae, fungi and also higher plants in natural product research, its shortcomings and future prospects. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Protha Biswas
- Department of Life Sciences, Presidency University, 86/1 College Street, Kolkata, West Bengal, 700073, India
| | - Uttpal Anand
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Mimosa Ghorai
- Department of Life Sciences, Presidency University, 86/1 College Street, Kolkata, West Bengal, 700073, India
| | - Devendra Kumar Pandey
- Department of Biotechnology, Lovely Faculty of Technology and Sciences, Lovely Professional University, Phagwara, Punjab, 144402, India
| | - Niraj Kumar Jha
- Department of Biotechnology, School of Engineering & Technology, Sharda University, Greater Noida, Uttar Pradesh, 201310, India
| | - Tapan Behl
- Department of Pharmacology, Chitkara College of Pharmacy, Chitkara University, Rajpura, Chandigarh, Punjab, 140401, India
| | - Manoj Kumar
- Chemical and Biochemical Processing Division, ICAR - Central Institute for Research on Cotton Technology, Mumbai, Maharashtra, 400019, India
| | - Radha Kumar
- School of Biological and Environmental Sciences, Shoolini University of Biotechnology and Management Sciences, Solan, Himachal Pradesh, 173229, India
| | - Mahipal S Shekhawat
- Plant Biotechnology Unit, Kanchi Mamunivar Government Institute for Postgraduate Studies and Research, Puducherry, 605 008, India
| | - Abhijit Dey
- Department of Life Sciences, Presidency University, 86/1 College Street, Kolkata, West Bengal, 700073, India
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Akella S, Ma X, Bacova R, Harmer ZP, Kolackova M, Wen X, Wright DA, Spalding MH, Weeks DP, Cerutti H. Co-targeting strategy for precise, scarless gene editing with CRISPR/Cas9 and donor ssODNs in Chlamydomonas. PLANT PHYSIOLOGY 2021; 187:2637-2655. [PMID: 34618092 PMCID: PMC8644747 DOI: 10.1093/plphys/kiab418] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/30/2021] [Indexed: 05/20/2023]
Abstract
Programmable site-specific nucleases, such as the clustered regularly interspaced short palindromic repeat (CRISPR)/ CRISPR-associated protein 9 (Cas9) ribonucleoproteins (RNPs), have allowed creation of valuable knockout mutations and targeted gene modifications in Chlamydomonas (Chlamydomonas reinhardtii). However, in walled strains, present methods for editing genes lacking a selectable phenotype involve co-transfection of RNPs and exogenous double-stranded DNA (dsDNA) encoding a selectable marker gene. Repair of the dsDNA breaks induced by the RNPs is usually accompanied by genomic insertion of exogenous dsDNA fragments, hindering the recovery of precise, scarless mutations in target genes of interest. Here, we tested whether co-targeting two genes by electroporation of pairs of CRISPR/Cas9 RNPs and single-stranded oligodeoxynucleotides (ssODNs) would facilitate the recovery of precise edits in a gene of interest (lacking a selectable phenotype) by selection for precise editing of another gene (creating a selectable marker)-in a process completely lacking exogenous dsDNA. We used PPX1 (encoding protoporphyrinogen IX oxidase) as the generated selectable marker, conferring resistance to oxyfluorfen, and identified precise edits in the homolog of bacterial ftsY or the WD and TetratriCopeptide repeats protein 1 genes in ∼1% of the oxyfluorfen resistant colonies. Analysis of the target site sequences in edited mutants suggested that ssODNs were used as templates for DNA synthesis during homology directed repair, a process prone to replicative errors. The Chlamydomonas acetolactate synthase gene could also be efficiently edited to serve as an alternative selectable marker. This transgene-free strategy may allow creation of individual strains containing precise mutations in multiple target genes, to study complex cellular processes, pathways, or structures.
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Affiliation(s)
- Soujanya Akella
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - Xinrong Ma
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - Romana Bacova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00, Brno, Czech Republic
| | - Zachary P Harmer
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - Martina Kolackova
- Department of Chemistry and Biochemistry, Mendel University in Brno, Zemedelska 1, CZ-613 00, Brno, Czech Republic
| | - Xiaoxue Wen
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
| | - David A Wright
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
| | - Martin H Spalding
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
| | - Donald P Weeks
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Heriberto Cerutti
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska–Lincoln, Lincoln, Nebraska 68588, USA
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36
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Ferenczi A, Chew YP, Kroll E, von Koppenfels C, Hudson A, Molnar A. Mechanistic and genetic basis of single-strand templated repair at Cas12a-induced DNA breaks in Chlamydomonas reinhardtii. Nat Commun 2021; 12:6751. [PMID: 34799578 PMCID: PMC8604939 DOI: 10.1038/s41467-021-27004-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 10/26/2021] [Indexed: 12/12/2022] Open
Abstract
Single-stranded oligodeoxynucleotides (ssODNs) are widely used as DNA repair templates in CRISPR/Cas precision genome editing. However, the underlying mechanisms of single-strand templated DNA repair (SSTR) are inadequately understood, constraining rational improvements to precision editing. Here we study SSTR at CRISPR/Cas12a-induced DNA double-strand breaks (DSBs) in the eukaryotic model green microalga Chlamydomonas reinhardtii. We demonstrate that ssODNs physically incorporate into the genome during SSTR at Cas12a-induced DSBs. This process is genetically independent of the Rad51-dependent homologous recombination and Fanconi anemia pathways, is strongly antagonized by non-homologous end-joining, and is mediated almost entirely by the alternative end-joining enzyme polymerase θ. These findings suggest differences in SSTR between C. reinhardtii and animals. Our work illustrates the promising potentially of C. reinhardtii as a model organism for studying nuclear DNA repair.
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Affiliation(s)
- Aron Ferenczi
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Yen Peng Chew
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Erika Kroll
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
- Department of Biointeractions and Crop Protection, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | | | - Andrew Hudson
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Attila Molnar
- Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK.
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37
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Noel EA, Weeks DP, Van Etten JL. Pursuit of chlorovirus genetic transformation and CRISPR/Cas9-mediated gene editing. PLoS One 2021; 16:e0252696. [PMID: 34673785 PMCID: PMC8530361 DOI: 10.1371/journal.pone.0252696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 09/29/2021] [Indexed: 11/18/2022] Open
Abstract
Genetic and molecular modifications of the large dsDNA chloroviruses, with genomes of 290 to 370 kb, would expedite studies to elucidate the functions of both identified and unidentified virus-encoded proteins. These plaque-forming viruses replicate in certain unicellular, eukaryotic chlorella-like green algae. However, to date, only a few of these algal species and virtually none of their viruses have been genetically manipulated due to lack of practical methods for genetic transformation and genome editing. Attempts at using Agrobacterium-mediated transfection of chlorovirus host Chlorella variabilis NC64A with a specially-designed binary vector resulted in successful transgenic cell selection based on expression of a hygromycin-resistance gene, initial expression of a green fluorescence gene and demonstration of integration of Agrobacterium T-DNA. However, expression of the integrated genes was soon lost. To develop gene editing tools for modifying specific chlorovirus CA-4B genes using preassembled Cas9 protein-sgRNA ribonucleoproteins (RNPs), we tested multiple methods for delivery of Cas9/sgRNA RNP complexes into infected cells including cell wall-degrading enzymes, electroporation, silicon carbide (SiC) whiskers, and cell-penetrating peptides (CPPs). In one experiment two independent virus mutants were isolated from macerozyme-treated NC64A cells incubated with Cas9/sgRNA RNPs targeting virus CA-4B-encoded gene 034r, which encodes a glycosyltransferase. Analysis of DNA sequences from the two mutant viruses showed highly targeted nucleotide sequence modifications in the 034r gene of each virus that were fully consistent with Cas9/RNP-directed gene editing. However, in ten subsequent experiments, we were unable to duplicate these results and therefore unable to achieve a reliable system to genetically edit chloroviruses. Nonetheless, these observations provide strong initial suggestions that Cas9/RNPs may function to promote editing of the chlorovirus genome, and that further experimentation is warranted and worthwhile.
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Affiliation(s)
- Eric A. Noel
- Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska, United States of America
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Donald P. Weeks
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska, United States of America
| | - James L. Van Etten
- Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska, United States of America
- Department of Plant Pathology, University of Nebraska, Lincoln, Nebraska, United States of America
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38
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Vavitsas K, Kugler A, Satta A, Hatzinikolaou DG, Lindblad P, Fewer DP, Lindberg P, Toivari M, Stensjö K. Doing synthetic biology with photosynthetic microorganisms. PHYSIOLOGIA PLANTARUM 2021; 173:624-638. [PMID: 33963557 DOI: 10.1111/ppl.13455] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/22/2021] [Accepted: 05/06/2021] [Indexed: 06/12/2023]
Abstract
The use of photosynthetic microbes as synthetic biology hosts for the sustainable production of commodity chemicals and even fuels has received increasing attention over the last decade. The number of studies published, tools implemented, and resources made available for microalgae have increased beyond expectations during the last few years. However, the tools available for genetic engineering in these organisms still lag those available for the more commonly used heterotrophic host organisms. In this mini-review, we provide an overview of the photosynthetic microbes most commonly used in synthetic biology studies, namely cyanobacteria, chlorophytes, eustigmatophytes and diatoms. We provide basic information on the techniques and tools available for each model group of organisms, we outline the state-of-the-art, and we list the synthetic biology tools that have been successfully used. We specifically focus on the latest CRISPR developments, as we believe that precision editing and advanced genetic engineering tools will be pivotal to the advancement of the field. Finally, we discuss the relative strengths and weaknesses of each group of organisms and examine the challenges that need to be overcome to achieve their synthetic biology potential.
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Affiliation(s)
- Konstantinos Vavitsas
- Enzyme and Microbial Biotechnology Unit, Department of Biology, National and Kapodistrian University of Athens, Zografou Campus, Athens, Greece
| | - Amit Kugler
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Alessandro Satta
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia
- CSIRO Synthetic Biology Future Science Platform, Brisbane, Australia
| | - Dimitris G Hatzinikolaou
- Enzyme and Microbial Biotechnology Unit, Department of Biology, National and Kapodistrian University of Athens, Zografou Campus, Athens, Greece
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - David P Fewer
- Department of Microbiology, University of Helsinki, Helsinki, Finland
| | - Pia Lindberg
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Mervi Toivari
- VTT, Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Karin Stensjö
- Microbial Chemistry, Department of Chemistry-Ångström Laboratory, Uppsala University, Uppsala, Sweden
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39
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Geisler K, Scaife MA, Mordaka PM, Holzer A, Tomsett EV, Mehrshahi P, Mendoza Ochoa GI, Smith AG. Exploring the Impact of Terminators on Transgene Expression in Chlamydomonas reinhardtii with a Synthetic Biology Approach. Life (Basel) 2021; 11:life11090964. [PMID: 34575113 PMCID: PMC8471596 DOI: 10.3390/life11090964] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/03/2021] [Accepted: 09/09/2021] [Indexed: 01/03/2023] Open
Abstract
Chlamydomonas reinhardtii has many attractive features for use as a model organism for both fundamental studies and as a biotechnological platform. Nonetheless, despite the many molecular tools and resources that have been developed, there are challenges for its successful engineering, in particular to obtain reproducible and high levels of transgene expression. Here we describe a synthetic biology approach to screen several hundred independent transformants using standardised parts to explore different parameters that might affect transgene expression. We focused on terminators and, using a standardised workflow and quantitative outputs, tested 9 different elements representing three different size classes of native terminators to determine their ability to support high level expression of a GFP reporter gene. We found that the optimal size reflected the median size of element found in the C. reinhardtii genome. The behaviour of the terminator parts was similar with different promoters, in different host strains and with different transgenes. This approach is applicable to the systematic testing of other genetic elements, facilitating comparison to determine optimal transgene design.
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Affiliation(s)
- Katrin Geisler
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (K.G.); (M.A.S.); (P.M.M.); (A.H.); (E.V.T.); (P.M.); (G.I.M.O.)
| | - Mark A. Scaife
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (K.G.); (M.A.S.); (P.M.M.); (A.H.); (E.V.T.); (P.M.); (G.I.M.O.)
- Mara Renewables Corporation, Dartmouth, NS B2Y 4T6, Canada
| | - Paweł M. Mordaka
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (K.G.); (M.A.S.); (P.M.M.); (A.H.); (E.V.T.); (P.M.); (G.I.M.O.)
| | - Andre Holzer
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (K.G.); (M.A.S.); (P.M.M.); (A.H.); (E.V.T.); (P.M.); (G.I.M.O.)
| | - Eleanor V. Tomsett
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (K.G.); (M.A.S.); (P.M.M.); (A.H.); (E.V.T.); (P.M.); (G.I.M.O.)
| | - Payam Mehrshahi
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (K.G.); (M.A.S.); (P.M.M.); (A.H.); (E.V.T.); (P.M.); (G.I.M.O.)
| | - Gonzalo I. Mendoza Ochoa
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (K.G.); (M.A.S.); (P.M.M.); (A.H.); (E.V.T.); (P.M.); (G.I.M.O.)
| | - Alison G. Smith
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK; (K.G.); (M.A.S.); (P.M.M.); (A.H.); (E.V.T.); (P.M.); (G.I.M.O.)
- Correspondence: ; Tel.: +44-1223-333952
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40
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Savadi S, Mangalassery S, Sandesh MS. Advances in genomics and genome editing for breeding next generation of fruit and nut crops. Genomics 2021; 113:3718-3734. [PMID: 34517092 DOI: 10.1016/j.ygeno.2021.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/21/2021] [Accepted: 09/02/2021] [Indexed: 12/18/2022]
Abstract
Fruit tree crops are an essential part of the food production systems and are key to achieve food and nutrition security. Genetic improvement of fruit trees by conventional breeding has been slow due to the long juvenile phase. Advancements in genomics and molecular biology have paved the way for devising novel genetic improvement tools like genome editing, which can accelerate the breeding of these perennial crops to a great extent. In this article, advancements in genomics of fruit trees covering genome sequencing, transcriptome sequencing, genome editing technologies (GET), CRISPR-Cas system based genome editing, potential applications of CRISPR-Cas9 in fruit tree crops improvement, the factors influencing the CRISPR-Cas editing efficiency and the challenges for CRISPR-Cas9 applications in fruit tree crops improvement are reviewed. Besides, base editing, a recently emerging more precise editing system, and the future perspectives of genome editing in the improvement of fruit and nut crops are covered.
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Affiliation(s)
- Siddanna Savadi
- ICAR- Directorate of Cashew Research (DCR), Puttur 574 202, Dakshina Kannada, Karnataka, India.
| | | | - M S Sandesh
- ICAR- Directorate of Cashew Research (DCR), Puttur 574 202, Dakshina Kannada, Karnataka, India
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41
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Rau EM, Ertesvåg H. Method Development Progress in Genetic Engineering of Thraustochytrids. Mar Drugs 2021; 19:515. [PMID: 34564177 PMCID: PMC8467673 DOI: 10.3390/md19090515] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/03/2021] [Accepted: 09/09/2021] [Indexed: 01/29/2023] Open
Abstract
Thraustochytrids are unicellular, heterotrophic marine eukaryotes. Some species are known to store surplus carbon as intracellular lipids, and these also contain the long-chain polyunsaturated fatty acid docosahexaenoic acid (DHA). Most vertebrates are unable to synthesize sufficient amounts of DHA, and this fatty acid is essential for, e.g., marine fish, domesticated animals, and humans. Thraustochytrids may also produce other commercially valuable fatty acids and isoprenoids. Due to the great potential of thraustochytrids as producers of DHA and other lipid-related molecules, a need for more knowledge on this group of organisms is needed. This necessitates the ability to do genetic manipulation of the different strains. Thus far, this has been obtained for a few strains, while it has failed for other strains. Here, we systematically review the genetic transformation methods used for different thraustochytrid strains, with the aim of aiding studies on strains not yet successfully transformed. The designs of transformation cassettes are also described and compared. Moreover, the potential problems when trying to establish transformation protocols in new thraustochytrid species/strains are discussed, along with suggestions utilized in other organisms to overcome similar challenges. The approaches discussed in this review could be a starting point when designing protocols for other non-model organisms.
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Affiliation(s)
| | - Helga Ertesvåg
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, N7491 Trondheim, Norway;
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42
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Badis Y, Scornet D, Harada M, Caillard C, Godfroy O, Raphalen M, Gachon CMM, Coelho SM, Motomura T, Nagasato C, Cock JM. Targeted CRISPR-Cas9-based gene knockouts in the model brown alga Ectocarpus. THE NEW PHYTOLOGIST 2021; 231:2077-2091. [PMID: 34076889 DOI: 10.1111/nph.17525] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
Brown algae are an important group of multicellular eukaryotes, phylogenetically distinct from both the animal and land plant lineages. Ectocarpus has emerged as a model organism to study diverse aspects of brown algal biology, but this system currently lacks an effective reverse genetics methodology to analyse the functions of selected target genes. Here, we report that mutations at specific target sites are generated following the introduction of CRISPR-Cas9 ribonucleoproteins into Ectocarpus cells, using either biolistics or microinjection as the delivery method. Individuals with mutations affecting the ADENINE PHOSPHORIBOSYL TRANSFERASE (APT) gene were isolated following treatment with 2-fluoroadenine, and this selection system was used to isolate individuals in which mutations had been introduced simultaneously at APT and at a second gene. This double mutation approach could potentially be used to isolate mutants affecting any Ectocarpus gene, providing an effective reverse genetics tool for this model organism. The availability of this tool will significantly enhance the utility of Ectocarpus as a model organism for this ecologically and economically important group of marine organisms. Moreover, the methodology described here should be readily transferable to other brown algal species.
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Affiliation(s)
- Yacine Badis
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
- The Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll,, PA37 1QA, UK
| | - Delphine Scornet
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
| | - Minori Harada
- Graduate School of Environmental Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Céline Caillard
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
| | - Olivier Godfroy
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
| | - Morgane Raphalen
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
| | - Claire M M Gachon
- The Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll,, PA37 1QA, UK
- UMR 7245 Molécules de Communication et Adaptation des Micro-organismes, Muséum National d'Histoire Naturelle, CP 54, 57 rue Cuvier, Paris, 75005, France
| | - Susana M Coelho
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
- Department of Algal Development and Evolution, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, Tübingen, 72076, Germany
| | - Taizo Motomura
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
| | - Chikako Nagasato
- Muroran Marine Station, Field Science Center for Northern Biosphere, Hokkaido University, Muroran, 051-0013, Japan
| | - J Mark Cock
- Roscoff Biological Station, Place Georges Teissier, Roscoff, 29680, France
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Sizova I, Kelterborn S, Verbenko V, Kateriya S, Hegemann P. Chlamydomonas POLQ is necessary for CRISPR/Cas9-mediated gene targeting. G3 (BETHESDA, MD.) 2021; 11:jkab114. [PMID: 33836052 PMCID: PMC8495919 DOI: 10.1093/g3journal/jkab114] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 03/18/2021] [Indexed: 02/06/2023]
Abstract
The use of CRISPR/Cas endonucleases has revolutionized gene editing techniques for research on Chlamydomonas reinhardtii. To better utilize the CRISPR/Cas system, it is essential to develop a more comprehensive understanding of the DNA repair pathways involved in genome editing. In this study, we have analyzed contributions from canonical KU80/KU70-dependent nonhomologous end-joining (cNHEJ) and DNA polymerase theta (POLQ)-mediated end joining on SpCas9-mediated untemplated mutagenesis and homology-directed repair (HDR)/gene inactivation in Chlamydomonas. Using CRISPR/SpCas9 technology, we generated DNA repair-defective mutants ku80, ku70, polQ for gene targeting experiments. Our results show that untemplated repair of SpCas9-induced double strand breaks results in mutation spectra consistent with an involvement of both KU80/KU70 and POLQ. In addition, the inactivation of POLQ was found to negatively affect HDR of the inactivated paromomycin-resistant mut-aphVIII gene when donor single-stranded oligos were used. Nevertheless, mut-aphVIII was still repaired by homologous recombination in these mutants. POLQ inactivation suppressed random integration of transgenes co-transformed with the donor ssDNA. KU80 deficiency did not affect these events but instead was surprisingly found to stimulate HDR/gene inactivation. Our data suggest that in Chlamydomonas, POLQ is the main contributor to CRISPR/Cas-induced HDR and random integration of transgenes, whereas KU80/KU70 potentially plays a secondary role. We expect our results will lead to improvement of genome editing in C. reinhardtii and can be used for future development of algal biotechnology.
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Affiliation(s)
- Irina Sizova
- Experimental Biophysics, Institute of Biology, Humboldt University of Berlin, Berlin D-10099, Germany
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Centre “Kurchatov Institute”, Gatchina 188300, Russia
- Kurchatov Genome Center - PNPI, Gatchina 188300, Russia
| | - Simon Kelterborn
- Experimental Biophysics, Institute of Biology, Humboldt University of Berlin, Berlin D-10099, Germany
| | - Valeriy Verbenko
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of National Research Centre “Kurchatov Institute”, Gatchina 188300, Russia
- Kurchatov Genome Center - PNPI, Gatchina 188300, Russia
| | - Suneel Kateriya
- Laboratory of Optobiology School of Biotechnology, Jawaharlal Nehru University, New Delhi 110067, India
| | - Peter Hegemann
- Experimental Biophysics, Institute of Biology, Humboldt University of Berlin, Berlin D-10099, Germany
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Huang T, Armstrong B, Schindele P, Puchta H. Efficient gene targeting in Nicotiana tabacum using CRISPR/SaCas9 and temperature tolerant LbCas12a. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:1314-1324. [PMID: 33511745 PMCID: PMC8313123 DOI: 10.1111/pbi.13546] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/29/2020] [Accepted: 01/04/2021] [Indexed: 05/12/2023]
Abstract
Nicotiana tabacum is a non-food herb that has the potential to be utilized as bio-factory for generating medicines, vaccines or valuable small metabolites. To achieve these goals, the improvement of genetic tools for pre-designed genome modifications is indispensable. The development of CRISPR/Cas nucleases allows the induction of site-specific double-strand breaks to enhance homologous recombination-mediated gene targeting (GT). However, the efficiency of GT is still a challenging obstacle for many crops including tobacco. Recently, studies in several plant species indicated that by replacing SpCas9 with other CRISPR/Cas-based nucleases, GT efficiencies might be enhanced considerably. Therefore, we tested SaCas9 as well as a temperature-insensitive version of LbCas12a (ttLbCas12a) for targeting the tobacco SuRB gene. At the same time, we also optimized the protocol for Agrobacterium-mediated tobacco transformation and tissue culture. In this way, we could improve GT efficiencies to up to a third of the inoculated cotyledons when using ttLbCas12a, which outperformed SaCas9 considerably. In addition, we could show that the conversion tract length of the GT reaction can be up to 606 bp long and in the majority of cases, it is longer than 250 bp. We obtained multiple heritable GT events, mostly heterozygous, but also biallelic GT events and some without T-DNA integration. Thus, we were not only able to obtain CRISPR/Cas-based heritable GT events in allotetraploid Nicotiana tabacum for the first time, but our results also indicate that ttLbCas12a might be a superior alternative for gene editing and GT in tobacco as well as in other crops.
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Affiliation(s)
- Teng‐Kuei Huang
- Botanical Institute IIKarlsruhe Institute of TechnologyKarlsruheGermany
| | | | - Patrick Schindele
- Botanical Institute IIKarlsruhe Institute of TechnologyKarlsruheGermany
| | - Holger Puchta
- Botanical Institute IIKarlsruhe Institute of TechnologyKarlsruheGermany
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Rawat J, Gupta PK, Pandit S, Prasad R, Pande V. Current perspectives on integrated approaches to enhance lipid accumulation in microalgae. 3 Biotech 2021; 11:303. [PMID: 34194896 DOI: 10.1007/s13205-021-02851-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 05/19/2021] [Indexed: 11/30/2022] Open
Abstract
In recent years, research initiatives on renewable bioenergy or biofuels have been gaining momentum, not only due to fast depletion of finite reserves of fossil fuels but also because of the associated concerns for the environment and future energy security. In the last few decades, interest is growing concerning microalgae as the third-generation biofuel feedstock. The CO2 fixation ability and conversion of it into value-added compounds, devoid of challenging food and feed crops, make these photosynthetic microorganisms an optimistic producer of biofuel from an environmental point of view. Microalgal-derived fuels are currently being considered as clean, renewable, and promising sustainable biofuel. Therefore, most research targets to obtain strains with the highest lipid productivity and a high growth rate at the lowest cultivation costs. Different methods and strategies to attain higher biomass and lipid accumulation in microalgae have been extensively reported in the previous research, but there are fewer inclusive reports that summarize the conventional methods with the modern techniques for lipid enhancement and biodiesel production from microalgae. Therefore, the current review focuses on the latest techniques and advances in different cultivation conditions, the effect of different abiotic and heavy metal stress, and the role of nanoparticles (NPs) in the stimulation of lipid accumulation in microalgae. Techniques such as genetic engineering, where particular genes associated with lipid metabolism, are modified to boost lipid synthesis within the microalgae, the contribution of "Omics" in metabolic pathway studies. Further, the contribution of CRISPR/Cas9 system technique to the production of microalgae biofuel is also briefly described.
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Affiliation(s)
- Jyoti Rawat
- Department of Biotechnology, Sir J. C. Bose Technical Campus Bhimtal, Kumaun University, Nainital, Uttarakhand 263136 India
| | - Piyush Kumar Gupta
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Knowledge Park III, Greater Noida, Uttar Pradesh 201310 India
| | - Soumya Pandit
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Knowledge Park III, Greater Noida, Uttar Pradesh 201310 India
| | - Ram Prasad
- Department of Botany, Mahatma Gandhi Central University, Motihari, Bihar 845801 India
| | - Veena Pande
- Department of Biotechnology, Sir J. C. Bose Technical Campus Bhimtal, Kumaun University, Nainital, Uttarakhand 263136 India
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Mushtaq M, Ahmad Dar A, Skalicky M, Tyagi A, Bhagat N, Basu U, Bhat BA, Zaid A, Ali S, Dar TUH, Rai GK, Wani SH, Habib-Ur-Rahman M, Hejnak V, Vachova P, Brestic M, Çığ A, Çığ F, Erman M, EL Sabagh A. CRISPR-Based Genome Editing Tools: Insights into Technological Breakthroughs and Future Challenges. Genes (Basel) 2021; 12:797. [PMID: 34073848 PMCID: PMC8225059 DOI: 10.3390/genes12060797] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 12/11/2022] Open
Abstract
Genome-editing (GE) is having a tremendous influence around the globe in the life science community. Among its versatile uses, the desired modifications of genes, and more importantly the transgene (DNA)-free approach to develop genetically modified organism (GMO), are of special interest. The recent and rapid developments in genome-editing technology have given rise to hopes to achieve global food security in a sustainable manner. We here discuss recent developments in CRISPR-based genome-editing tools for crop improvement concerning adaptation, opportunities, and challenges. Some of the notable advances highlighted here include the development of transgene (DNA)-free genome plants, the availability of compatible nucleases, and the development of safe and effective CRISPR delivery vehicles for plant genome editing, multi-gene targeting and complex genome editing, base editing and prime editing to achieve more complex genetic engineering. Additionally, new avenues that facilitate fine-tuning plant gene regulation have also been addressed. In spite of the tremendous potential of CRISPR and other gene editing tools, major challenges remain. Some of the challenges are related to the practical advances required for the efficient delivery of CRISPR reagents and for precision genome editing, while others come from government policies and public acceptance. This review will therefore be helpful to gain insights into technological advances, its applications, and future challenges for crop improvement.
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Affiliation(s)
- Muntazir Mushtaq
- School of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu 180009, India; (M.M.); (A.A.D.)
| | - Aejaz Ahmad Dar
- School of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu 180009, India; (M.M.); (A.A.D.)
| | - Milan Skalicky
- Department of Botany and Plant Physiology, Faculty of Agrobiology, Food, and Natural Resources, Czech University of Life Sciences Prague, Kamycka 129, 165 00 Prague, Czech Republic; (M.S.); (V.H.); (P.V.); (M.B.)
| | - Anshika Tyagi
- ICAR-National Institute for Plant Biotechnology, New Delhi 110012, India;
| | - Nancy Bhagat
- School of Biotechnology, University of Jammu, Jammu 180006, India;
| | - Umer Basu
- Division of Plant Pathology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu 180009, India;
| | | | - Abbu Zaid
- Plant Physiology and Biochemistry Section, Department of Botany Aligarh Muslim University, Aigarh 202002, India;
| | - Sajad Ali
- Centre of Research for Development, University of Kashmir, Srinagar 190006, India;
| | | | - Gyanendra Kumar Rai
- School of Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Jammu 180009, India; (M.M.); (A.A.D.)
| | - Shabir Hussain Wani
- Mountain Research Centre for Field Crops, Khudwani, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, Jammu 192101, India
| | - Muhammad Habib-Ur-Rahman
- Department of Crop Science, Institute of Crop Science and Resource Conservation (INRES), University Bonn, 53115 Bonn, Germany;
| | - Vaclav Hejnak
- Department of Botany and Plant Physiology, Faculty of Agrobiology, Food, and Natural Resources, Czech University of Life Sciences Prague, Kamycka 129, 165 00 Prague, Czech Republic; (M.S.); (V.H.); (P.V.); (M.B.)
| | - Pavla Vachova
- Department of Botany and Plant Physiology, Faculty of Agrobiology, Food, and Natural Resources, Czech University of Life Sciences Prague, Kamycka 129, 165 00 Prague, Czech Republic; (M.S.); (V.H.); (P.V.); (M.B.)
| | - Marian Brestic
- Department of Botany and Plant Physiology, Faculty of Agrobiology, Food, and Natural Resources, Czech University of Life Sciences Prague, Kamycka 129, 165 00 Prague, Czech Republic; (M.S.); (V.H.); (P.V.); (M.B.)
- Department of Plant Physiology, Slovak University of Agriculture, Nitra, Tr. A. Hlinku 2, 949 01 Nitra, Slovakia
| | - Arzu Çığ
- Department of Horticulture, Faculty of Agriculture, Siirt University, Siirt 56100, Turkey;
| | - Fatih Çığ
- Department of Field Crops, Faculty of Agriculture, Siirt University, Siirt 56100, Turkey; (F.Ç.); (M.E.)
| | - Murat Erman
- Department of Field Crops, Faculty of Agriculture, Siirt University, Siirt 56100, Turkey; (F.Ç.); (M.E.)
| | - Ayman EL Sabagh
- Department of Field Crops, Faculty of Agriculture, Siirt University, Siirt 56100, Turkey; (F.Ç.); (M.E.)
- Department of Agronomy, Faculty of Agriculture, Kafrelsheikh University, Kafrelsheikh 33516, Egypt
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Wang Q, Gong Y, He Y, Xin Y, Lv N, Du X, Li Y, Jeong BR, Xu J. Genome engineering of Nannochloropsis with hundred-kilobase fragment deletions by Cas9 cleavages. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:1148-1162. [PMID: 33719095 DOI: 10.1111/tpj.15227] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/21/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Industrial microalgae are promising photosynthetic cell factories, yet tools for large-scale targeted genome engineering are limited. Here for the model industrial oleaginous microalga Nannochloropsis oceanica, we established a method to precisely and serially delete large genome fragments of ~100 kb from its 30.01 Mb nuclear genome. We started by identifying the 'non-essential' chromosomal regions (i.e. low expression region or LER) based on minimal gene expression under N-replete and N-depleted conditions. The largest such LER (LER1) is ~98 kb in size, located near the telomere of the 502.09-kb-long Chromosome 30 (Chr 30). We deleted 81 kb and further distal and proximal deletions of up to 110 kb (21.9% of Chr 30) in LER1 by dual targeting the boundaries with the episome-based CRISPR/Cas9 system. The telomere-deletion mutants showed normal telomeres consisting of CCCTAA repeats, revealing telomere regeneration capability after losing the distal part of Chr 30. Interestingly, the deletions caused no significant alteration in growth, lipid production or photosynthesis (transcript-abundance change for < 3% genes under N depletion). We also achieved double-deletion of both LER1 and LER2 (from Chr 9) that total ~214 kb at maximum, which can result in slightly higher growth rate and biomass productivity than the wild-type. Therefore, loss of the large, yet 'non-essential' regions does not necessarily sacrifice important traits. Such serial targeted deletions of large genomic regions had not been previously reported in microalgae, and will accelerate crafting minimal genomes as chassis for photosynthetic production.
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Affiliation(s)
- Qintao Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanhai Gong
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuehui He
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yi Xin
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Nana Lv
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xuefeng Du
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yun Li
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Byeong-Ryool Jeong
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, Korea
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Qingdao National Laboratory of Marine Science and Technology, Qingdao, 266237, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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Tong B, Dong H, Cui Y, Jiang P, Jin Z, Zhang D. The Versatile Type V CRISPR Effectors and Their Application Prospects. Front Cell Dev Biol 2021; 8:622103. [PMID: 33614630 PMCID: PMC7889808 DOI: 10.3389/fcell.2020.622103] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022] Open
Abstract
The class II clustered regularly interspaced short palindromic repeats (CRISPR)–Cas systems, characterized by a single effector protein, can be further subdivided into types II, V, and VI. The application of the type II CRISPR effector protein Cas9 as a sequence-specific nuclease in gene editing has revolutionized this field. Similarly, Cas13 as the effector protein of type VI provides a convenient tool for RNA manipulation. Additionally, the type V CRISPR–Cas system is another valuable resource with many subtypes and diverse functions. In this review, we summarize all the subtypes of the type V family that have been identified so far. According to the functions currently displayed by the type V family, we attempt to introduce the functional principle, current application status, and development prospects in biotechnology for all major members.
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Affiliation(s)
- Baisong Tong
- School of Biological Engineering, Dalian Polytechnic University, Dalian, China.,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Huina Dong
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Yali Cui
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Pingtao Jiang
- School of Biological Engineering, Dalian Polytechnic University, Dalian, China.,Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Zhaoxia Jin
- School of Biological Engineering, Dalian Polytechnic University, Dalian, China
| | - Dawei Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, China.,University of Chinese Academy of Sciences, Beijing, China
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50
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Jackson HO, Taunt HN, Mordaka PM, Smith AG, Purton S. The Algal Chloroplast as a Testbed for Synthetic Biology Designs Aimed at Radically Rewiring Plant Metabolism. FRONTIERS IN PLANT SCIENCE 2021; 12:708370. [PMID: 34630459 PMCID: PMC8497815 DOI: 10.3389/fpls.2021.708370] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 08/10/2021] [Indexed: 05/04/2023]
Abstract
Sustainable and economically viable support for an ever-increasing global population requires a paradigm shift in agricultural productivity, including the application of biotechnology to generate future crop plants. Current genetic engineering approaches aimed at enhancing the photosynthetic efficiency or composition of the harvested tissues involve relatively simple manipulations of endogenous metabolism. However, radical rewiring of central metabolism using new-to-nature pathways, so-called "synthetic metabolism", may be needed to really bring about significant step changes. In many cases, this will require re-programming the metabolism of the chloroplast, or other plastids in non-green tissues, through a combination of chloroplast and nuclear engineering. However, current technologies for sophisticated chloroplast engineering ("transplastomics") of plants are limited to just a handful of species. Moreover, the testing of metabolic rewiring in the chloroplast of plant models is often impractical given their obligate phototrophy, the extended time needed to create stable non-chimeric transplastomic lines, and the technical challenges associated with regeneration of whole plants. In contrast, the unicellular green alga, Chlamydomonas reinhardtii is a facultative heterotroph that allows for extensive modification of chloroplast function, including non-photosynthetic designs. Moreover, chloroplast engineering in C. reinhardtii is facile, with the ability to generate novel lines in a matter of weeks, and a well-defined molecular toolbox allows for rapid iterations of the "Design-Build-Test-Learn" (DBTL) cycle of modern synthetic biology approaches. The recent development of combinatorial DNA assembly pipelines for designing and building transgene clusters, simple methods for marker-free delivery of these clusters into the chloroplast genome, and the pre-existing wealth of knowledge regarding chloroplast gene expression and regulation in C. reinhardtii further adds to the versatility of transplastomics using this organism. Herein, we review the inherent advantages of the algal chloroplast as a simple and tractable testbed for metabolic engineering designs, which could then be implemented in higher plants.
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Affiliation(s)
- Harry O. Jackson
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Henry N. Taunt
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Pawel M. Mordaka
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Alison G. Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom
| | - Saul Purton
- Department of Structural and Molecular Biology, University College London, London, United Kingdom
- *Correspondence: Saul Purton
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