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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: 0] [Impact Index Per Article: 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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2
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Calatrava V, Tejada-Jimenez M, Sanz-Luque E, Fernandez E, Galvan A, Llamas A. Chlamydomonas reinhardtii, a Reference Organism to Study Algal-Microbial Interactions: Why Can't They Be Friends? PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12040788. [PMID: 36840135 PMCID: PMC9965935 DOI: 10.3390/plants12040788] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 05/13/2023]
Abstract
The stability and harmony of ecological niches rely on intricate interactions between their members. During evolution, organisms have developed the ability to thrive in different environments, taking advantage of each other. Among these organisms, microalgae are a highly diverse and widely distributed group of major primary producers whose interactions with other organisms play essential roles in their habitats. Understanding the basis of these interactions is crucial to control and exploit these communities for ecological and biotechnological applications. The green microalga Chlamydomonas reinhardtii, a well-established model, is emerging as a model organism for studying a wide variety of microbial interactions with ecological and economic significance. In this review, we unite and discuss current knowledge that points to C. reinhardtii as a model organism for studying microbial interactions.
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Affiliation(s)
- Victoria Calatrava
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
- Department of Plant Biology, Carnegie Institution for Science, 260 Panama St., Stanford, CA 94305, USA
| | - Manuel Tejada-Jimenez
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
| | - Emanuel Sanz-Luque
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
| | - Emilio Fernandez
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
| | - Aurora Galvan
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
| | - Angel Llamas
- Department of Biochemistry and Molecular Biology, Campus de Rabanales and Campus Internacional de Excelencia Agroalimentario (CeiA3), Edificio Severo Ochoa, University of Córdoba, 14071 Córdoba, Spain
- Correspondence: ; Tel.: +34-957-218352
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Bafort Q, Prost L, Aydogdu E, Van de Vloet A, Casteleyn G, Van de Peer Y, De Clerck O. Studying Whole-Genome Duplication Using Experimental Evolution of Chlamydomonas. Methods Mol Biol 2023; 2545:351-372. [PMID: 36720822 DOI: 10.1007/978-1-0716-2561-3_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In this chapter, we present the use of Chlamydomonas reinhardtii in experiments designed to study the evolutionary impacts of whole genome duplication. We shortly introduce the algal species and depict why it is an excellent model for experimental evolution. Subsequently, we discuss the most relevant steps and methods in the design of a ploidy-related Chlamydomonas experiment. These steps include strain selection, ploidy determination, different methods of making diplo- and polyploid Chlamydomonas cells, replication, culturing conditions, preservation, and the ways to quantify phenotypic and genotypic change.
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Affiliation(s)
- Quinten Bafort
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium. .,Department of Biology, Ghent University, Ghent, Belgium. .,VIB Center for Plant Systems Biology, VIB, Ghent, Belgium.
| | - Lucas Prost
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium. .,Department of Biology, Ghent University, Ghent, Belgium. .,VIB Center for Plant Systems Biology, VIB, Ghent, Belgium.
| | - Eylem Aydogdu
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,VIB Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Antoine Van de Vloet
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,Department of Biology, Ghent University, Ghent, Belgium.,VIB Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Griet Casteleyn
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,Department of Biology, Ghent University, Ghent, Belgium.,VIB Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Yves Van de Peer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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Kariyawasam T, Joo S, Lee J, Toor D, Gao AF, Noh KC, Lee JH. TALE homeobox heterodimer GSM1/GSP1 is a molecular switch that prevents unwarranted genetic recombination in Chlamydomonas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 100:938-953. [PMID: 31368133 DOI: 10.1111/tpj.14486] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/23/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
Eukaryotic sexual life cycles alternate between haploid and diploid stages, the transitions between which are delineated by cell fusion and meiotic division. Transcription factors in the TALE-class homeobox family, GSM1 and GSP1, predominantly control gene expression for the haploid-to-diploid transition during sexual reproduction in the unicellular green alga, Chlamydomonas reinhardtii. To understand the roles that GSM1 and GSP1 play in zygote development, we used gsm1 and gsp1 mutants and examined fused gametes that normally undergo the multiple organellar fusions required for the genetic unity of the zygotes. In gsm1 and gsp1 zygotes, no fusion was observed for the nucleus and chloroplast. Surprisingly, mitochondria and endoplasmic reticulum, which undergo dynamic autologous fusion/fission, did not undergo heterologous fusions in gsm1 or gsp1 zygotes. Furthermore, the mutants failed to resorb their flagella, an event that normally renders the zygotes immotile. When gsm1 and gsp1 zygotes resumed the mitotic cycle, their two nuclei fused prior to mitosis, but neither chloroplastic nor mitochondrial fusion took place, suggesting that these fusions are specifically turned on by GSM1/GSP1. Taken together, this study shows that organellar restructuring during zygotic diploidization does not occur by default but is triggered by a combinatorial switch, the GSM1/GSP1 dyad. This switch may represent an ancient mechanism that evolved to restrict genetic recombination during sexual development.
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Affiliation(s)
| | - Sunjoo Joo
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Jenny Lee
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Deepak Toor
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Ally F Gao
- Department of Botany, University of British Columbia, Vancouver, Canada
| | - Kyung-Chul Noh
- Department of Biology, Washington University, St. Louis, MO, USA
| | - Jae-Hyeok Lee
- Department of Botany, University of British Columbia, Vancouver, Canada
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5
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Navarro FJ, Baulcombe DC. miRNA-Mediated Regulation of Synthetic Gene Circuits in the Green Alga Chlamydomonas reinhardtii. ACS Synth Biol 2019; 8:358-370. [PMID: 30624905 DOI: 10.1021/acssynbio.8b00393] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
MicroRNAs (miRNAs), small RNA molecules of 20-24 nts, have many features that make them useful tools for gene expression regulation-small size, flexible design, target predictability, and action at a late stage of the gene expression pipeline. In addition, their role in fine-tuning gene expression can be harnessed to increase robustness of synthetic gene networks. In this work, we apply a synthetic biology approach to characterize miRNA-mediated gene expression regulation in the unicellular green alga Chlamydomonas reinhardtii. This characterization is then used to build tools based on miRNAs, such as synthetic miRNAs, miRNA-responsive 3'UTRs, miRNA decoys, and self-regulatory loops. These tools will facilitate the engineering of gene expression for new applications and improved traits in this alga.
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Affiliation(s)
- Francisco J. Navarro
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - David C. Baulcombe
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
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7
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Crozet P, Navarro FJ, Willmund F, Mehrshahi P, Bakowski K, Lauersen KJ, Pérez-Pérez ME, Auroy P, Gorchs Rovira A, Sauret-Gueto S, Niemeyer J, Spaniol B, Theis J, Trösch R, Westrich LD, Vavitsas K, Baier T, Hübner W, de Carpentier F, Cassarini M, Danon A, Henri J, Marchand CH, de Mia M, Sarkissian K, Baulcombe DC, Peltier G, Crespo JL, Kruse O, Jensen PE, Schroda M, Smith AG, Lemaire SD. Birth of a Photosynthetic Chassis: A MoClo Toolkit Enabling Synthetic Biology in the Microalga Chlamydomonas reinhardtii. ACS Synth Biol 2018; 7:2074-2086. [PMID: 30165733 DOI: 10.1021/acssynbio.8b00251] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Microalgae are regarded as promising organisms to develop innovative concepts based on their photosynthetic capacity that offers more sustainable production than heterotrophic hosts. However, to realize their potential as green cell factories, a major challenge is to make microalgae easier to engineer. A promising approach for rapid and predictable genetic manipulation is to use standardized synthetic biology tools and workflows. To this end we have developed a Modular Cloning toolkit for the green microalga Chlamydomonas reinhardtii. It is based on Golden Gate cloning with standard syntax, and comprises 119 openly distributed genetic parts, most of which have been functionally validated in several strains. It contains promoters, UTRs, terminators, tags, reporters, antibiotic resistance genes, and introns cloned in various positions to allow maximum modularity. The toolkit enables rapid building of engineered cells for both fundamental research and algal biotechnology. This work will make Chlamydomonas the next chassis for sustainable synthetic biology.
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Affiliation(s)
- Pierre Crozet
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | | | - Felix Willmund
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Payam Mehrshahi
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Kamil Bakowski
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kyle J. Lauersen
- Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, 33615, Germany
| | - Maria-Esther Pérez-Pérez
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, 41092, Spain
| | - Pascaline Auroy
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues Cadarache, Aix Marseille University, CEA, CNRS, BIAM, Saint Paul-Lez-Durance, France
| | - Aleix Gorchs Rovira
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Susana Sauret-Gueto
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Justus Niemeyer
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Benjamin Spaniol
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Jasmine Theis
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Raphael Trösch
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Lisa-Desiree Westrich
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Konstantinos Vavitsas
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Baier
- Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, 33615, Germany
| | - Wolfgang Hübner
- Biomolecular Photonics, Department of Physics, Bielefeld University, Bielefeld, 33615, Germany
| | - Felix de Carpentier
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Mathieu Cassarini
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Antoine Danon
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Julien Henri
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Christophe H. Marchand
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Marcello de Mia
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Kevin Sarkissian
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - David C. Baulcombe
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Gilles Peltier
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues Cadarache, Aix Marseille University, CEA, CNRS, BIAM, Saint Paul-Lez-Durance, France
| | - José-Luis Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Sevilla, 41092, Spain
| | - Olaf Kruse
- Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, 33615, Germany
| | - Poul-Erik Jensen
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael Schroda
- Department of Biology, Technische Universität Kaiserslautern, Kaiserslautern, 67663, Germany
| | - Alison G. Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, U.K
| | - Stéphane D. Lemaire
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
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Choix FJ, López-Cisneros CG, Méndez-Acosta HO. Azospirillum brasilense Increases CO 2 Fixation on Microalgae Scenedesmus obliquus, Chlorella vulgaris, and Chlamydomonas reinhardtii Cultured on High CO 2 Concentrations. MICROBIAL ECOLOGY 2018; 76:430-442. [PMID: 29327073 DOI: 10.1007/s00248-017-1139-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/28/2017] [Indexed: 06/07/2023]
Abstract
Mutualism interactions of microalgae with other microorganisms are widely used in several biotechnological processes since symbiotic interaction improves biotechnological capabilities of the microorganisms involved. The interaction of the bacterium Azospirillum brasilense was assessed with three microalgae genus, Scenedesmus, Chlorella, and Chlamydomonas, during CO2 fixation under high CO2 concentrations. The results in this study have demonstrated that A. brasilense maintained a mutualistic interaction with the three microalgae assessed, supported by the metabolic exchange of indole-3-acetic acid (IAA) and tryptophan (Trp), respectively. Besides, CO2 fixation increased, as well as growth and cell compound accumulation, mainly carbohydrates, in each microalgae evaluated, interacting with the bacterium. Overall, these results propose the mutualism interaction of A. brasilense with microalgae for improving biotechnological processes based on microalgae as CO2 capture and their bio-refinery capacity.
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Affiliation(s)
- Francisco J Choix
- Departamento de Ingeniería Química, CUCEI-Universidad de Guadalajara, Blvd. M. García Barragán 1421, C.P. 44430, Guadalajara, Jalisco, Mexico.
- CONACYT - CUCEI-Universidad de Guadalajara, Blvd. M. García Barragán 1421, C.P. 44430, Guadalajara, Jalisco, Mexico.
| | - Cecilia Guadalupe López-Cisneros
- Departamento de Ingeniería Química, CUCEI-Universidad de Guadalajara, Blvd. M. García Barragán 1421, C.P. 44430, Guadalajara, Jalisco, Mexico
| | - Hugo Oscar Méndez-Acosta
- Departamento de Ingeniería Química, CUCEI-Universidad de Guadalajara, Blvd. M. García Barragán 1421, C.P. 44430, Guadalajara, Jalisco, Mexico
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9
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Shin SE, Lim JM, Koh HG, Kim EK, Kang NK, Jeon S, Kwon S, Shin WS, Lee B, Hwangbo K, Kim J, Ye SH, Yun JY, Seo H, Oh HM, Kim KJ, Kim JS, Jeong WJ, Chang YK, Jeong BR. CRISPR/Cas9-induced knockout and knock-in mutations in Chlamydomonas reinhardtii. Sci Rep 2016; 6:27810. [PMID: 27291619 PMCID: PMC4904240 DOI: 10.1038/srep27810] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 05/25/2016] [Indexed: 01/20/2023] Open
Abstract
Genome editing is crucial for genetic engineering of organisms for improved traits, particularly in microalgae due to the urgent necessity for the next generation biofuel production. The most advanced CRISPR/Cas9 system is simple, efficient and accurate in some organisms; however, it has proven extremely difficult in microalgae including the model alga Chlamydomonas. We solved this problem by delivering Cas9 ribonucleoproteins (RNPs) comprising the Cas9 protein and sgRNAs to avoid cytotoxicity and off-targeting associated with vector-driven expression of Cas9. We obtained CRISPR/Cas9-induced mutations at three loci including MAA7, CpSRP43 and ChlM, and targeted mutagenic efficiency was improved up to 100 fold compared to the first report of transgenic Cas9-induced mutagenesis. Interestingly, we found that unrelated vectors used for the selection purpose were predominantly integrated at the Cas9 cut site, indicative of NHEJ-mediated knock-in events. As expected with Cas9 RNPs, no off-targeting was found in one of the mutagenic screens. In conclusion, we improved the knockout efficiency by using Cas9 RNPs, which opens great opportunities not only for biological research but also industrial applications in Chlamydomonas and other microalgae. Findings of the NHEJ-mediated knock-in events will allow applications of the CRISPR/Cas9 system in microalgae, including "safe harboring" techniques shown in other organisms.
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Affiliation(s)
- Sung-Eun Shin
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Jong-Min Lim
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Hyun Gi Koh
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Eun Kyung Kim
- Advanced Biomass R&D Center (ABC), KAIST, Daejeon 34141, Republic of Korea
| | - Nam Kyu Kang
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Seungjib Jeon
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Sohee Kwon
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Won-Sub Shin
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Bongsoo Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Kwon Hwangbo
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
- Department of Biological Science, Chungnam National University (CNU), Daejeon 34134, Republic of Korea
| | - Jungeun Kim
- Center for Genome Engineering, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Chemistry, Seoul National University (SNU), Seoul 08826, Republic of Korea
| | - Sung Hyeok Ye
- Center for Genome Engineering, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Basic science, IBS school, Korea University of Science and Technology (UST), Seoul 08826, Republic of Korea
| | - Jae-Young Yun
- Center for Genome Engineering, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
| | - Hogyun Seo
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University (KNU), Daegu 41566, Republic of Korea
| | - Hee-Mock Oh
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Kyung-Jin Kim
- School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University (KNU), Daegu 41566, Republic of Korea
| | - Jin-Soo Kim
- Center for Genome Engineering, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Chemistry, Seoul National University (SNU), Seoul 08826, Republic of Korea
| | - Won-Joong Jeong
- Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 34141, Republic of Korea
| | - Yong Keun Chang
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
- Advanced Biomass R&D Center (ABC), KAIST, Daejeon 34141, Republic of Korea
| | - Byeong-ryool Jeong
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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Palacios OA, Choix FJ, Bashan Y, de-Bashan LE. Influence of tryptophan and indole-3-acetic acid on starch accumulation in the synthetic mutualistic Chlorella sorokiniana – Azospirillum brasilense system under heterotrophic conditions. Res Microbiol 2016; 167:367-79. [DOI: 10.1016/j.resmic.2016.02.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 09/07/2015] [Accepted: 02/15/2016] [Indexed: 01/08/2023]
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Lin H, Zhang Z, Guo S, Chen F, Kessler JM, Wang YM, Dutcher SK. A NIMA-Related Kinase Suppresses the Flagellar Instability Associated with the Loss of Multiple Axonemal Structures. PLoS Genet 2015; 11:e1005508. [PMID: 26348919 PMCID: PMC4562644 DOI: 10.1371/journal.pgen.1005508] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 08/17/2015] [Indexed: 11/18/2022] Open
Abstract
CCDC39 and CCDC40 were first identified as causative mutations in primary ciliary dyskinesia patients; cilia from patients show disorganized microtubules, and they are missing both N-DRC and inner dynein arms proteins. In Chlamydomonas, we used immunoblots and microtubule sliding assays to show that mutants in CCDC40 (PF7) and CCDC39 (PF8) fail to assemble N-DRC, several inner dynein arms, tektin, and CCDC39. Enrichment screens for suppression of pf7; pf8 cells led to the isolation of five independent extragenic suppressors defined by four different mutations in a NIMA-related kinase, CNK11. These alleles partially rescue the flagellar length defect, but not the motility defect. The suppressor does not restore the missing N-DRC and inner dynein arm proteins. In addition, the cnk11 mutations partially suppress the short flagella phenotype of N-DRC and axonemal dynein mutants, but do not suppress the motility defects. The tpg1 mutation in TTLL9, a tubulin polyglutamylase, partially suppresses the length phenotype in the same axonemal dynein mutants. In contrast to cnk11, tpg1 does not suppress the short flagella phenotype of pf7. The polyglutamylated tubulin in the proximal region that remains in the tpg1 mutant is reduced further in the pf7; tpg1 double mutant by immunofluorescence. CCDC40, which is needed for docking multiple other axonemal complexes, is needed for tubulin polyglutamylation in the proximal end of the flagella. The CCDC39 and CCDC40 proteins are likely to be involved in recruiting another tubulin glutamylase(s) to the flagella. Another difference between cnk11-1 and tpg1 mutants is that cnk11-1 cells show a faster turnover rate of tubulin at the flagellar tip than in wild-type flagella and tpg1 flagella show a slower rate. The double mutant shows a turnover rate similar to tpg1, which suggests the faster turnover rate in cnk11-1 flagella requires polyglutamylation. Thus, we hypothesize that many short flagella mutants in Chlamydomonas have increased instability of axonemal microtubules. Both CNK11 and tubulin polyglutamylation play roles in regulating the stability of axonemal microtubules.
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Affiliation(s)
- Huawen Lin
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Zhengyan Zhang
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Suyang Guo
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Fan Chen
- Department of Physics, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Jonathan M. Kessler
- Department of Physics, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Yan Mei Wang
- Department of Physics, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Susan K. Dutcher
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
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Esparza JM, O’Toole E, Li L, Giddings TH, Kozak B, Albee AJ, Dutcher SK. Katanin localization requires triplet microtubules in Chlamydomonas reinhardtii. PLoS One 2013; 8:e53940. [PMID: 23320108 PMCID: PMC3540033 DOI: 10.1371/journal.pone.0053940] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 12/04/2012] [Indexed: 12/26/2022] Open
Abstract
Centrioles and basal bodies are essential for a variety of cellular processes that include the recruitment of proteins to these structures for both centrosomal and ciliary function. This recruitment is compromised when centriole/basal body assembly is defective. Mutations that cause basal body assembly defects confer supersensitivity to Taxol. These include bld2, bld10, bld12, uni3, vfl1, vfl2, and vfl3. Flagellar motility mutants do not confer sensitivity with the exception of mutations in the p60 (pf19) and p80 (pf15) subunits of the microtubule severing protein katanin. We have identified additional pf15 and bld2 (ε-tubulin) alleles in screens for Taxol sensitivity. Null pf15 and bld2 alleles are viable and are not essential genes in Chlamydomonas. Analysis of double mutant strains with the pf15-3 and bld2-6 null alleles suggests that basal bodies in Chlamydomonas may recruit additional proteins beyond katanin that affect spindle microtubule stability. The bld2-5 allele is a hypomorphic allele and its phenotype is modulated by nutritional cues. Basal bodies in bld2-5 cells are missing proximal ends. The basal body mutants show aberrant localization of an epitope-tagged p80 subunit of katanin. Unlike IFT proteins, katanin p80 does not localize to the transition fibers of the basal bodies based on an analysis of the uni1 mutant as well as the lack of colocalization of katanin p80 with IFT74. We suggest that the triplet microtubules are likely to play a key role in katanin p80 recruitment to the basal body of Chlamydomonas rather than the transition fibers that are needed for IFT localization.
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Affiliation(s)
- Jessica M. Esparza
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Eileen O’Toole
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Linya Li
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Thomas H. Giddings
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Benjamin Kozak
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Alison J. Albee
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Susan K. Dutcher
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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He M, Wang Y, Hua W, Zhang Y, Wang Z. De novo sequencing of Hypericum perforatum transcriptome to identify potential genes involved in the biosynthesis of active metabolites. PLoS One 2012; 7:e42081. [PMID: 22860059 PMCID: PMC3408400 DOI: 10.1371/journal.pone.0042081] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 07/02/2012] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Hypericum perforatum L. (St. John's wort) is a medicinal plant with pharmacological properties that are antidepressant, anti-inflammatory, antiviral, anti-cancer, and antibacterial. Its major active metabolites are hypericins, hyperforins, and melatonin. However, little genetic information is available for this species, especially that concerning the biosynthetic pathways for active ingredients. METHODOLOGY/PRINCIPAL FINDINGS Using de novo transcriptome analysis, we obtained 59,184 unigenes covering the entire life cycle of these plants. In all, 40,813 unigenes (68.86%) were annotated and 2,359 were assigned to secondary metabolic pathways. Among them, 260 unigenes are involved in the production of hypericin, hyperforin, and melatonin. Another 2,291 unigenes are classified as potential Type III polyketide synthase. Our BlastX search against the AGRIS database reveals 1,772 unigenes that are homologous to 47 known Arabidopsis transcription factor families. Further analysis shows that 10.61% (6,277) of these unigenes contain 7,643 SSRs. CONCLUSION We have identified a set of putative genes involved in several secondary metabolism pathways, especially those related to the synthesis of its active ingredients. Our results will serve as an important platform for public information about gene expression, genomics, and functional genomics in H. perforatum.
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Affiliation(s)
- Miao He
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi’an, Shaanxi, People’s Republic of China
| | - Ying Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), Institute of Life Science, Northwest University, Xi’an, Shaanxi, People’s Republic of China
| | - Wenping Hua
- Department of Life Sciences, Shaanxi Institute of Education, Xi’an, Shaanxi, People’s Republic of China
| | - Yuan Zhang
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi’an, Shaanxi, People’s Republic of China
| | - Zhezhi Wang
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi’an, Shaanxi, People’s Republic of China
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Luo L, Herrin DL. A novel rhodanese is required to maintain chloroplast translation in Chlamydomonas. PLANT MOLECULAR BIOLOGY 2012; 79:495-508. [PMID: 22644440 DOI: 10.1007/s11103-012-9926-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 05/11/2012] [Indexed: 06/01/2023]
Abstract
Rhodanese-domain proteins (RDPs) are widespread in plants and other organisms, but their biological roles are mostly unknown. Here we report on a novel RDP from Chlamydomonas that has a single rhodanese domain, and a predicted chloroplast transit peptide. The protein was produced in Escherichia coli with a His-tag, but lacking most of the N-terminal transit peptide, and after purification was found to have rhodanese activity in vitro. It was also used to elicit antibodies for western blot analysis, which showed that the native Chlamydomonas protein migrated slower on SDS gels (apparent M(r) =34 kDa) than its predicted size (27 kDa), and co-fractionated with chloroplasts. To assess function in vivo, the tandem-RNAi approach was used to generate Chlamydomonas strains that had reductions of 30-70% for the mRNA and ~20-40% for the 34-kDa protein. These strains showed reduced growth under all trophic conditions, and were sensitive to even moderate light; properties reminiscent of chloroplast translation mutants. Pulse-labeling in the presence of cycloheximide indicated that chloroplast protein synthesis was broadly reduced in the RNAi strains, and transcript analysis (by RT-PCR and northern blotting) indicated the effect was mainly translational. These results identify a novel rhodanese-like protein that we have named CRLT, because it is required to maintain chloroplast translation.
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Affiliation(s)
- Liming Luo
- Section of Molecular Cell and Developmental Biology, School of Biological Sciences, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, 78712, USA
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15
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Prajapati SI, Kilcoyne A, Samano AK, Green DP, McCarthy SD, Blackman BA, Brady MM, Zarzabal LA, Tatiparthi AK, Sledz TJ, Duong T, Ohshima-Hosoyama S, Giles FJ, Michalek JE, Rubin BP, Keller C. MicroCT-based virtual histology evaluation of preclinical medulloblastoma. Mol Imaging Biol 2011; 13:493-499. [PMID: 20617390 PMCID: PMC4770897 DOI: 10.1007/s11307-010-0372-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The purpose of this paper is to validate a rapid and cost-effective ex vivo technique, microCT-based virtual histology, as an alternative to MRI imaging for assessing the therapeutic response in genetically engineered mouse models of cancer. PROCEDURES All animal procedures were conducted in accordance with the Guidelines for the Care and Use of Laboratory Animals and were approved by the Institutional Animal Care and Use Committee (IACUC) at the University of Texas Health Science Center at San Antonio. MRI imaging was performed on 6-week-old, bortezomib-treated genetically engineered Patched1, p53 mice that recapitulate the characteristics of human medulloblastoma. After MRI scans, the same mice were euthanized to collect brain or spine samples for virtual histology staining followed by microCT scanning. RESULTS Nine-micrometer resolution ex vivo micro X-ray computed tomography (microCT)-based virtual histology images were qualitatively reflective of high-field live animal images obtained with magnetic resonance imaging (MRI) and histopathology. Cerebellar volumes on microCT-based virtual histology correlated closely with MRI cerebellar volumes (R = 0.998). MRI and microCT-based virtual histology both indicated a significant difference between cerebellar volumes of untreated and treated mice (p = 0.02 and p = 0.04, respectively). The ex vivo microCT method also allowed a 7,430-fold improvement in voxel resolution (voxel volume of 729 μm³ for 9-μm isometric resolution microCT vs. 5,416,800 μm³ for 400 × 111 × 122 μm resolution MRI) at a 28% cost savings ($400 vs. $555 per animal). CONCLUSION The ex vivo, en bloc technique of microCT-based virtual histology matched MRI in reflecting histopathology. MicroCT-based virtual histology proved to be a more cost-effective technique and less labor-intensive. On the other hand, MRI provides ability to perform in vivo imaging, faster scanning and lower radiation dose by sacrificing the spatial resolution. Thus, both in vivo MRI and ex vivo microCT-based virtual histology are effective means of quantitatively evaluating therapeutic response in preclinical models of cerebellar tumors including the childhood cancer, medulloblastoma.
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Affiliation(s)
- Suresh I Prajapati
- Greehey Children's Cancer Research Institute, University of Texas Health Science Center, 8403 Floyd Curl Drive, MC-7784, San Antonio, TX, 78229, USA
| | - Aoife Kilcoyne
- Greehey Children's Cancer Research Institute, University of Texas Health Science Center, 8403 Floyd Curl Drive, MC-7784, San Antonio, TX, 78229, USA
- Department of Medicine, University of Texas Health Science Center, 7703 Floyd Curl, San Antonio, TX, 78229, USA
| | - Aislynn K Samano
- Greehey Children's Cancer Research Institute, University of Texas Health Science Center, 8403 Floyd Curl Drive, MC-7784, San Antonio, TX, 78229, USA
| | - Dustin P Green
- Greehey Children's Cancer Research Institute, University of Texas Health Science Center, 8403 Floyd Curl Drive, MC-7784, San Antonio, TX, 78229, USA
| | - Steven D McCarthy
- Greehey Children's Cancer Research Institute, University of Texas Health Science Center, 8403 Floyd Curl Drive, MC-7784, San Antonio, TX, 78229, USA
| | - Barron A Blackman
- Greehey Children's Cancer Research Institute, University of Texas Health Science Center, 8403 Floyd Curl Drive, MC-7784, San Antonio, TX, 78229, USA
| | - Michelle M Brady
- Greehey Children's Cancer Research Institute, University of Texas Health Science Center, 8403 Floyd Curl Drive, MC-7784, San Antonio, TX, 78229, USA
| | - Lee Ann Zarzabal
- Epidemiology and Biostatistics, University of Texas Health Science Center, 7703 Floyd Curl, San Antonio, TX, 78229, USA
| | | | | | - Timothy Duong
- Research Imaging Institute, University of Texas Health Science Center, 7703 Floyd Curl, San Antonio, TX, 78229, USA
| | - Sachiko Ohshima-Hosoyama
- Greehey Children's Cancer Research Institute, University of Texas Health Science Center, 8403 Floyd Curl Drive, MC-7784, San Antonio, TX, 78229, USA
| | - Francis J Giles
- Department of Medicine, University of Texas Health Science Center, 7703 Floyd Curl, San Antonio, TX, 78229, USA
| | - Joel E Michalek
- Epidemiology and Biostatistics, University of Texas Health Science Center, 7703 Floyd Curl, San Antonio, TX, 78229, USA
| | - Brian P Rubin
- Department of Anatomic Pathology, Cleveland Clinic, Taussig Cancer Center and the Lerner Research Institute, Cleveland, OH, USA
| | - Charles Keller
- Greehey Children's Cancer Research Institute, University of Texas Health Science Center, 8403 Floyd Curl Drive, MC-7784, San Antonio, TX, 78229, USA.
- Cellular and Structural Biology, University of Texas Health Science Center, 7703 Floyd Curl, San Antonio, TX, 78229, USA.
- Pediatrics University of Texas Health Science Center, 7703 Floyd Curl, San Antonio, TX, 78229, USA.
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16
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Ahn JW, Yin CJ, Liu JR, Jeong WJ. Cucumber mosaic virus 2b protein inhibits RNA silencing pathways in green alga Chlamydomonas reinhardtii. PLANT CELL REPORTS 2010; 29:967-75. [PMID: 20532888 DOI: 10.1007/s00299-010-0882-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 05/24/2010] [Accepted: 05/25/2010] [Indexed: 05/10/2023]
Abstract
The functions of RNA silencing are repression of endogenous gene expression and antiviral defense in plants and animals. Cucumber mosaic virus 2b (CMV2b) is a suppressor of RNA silencing in higher plants. In the present study, we evaluated the RNA silencing suppressor activity of CMV2b in Chlamydomonas reinhardtii. Before transformation, we modified CMV2b codons to increase the GC content for optimal expression in C. reinhardtii. Inhibition of Maa7 silencing was detected in CMV2b-expressing Maa7-IR44 strains, indicating that CMV2b suppressed siRNA pathways in C. reinhardtii as in higher plants. In addition, mRNA expression targeted for cleavage by miRNA was significantly higher in CMV2b-expressing strains, but increased accumulation of miRNA was not detected. These results indicate that the suppression of miRNA pathways is mediated by CMV2b in C. reinhardtii. Interestingly, expression of both Argonaute 1 (AGO1) and Dicer-like 1 (DCL1), regulated by a bidirectional promoter, was reduced in CMV2b-expressing strains, suggesting that CMV2b may affect transcription factors involved in RNA silencing pathways. Furthermore, reduction of AGO2 and AGO3 expression was detected in CMV2b-expressing strains. Taken together, our results demonstrate that CMV2b may suppress both siRNA and miRNA pathways, and also impair AGOs and DCL1 expression in C. reinhardtii.
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Affiliation(s)
- Joon-Woo Ahn
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, 111 Gwahangno, Yuseong-gu, Daejeon, 305-806, Korea
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Abstract
Small RNA-guided gene silencing is an evolutionarily conserved process that operates by a variety of molecular mechanisms and plays an essential role in developmental pathways and defense responses against genomic parasites in eukaryotes. Double-stranded RNA (dsRNA) triggered posttranscriptional gene silencing, termed RNA interference (RNAi), is also becoming a powerful tool for reverse genetics studies. Stable RNAi, induced by the expression of long dsRNAs or duplex small RNAs from genome-integrated transgenes, has been achieved in multiple organisms, including the green alga Chlamydomonas reinhardtii. However, the level of gene repression is often quite variable, depending on the type of construct, transgene copy number, site of integration, and target gene. Moreover, unintended transcripts partly complementary to a trigger dsRNA can also be silenced, making difficult the interpretation of observed phenotypes. To obviate some of these problems we have developed a tandem inverted repeat system that consistently induces cosilencing of a gene with a selectable RNAi-induced phenotype (encoding tryptophan synthase beta-subunit) and any other (nonessential) gene of interest. In addition, to circumvent off-target effects, for each tested gene, RNAi lines are generated with at least two transgenes, homologous to distinct and nonoverlapping sequences of the target transcript. A common phenotype among these independent RNAi strains is expected to result from suppression of expression of the gene of interest. We demonstrate this approach for the characterization of a gene of unknown function in Chlamydomonas, encoding a predicted exoribonuclease with weak similarity to 3'hExo/ERI-1.
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Zhao T, Wang W, Bai X, Qi Y. Gene silencing by artificial microRNAs in Chlamydomonas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 58:157-64. [PMID: 19054364 DOI: 10.1111/j.1365-313x.2008.03758.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Chlamydomonas reinhardtii is a unicellular green alga. It is a model system for studying functions of the chloroplast, basal body and flagella. The completion of the Chlamydomonas genome sequence makes it possible to use reverse genetic approaches in this organism. Chlamydomonas contains a set of endogenous microRNAs (miRNAs) that down-regulate their target gene expression through mRNA cleavage. Here we developed an artificial miRNA-based strategy to knock down gene expression in Chlamydomonas. Using an endogenous Chlamydomonas miRNA precursor as the backbone, we constructed two artificial miRNAs (amiRNAs) targeting the MAA7 and RBCS1/2 genes, respectively. When overexpressed, these two amiRNAs could cleave their respective targets precisely at the predicted sites, resulting in greatly decreased accumulation of MAA7 and RBCS1/2 transcripts and expected mutant phenotypes. We further showed that the two amiRNAs could be produced simultaneously from a dimeric amiRNA precursor. We anticipate that the amiRNA technology developed in this study will be very useful in assessing the functions of individual genes and in genome-wide approaches.
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Affiliation(s)
- Tao Zhao
- National Institute of Biological Sciences, No.7 Science Park Road, Zhongguancun Life Science Park, Beijing 102206, China
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Grossman AR. In the Grip of Algal Genomics. TRANSGENIC MICROALGAE AS GREEN CELL FACTORIES 2008; 616:54-76. [DOI: 10.1007/978-0-387-75532-8_6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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A ferroxidase encoded by FOX1 contributes to iron assimilation under conditions of poor iron nutrition in Chlamydomonas. EUKARYOTIC CELL 2008; 7:541-5. [PMID: 18245275 DOI: 10.1128/ec.00463-07] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
When the abundance of the FOX1 gene product is reduced, Chlamydomonas cells grow poorly in iron-deficient medium, but not in iron-replete medium, suggesting that FOX1-dependent iron uptake is a high-affinity pathway. Alternative pathways for iron assimilation, such as those involving ZIP family transporters IRT1 and IRT2, may be operational.
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Schroda M. RNA silencing in Chlamydomonas: mechanisms and tools. Curr Genet 2005; 49:69-84. [PMID: 16308700 DOI: 10.1007/s00294-005-0042-1] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2005] [Revised: 10/19/2005] [Accepted: 10/26/2005] [Indexed: 10/25/2022]
Abstract
The generation of a comprehensive EST library and the sequencing of its genome set the stage for reverse genetics approaches in Chlamydomonas reinhardtii. However, these also require tools for the specific downregulation of target gene expression. Consequently, a large number of diverse constructs were developed aimed at reducing target gene expression in Chlamydomonas via the stable expression of antisense or inverted repeat-containing RNA. Double-stranded RNA (dsRNA) generated by the annealing of antisense and sense RNAs or by hairpin formation of an inverted repeat, feeds into the RNA silencing pathway. In this pathway, dsRNA is cleaved into approximately 25-bp small interfering RNAs (siRNAs) by the endonuclease Dicer. One of the two complementary strands of a siRNA is then loaded onto an Argonaute-like protein present as core component within larger complexes. Guided by this single-stranded RNA, the Argonaute-like protein either detects homologous transcripts and cleaves these endonucleolytically, or initiates transcriptional gene silencing. This article summarizes current information derived mainly from the Chlamydomonas genome project on components that are assumed to be involved in RNA silencing mechanisms in Chlamydomonas. Furthermore, all approaches employed in Chlamydomonas to date to downregulate target gene expression by antisense or inverted repeat constructs are reviewed and discussed critically.
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Affiliation(s)
- Michael Schroda
- Institute of Biology II/Plant Biochemistry, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany.
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Miller MS, Esparza JM, Lippa AM, Lux FG, Cole DG, Dutcher SK. Mutant kinesin-2 motor subunits increase chromosome loss. Mol Biol Cell 2005; 16:3810-20. [PMID: 15944218 PMCID: PMC1182318 DOI: 10.1091/mbc.e05-05-0404] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The Chlamydomonas anterograde intraflagellar transport motor, kinesin-2, is isolated as a heterotrimeric complex containing two motor subunits and a nonmotor subunit known as kinesin-associated polypeptide or KAP. One of the two motor subunits is encoded by the FLA10 gene. The sequence of the second motor subunit was obtained by mass spectrometry and sequencing. It shows 46.9% identity with the Fla10 motor subunit and the gene maps to linkage group XII/XIII near RPL9. The temperature-sensitive flagellar assembly mutants fla1 and fla8 are linked to this kinesin-2 motor subunit. In each strain, a unique single point mutation gives rise to a unique single amino acid substitution within the motor domain. The fla8 strain is named fla8-1 and the fla1 strain is named fla8-2. The fla8 and fla10 alleles show a chromosome loss phenotype. To analyze this chromosome loss phenotype, intragenic revertants of fla8-1, fla8-2, and fla10-14 were generated. The analysis of the mutants and the revertants demonstrates the importance of a pocket in the amino terminus of these motor subunits for both motor activity and for a novel, dominant effect on the fidelity of chromosome segregation.
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Affiliation(s)
- Mark S Miller
- Department of Microbiology, Molecular Biology, and Biochemistry, University of Idaho, Moscow, ID 83844-3052, USA
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Abstract
This review focuses on the biosynthesis of pigments in the unicellular alga Chlamydomonas reinhardtii and their physiological and regulatory functions in the context of information gathered from studies of other photosynthetic organisms. C. reinhardtii is serving as an important model organism for studies of photosynthesis and the pigments associated with the photosynthetic apparatus. Despite extensive information pertaining to the biosynthetic pathways critical for making chlorophylls and carotenoids, we are just beginning to understand the control of these pathways, the coordination between pigment and apoprotein synthesis, and the interactions between the activities of these pathways and those for other important cellular metabolites branching from these pathways. Other exciting areas relating to pigment function are also emerging: the role of intermediates of pigment biosynthesis as messengers that coordinate metabolism in the chloroplast with nuclear gene activity, and the identification of photoreceptors and their participation in critical cellular processes including phototaxis, gametogenesis, and the biogenesis of the photosynthetic machinery. These areas of research have become especially attractive for intensive development with the application of potent molecular and genomic tools currently being applied to studies of C. reinhardtii.
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Affiliation(s)
- Arthur R Grossman
- The Carnegie Institution of Washington, Department of Plant Biology, Stanford, California 94305, USA.
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Zamora I, Feldman JL, Marshall WF. PCR-based assay for mating type and diploidy in Chlamydomonas. Biotechniques 2005; 37:534-6. [PMID: 15517961 DOI: 10.2144/04374bm01] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Ivan Zamora
- University of California, San Francisco, CA 94143, USA
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25
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Affiliation(s)
- Arthur R Grossman
- The Carnegie Institution, Department of Plant Biology, Stanford, California 94305, USA.
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Rohr J, Sarkar N, Balenger S, Jeong BR, Cerutti H. Tandem inverted repeat system for selection of effective transgenic RNAi strains in Chlamydomonas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 40:611-21. [PMID: 15500475 DOI: 10.1111/j.1365-313x.2004.02227.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
RNA interference (RNAi), the double-stranded RNA (dsRNA) triggered post-transcriptional gene silencing, is becoming a powerful tool for reverse genetics studies. Stable RNAi, induced by the expression of inverted repeat (IR) transgenes, has been achieved in protozoa, algae, fungi, plants, and metazoans. However, the level of gene silencing is often quite variable, depending on the type of construct, transgene copy number, site of integration, and target gene. This is a hindrance in functional genomics studies, where it is desirable to suppress target genes reliably to analyze unknown phenotypes. Consequently, we explored strategies for direct selection of effective transgenic RNAi lines in Chlamydomonas reinhardtii. We initially attempted to suppress expression of the Rubisco small subunit multigene family by placing an IR, homologous to the conserved coding sequence, in the 3'UTR of a transgene conferring resistance to bleomycin. However, this approach was fairly inefficient at inducing RNAi as many strains displayed defective transgene integration, resulting in partial or complete deletion of the IR, or low levels of dsRNA expression, presumably due to transcriptional silencing of the integrated IR transgenes. To overcome these problems we designed a system consisting of tandem IR transgenes that consistently triggered co-silencing of a gene with a selectable RNAi-induced phenotype (encoding tryptophan synthase beta subunit) and another gene of interest (encoding either Ku80, an RNA-binding protein, or a thioredoxin isoform). We anticipate that this approach will be useful for generating stable hypomorphic epi-mutants in high-throughput phenotypic screens.
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Affiliation(s)
- Jennifer Rohr
- School of Biological Sciences and Plant Science Initiative, University of Nebraska-Lincoln, E215 Beadle Center, PO Box 880666, Lincoln, NE 68588, USA
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Grossman AR, Harris EE, Hauser C, Lefebvre PA, Martinez D, Rokhsar D, Shrager J, Silflow CD, Stern D, Vallon O, Zhang Z. Chlamydomonas reinhardtii at the crossroads of genomics. EUKARYOTIC CELL 2004; 2:1137-50. [PMID: 14665449 PMCID: PMC326643 DOI: 10.1128/ec.2.6.1137-1150.2003] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Arthur R Grossman
- The Carnegie Institution of Washington, Department of Plant Biology, Stanford, California 94305. Biology Department, Duke University, Durham, North Carolina 27708, USA.
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Fromherz S, Giddings TH, Gomez-Ospina N, Dutcher SK. Mutations in α-tubulin promote basal body maturation and flagellar assembly in the absence of δ-tubulin. J Cell Sci 2004; 117:303-14. [PMID: 14676280 DOI: 10.1242/jcs.00859] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have isolated suppressors of the deletion allele of δ-tubulin, uni3-1, in the biflagellate green alga Chlamydomonas reinhardtii. The deletion of δ-tubulin produces cells that assemble zero, one or two flagella and have basal bodies composed primarily of doublet rather than triplet microtubules. Flagellar number is completely restored in the suppressed strains. Most of the uni3-1 suppressors map to the TUA2 locus, which encodes α2-tubulin. Twelve independent tua2 mutations were sequenced. Amino acids D205 or A208, which are nearly invariant residues in α-tubulin, were altered. The tua2 mutations on their own have a second phenotype - they make the cells colchicine supersensitive. Colchicine supersensitivity itself is not needed for suppression and colchicine cannot phenocopy the suppression. The suppressors partially restore the assembly of triplet microtubules. These results suggest that the δ-tubulin plays two roles: it is needed for extension or stability of the triplet microtubule and also for early maturation of basal bodies. We suggest that the mutant α-tubulin promotes the early maturation of the basal body in the absence of δ-tubulin, perhaps through interactions with other partners, and this allows assembly of the flagella.
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Affiliation(s)
- Sylvia Fromherz
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Boulder, CO 80309-0347, USA
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Bowers AK, Keller JA, Dutcher SK. Molecular markers for rapidly identifying candidate genes in Chlamydomonas reinhardtii. Ery1 and ery2 encode chloroplast ribosomal proteins. Genetics 2003; 164:1345-53. [PMID: 12930744 PMCID: PMC1462650 DOI: 10.1093/genetics/164.4.1345] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To take advantage of available expressed sequence tags and genomic sequence, we have developed 64 PCR-based molecular markers in Chlamydomonas reinhardtii that map to the 17 linkage groups. These markers will allow the rapid association of a candidate gene sequence with previously identified mutations. As proof of principle, we have identified the genes encoded by the ERY1 and ERY2 loci. Mendelian mutations that confer resistance to erythromycin define three unlinked nuclear loci in C. reinhardtii. Candidate genes ribosomal protein L4 (RPL4) and L22 (RPL22) are tightly linked to the ERY1 locus and ERY2 locus, respectively. Genomic DNA for RPL4 from wild type and five mutant ery1 alleles was amplified and sequenced and three different point mutations were found. Two different glycine residues (G(102) and G(112)) are replaced by aspartic acid and both are in the unstructured region of RPL4 that lines the peptide exit tunnel of the chloroplast ribosome. The other two alleles change a splice site acceptor site. Genomic DNA for RPL22 from wild type and three mutant ery2 alleles was amplified and sequenced and revealed three different point mutations. Two alleles have premature stop codons and one allele changes a splice site acceptor site.
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Affiliation(s)
- Amber K Bowers
- Department of Genetics, Washington University School of Medicine, 660 S. Euclid Avenue, St Louis, MO 63110, USA
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Kathir P, LaVoie M, Brazelton WJ, Haas NA, Lefebvre PA, Silflow CD. Molecular map of the Chlamydomonas reinhardtii nuclear genome. EUKARYOTIC CELL 2003; 2:362-79. [PMID: 12684385 PMCID: PMC154841 DOI: 10.1128/ec.2.2.362-379.2003] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2002] [Accepted: 12/10/2002] [Indexed: 11/20/2022]
Abstract
We have prepared a molecular map of the Chlamydomonas reinhardtii genome anchored to the genetic map. The map consists of 264 markers, including sequence-tagged sites (STS), scored by use of PCR and agarose gel electrophoresis, and restriction fragment length polymorphism markers, scored by use of Southern blot hybridization. All molecular markers tested map to one of the 17 known linkage groups of C. reinhardtii. The map covers approximately 1,000 centimorgans (cM). Any position on the C. reinhardtii genetic map is, on average, within 2 cM of a mapped molecular marker. This molecular map, in combination with the ongoing mapping of bacterial artificial chromosome (BAC) clones and the forthcoming sequence of the C. reinhardtii nuclear genome, should greatly facilitate isolation of genes of interest by using positional cloning methods. In addition, the presence of easily assayed STS markers on each arm of each linkage group should be very useful in mapping new mutations in preparation for positional cloning.
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Affiliation(s)
- Pushpa Kathir
- Department of Genetics, University of Minnesota, St. Paul, Minnesota, USA
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Preble AM, Giddings TH, Dutcher SK. Extragenic bypass suppressors of mutations in the essential gene BLD2 promote assembly of basal bodies with abnormal microtubules in Chlamydomonas reinhardtii. Genetics 2001; 157:163-81. [PMID: 11139500 PMCID: PMC1461482 DOI: 10.1093/genetics/157.1.163] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
bld2-1 mutant Chlamydomonas reinhardtii strains assemble basal bodies with singlet microtubules; bld2-1 cells display flagellar assembly defects as well as positioning defects of the mitotic spindle and cleavage furrow. To further understand the role of the BLD2 gene, we have isolated three new bld2 alleles and three partially dominant extragenic suppressors, rgn1-1, rgn1-2, and rgn1-3. bld2 rgn1-1 strains have phenotypes intermediate between those of bld2 and wild-type strains with respect to flagellar number, microtubule rootlet organization, cleavage furrow positioning, and basal body structural phenotypes. Instead of the triplet microtubules of wild-type cells, bld2 rgn1-1 basal bodies have mixtures of no, singlet, doublet, and triplet microtubules. The bld2-4 allele was made by insertional mutagenesis and identified in a noncomplementation screen in a diploid strain. The bld2-4 allele has a lethal phenotype based on mitotic segregation in diploid strains and in haploid strains generated by meiotic recombination. The lethal phenotype in haploid strains is suppressed by rgn1-1; these suppressed strains have similar phenotypes to other bld2 rgn1-1 double mutants. It is likely that BLD2 is an essential gene that is needed for basal body assembly and function.
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Affiliation(s)
- A M Preble
- Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347, USA
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Abstract
Chlamydomonas reinhardtii has been the subject of genetic, biochemical, cytological, and molecular analyses for over 50 years. It is an ideal model system for the study of flagella and basal bodies as well as the study of photosynthesis and chloroplast biogenesis, cell-cell recognition and fusion, phototaxis, and secretion. It is clear that many of the genes identified in Chlamydomonas have homologs in land plants as well as animals. Thus, a genomic approach in Chlamydomonas will provide another important avenue for the understanding of important biological processes.
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Affiliation(s)
- S K Dutcher
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA.
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