101
|
Novel Modular Rhodopsins from Green Algae Hold Great Potential for Cellular Optogenetic Modulation Across the Biological Model Systems. Life (Basel) 2020; 10:life10110259. [PMID: 33126644 PMCID: PMC7693036 DOI: 10.3390/life10110259] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/18/2020] [Accepted: 10/19/2020] [Indexed: 01/07/2023] Open
Abstract
Light-gated ion channel and ion pump rhodopsins are widely used as optogenetic tools and these can control the electrically excitable cells as (1) they are a single-component system i.e., their light sensing and ion-conducting functions are encoded by the 7-transmembrane domains and, (2) they show fast kinetics with small dark-thermal recovery time. In cellular signaling, a signal receptor, modulator, and the effector components are involved in attaining synchronous regulation of signaling. Optical modulation of the multicomponent network requires either receptor to effector encoded in a single ORF or direct modulation of the effector domain through bypassing all upstream players. Recently discovered modular rhodopsins like rhodopsin guanylate cyclase (RhoGC) and rhodopsin phosphodiesterase (RhoPDE) paves the way to establish a proof of concept for utilization of complex rhodopsin (modular rhodopsin) for optogenetic applications. Light sensor coupled modular system could be expressed in any cell type and hence holds great potential in the advancement of optogenetics 2.0 which would enable manipulating the entire relevant cell signaling system. Here, we had identified 50 novel modular rhodopsins with variant domains and their diverse cognate signaling cascades encoded in a single ORF, which are associated with specialized functions in the cells. These novel modular algal rhodopsins have been characterized based on their sequence and structural homology with previously reported rhodopsins. The presented novel modular rhodopsins with various effector domains leverage the potential to expand the optogenetic tool kit to regulate various cellular signaling pathways across the diverse biological model systems.
Collapse
|
102
|
Dhokane D, Bhadra B, Dasgupta S. CRISPR based targeted genome editing of Chlamydomonas reinhardtii using programmed Cas9-gRNA ribonucleoprotein. Mol Biol Rep 2020; 47:8747-8755. [PMID: 33074412 DOI: 10.1007/s11033-020-05922-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 10/13/2020] [Indexed: 11/26/2022]
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR) - Cas associated protein 9 (Cas9) system is very precise, efficient and relatively simple in creating genetic modifications at a predetermined locus in the genome. Genome editing with Cas9 ribonucleoproteins (RNPs) has reduced cytotoxic effects, off-target cleavage and increased on-target activity and the editing efficiencies. The unicellular alga Chlamydomonas reinhardtii is an emerging model for studying the production of high-value products for industrial applications. Development of C. reinhardtii as an industrial biotechnology host can be achieved more efficiently through genetic modifications using genome editing tools. We made an attempt to target MAA7 gene that encodes the tryptophan synthase β-Subunit using CRISPR-Cas9 RNPs to demonstrate knock-out and knock-in through homology-dependent repair template at the target site. In this study, we have demonstrated targeted gene knock-out in C. reinhardtii using programmed RNPs. Targeted editing of MAA7 gene was confirmed by sequencing the clones that were resistant to 5-Fluoroindole (5-FI). Non-homologous end joining (NHEJ) repair mechanism led to insertion, deletion, and/or base substitution in the Cas9 cleavage vicinity, encoding non-functional MAA7 protein product (knock-out), conferring resistance to 5-FI. Here, we report an efficient protocol for developing knock-out mutants in Chlamydomonas using CRISPR-Cas9 RNPs. The high potential efficiency of editing may also eliminate the need to select mutants by phenotype. These research findings would be more likely applied to other green algae for developing green cell factories to produce high-value molecules.
Collapse
Affiliation(s)
- Dhananjay Dhokane
- Synthetic Biology Group, Reliance Corporate Park, Reliance Industries Ltd, Ghansoli, Navi Mumbai, 400701, India
| | - Bhaskar Bhadra
- Synthetic Biology Group, Reliance Corporate Park, Reliance Industries Ltd, Ghansoli, Navi Mumbai, 400701, India.
| | - Santanu Dasgupta
- Synthetic Biology Group, Reliance Corporate Park, Reliance Industries Ltd, Ghansoli, Navi Mumbai, 400701, India
| |
Collapse
|
103
|
Kurita T, Moroi K, Iwai M, Okazaki K, Shimizu S, Nomura S, Saito F, Maeda S, Takami A, Sakamoto A, Ohta H, Sakuma T, Yamamoto T. Efficient and multiplexable genome editing using Platinum TALENs in oleaginous microalga, Nannochloropsis oceanica NIES-2145. Genes Cells 2020; 25:695-702. [PMID: 32888368 DOI: 10.1111/gtc.12805] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/24/2020] [Accepted: 08/25/2020] [Indexed: 12/25/2022]
Abstract
Algae accumulate large amounts of lipids produced by photosynthesis, and these lipids are expected to be utilized as feedstocks for sustainable new energies, known as biodiesels. Nannochloropsis species are eukaryotic microalgae that produce high levels of lipids. However, since the production costs of algal biodiesels are higher than those of fossil fuels, the improved productivity of algal lipids by molecular breeding of algae is required for practical use. In the present study, we developed a highly efficient genome-editing system involving Platinum transcription activator-like effector nucleases (TALENs) in Nannochloropsis oceanica. Platinum TALENs codon-optimized for N. oceanica were synthesized, and their DNA-binding activity was confirmed by single-strand annealing assays in human HEK293T cells. All-in-one expression vectors for Platinum TALEN targeting the nitrate reductase gene, NoNR, and acyltransferase gene, LPAT1, were transfected into Nannochloropsis species. The introduction of each Platinum TALEN revealed high genome-editing efficiency with no detectable off-target mutations at the candidate sites in N. oceanica. By simultaneously introducing TALENs targeting two genes, we obtained double mutant strains. The loss-of-function phenotype of NoNR was also confirmed. These findings will provide an essential technology for molecular breeding in Nannochloropsis species.
Collapse
Affiliation(s)
- Tomokazu Kurita
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Keishi Moroi
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Masako Iwai
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Kumiko Okazaki
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Shinsuke Shimizu
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Seiji Nomura
- Mazda Motor Corporation, Fuchu-cho, Hiroshima, Japan
| | | | | | | | - Atsushi Sakamoto
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Hiroyuki Ohta
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Tetsushi Sakuma
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Takashi Yamamoto
- Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| |
Collapse
|
104
|
CRISPR/Cas technology promotes the various application of Dunaliella salina system. Appl Microbiol Biotechnol 2020; 104:8621-8630. [PMID: 32918585 DOI: 10.1007/s00253-020-10892-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 09/01/2020] [Accepted: 09/05/2020] [Indexed: 12/15/2022]
Abstract
Dunaliella salina (D. salina) has been widely applied in various fields because of its inherent advantages, such as the study of halotolerant mechanism, wastewater treatment, recombinant proteins expression, biofuel production, preparation of natural materials, and others. However, owing to the existence of low yield or in the laboratory exploration stage, D. salina system has been greatly restricted for practical production of various components. In past decade, significant progresses have been achieved for research of D. salina in these fields. Among them, D. salina as a novel expression system demonstrated a bright prospect, especially for large-scale production of foreign proteins, like the vaccines, antibodies, and other therapeutic proteins. Due to the low efficiency, application of traditional regulation tools is also greatly limited for exploration of D. salina system. The emergence of the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas system offers a precise editing tool to overcome the obstacles of D. salina system. This review not only comprehensively summarizes the recent progresses of D. salina in domain of gene engineering but also gives a deep analysis of problems and deficiencies in different fields of D. salina. Moreover, further prospects of CRISPR/Cas system and its significant challenges have been discussed in various aspects of D. salina. It provides a great referencing value for speeding up the maturity of D. salina system, and also supplies practical guiding significance to expand the new application fields for D. salina. KEY POINTS: • The review provides recent research progresses of various applications of D. salina. • The problems and deficiencies in different fields of D. salina were deeply analyzed. • The further prospects of CRISPR/Cas technology in D. salina system were predicted. • CRISPR/Cas system will promote the new application fields and maturity for D. salina.
Collapse
|
105
|
Teng SY, Yew GY, Sukačová K, Show PL, Máša V, Chang JS. Microalgae with artificial intelligence: A digitalized perspective on genetics, systems and products. Biotechnol Adv 2020; 44:107631. [PMID: 32931875 DOI: 10.1016/j.biotechadv.2020.107631] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 09/08/2020] [Accepted: 09/08/2020] [Indexed: 12/18/2022]
Abstract
With recent advances in novel gene-editing tools such as RNAi, ZFNs, TALENs, and CRISPR-Cas9, the possibility of altering microalgae toward designed properties for various application is becoming a reality. Alteration of microalgae genomes can modify metabolic pathways to give elevated yields in lipids, biomass, and other components. The potential of such genetically optimized microalgae can give a "domino effect" in further providing optimization leverages down the supply chain, in aspects such as cultivation, processing, system design, process integration, and revolutionary products. However, the current level of understanding the functional information of various microalgae gene sequences is still primitive and insufficient as microalgae genome sequences are long and complex. From this perspective, this work proposes to link up this knowledge gap between microalgae genetic information and optimized bioproducts using Artificial Intelligence (AI). With the recent acceleration of AI research, large and complex data from microalgae research can be properly analyzed by combining the cutting-edge of both fields. In this work, the most suitable class of AI algorithms (such as active learning, semi-supervised learning, and meta-learning) are discussed for different cases of microalgae applications. This work concisely reviews the current state of the research milestones and highlight some of the state-of-art that has been carried out, providing insightful future pathways. The utilization of AI algorithms in microalgae cultivation, system optimization, and other aspects of the supply chain is also discussed. This work opens the pathway to a digitalized future for microalgae research and applications.
Collapse
Affiliation(s)
- Sin Yong Teng
- Brno University of Technology, Institute of Process Engineering, Technická 2896/2, 616 69, Brno, Czech Republic.
| | - Guo Yong Yew
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
| | - Kateřina Sukačová
- Global Change Research Institute of the Czech Academy of Sciences, Bělidla 986/4a, Brno 603 00, Czech Republic.
| | - Pau Loke Show
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
| | - Vítězslav Máša
- Brno University of Technology, Institute of Process Engineering, Technická 2896/2, 616 69, Brno, Czech Republic.
| | - Jo-Shu Chang
- Department of Chemical and Materials Engineering, College of Engineering, Tunghai University, Taichung 407, Taiwan; Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung 407, Taiwan.
| |
Collapse
|
106
|
Kumar G, Shekh A, Jakhu S, Sharma Y, Kapoor R, Sharma TR. Bioengineering of Microalgae: Recent Advances, Perspectives, and Regulatory Challenges for Industrial Application. Front Bioeng Biotechnol 2020; 8:914. [PMID: 33014997 PMCID: PMC7494788 DOI: 10.3389/fbioe.2020.00914] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 07/15/2020] [Indexed: 01/14/2023] Open
Abstract
Microalgae, due to their complex metabolic capacity, are being continuously explored for nutraceuticals, pharmaceuticals, and other industrially important bioactives. However, suboptimal yield and productivity of the bioactive of interest in local and robust wild-type strains are of perennial concerns for their industrial applications. To overcome such limitations, strain improvement through genetic engineering could play a decisive role. Though the advanced tools for genetic engineering have emerged at a greater pace, they still remain underused for microalgae as compared to other microorganisms. Pertaining to this, we reviewed the progress made so far in the development of molecular tools and techniques, and their deployment for microalgae strain improvement through genetic engineering. The recent availability of genome sequences and other omics datasets form diverse microalgae species have remarkable potential to guide strategic momentum in microalgae strain improvement program. This review focuses on the recent and significant improvements in the omics resources, mutant libraries, and high throughput screening methodologies helpful to augment research in the model and non-model microalgae. Authors have also summarized the case studies on genetically engineered microalgae and highlight the opportunities and challenges that are emerging from the current progress in the application of genome-editing to facilitate microalgal strain improvement. Toward the end, the regulatory and biosafety issues in the use of genetically engineered microalgae in commercial applications are described.
Collapse
Affiliation(s)
- Gulshan Kumar
- Agricultural Biotechnology Division, National Agri-Food Biotechnology Institute (NABI), Sahibzada Ajit Singh Nagar, India
| | - Ajam Shekh
- Plant Cell Biotechnology Department, CSIR-Central Food Technological Research Institute (CFTRI), Mysuru, India
| | - Sunaina Jakhu
- Agricultural Biotechnology Division, National Agri-Food Biotechnology Institute (NABI), Sahibzada Ajit Singh Nagar, India
| | - Yogesh Sharma
- Agricultural Biotechnology Division, National Agri-Food Biotechnology Institute (NABI), Sahibzada Ajit Singh Nagar, India
| | - Ritu Kapoor
- Agricultural Biotechnology Division, National Agri-Food Biotechnology Institute (NABI), Sahibzada Ajit Singh Nagar, India
| | - Tilak Raj Sharma
- Division of Crop Science, Indian Council of Agricultural Research, New Delhi, India
| |
Collapse
|
107
|
Ho SH, Zhang C, Tao F, Zhang C, Chen WH. Microalgal Torrefaction for Solid Biofuel Production. Trends Biotechnol 2020; 38:1023-1033. [DOI: 10.1016/j.tibtech.2020.02.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 02/15/2020] [Accepted: 02/18/2020] [Indexed: 12/19/2022]
|
108
|
Achievements and challenges of genetic engineering of the model green alga Chlamydomonas reinhardtii. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101986] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
109
|
Lin YL, Chung CL, Huang PJ, Chen CH, Fang SC. Revised annotation and extended characterizations of components of the Chlamydomonas reinhardtii SUMOylation system. PLANT DIRECT 2020; 4:e00266. [PMID: 33015534 PMCID: PMC7522501 DOI: 10.1002/pld3.266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 08/19/2020] [Accepted: 08/21/2020] [Indexed: 05/16/2023]
Abstract
Small ubiquitin-like modifier (SUMO) conjugation, or SUMOylation, is a reversible post-translational modification that is important for regulation of many cellular processes including cell division cycle in the eukaryotic kingdom. However, only a portion of the components of the Chlamydomonas SUMOylation system are known and their functions and regulation investigated. The present studies are aimed at extending discovery and characterization of new components and improving the annotation and nomenclature of all known proteins and genes involved in the system. Even though only one copy of the heterodimerized SUMO-activating enzyme, SAE1 and SAE2, was identified, the number of SUMO-conjugating enzymes (SCEs) and SUMO proteases/isopeptidase was expanded in Chlamydomonas. Using the reconstituted SUMOylation system, we showed that SCE1, SCE2, and SCE3 have SUMO-conjugating activity. In addition to SUMOylation, components required for other post-translational modifications such as NEDDylation, URMylation, and UFMylation, were confirmed to be present in Chlamydomonas. Our data also showed that besides isopeptidase activity, the SUMO protease domain of SUPPRESSOR OF MAT3 7/SENTRIN-SPECIFIC PROTEASE 1 (SMT7/SENP1) has endopeptidase activity that is capable of processing SUMO precursors. Moreover, the key cell cycle regulators of Chlamydomonas E2F1, DP1, CDKG1, CYCD2, and CYCD3 were SUMOylated in vitro, suggesting SUMOylation may be part of regulatory pathway modulating cell cycle regulators.
Collapse
Affiliation(s)
- Yen-Ling Lin
- Biotechnology Center in Southern Taiwan Academia Sinica Tainan Taiwan
- Agricultural Biotechnology Research Center Academia Sinica Taipei Taiwan
- Ph.D. Program in Microbial Genomics National Chung Hsing University and Academia Sinica Taichung Taiwan
| | - Chin-Lin Chung
- Biotechnology Center in Southern Taiwan Academia Sinica Tainan Taiwan
- Agricultural Biotechnology Research Center Academia Sinica Taipei Taiwan
| | - Pin-Jui Huang
- Biotechnology Center in Southern Taiwan Academia Sinica Tainan Taiwan
- Agricultural Biotechnology Research Center Academia Sinica Taipei Taiwan
| | - Chun-Han Chen
- Biotechnology Center in Southern Taiwan Academia Sinica Tainan Taiwan
- Agricultural Biotechnology Research Center Academia Sinica Taipei Taiwan
| | - Su-Chiung Fang
- Biotechnology Center in Southern Taiwan Academia Sinica Tainan Taiwan
- Agricultural Biotechnology Research Center Academia Sinica Taipei Taiwan
- Ph.D. Program in Microbial Genomics National Chung Hsing University and Academia Sinica Taichung Taiwan
- Institute of Tropical Plant Sciences and Microbiology National Cheng Kung University Tainan Taiwan
- National Cheng Kung University-Academia Sinica Graduate Program in Translational Agricultural Sciences Tainan Taiwan
| |
Collapse
|
110
|
Krishnan A, Cano M, Burch TA, Weissman JC, Posewitz MC. Genome editing using Cas9-RNA ribonucleoprotein complexes in the high-productivity marine alga Picochlorum celeri. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101944] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
|
111
|
Metabolic engineering of ketocarotenoids biosynthetic pathway in Chlamydomonas reinhardtii strain CC-4102. Sci Rep 2020; 10:10688. [PMID: 32612116 PMCID: PMC7329852 DOI: 10.1038/s41598-020-67756-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 05/29/2020] [Indexed: 11/23/2022] Open
Abstract
In Chlamydomonas reinhardtii, ketocarotenoid biosynthesis is limited to the diploid zygospore stage. In this study, we attempted to engineer the ketocarotenoid pathway into Chlamydomonas haploid vegetative green cells by overexpressing the key enzyme ß-carotene ketolase (CrBKT). We chose strain CC-4102 for the approach; competitive pathways, α-carotene biosynthesis and xanthophyll cycle are silenced in this strain. Driven by the strong constitutive HSP70/RBCS2 promoter CrBKT overexpression resulted in the production of canthaxanthin, the ketolation product from ß-carotene as well as a drastic reduction in the chlorophyll concentration. Intriguingly, these phenotypes could only be detected from lines transformed and grown heterotrophically in the dark. Once exposed to light, these transformants lost the aforementioned phenotypes as well as their antibiotic resistance. This phenomenon is in agreement with the fact that we were unable to recover any canthaxanthin-producing line among light-selected transformants.
Collapse
|
112
|
George J, Kahlke T, Abbriano RM, Kuzhiumparambil U, Ralph PJ, Fabris M. Metabolic Engineering Strategies in Diatoms Reveal Unique Phenotypes and Genetic Configurations With Implications for Algal Genetics and Synthetic Biology. Front Bioeng Biotechnol 2020; 8:513. [PMID: 32582656 PMCID: PMC7290003 DOI: 10.3389/fbioe.2020.00513] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 04/30/2020] [Indexed: 12/23/2022] Open
Abstract
Diatoms are photosynthetic microeukaryotes that dominate phytoplankton populations and have increasing applicability in biotechnology. Uncovering their complex biology and elevating strains to commercial standards depends heavily on robust genetic engineering tools. However, engineering microalgal genomes predominantly relies on random integration of transgenes into nuclear DNA, often resulting in detrimental “position-effects” such as transgene silencing, integration into transcriptionally-inactive regions, and endogenous sequence disruption. With the recent development of extrachromosomal transgene expression via independent episomes, it is timely to investigate both strategies at the phenotypic and genomic level. Here, we engineered the model diatom Phaeodactylum tricornutum to produce the high-value heterologous monoterpenoid geraniol, which, besides applications as fragrance and insect repellent, is a key intermediate of high-value pharmaceuticals. Using high-throughput phenotyping we confirmed the suitability of episomes for synthetic biology applications and identified superior geraniol-yielding strains following random integration. We used third generation long-read sequencing technology to generate a complete analysis of all transgene integration events including their genomic locations and arrangements associated with high-performing strains at a genome-wide scale with subchromosomal detail, never before reported in any microalga. This revealed very large, highly concatenated insertion islands, offering profound implications on diatom functional genetics and next generation genome editing technologies, and is key for developing more precise genome engineering approaches in diatoms, including possible genomic safe harbour locations to support high transgene expression for targeted integration approaches. Furthermore, we have demonstrated that exogenous DNA is not integrated inadvertently into the nuclear genome of extrachromosomal-expression clones, an important characterisation of this novel engineering approach that paves the road to synthetic biology applications.
Collapse
Affiliation(s)
- Jestin George
- University of Technology Sydney, Climate Change Cluster, Faculty of Science, Ultimo, NSW, Australia
| | - Tim Kahlke
- University of Technology Sydney, Climate Change Cluster, Faculty of Science, Ultimo, NSW, Australia
| | - Raffaela M Abbriano
- University of Technology Sydney, Climate Change Cluster, Faculty of Science, Ultimo, NSW, Australia
| | | | - Peter J Ralph
- University of Technology Sydney, Climate Change Cluster, Faculty of Science, Ultimo, NSW, Australia
| | - Michele Fabris
- University of Technology Sydney, Climate Change Cluster, Faculty of Science, Ultimo, NSW, Australia.,CSIRO Synthetic Biology Future Science Platform, Brisbane, QLD, Australia
| |
Collapse
|
113
|
Picariello T, Hou Y, Kubo T, McNeill NA, Yanagisawa HA, Oda T, Witman GB. TIM, a targeted insertional mutagenesis method utilizing CRISPR/Cas9 in Chlamydomonas reinhardtii. PLoS One 2020; 15:e0232594. [PMID: 32401787 PMCID: PMC7219734 DOI: 10.1371/journal.pone.0232594] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/18/2020] [Indexed: 01/16/2023] Open
Abstract
Generation and subsequent analysis of mutants is critical to understanding the functions of genes and proteins. Here we describe TIM, an efficient, cost-effective, CRISPR-based targeted insertional mutagenesis method for the model organism Chlamydomonas reinhardtii. TIM utilizes delivery into the cell of a Cas9-guide RNA (gRNA) ribonucleoprotein (RNP) together with exogenous double-stranded (donor) DNA. The donor DNA contains gene-specific homology arms and an integral antibiotic-resistance gene that inserts at the double-stranded break generated by Cas9. After optimizing multiple parameters of this method, we were able to generate mutants for six out of six different genes in two different cell-walled strains with mutation efficiencies ranging from 40% to 95%. Furthermore, these high efficiencies allowed simultaneous targeting of two separate genes in a single experiment. TIM is flexible with regard to many parameters and can be carried out using either electroporation or the glass-bead method for delivery of the RNP and donor DNA. TIM achieves a far higher mutation rate than any previously reported for CRISPR-based methods in C. reinhardtii and promises to be effective for many, if not all, non-essential nuclear genes.
Collapse
Affiliation(s)
- Tyler Picariello
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Yuqing Hou
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Tomohiro Kubo
- Department of Anatomy and Structural Biology, Interdisciplinary Graduate School, University of Yamanashi, Chuo, Yamanashi, Japan
| | - Nathan A. McNeill
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | | | - Toshiyuki Oda
- Department of Anatomy and Structural Biology, Interdisciplinary Graduate School, University of Yamanashi, Chuo, Yamanashi, Japan
| | - George B. Witman
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| |
Collapse
|
114
|
Lin YL, Chung CL, Chen MH, Chen CH, Fang SC. SUMO Protease SMT7 Modulates Ribosomal Protein L30 and Regulates Cell-Size Checkpoint Function. THE PLANT CELL 2020; 32:1285-1307. [PMID: 32060174 PMCID: PMC7145494 DOI: 10.1105/tpc.19.00301] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 01/02/2020] [Accepted: 02/11/2020] [Indexed: 05/10/2023]
Abstract
Proliferating cells actively coordinate growth and cell division to ensure cell-size homeostasis; however, the underlying mechanism through which size is controlled is poorly understood. Defect in a SUMO protease protein, suppressor of mat3 7 (SMT7), has been shown to reduce cell division number and increase cell size of the small-size mutant mating type locus 3-4 (mat3-4), which contains a defective retinoblastoma tumor suppressor-related protein of Chlamydomonas (Chlamydomonas reinhardtii). Here we describe development of an in vitro SUMOylation system using Chlamydomonas components and use it to provide evidence that SMT7 is a bona fide SUMO protease. We further demonstrate that the SUMO protease activity is required for supernumerous mitotic divisions of the mat3-4 cells. In addition, we identified RIBOSOMAL PROTEIN L30 (RPL30) as a prime SMT7 target and demonstrated that its SUMOylation is an important modulator of cell division in mat3-4 cells. Loss of SMT7 caused elevated SUMOylated RPL30 levels. Importantly, overexpression of the translational fusion version of RPL30-SUMO4, which mimics elevation of the SUMOylated RPL30 protein in mat3-4, caused a decrease in mitotic division and recapitulated the size-increasing phenotype of the smt7-1 mat3-4 cells. In summary, our study reveals a novel mechanism through which a SUMO protease regulates cell division in the mat3-4 mutant of Chlamydomonas and provides yet another important example of the role that protein SUMOylation can play in regulating key cellular processes, including cell division.
Collapse
Affiliation(s)
- Yen-Ling Lin
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 741, Taiwan
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
- Ph.D. Program in Microbial Genomics, National Chung Hsing University and Academia Sinica, Taichung 402, Taiwan
| | - Chin-Lin Chung
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 741, Taiwan
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Ming-Hui Chen
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 741, Taiwan
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Chun-Han Chen
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 741, Taiwan
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Su-Chiung Fang
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 741, Taiwan
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
| |
Collapse
|
115
|
von der Heyde EL, Hallmann A. Babo1, formerly Vop1 and Cop1/2, is no eyespot photoreceptor but a basal body protein illuminating cell division in Volvox carteri. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:276-298. [PMID: 31778231 DOI: 10.1111/tpj.14623] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 10/29/2019] [Accepted: 11/19/2019] [Indexed: 06/10/2023]
Abstract
In photosynthetic organisms many processes are light dependent and sensing of light requires light-sensitive proteins. The supposed eyespot photoreceptor protein Babo1 (formerly Vop1) has previously been classified as an opsin due to the capacity for binding retinal. Here, we analyze Babo1 and provide evidence that it is no opsin. Due to the localization at the basal bodies, the former Vop1 and Cop1/2 proteins were renamed V.c. Babo1 and C.r. Babo1. We reveal a large family of more than 60 Babo1-related proteins from a wide range of species. The detailed subcellular localization of fluorescence-tagged Babo1 shows that it accumulates at the basal apparatus. More precisely, it is located predominantly at the basal bodies and to a lesser extent at the four strands of rootlet microtubules. We trace Babo1 during basal body separation and cell division. Dynamic structural rearrangements of Babo1 particularly occur right before the first cell division. In four-celled embryos Babo1 was exclusively found at the oldest basal bodies of the embryo and on the corresponding d-roots. The unequal distribution of Babo1 in four-celled embryos could be an integral part of a geometrical system in early embryogenesis, which establishes the anterior-posterior polarity and influences the spatial arrangement of all embryonic structures and characteristics. Due to its retinal-binding capacity, Babo1 could also be responsible for the unequal distribution of retinoids, knowing that such concentration gradients of retinoids can be essential for the correct patterning during embryogenesis of more complex organisms. Thus, our findings push the Babo1 research in another direction.
Collapse
Affiliation(s)
- Eva L von der Heyde
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr 25, 33615, Bielefeld, Germany
| | - Armin Hallmann
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr 25, 33615, Bielefeld, Germany
| |
Collapse
|
116
|
Kim J, Lee S, Baek K, Jin E. Site-Specific Gene Knock-Out and On-Site Heterologous Gene Overexpression in Chlamydomonas reinhardtii via a CRISPR-Cas9-Mediated Knock-in Method. FRONTIERS IN PLANT SCIENCE 2020; 11:306. [PMID: 32265959 PMCID: PMC7099044 DOI: 10.3389/fpls.2020.00306] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 03/03/2020] [Indexed: 05/27/2023]
Abstract
Chlamydomonas reinhardtii is being transformed from a model organism to an industrial organism for the production of pigments, fatty acids, and pharmaceuticals. Genetic modification has been used to increase the economic value of C. reinhardtii. However, low gene-editing efficiency and position-effects hinder the genetic improvement of this microorganism. Recently, site-specific double-stranded DNA cleavage using CRISPR-Cas9 system has been applied to regulate a metabolic pathway in C. reinhardtii. In this study, we proved that site-specific gene expression can be induced by CRISPR-Cas9-mediated double-strand cleavage and non-homologous end joining (NHEJ) mechanism. The CRISPR-Cas9-mediated knock-in method was adopted to improve gene-editing efficiency and express the reporter gene on the intended site. Knock-in was performed using a combination of ribonucleoprotein (RNP) complex and DNA fragment (antibiotics resistance gene). Gene-editing efficiency was improved via optimization of a component of RNP complex. We found that when the gene CrFTSY was targeted, the efficiency of obtaining the desired mutant by the knock-in method combined with antibiotic resistance was nearly 37%; 2.5 times higher than the previous reports. Additionally, insertion of a long DNA fragment (3.2 and 6.4 kb) and site-specific gene expression were analyzed. We demonstrated the knock-out phenotype of CrFTSY and on-site inserted gene expression of luciferase and mVenus at the same time. This result showed that CRISPR-Cas9-mediated knock-in can be used to express the gene of interest avoiding position-effects in C. reinhardtii. This report could provide a new perspective to the use of gene-editing. Furthermore, the technical improvements in genetic modification may accelerate the commercialization of C. reinhardtii.
Collapse
Affiliation(s)
| | | | | | - EonSeon Jin
- Department of Life Science, Research Institute for Natural Science, Hanyang University, Seoul, South Korea
| |
Collapse
|
117
|
Fabris M, Abbriano RM, Pernice M, Sutherland DL, Commault AS, Hall CC, Labeeuw L, McCauley JI, Kuzhiuparambil U, Ray P, Kahlke T, Ralph PJ. Emerging Technologies in Algal Biotechnology: Toward the Establishment of a Sustainable, Algae-Based Bioeconomy. FRONTIERS IN PLANT SCIENCE 2020; 11:279. [PMID: 32256509 PMCID: PMC7090149 DOI: 10.3389/fpls.2020.00279] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 02/24/2020] [Indexed: 05/18/2023]
Abstract
Mankind has recognized the value of land plants as renewable sources of food, medicine, and materials for millennia. Throughout human history, agricultural methods were continuously modified and improved to meet the changing needs of civilization. Today, our rapidly growing population requires further innovation to address the practical limitations and serious environmental concerns associated with current industrial and agricultural practices. Microalgae are a diverse group of unicellular photosynthetic organisms that are emerging as next-generation resources with the potential to address urgent industrial and agricultural demands. The extensive biological diversity of algae can be leveraged to produce a wealth of valuable bioproducts, either naturally or via genetic manipulation. Microalgae additionally possess a set of intrinsic advantages, such as low production costs, no requirement for arable land, and the capacity to grow rapidly in both large-scale outdoor systems and scalable, fully contained photobioreactors. Here, we review technical advancements, novel fields of application, and products in the field of algal biotechnology to illustrate how algae could present high-tech, low-cost, and environmentally friendly solutions to many current and future needs of our society. We discuss how emerging technologies such as synthetic biology, high-throughput phenomics, and the application of internet of things (IoT) automation to algal manufacturing technology can advance the understanding of algal biology and, ultimately, drive the establishment of an algal-based bioeconomy.
Collapse
Affiliation(s)
- Michele Fabris
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
- CSIRO Synthetic Biology Future Science Platform, Brisbane, QLD, Australia
| | - Raffaela M. Abbriano
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Mathieu Pernice
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Donna L. Sutherland
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Audrey S. Commault
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Christopher C. Hall
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Leen Labeeuw
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Janice I. McCauley
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | | | - Parijat Ray
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Tim Kahlke
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| | - Peter J. Ralph
- Climate Change Cluster (C3), University of Technology Sydney, Ultimo, NSW, Australia
| |
Collapse
|
118
|
Park RV, Asbury H, Miller SM. Modification of a Chlamydomonas reinhardtii CRISPR/Cas9 transformation protocol for use with widely available electroporation equipment. MethodsX 2020; 7:100855. [PMID: 32280600 PMCID: PMC7139109 DOI: 10.1016/j.mex.2020.100855] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/03/2020] [Indexed: 12/14/2022] Open
Abstract
A recently reported protocol demonstrates efficient CRISPR/Cas9 gene editing of Chlamydomonas reinhardtii[1]. The published protocol demonstrates transformation and editing of a wall-less strain of C. reinhardtii using plasmid encoded Cas9 and sgRNA. However, the published protocol utilizes a complex electroporation waveform that cannot be generated by most electroporation systems. It is unknown whether transformation via this complex electroporation waveform is essential for high efficiency of Cas9 edits, perhaps by optimizing Cas9 or guide RNA gene expression or incorporation into the genome. We demonstrate that a simple electroporation waveform can deliver plasmid encoded CRISPR/Cas9 into and edit the genome of a wall-less strain of C. reinhardtii as efficiently as the more complex waveform. Our modified electroporation protocol makes the plasmid based CRISPR/Cas9 genome editing method accessible to a greater number of Chlamydomonas researchers.Our protocol uses a simple electroporation waveform to replace a complex waveform used to achieve efficient CRISPR/Cas9 gene editing in a wall-less strain of Chlamydomonas reinhardtii. We also increased concentration of plasmids to maintain high gene editing efficiency. We minimized modifications to other steps of the original protocol.
Collapse
Affiliation(s)
- Rudolph V Park
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Holly Asbury
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| | - Stephen M Miller
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD 21250, USA
| |
Collapse
|
119
|
Ng I, Keskin BB, Tan S. A Critical Review of Genome Editing and Synthetic Biology Applications in Metabolic Engineering of Microalgae and Cyanobacteria. Biotechnol J 2020; 15:e1900228. [DOI: 10.1002/biot.201900228] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/07/2020] [Indexed: 12/13/2022]
Affiliation(s)
- I‐Son Ng
- Department of Chemical EngineeringNational Cheng Kung University Tainan 701 Taiwan
| | - Batuhan Birol Keskin
- Department of Chemical EngineeringNational Cheng Kung University Tainan 701 Taiwan
| | - Shih‐I Tan
- Department of Chemical EngineeringNational Cheng Kung University Tainan 701 Taiwan
| |
Collapse
|
120
|
Shahar N, Landman S, Weiner I, Elman T, Dafni E, Feldman Y, Tuller T, Yacoby I. The Integration of Multiple Nuclear-Encoded Transgenes in the Green Alga Chlamydomonas reinhardtii Results in Higher Transcription Levels. FRONTIERS IN PLANT SCIENCE 2020; 10:1784. [PMID: 32117346 PMCID: PMC7033495 DOI: 10.3389/fpls.2019.01784] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 12/20/2019] [Indexed: 06/10/2023]
Abstract
The integration of genes into the nuclear genome of Chlamydomonas reinhardtii is mediated by Non-Homologous-End-Joining, thus resulting in unpredicted insertion locations. This phenomenon defines 'the position-effect', which is used to explain the variation of expression levels between different clones transformed with the same DNA fragment. Likewise, nuclear transgenes often undergo epigenetic silencing that reduces their expression; hence, nuclear transformations require high-throughput screening methods to isolate clones that express the foreign gene at a desirable level. Here, we show that the number of integration sites of heterologous genes results in higher mRNA levels. By transforming both a synthetic ferredoxin-hydrogenase fusion enzyme and a Gaussia-Luciferase reporter protein, we were able to obtain 33 positive clones that exhibit a wide range of synthetic expression. We then performed a droplet-digital polymerase-chain-reaction for these lines to measure their transgene DNA copy-number and mRNA levels. Surprisingly, most clones contain two integration sites of the synthetic gene (45.5%), whilst 33.3% contain one, 18.1% include three and 3.1% encompass four. Remarkably, we observed a positive correlation between the raw DNA copy-number values to the mRNA levels, suggesting a general effect of which transcription of transgenes is partially modulated by their number of copies in the genome. However, our data indicate that only clones harboring at least three copies of the target amplicon show a significant increment in mRNA levels of the reporter transgene. Lastly, we measured protein activity for each of the reporter genes to elucidate the effect of copy-number variation on heterologous expression.
Collapse
Affiliation(s)
- Noam Shahar
- The George S. Wise Faculty of Life Sciences, School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
| | - Shira Landman
- The George S. Wise Faculty of Life Sciences, School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
| | - Iddo Weiner
- The George S. Wise Faculty of Life Sciences, School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
- Department of Biomedical Engineering, The Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Tamar Elman
- The George S. Wise Faculty of Life Sciences, School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
| | - Eyal Dafni
- The George S. Wise Faculty of Life Sciences, School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
| | - Yael Feldman
- The George S. Wise Faculty of Life Sciences, School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
| | - Tamir Tuller
- Department of Biomedical Engineering, The Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Iftach Yacoby
- The George S. Wise Faculty of Life Sciences, School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
121
|
Oltmanns A, Hoepfner L, Scholz M, Zinzius K, Schulze S, Hippler M. Novel Insights Into N-Glycan Fucosylation and Core Xylosylation in C. reinhardtii. FRONTIERS IN PLANT SCIENCE 2020; 10:1686. [PMID: 32010168 PMCID: PMC6974686 DOI: 10.3389/fpls.2019.01686] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/29/2019] [Indexed: 05/28/2023]
Abstract
Chlamydomonas reinhardtii (C. reinhardtii) N-glycans carry plant typical β1,2-core xylose, α1,3-fucose residues, as well as plant atypical terminal β1,4-xylose and methylated mannoses. In a recent study, XylT1A was shown to act as core xylosyltransferase, whereby its action was of importance for an inhibition of excessive Man1A dependent trimming. N-Glycans found in a XylT1A/Man1A double mutant carried core xylose residues, suggesting the existence of a second core xylosyltransferase in C. reinhardtii. To further elucidate enzymes important for N-glycosylation, novel single knockdown mutants of candidate genes involved in the N-glycosylation pathway were characterized. In addition, double, triple, and quadruple mutants affecting already known N-glycosylation pathway genes were generated. By characterizing N-glycan compositions of intact N-glycopeptides from these mutant strains by mass spectrometry, a candidate gene encoding for a second putative core xylosyltransferase (XylT1B) was identified. Additionally, the role of a putative fucosyltransferase was revealed. Mutant strains with knockdown of both xylosyltransferases and the fucosyltransferase resulted in the formation of N-glycans with strongly diminished core modifications. Thus, the mutant strains generated will pave the way for further investigations on how single N-glycan core epitopes modulate protein function in C. reinhardtii.
Collapse
Affiliation(s)
- Anne Oltmanns
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany
| | - Lara Hoepfner
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany
| | - Martin Scholz
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany
| | - Karen Zinzius
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany
| | - Stefan Schulze
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany
- Department of Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Michael Hippler
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany
- Institute of Plant Science and Resources, Okayama University, Okayama, Japan
| |
Collapse
|
122
|
de Carpentier F, Le Peillet J, Boisset ND, Crozet P, Lemaire SD, Danon A. Blasticidin S Deaminase: A New Efficient Selectable Marker for Chlamydomonas reinhardtii. FRONTIERS IN PLANT SCIENCE 2020; 11:242. [PMID: 32211000 PMCID: PMC7066984 DOI: 10.3389/fpls.2020.00242] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 02/17/2020] [Indexed: 05/21/2023]
Abstract
Chlamydomonas reinhardtii is a model unicellular organism for basic or biotechnological research, such as the production of high-value molecules or biofuels thanks to its photosynthetic ability. To enable rapid construction and optimization of multiple designs and strains, our team and collaborators have developed a versatile Chlamydomonas Modular Cloning toolkit comprising 119 biobricks. Having the ability to use a wide range of selectable markers is an important benefit for forward and reverse genetics in Chlamydomonas. We report here the development of a new selectable marker based on the resistance to the antibiotic blasticidin S, using the Bacillus cereus blasticidin S deaminase (BSR) gene. The optimal concentration of blasticidin S for effective selection was determined in both liquid and solid media and tested for multiple laboratory strains. In addition, we have shown that our new selectable marker does not interfere with other common antibiotic resistances: zeocin, hygromycin, kanamycin, paromomycin, and spectinomycin. The blasticidin resistance biobrick has been added to the Chlamydomonas Modular Cloning toolkit and is now available to the entire scientific community.
Collapse
Affiliation(s)
- Félix de Carpentier
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
- Université Paris-Saclay, Saint-Aubin, France
| | - Jeanne Le Peillet
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Nicolas D. Boisset
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
- Université Paris-Saclay, Saint-Aubin, France
| | - Pierre Crozet
- Institut de Biologie Physico-Chimique, UMR 8226, CNRS, Sorbonne Université, Paris, France
| | - Stéphane D. Lemaire
- 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
- *Correspondence: Antoine Danon,
| |
Collapse
|
123
|
Good News for Nuclear Transgene Expression in Chlamydomonas. Cells 2019; 8:cells8121534. [PMID: 31795196 PMCID: PMC6952782 DOI: 10.3390/cells8121534] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 11/13/2019] [Accepted: 11/25/2019] [Indexed: 12/20/2022] Open
Abstract
Chlamydomonas reinhardtii is a well-established model system for basic research questions ranging from photosynthesis and organelle biogenesis, to the biology of cilia and basal bodies, to channelrhodopsins and photoreceptors. More recently, Chlamydomonas has also been recognized as a suitable host for the production of high-value chemicals and high-value recombinant proteins. However, basic and applied research have suffered from the inefficient expression of nuclear transgenes. The combined efforts of the Chlamydomonas community over the past decades have provided insights into the mechanisms underlying this phenomenon and have resulted in mutant strains defective in some silencing mechanisms. Moreover, many insights have been gained into the parameters that affect nuclear transgene expression, like promoters, introns, codon usage, or terminators. Here I critically review these insights and try to integrate them into design suggestions for the construction of nuclear transgenes that are to be expressed at high levels.
Collapse
|
124
|
The CONSTANS flowering complex controls the protective response of photosynthesis in the green alga Chlamydomonas. Nat Commun 2019; 10:4099. [PMID: 31506429 PMCID: PMC6736836 DOI: 10.1038/s41467-019-11989-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 08/16/2019] [Indexed: 11/26/2022] Open
Abstract
Light is essential for photosynthesis, but the amounts of light that exceed an organism’s assimilation capacity can result in oxidative stress and even cell death. Plants and microalgae have developed a photoprotective response mechanism, qE, that dissipates excess light energy as thermal energy. In the green alga Chlamydomonas reinhardtii, qE is regulated by light-inducible photoprotective proteins, but the pathway from light perception to qE is not fully understood. Here, we show that the transcription factors CONSTANS and Nuclear transcription Factor Ys (NF-Ys) form a complex that governs light-dependent photoprotective responses in C. reinhardtii. The qE responses do not occur in CONSTANS or NF-Y mutants. The signal from light perception to the CONSTANS/NF-Ys complex is directly inhibited by the SPA1/COP1-dependent E3 ubiquitin ligase. This negative regulation mediated by the E3 ubiquitin ligase and the CONSTANS/NF-Ys complex is common to photoprotective response in algal photosynthesis and flowering in plants. In flowering plants, the CONSTANS (CO) and Nuclear Factor Y (NF-Y) transcription factors connect light perception to floral induction. Here Tokutsu et al. show that in the green alga Chlamydomonas, CO and NF-Y form an analogous complex that can prevent photodamage in response to excess light.
Collapse
|
125
|
Vavitsas K, Crozet P, Vinde MH, Davies F, Lemaire SD, Vickers CE. The Synthetic Biology Toolkit for Photosynthetic Microorganisms. PLANT PHYSIOLOGY 2019; 181:14-27. [PMID: 31262955 PMCID: PMC6716251 DOI: 10.1104/pp.19.00345] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/09/2019] [Indexed: 05/10/2023]
Abstract
Photosynthetic microorganisms offer novel characteristics as synthetic biology chassis, and the toolbox of components and techniques for cyanobacteria and algae is rapidly increasing.
Collapse
Affiliation(s)
- Konstantinos Vavitsas
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Synthetic Biology Future Science Platform, CSIRO Land & Water, Brisbane, Queensland 4001, Australia
| | - Pierre Crozet
- Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 8226, Centre National de la Recherche Scientifique, Sorbonne Université, 75005 Paris, France
| | - Marcos Hamborg Vinde
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Synthetic Biology Future Science Platform, CSIRO Land & Water, Brisbane, Queensland 4001, Australia
| | - Fiona Davies
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401
| | - Stéphane D Lemaire
- Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 8226, Centre National de la Recherche Scientifique, Sorbonne Université, 75005 Paris, France
| | - Claudia E Vickers
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Synthetic Biology Future Science Platform, CSIRO Land & Water, Brisbane, Queensland 4001, Australia
| |
Collapse
|
126
|
Salomé PA, Merchant SS. A Series of Fortunate Events: Introducing Chlamydomonas as a Reference Organism. THE PLANT CELL 2019; 31:1682-1707. [PMID: 31189738 PMCID: PMC6713297 DOI: 10.1105/tpc.18.00952] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 05/20/2019] [Accepted: 06/08/2019] [Indexed: 05/13/2023]
Abstract
The unicellular alga Chlamydomonas reinhardtii is a classical reference organism for studying photosynthesis, chloroplast biology, cell cycle control, and cilia structure and function. It is also an emerging model for studying sensory cilia, the production of high-value bioproducts, and in situ structural determination. Much of the early appeal of Chlamydomonas was rooted in its promise as a genetic system, but like other classic model organisms, this rise to prominence predated the discovery of the structure of DNA, whole-genome sequences, and molecular techniques for gene manipulation. The haploid genome of C. reinhardtii facilitates genetic analyses and offers many of the advantages of microbial systems applied to a photosynthetic organism. C. reinhardtii has contributed to our understanding of chloroplast-based photosynthesis and cilia biology. Despite pervasive transgene silencing, technological advances have allowed researchers to address outstanding lines of inquiry in algal research. The most thoroughly studied unicellular alga, C. reinhardtii, is the current standard for algal research, and although genome editing is still far from efficient and routine, it nevertheless serves as a template for other algae. We present a historical retrospective of the rise of C. reinhardtii to illuminate its past and present. We also present resources for current and future scientists who may wish to expand their studies to the realm of microalgae.
Collapse
Affiliation(s)
- Patrice A Salomé
- University of California, Los Angeles, Department of Chemistry and Biochemistry, Los Angeles, CA 90095
| | - Sabeeha S Merchant
- University of California, Los Angeles, Department of Chemistry and Biochemistry, Los Angeles, CA 90095
- University of California, Berkeley, Departments of Plant and Microbial Biology and Molecular and Cell Biology, Berkeley, CA 94720
| |
Collapse
|
127
|
Grossman A, Sanz-Luque E, Yi H, Yang W. Building the GreenCut2 suite of proteins to unmask photosynthetic function and regulation. Microbiology (Reading) 2019; 165:697-718. [DOI: 10.1099/mic.0.000788] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Arthur Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Emanuel Sanz-Luque
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Heng Yi
- Key Laboratory of Photobiology, Institute of Botany (CAS), Beijing, PR China
- University of Chinese Academy of Sciences, Beijing, PR China
| | - Wenqiang Yang
- Key Laboratory of Photobiology, Institute of Botany (CAS), Beijing, PR China
- University of Chinese Academy of Sciences, Beijing, PR China
| |
Collapse
|
128
|
Kong F, Yamaoka Y, Ohama T, Lee Y, Li-Beisson Y. Molecular Genetic Tools and Emerging Synthetic Biology Strategies to Increase Cellular Oil Content in Chlamydomonas reinhardtii. PLANT & CELL PHYSIOLOGY 2019; 60:1184-1196. [PMID: 30715500 DOI: 10.1093/pcp/pcz022] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/18/2019] [Indexed: 05/26/2023]
Abstract
Microalgae constitute a highly diverse group of eukaryotic and photosynthetic microorganisms that have developed extremely efficient systems for harvesting and transforming solar energy into energy-rich molecules such as lipids. Although microalgae are considered to be one of the most promising platforms for the sustainable production of liquid oil, the oil content of these organisms is naturally low, and algal oil production is currently not economically viable. Chlamydomonas reinhardtii (Chlamydomonas) is an established algal model due to its fast growth, high transformation efficiency, and well-understood physiology and to the availability of detailed genome information and versatile molecular tools for this organism. In this review, we summarize recent advances in the development of genetic manipulation tools for Chlamydomonas, from gene delivery methods to state-of-the-art genome-editing technologies and fluorescent dye-based high-throughput mutant screening approaches. Furthermore, we discuss practical strategies and toolkits that enhance transgene expression, such as choice of expression vector and background strain. We then provide examples of how advanced genetic tools have been used to increase oil content in Chlamydomonas. Collectively, the current literature indicates that microalgal oil content can be increased by overexpressing key enzymes that catalyze lipid biosynthesis, blocking lipid degradation, silencing metabolic pathways that compete with lipid biosynthesis and modulating redox state. The tools and knowledge generated through metabolic engineering studies should pave the way for developing a synthetic biological approach to enhance lipid productivity in microalgae.
Collapse
Affiliation(s)
- Fantao Kong
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, China
| | - Yasuyo Yamaoka
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
| | - Takeshi Ohama
- School of Environmental Science and Engineering, Kochi University of Technology (KUT), Tosayamada, Kochi, Japan
| | - Youngsook Lee
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
- Department of Life Science, Pohang University of Science and Technology, Pohang, Korea
| | - Yonghua Li-Beisson
- Aix-Marseille Univ., CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance F, France
| |
Collapse
|
129
|
|
130
|
Böhm M, Boness D, Fantisch E, Erhard H, Frauenholz J, Kowalzyk Z, Marcinkowski N, Kateriya S, Hegemann P, Kreimer G. Channelrhodopsin-1 Phosphorylation Changes with Phototactic Behavior and Responds to Physiological Stimuli in Chlamydomonas. THE PLANT CELL 2019; 31:886-910. [PMID: 30862615 PMCID: PMC6501600 DOI: 10.1105/tpc.18.00936] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/25/2019] [Accepted: 03/11/2019] [Indexed: 05/26/2023]
Abstract
The unicellular alga Chlamydomonas (Chlamydomonas reinhardtii) exhibits oriented movement responses (phototaxis) to light over more than three log units of intensity. Phototaxis thus depends on the cell's ability to adjust the sensitivity of its photoreceptors to ambient light conditions. In Chlamydomonas, the photoreceptors for phototaxis are the channelrhodopsins (ChR)1 and ChR2; these light-gated cation channels are located in the plasma membrane. Although ChRs are widely used in optogenetic studies, little is known about ChR signaling in algae. We characterized the in vivo phosphorylation of ChR1. Its reversible phosphorylation occurred within seconds as a graded response to changes in the light intensity and ionic composition of the medium and depended on an elevated cytosolic Ca2+ concentration. Changes in the phototactic sign were accompanied by alterations in the phosphorylation status of ChR1. Furthermore, compared with the wild type, a permanently negative phototactic mutant required higher light intensities to evoke ChR1 phosphorylation. C-terminal truncation of ChR1 disturbed its reversible phosphorylation, whereas it was normal in ChR2-knockout and eyespot-assembly mutants. The identification of phosphosites in regions important for ChR1 function points to their potential regulatory role(s). We propose that multiple ChR1 phosphorylation, regulated via a Ca2+-based feedback loop, is an important component in the adaptation of phototactic sensitivity in Chlamydomonas.
Collapse
Affiliation(s)
- Michaela Böhm
- Department of Biology, Friedrich-Alexander University, 91058 Erlangen, Germany
| | - David Boness
- Department of Biology, Friedrich-Alexander University, 91058 Erlangen, Germany
| | - Elisabeth Fantisch
- Department of Biology, Friedrich-Alexander University, 91058 Erlangen, Germany
| | - Hanna Erhard
- Department of Biology, Friedrich-Alexander University, 91058 Erlangen, Germany
| | - Julia Frauenholz
- Department of Biology, Friedrich-Alexander University, 91058 Erlangen, Germany
| | - Zarah Kowalzyk
- Department of Biology, Friedrich-Alexander University, 91058 Erlangen, Germany
| | - Nadin Marcinkowski
- Department of Biology, Friedrich-Alexander University, 91058 Erlangen, Germany
| | - Suneel Kateriya
- School of Biotechnology, Jawaharlal Nehru University, 110067 New Delhi, India
| | - Peter Hegemann
- Institute for Experimental Biophysics, Humboldt University, 10115 Berlin, Germany
| | - Georg Kreimer
- Department of Biology, Friedrich-Alexander University, 91058 Erlangen, Germany
| |
Collapse
|
131
|
Li X, Patena W, Fauser F, Jinkerson RE, Saroussi S, Meyer MT, Ivanova N, Robertson JM, Yue R, Zhang R, Vilarrasa-Blasi J, Wittkopp TM, Ramundo S, Blum SR, Goh A, Laudon M, Srikumar T, Lefebvre PA, Grossman AR, Jonikas MC. A genome-wide algal mutant library and functional screen identifies genes required for eukaryotic photosynthesis. Nat Genet 2019. [PMID: 30886426 DOI: 10.1038/s41588-019-0370-376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Photosynthetic organisms provide food and energy for nearly all life on Earth, yet half of their protein-coding genes remain uncharacterized1,2. Characterization of these genes could be greatly accelerated by new genetic resources for unicellular organisms. Here we generated a genome-wide, indexed library of mapped insertion mutants for the unicellular alga Chlamydomonas reinhardtii. The 62,389 mutants in the library, covering 83% of nuclear protein-coding genes, are available to the community. Each mutant contains unique DNA barcodes, allowing the collection to be screened as a pool. We performed a genome-wide survey of genes required for photosynthesis, which identified 303 candidate genes. Characterization of one of these genes, the conserved predicted phosphatase-encoding gene CPL3, showed that it is important for accumulation of multiple photosynthetic protein complexes. Notably, 21 of the 43 higher-confidence genes are novel, opening new opportunities for advances in understanding of this biogeochemically fundamental process. This library will accelerate the characterization of thousands of genes in algae, plants, and animals.
Collapse
Affiliation(s)
- Xiaobo Li
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
- School of Life Sciences, Westlake Institute for Advanced Study, Westlake University, Hangzhou, China
| | - Weronika Patena
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Friedrich Fauser
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Robert E Jinkerson
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
- Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, CA, USA
| | - Shai Saroussi
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Moritz T Meyer
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Nina Ivanova
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Jacob M Robertson
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Rebecca Yue
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Ru Zhang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | | | - Tyler M Wittkopp
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
- Department of Biology, Stanford University, Stanford, CA, USA
- Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Silvia Ramundo
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Sean R Blum
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Audrey Goh
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Matthew Laudon
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA
| | - Tharan Srikumar
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Paul A Lefebvre
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, USA
| | - Arthur R Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA
| | - Martin C Jonikas
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, USA.
| |
Collapse
|
132
|
Naduthodi MIS, Mohanraju P, Südfeld C, D’Adamo S, Barbosa MJ, van der Oost J. CRISPR-Cas ribonucleoprotein mediated homology-directed repair for efficient targeted genome editing in microalgae Nannochloropsis oceanica IMET1. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:66. [PMID: 30962821 PMCID: PMC6432748 DOI: 10.1186/s13068-019-1401-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 03/09/2019] [Indexed: 06/07/2023]
Abstract
BACKGROUND Microalgae are considered as a sustainable feedstock for the production of biofuels and other value-added compounds. In particular, Nannochloropsis spp. stand out from other microalgal species due to their capabilities to accumulate both triacylglycerol (TAG) and polyunsaturated fatty acids (PUFAs). However, the commercialization of microalgae-derived products is primarily hindered by the high production costs compared to less sustainable alternatives. Efficient genome editing techniques leading to effective metabolic engineering could result in strains with enhanced productivities of interesting metabolites and thereby reduce the production costs. Competent CRISPR-based genome editing techniques have been reported in several microalgal species, and only very recently in Nannochloropsis spp. (2017). All the reported CRISPR-Cas-based systems in Nannochloropsis spp. rely on plasmid-borne constitutive expression of Cas9 and a specific guide, combined with repair of double-stranded breaks (DSB) by non-homologous end joining (NHEJ) for the target gene knockout. RESULTS In this study, we report for the first time an alternative approach for CRISPR-Cas-mediated genome editing in Nannochloropsis sp.; the Cas ribonucleoproteins (RNP) and an editing template were directly delivered into microalgal cells via electroporation, making Cas expression dispensable and homology-directed repair (HDR) possible with high efficiency. Apart from widely used SpCas9, Cas12a variants from three different bacterium were used for this approach. We observed that FnCas12a from Francisella novicida generated HDR-based targeted mutants with highest efficiency (up to 93% mutants among transformants) while AsCas12a from Acidaminococcus sp. resulted in the lowest efficiency. We initially show that the native homologous recombination (HR) system in N. oceanica IMET1 is not efficient for easy isolation of targeted mutants by HR. Cas9/sgRNA RNP delivery greatly enhanced HR at the target site, generating around 70% of positive mutant lines. CONCLUSION We show that the delivery of Cas RNP by electroporation can be an alternative approach to the presently reported plasmid-based Cas9 method for generating mutants of N. oceanica. The co-delivery of Cas-RNPs along with a dsDNA repair template efficiently enhanced HR at the target site, resulting in a remarkable higher percentage of positive mutant lines. Therefore, this approach can be used for efficient generation of targeted mutants in Nannochloropsis sp. In addition, we here report the activity of several Cas12a homologs in N. oceanica IMET1, identifying FnCas12a as the best performer for high efficiency targeted genome editing.
Collapse
Affiliation(s)
- Mihris Ibnu Saleem Naduthodi
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 PD Wageningen, The Netherlands
- Bioprocess Engineering Department, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Prarthana Mohanraju
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 PD Wageningen, The Netherlands
| | - Christian Südfeld
- Bioprocess Engineering Department, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Sarah D’Adamo
- Bioprocess Engineering Department, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Maria J. Barbosa
- Bioprocess Engineering Department, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 PD Wageningen, The Netherlands
| |
Collapse
|
133
|
A genome-wide algal mutant library and functional screen identifies genes required for eukaryotic photosynthesis. Nat Genet 2019; 51:627-635. [PMID: 30886426 PMCID: PMC6636631 DOI: 10.1038/s41588-019-0370-6] [Citation(s) in RCA: 155] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 02/08/2019] [Indexed: 12/22/2022]
Abstract
Photosynthetic organisms provide food and energy for nearly all life on Earth, yet half of their protein-coding genes remain uncharacterized1,2. Characterization of these genes could be greatly accelerated by new genetic resources for unicellular organisms. Here, we generated a genome-wide, indexed library of mapped insertion mutants for the unicellular alga Chlamydomonas reinhardtii. The 62,389 mutants in the library, covering 83% of nuclear, protein-coding genes, are available to the community. Each mutant contains unique DNA barcodes, allowing the collection to be screened as a pool. We performed a genome-wide survey of genes required for photosynthesis, which identified 303 candidate genes. Characterization of one of these genes, the conserved predicted phosphatase-encoding gene CPL3, showed it is important for accumulation of multiple photosynthetic protein complexes. Notably, 21 of the 43 highest-confidence genes are novel, opening new opportunities for advances in our understanding of this biogeochemically fundamental process. This library will accelerate the characterization of thousands of genes in algae, plants and animals. Generation of a library of 62,389 mapped insertion mutants for the unicellular alga Chlamydomonas reinhardtii enables screening for genes required for photosynthesis and the identification of 303 candidate genes.
Collapse
|
134
|
The dynamin-like protein Fzl promotes thylakoid fusion and resistance to light stress in Chlamydomonas reinhardtii. PLoS Genet 2019; 15:e1008047. [PMID: 30875368 PMCID: PMC6436760 DOI: 10.1371/journal.pgen.1008047] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 03/27/2019] [Accepted: 02/25/2019] [Indexed: 12/22/2022] Open
Abstract
Large GTPases of the Dynamin Related Proteins (DRP) family shape lipid bilayers through membrane fission or fusion processes. Despite the highly organized photosynthetic membranes of thylakoids, a single DRP is known to be targeted inside the chloroplast. Fzl from the land plant Arabidopsis thaliana is inserted in the inner envelope and thylakoid membranes to regulate their morphology. Fzl may promote the fusion of thylakoids but this remains to be proven. Moreover, the physiological requirement for fusing thylakoids is currently unknown. Here, we find that the unicellular microalga Chlamydomonas reinhardtii encodes an Fzl ortholog (CrFzl) that is localized in the chloroplast where it is soluble. To explore its function, the CRISPR/Cas9 technology was employed to generate multiple CrFzl knock out strains. Phenotypic analyzes revealed a specific requirement of CrFzl for survival upon light stress. Consistent with this, strong irradiance lead to increased photoinhibition of photosynthesis in mutant cells. Fluorescence and electron microscopy analysis demonstrated that upon exposure to high light, CrFzl mutants show defects in chloroplast morphology but also large cytosolic vacuoles in close contact with the plastid. We further observe that strong irradiance induces an increased recruitment of the DRP to thylakoid membranes. Most importantly, we show that CrFzl is required for the fusion of thylakoids during mating. Together, our results suggest that thylakoids fusion may be necessary for resistance to light stress. All eukaryotic cells are composed of compartments with defined functions. Among those, mitochondria generate the main source of energy in human and animal cells. Their capacity to generate and diffuse energy in the cell is regulated by fusion and fragmentation processes. Together with mitochondria that produce energy from oxygen, plant cells include an additional compartment called the chloroplast that produces energy from light. The machinery that converts light into energy is more precisely located inside the chloroplast within stacks of membranes called the thylakoids. Here, we elucidate the function of CrFzl, a previously uncharacterized protein encoded by the genome of the unicellular alga Chlamydomonas reinhardtii. Algal cells that do not contain CrFzl are impaired in their capacity to grow when they receive too much light and our results indicate that CrFzl promotes the fusion of thylakoids during mating. These results suggest that membrane fusion is an essential tool for energy production in stress conditions by living organisms.
Collapse
|
135
|
Guzmán-Zapata D, Sandoval-Vargas JM, Macedo-Osorio KS, Salgado-Manjarrez E, Castrejón-Flores JL, Oliver-Salvador MDC, Durán-Figueroa NV, Nogué F, Badillo-Corona JA. Efficient Editing of the Nuclear APT Reporter Gene in Chlamydomonas reinhardtii via Expression of a CRISPR-Cas9 Module. Int J Mol Sci 2019; 20:E1247. [PMID: 30871076 PMCID: PMC6429146 DOI: 10.3390/ijms20051247] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 03/04/2019] [Accepted: 03/07/2019] [Indexed: 12/20/2022] Open
Abstract
The clustered regularly interspaced short palindromic repeat/CRISPR-associated protein 9 (CRISPR/Cas9) technology is a versatile and useful tool to perform genome editing in different organisms ranging from bacteria and yeast to plants and mammalian cells. For a couple of years, it was believed that the system was inefficient and toxic in the alga Chlamydomonas reinhardtii. However, recently the system has been successfully implemented in this model organism, albeit relying mostly on the electroporation of ribonucleoproteins (RNPs) into cell wall deficient strains. This requires a constant source of RNPs and limits the application of the technology to strains that are not necessarily the most relevant from a biotechnological point of view. Here, we show that transient expression of the Streptococcus pyogenes Cas9 gene and sgRNAs, targeted to the single-copy nuclear apt9 gene, encoding an adenine phosphoribosyl transferase (APT), results in efficient disruption at the expected locus. Introduction of indels to the apt9 locus results in cell insensitivity to the otherwise toxic compound 2-fluoroadenine (2-FA). We have used agitation with glass beads and particle bombardment to introduce the plasmids carrying the coding sequences for Cas9 and the sgRNAs in a cell-walled strain of C. reinhardtii (CC-125). Using sgRNAs targeting exons 1 and 3 of apt9, we obtained disruption efficiencies of 3 and 30% on preselected 2-FA resistant colonies, respectively. Our results show that transient expression of Cas9 and a sgRNA can be used for editing of the nuclear genome inexpensively and at high efficiency. Targeting of the APT gene could potentially be used as a pre-selection marker for multiplexed editing or disruption of genes of interest.
Collapse
Affiliation(s)
- Daniel Guzmán-Zapata
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología. Av. Acueducto S/N., Col. Barrio La Laguna Ticomán, 07340 Mexico City, Mexico.
| | - José M Sandoval-Vargas
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología. Av. Acueducto S/N., Col. Barrio La Laguna Ticomán, 07340 Mexico City, Mexico.
| | - Karla S Macedo-Osorio
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología. Av. Acueducto S/N., Col. Barrio La Laguna Ticomán, 07340 Mexico City, Mexico.
| | - Edgar Salgado-Manjarrez
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología. Av. Acueducto S/N., Col. Barrio La Laguna Ticomán, 07340 Mexico City, Mexico.
| | - José L Castrejón-Flores
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología. Av. Acueducto S/N., Col. Barrio La Laguna Ticomán, 07340 Mexico City, Mexico.
| | - María Del Carmen Oliver-Salvador
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología. Av. Acueducto S/N., Col. Barrio La Laguna Ticomán, 07340 Mexico City, Mexico.
| | - Noé V Durán-Figueroa
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología. Av. Acueducto S/N., Col. Barrio La Laguna Ticomán, 07340 Mexico City, Mexico.
| | - Fabien Nogué
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France.
| | - Jesús A Badillo-Corona
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología. Av. Acueducto S/N., Col. Barrio La Laguna Ticomán, 07340 Mexico City, Mexico.
| |
Collapse
|
136
|
Ortega-Escalante JA, Jasper R, Miller SM. CRISPR/Cas9 mutagenesis in Volvox carteri. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 97:661-672. [PMID: 30406958 DOI: 10.1111/tpj.14149] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 10/18/2018] [Accepted: 10/23/2018] [Indexed: 06/08/2023]
Abstract
Volvox carteri and other volvocine green algae comprise an excellent model for investigating developmental complexity and its origins. Here we describe a method for targeted mutagenesis in V. carteri using CRISPR/Cas9 components expressed from transgenes. We used V. carteri nitrate reductase gene (nitA) regulatory sequences to conditionally express Streptococcus pyogenes Cas9, and V. carteri U6 RNA gene regulatory sequences to constitutively express single-guide RNA (sgRNA) transcripts. Volvox carteri was bombarded with both Cas9 vector and one of several sgRNA vectors programmed to target different test genes (glsA, regA and invA), and transformants were selected for expression of a hygromycin-resistance marker present on the sgRNA vector. Hygromycin-resistant transformants grown with nitrate as sole nitrogen source (inducing for nitA) were tested for Cas9 and sgRNA expression, and for the ability to generate progeny with expected mutant phenotypes. Some transformants of a somatic regenerator (Reg) mutant strain receiving sgRNA plasmid with glsA protospacer sequence yielded progeny (at a rate of ~0.01%) with a gonidialess (Gls) phenotype similar to that observed for previously described glsA mutants, and sequencing of the glsA gene in independent mutants revealed short deletions within the targeted region of glsA, indicative of Cas9-directed non-homologous end joining. Similarly, bombardment of a morphologically wild-type strain with the Cas9 plasmid and sgRNA plasmids targeting regA or invA yielded regA and invA mutant transformants/progeny, respectively (at rates of 0.1-100%). The capacity to make precisely directed frameshift mutations should greatly accelerate the molecular genetic analysis of development in V. carteri, and of developmental novelty in the volvocine algae.
Collapse
Affiliation(s)
- José A Ortega-Escalante
- Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA
| | - Robyn Jasper
- Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA
| | - Stephen M Miller
- Department of Biological Sciences, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD, 21250, USA
| |
Collapse
|
137
|
De Mia M, Lemaire SD, Choquet Y, Wollman FA. Nitric Oxide Remodels the Photosynthetic Apparatus upon S-Starvation in Chlamydomonas reinhardtii. PLANT PHYSIOLOGY 2019; 179:718-731. [PMID: 30530737 PMCID: PMC6426411 DOI: 10.1104/pp.18.01164] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 11/20/2018] [Indexed: 05/02/2023]
Abstract
Many photosynthetic autotrophs have evolved responses that adjust their metabolism to limitations in nutrient availability. Here we report a detailed characterization of the remodeling of photosynthesis upon sulfur starvation under heterotrophy and photo-autotrophy in the green alga (Chlamydomonas reinhardtii). Photosynthetic inactivation under low light and darkness is achieved through specific degradation of Rubisco and cytochrome b 6 f and occurs only in the presence of reduced carbon in the medium. The process is likely regulated by nitric oxide (NO), which is produced 24 h after the onset of starvation, as detected with NO-sensitive fluorescence probes visualized by fluorescence microscopy. We provide pharmacological evidence that intracellular NO levels govern this degradation pathway: the addition of a NO scavenger decreases the rate of cytochrome b 6 f and Rubisco degradation, whereas NO donors accelerate the degradation. Based on our analysis of the relative contribution of the different NO synthesis pathways, we conclude that the NO2-dependent nitrate reductase-independent pathway is crucial for NO production under sulfur starvation. Our data argue for an active role for NO in the remodeling of thylakoid protein complexes upon sulfur starvation.
Collapse
Affiliation(s)
- Marcello De Mia
- Laboratoire de Physiologie Membranaire et Moléculaire du Chloroplaste, Centre National de la Recherche Scientifique, Sorbonne Université, Institut de Biologie Physico-Chimique, 75005 Paris, France
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Centre National de la Recherche Scientifique, Sorbonne Université, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Stéphane D Lemaire
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Centre National de la Recherche Scientifique, Sorbonne Université, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Yves Choquet
- Laboratoire de Physiologie Membranaire et Moléculaire du Chloroplaste, Centre National de la Recherche Scientifique, Sorbonne Université, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Francis-André Wollman
- Laboratoire de Physiologie Membranaire et Moléculaire du Chloroplaste, Centre National de la Recherche Scientifique, Sorbonne Université, Institut de Biologie Physico-Chimique, 75005 Paris, France
| |
Collapse
|
138
|
Abstract
This review summarizes the current state of the art of CRISPR/Cas-based genome editing technologies for natural product producers.
Collapse
Affiliation(s)
- Yaojun Tong
- The Novo Nordisk Foundation Center for Biosustainability
- Technical University of Denmark
- Denmark
| | - Tilmann Weber
- The Novo Nordisk Foundation Center for Biosustainability
- Technical University of Denmark
- Denmark
| | - Sang Yup Lee
- The Novo Nordisk Foundation Center for Biosustainability
- Technical University of Denmark
- Denmark
- Metabolic and Biomolecular Engineering National Research Laboratory
- Department of Chemical and Biomolecular Engineering (BK21 Plus Program)
| |
Collapse
|
139
|
Tong Y, Weber T, Lee SY. CRISPR/Cas-based genome engineering in natural product discovery. Nat Prod Rep 2019; 36:1262-1280. [DOI: 10.1039/c8np00089a] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This review summarizes the current state of the art of CRISPR/Cas-based genome editing technologies for natural product producers.
Collapse
Affiliation(s)
- Yaojun Tong
- The Novo Nordisk Foundation Center for Biosustainability
- Technical University of Denmark
- Denmark
| | - Tilmann Weber
- The Novo Nordisk Foundation Center for Biosustainability
- Technical University of Denmark
- Denmark
| | - Sang Yup Lee
- The Novo Nordisk Foundation Center for Biosustainability
- Technical University of Denmark
- Denmark
- Metabolic and Biomolecular Engineering National Research Laboratory
- Department of Chemical and Biomolecular Engineering (BK21 Plus Program)
| |
Collapse
|
140
|
Yoshimitsu Y, Abe J, Harayama S. Cas9-guide RNA ribonucleoprotein-induced genome editing in the industrial green alga Coccomyxa sp. strain KJ. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:326. [PMID: 30555532 PMCID: PMC6287348 DOI: 10.1186/s13068-018-1327-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 11/30/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Oxygen-evolving photosynthetic microorganisms, collectively termed as microalgae, are gaining attention as alternative fuel sources. The unicellular alga Coccomyxa sp. strain KJ that belongs to the class Trebouxiophyceae can grow rapidly in minimal mineral media and accumulate triacylglycerols at levels > 60% (w/w) of its dry weight under nitrogen depletion conditions. Thus, the strain can be a good candidate for biofuel production. Still, substantial improvements in lipid productivity and other traits of this strain are needed to meet commercial production requirements. Consequently, the development of new genetic tools including genome editing that are applicable to this strain is highly desired. RESULTS In this paper, we report successful genome editing of strain KJ by intracellular delivery of a ribonucleoprotein complex comprising recombinant Cas9 protein and guide RNA. For introduction of Cas9-guide RNA ribonucleoprotein into strain KJ cells, we used an electroporator with a short (2.5 ms) electric pulse at a high field strength (7500 V cm-1) followed by multiple 50-ms electric pulses at low field strength (250 V cm-1). Under these conditions, we successfully isolated several knockout lines of the FTSY gene of strain KJ, encoding a signal recognition particle-docking protein at a frequency of 0.01%. CONCLUSIONS Our study shows applicability of DNA-free genome editing in Coccomyxa, which may be applicable in other Trebouxiophyceae species.
Collapse
Affiliation(s)
- Yuya Yoshimitsu
- Advanced Research and Innovation Center, DENSO CORPORATION, Komenoki-cho, Nisshin-Shi, Aichi 470-0111 Japan
| | - Jun Abe
- Research and Development Initiative, Chuo University, Bunkyo-ku, Tokyo, 112-8551 Japan
| | - Shigeaki Harayama
- Research and Development Initiative, Chuo University, Bunkyo-ku, Tokyo, 112-8551 Japan
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, Bunkyo-ku, Tokyo, 112-8551 Japan
| |
Collapse
|
141
|
Tian Y, Gao S, von der Heyde EL, Hallmann A, Nagel G. Two-component cyclase opsins of green algae are ATP-dependent and light-inhibited guanylyl cyclases. BMC Biol 2018; 16:144. [PMID: 30522480 PMCID: PMC6284317 DOI: 10.1186/s12915-018-0613-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/20/2018] [Indexed: 11/10/2022] Open
Abstract
Background The green algae Chlamydomonas reinhardtii and Volvox carteri are important models for studying light perception and response, expressing many different photoreceptors. More than 10 opsins were reported in C. reinhardtii, yet only two—the channelrhodopsins—were functionally characterized. Characterization of new opsins would help to understand the green algae photobiology and to develop new tools for optogenetics. Results Here we report the characterization of a novel opsin family from these green algae: light-inhibited guanylyl cyclases regulated through a two-component-like phosphoryl transfer, called “two-component cyclase opsins” (2c-Cyclops). We prove the existence of such opsins in C. reinhardtii and V. carteri and show that they have cytosolic N- and C-termini, implying an eight-transmembrane helix structure. We also demonstrate that cGMP production is both light-inhibited and ATP-dependent. The cyclase activity of Cr2c-Cyclop1 is kept functional by the ongoing phosphorylation and phosphoryl transfer from the histidine kinase to the response regulator in the dark, proven by mutagenesis. Absorption of a photon inhibits the cyclase activity, most likely by inhibiting the phosphoryl transfer. Overexpression of Vc2c-Cyclop1 protein in V. carteri leads to significantly increased cGMP levels, demonstrating guanylyl cyclase activity of Vc2c-Cyclop1 in vivo. Live cell imaging of YFP-tagged Vc2c-Cyclop1 in V. carteri revealed a development-dependent, layer-like structure at the immediate periphery of the nucleus and intense spots in the cell periphery. Conclusions Cr2c-Cyclop1 and Vc2c-Cyclop1 are light-inhibited and ATP-dependent guanylyl cyclases with an unusual eight-transmembrane helix structure of the type I opsin domain which we propose to classify as type Ib, in contrast to the 7 TM type Ia opsins. Overexpression of Vc2c-Cyclop1 protein in V. carteri led to a significant increase of cGMP, demonstrating enzyme functionality in the organism of origin. Fluorescent live cell imaging revealed that Vc2c-Cyclop1 is located in the periphery of the nucleus and in confined areas at the cell periphery. Electronic supplementary material The online version of this article (10.1186/s12915-018-0613-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Yuehui Tian
- Botanik I, Julius-Maximilians-Universität Würzburg, Biozentrum, Julius-von-Sachs-Platz 2, 97082, Würzburg, Germany
| | - Shiqiang Gao
- Botanik I, Julius-Maximilians-Universität Würzburg, Biozentrum, Julius-von-Sachs-Platz 2, 97082, Würzburg, Germany.
| | - Eva Laura von der Heyde
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Armin Hallmann
- Department of Cellular and Developmental Biology of Plants, University of Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany.
| | - Georg Nagel
- Botanik I, Julius-Maximilians-Universität Würzburg, Biozentrum, Julius-von-Sachs-Platz 2, 97082, Würzburg, Germany.
| |
Collapse
|
142
|
Umen JG. Sizing up the cell cycle: systems and quantitative approaches in Chlamydomonas. CURRENT OPINION IN PLANT BIOLOGY 2018; 46:96-103. [PMID: 30212737 PMCID: PMC6269190 DOI: 10.1016/j.pbi.2018.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/14/2018] [Accepted: 08/16/2018] [Indexed: 05/06/2023]
Abstract
The unicellular green alga Chlamydomonas provides a simplified model for defining core cell cycle functions conserved in the green lineage and for understanding multiple fission, a common cell cycle variation found in many algae. Systems-level approaches including a recent groundbreaking screen for conditional lethal cell cycle mutants and genome-wide transcriptome analyses are revealing the complex relationships among cell cycle regulators and helping define roles for CDKA/CDK1 and CDKB, the latter of which is unique to the green lineage and plays a central role in mitotic regulation. Genetic screens and quantitative single-cell analyses have provided insight into cell-size control during multiple fission including the identification of a candidate `sizer' protein. Quantitative single-cell tracking and modeling are promising approaches for gaining additional insight into regulation of cellular and subcellular scaling during the Chlamydomonas cell cycle.
Collapse
Affiliation(s)
- James G Umen
- Donald Danforth Plant Science Center, 975 N. Warson Rd., St. Louis, MO 63132, USA.
| |
Collapse
|
143
|
|
144
|
Lemaire SD, Tedesco D, Crozet P, Michelet L, Fermani S, Zaffagnini M, Henri J. Crystal Structure of Chloroplastic Thioredoxin f2 from Chlamydomonas reinhardtii Reveals Distinct Surface Properties. Antioxidants (Basel) 2018; 7:E171. [PMID: 30477165 PMCID: PMC6316601 DOI: 10.3390/antiox7120171] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/13/2018] [Accepted: 11/20/2018] [Indexed: 12/14/2022] Open
Abstract
Protein disulfide reduction by thioredoxins (TRXs) controls the conformation of enzyme active sites and their multimeric complex formation. TRXs are small oxidoreductases that are broadly conserved in all living organisms. In photosynthetic eukaryotes, TRXs form a large multigenic family, and they have been classified in different types: f, m, x, y, and z types are chloroplastic, while o and h types are located in mitochondria and cytosol. In the model unicellular alga Chlamydomonas reinhardtii, the TRX family contains seven types, with f- and h-types represented by two isozymes. Type-f TRXs interact specifically with targets in the chloroplast, controlling photosynthetic carbon fixation by the Calvin⁻Benson cycle. We solved the crystal structures of TRX f2 and TRX h1 from C. reinhardtii. The systematic comparison of their atomic features revealed a specific conserved electropositive crown around the active site of TRX f, complementary to the electronegative surface of their targets. We postulate that this surface provides specificity to each type of TRX.
Collapse
Affiliation(s)
- Stéphane D Lemaire
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 8226 CNRS Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Daniele Tedesco
- Bio-Pharmaceutical Analysis Section (Bio-PhASe), Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy.
| | - Pierre Crozet
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 8226 CNRS Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Laure Michelet
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 8226 CNRS Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Simona Fermani
- Department of Chemistry "Giacomo Ciamician", University of Bologna, via Selmi 2, 40126 Bologna, Italy.
| | - Mirko Zaffagnini
- Laboratory of Molecular Plant Physiology, Department of Pharmacy and Biotechnology, University of Bologna, via Irnerio 42, 40126 Bologna, Italy.
| | - Julien Henri
- Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 8226 CNRS Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| |
Collapse
|
145
|
Sekiguchi M, Kameda S, Kurosawa S, Yoshida M, Yoshimura K. Thermotaxis in Chlamydomonas is brought about by membrane excitation and controlled by redox conditions. Sci Rep 2018; 8:16114. [PMID: 30382191 PMCID: PMC6208428 DOI: 10.1038/s41598-018-34487-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 10/18/2018] [Indexed: 11/09/2022] Open
Abstract
Temperature is physiologically critical for all living organisms, which cope with temperature stress using metabolic and behavioral responses. In unicellular and some multicellular organisms, thermotaxis is a behavioral response to avoid stressful thermal environments and promote accumulation in an optimal thermal environment. In this study, we examined whether Chlamydomonas reinhardtii, a unicellular green alga, demonstrated thermotaxis. We found that between 10 °C and 30 °C, Chlamydomonas cells migrated toward lower temperatures independent of cultivation temperature. Interestingly, when we applied reagents to change intracellular reduction-oxidation (redox) conditions, we saw that thermotaxis was enhanced, suppressed, or reversed, depending on the redox conditions and cultivation temperature. Thermotaxis was almost absent in ppr2 and ppr3 mutants, which cannot swim backward because of a defect in generating calcium current in flagella. The frequency of spontaneous backward swimming was lower at more favorable temperature, suggesting a pivotal role of spontaneous backward swimming generated by flagellar membrane excitation.
Collapse
Affiliation(s)
- Masaya Sekiguchi
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, 337-8570, Japan
| | - Shigetoshi Kameda
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, 337-8570, Japan
| | - Satoshi Kurosawa
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, 337-8570, Japan
| | - Megumi Yoshida
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, 337-8570, Japan
| | - Kenjiro Yoshimura
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, 337-8570, Japan.
| |
Collapse
|
146
|
Sugano SS, Nishihama R, Shirakawa M, Takagi J, Matsuda Y, Ishida S, Shimada T, Hara-Nishimura I, Osakabe K, Kohchi T. Efficient CRISPR/Cas9-based genome editing and its application to conditional genetic analysis in Marchantia polymorpha. PLoS One 2018; 13:e0205117. [PMID: 30379827 PMCID: PMC6209168 DOI: 10.1371/journal.pone.0205117] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 09/15/2018] [Indexed: 01/30/2023] Open
Abstract
Marchantia polymorpha is one of the model species of basal land plants. Although CRISPR/Cas9-based genome editing has already been demonstrated for this plant, the efficiency was too low to apply to functional analysis. In this study, we show the establishment of CRISPR/Cas9 genome editing vectors with high efficiency for both construction and genome editing. Codon optimization of Cas9 to Arabidopsis achieved over 70% genome editing efficiency at two loci tested. Systematic assessment revealed that guide sequences of 17 nt or shorter dramatically decreased this efficiency. We also demonstrated that a combinatorial use of this system and a floxed complementation construct enabled conditional analysis of a nearly essential gene. This study reports that simple, rapid, and efficient genome editing is feasible with the series of developed vectors.
Collapse
Affiliation(s)
- Shigeo S. Sugano
- R-GIRO, Ritsumeikan University, Kusatsu, Shiga, Japan
- JST, PRESTO, Kawaguchi, Saitama, Japan
| | | | | | - Junpei Takagi
- Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Yoriko Matsuda
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Sakiko Ishida
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Tomoo Shimada
- Graduate School of Science, Kyoto University, Kyoto, Japan
| | | | - Keishi Osakabe
- Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Tokushima, Japan
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
- * E-mail:
| |
Collapse
|
147
|
Kroth PG, Bones AM, Daboussi F, Ferrante MI, Jaubert M, Kolot M, Nymark M, Río Bártulos C, Ritter A, Russo MT, Serif M, Winge P, Falciatore A. Genome editing in diatoms: achievements and goals. PLANT CELL REPORTS 2018; 37:1401-1408. [PMID: 30167805 DOI: 10.1007/s00299-018-2334-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 08/07/2018] [Indexed: 05/20/2023]
Abstract
Diatoms are major components of phytoplankton and play a key role in the ecology of aquatic ecosystems. These algae are of great scientific importance for a wide variety of research areas, ranging from marine ecology and oceanography to biotechnology. During the last 20 years, the availability of genomic information on selected diatom species and a substantial progress in genetic manipulation, strongly contributed to establishing diatoms as molecular model organisms for marine biology research. Recently, tailored TALEN endonucleases and the CRISPR/Cas9 system were utilized in diatoms, allowing targeted genetic modifications and the generation of knockout strains. These approaches are extremely valuable for diatom research because breeding, forward genetic screens by random insertion, and chemical mutagenesis are not applicable to the available model species Phaeodactylum tricornutum and Thalassiosira pseudonana, which do not cross sexually in the lab. Here, we provide an overview of the genetic toolbox that is currently available for performing stable genetic modifications in diatoms. We also discuss novel challenges that need to be addressed to fully exploit the potential of these technologies for the characterization of diatom biology and for metabolic engineering.
Collapse
Affiliation(s)
- Peter G Kroth
- Fachbereich Biologie, Universität Konstanz, 78457, Konstanz, Germany.
| | - Atle M Bones
- Cell, Molecular Biology and Genomics Group, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Fayza Daboussi
- LISBP, Université de Toulouse, CNRS, INSA, 135 Avenue de Rangueil, 31077, Toulouse, France
| | - Maria I Ferrante
- Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Villa Comunale 1, Naples, 80121, Italy
| | - Marianne Jaubert
- Laboratoire de Biologie Computationnelle et Quantitative, Institut de Biologie Paris-Seine, Sorbonne Université, CNRS, 75005, Paris, France
| | - Misha Kolot
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100, Rehovot, Israel
- Department of Biochemistry and Molecular Biology, Tel-Aviv University, Tel-Aviv, 69978, Israel
| | - Marianne Nymark
- Cell, Molecular Biology and Genomics Group, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | | | - Andrés Ritter
- Laboratoire de Biologie Computationnelle et Quantitative, Institut de Biologie Paris-Seine, Sorbonne Université, CNRS, 75005, Paris, France
| | - Monia T Russo
- Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Villa Comunale 1, Naples, 80121, Italy
| | - Manuel Serif
- LISBP, Université de Toulouse, CNRS, INSA, 135 Avenue de Rangueil, 31077, Toulouse, France
| | - Per Winge
- Cell, Molecular Biology and Genomics Group, Department of Biology, Norwegian University of Science and Technology, 7491, Trondheim, Norway
| | - Angela Falciatore
- Laboratoire de Biologie Computationnelle et Quantitative, Institut de Biologie Paris-Seine, Sorbonne Université, CNRS, 75005, Paris, France.
| |
Collapse
|
148
|
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: 141] [Impact Index Per Article: 23.5] [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.
Collapse
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
| |
Collapse
|
149
|
CFAP70 Is a Novel Axoneme-Binding Protein That Localizes at the Base of the Outer Dynein Arm and Regulates Ciliary Motility. Cells 2018; 7:cells7090124. [PMID: 30158508 PMCID: PMC6162463 DOI: 10.3390/cells7090124] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 08/24/2018] [Accepted: 08/28/2018] [Indexed: 12/11/2022] Open
Abstract
In the present study, we characterized CFAP70, a candidate of cilia-related protein in mice. As this protein has a cluster of tetratricopeptide repeat (TPR) domains like many components of the intraflagellar transport (IFT) complex, we investigated the domain functions of particular interest in ciliary targeting and/or localization. RT-PCR and immunohistochemistry of various mouse tissues demonstrated the association of CFAP70 with motile cilia and flagella. A stepwise extraction of proteins from swine tracheal cilia showed that CFAP70 bound tightly to the ciliary axoneme. Fluorescence microscopy of the cultured ependyma expressing fragments of CFAP70 demonstrated that the N-terminus rather than the C-terminus with the TPR domains was more important for the ciliary localization. When CFAP70 was knocked down in cultured mouse ependyma, reductions in cilia beating frequency were observed. Consistent with these observations, a Chlamydomonas mutant lacking the CFAP70 homolog, FAP70, showed defects in outer dynein arm (ODA) activity and a reduction in flagellar motility. Cryo-electron tomography revealed that the N-terminus of FAP70 resided stably at the base of the ODA. These results demonstrated that CFAP70 is a novel regulatory component of the ODA in motile cilia and flagella, and that the N-terminus is important for its ciliary localization.
Collapse
|
150
|
Breker M, Lieberman K, Cross FR. Comprehensive Discovery of Cell-Cycle-Essential Pathways in Chlamydomonas reinhardtii. THE PLANT CELL 2018; 30:1178-1198. [PMID: 29743196 PMCID: PMC6048789 DOI: 10.1105/tpc.18.00071] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/26/2018] [Accepted: 05/08/2018] [Indexed: 05/05/2023]
Abstract
We generated a large collection of temperature-sensitive lethal mutants in the unicellular green alga Chlamydomonas reinhardtii, focusing on mutations specifically affecting cell cycle regulation. We used UV mutagenesis and robotically assisted phenotypic screening to isolate candidates. To overcome the bottleneck at the critical step of molecular identification of the causative mutation ("driver"), we developed MAPS-SEQ (meiosis-assisted purifying selection sequencing), a multiplexed genetic/bioinformatics strategy. MAPS-SEQ allowed us to perform multiplexed simultaneous determination of the driver mutations from hundreds of neutral "passenger" mutations in each member of a large pool of mutants. This method should work broadly, including in multicellular diploid genetic systems, for any scorable trait. Using MAPS-SEQ, we identified essential genes spanning a wide range of molecular functions. Phenotypic clustering based on DNA content analysis and cell morphology indicated that the mutated genes function in the cell cycle at multiple points and by diverse mechanisms. The collection is sufficiently complete to allow specific conditional inactivation of almost all cell-cycle-regulatory pathways. Approximately seventy-five percent of the essential genes identified in this project had clear orthologs in land plant genomes, a huge enrichment compared with the value of ∼20% for the Chlamydomonas genome overall. Findings about these mutants will likely have direct relevance to essential cell biology in land plants.
Collapse
Affiliation(s)
- Michal Breker
- Laboratory of Cell Cycle Genetics, The Rockefeller University, New York, New York 10065
| | - Kristi Lieberman
- Laboratory of Cell Cycle Genetics, The Rockefeller University, New York, New York 10065
| | - Frederick R Cross
- Laboratory of Cell Cycle Genetics, The Rockefeller University, New York, New York 10065
| |
Collapse
|