1
|
Imamura S, Yamada K, Takebe H, Kiuchi R, Iwashita H, Toyokawa C, Suzuki K, Sakurai A, Takaya K. Optimal conditions of algal breeding using neutral beam and applying it to breed Euglena gracilis strains with improved lipid accumulation. Sci Rep 2024; 14:14716. [PMID: 38961078 DOI: 10.1038/s41598-024-65175-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Accepted: 06/18/2024] [Indexed: 07/05/2024] Open
Abstract
Microalgae are considered to be more useful and effective to use in biomass production than other photosynthesis organisms. However, microalgae need to be altered to acquire more desirable traits for the relevant purpose. Although neutron radiation is known to induce DNA mutations, there have been few studies on its application to microalgae, and the optimal relationship between irradiation intensity and mutation occurrence has not been established. In this study, using the unicellular red alga Cyanidioschyzon merolae as a model, we analyzed the relationship between the absorbed dose of two types of neutrons, high-energy (above 1 MeV) and thermal (around 25 meV) neutrons, and mutation occurrence while monitoring mutations in URA5.3 gene encoding UMP synthase. As a result, the highest mutational occurrence was observed when the cells were irradiated with 20 Gy of high-energy neutrons and 13 Gy of thermal neutrons. Using these optimal neutron irradiation conditions, we next attempted to improve the lipid accumulation of Euglena gracilis, which is a candidate strain for biofuel feedstock production. As a result, we obtained several strains with a maximum 1.3-fold increase in lipid accumulation compared with the wild-type. These results indicate that microalgae breeding by neutron irradiation is effective.
Collapse
Affiliation(s)
- Sousuke Imamura
- Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, Musashino-shi, 180-8585, Japan.
| | - Koji Yamada
- Advanced Science Research Institute, Euglena Co., Ltd., Yokohama-shi, 230-0045, Japan
| | - Hiroaki Takebe
- Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, Musashino-shi, 180-8585, Japan
| | - Ryu Kiuchi
- Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, Musashino-shi, 180-8585, Japan
| | - Hidenori Iwashita
- Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, Musashino-shi, 180-8585, Japan
| | - Chihana Toyokawa
- Advanced Science Research Institute, Euglena Co., Ltd., Yokohama-shi, 230-0045, Japan
| | - Kengo Suzuki
- Advanced Science Research Institute, Euglena Co., Ltd., Yokohama-shi, 230-0045, Japan
| | - Atsushi Sakurai
- Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, Musashino-shi, 180-8585, Japan
| | - Kazuhiro Takaya
- Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, Musashino-shi, 180-8585, Japan
| |
Collapse
|
2
|
Takeue N, Kuroyama A, Hayashi Y, Tanaka K, Imamura S. Autofluorescence-based high-throughput isolation of nonbleaching Cyanidioschyzon merolae strains under nitrogen-depletion. FRONTIERS IN PLANT SCIENCE 2022; 13:1036839. [PMID: 36589047 PMCID: PMC9794624 DOI: 10.3389/fpls.2022.1036839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
Photosynthetic organisms maintain optimum levels of photosynthetic pigments in response to environmental changes to adapt to the conditions. The identification of cyanobacteria strains that alleviate bleaching has revealed genes that regulate levels of phycobilisome, the main light-harvesting complex. In contrast, the mechanisms of pigment degradation in algae remain unclear, as no nonbleaching strains have previously been isolated. To address this issue, this study attempted to isolate nonbleaching strains of the unicellular red alga Cyanidioschyzon merolae after exposure to nitrogen (N)-depletion based on autofluorescence information. After four weeks under N-depletion, 13 cells from 500,000 cells with almost identical pre- and post-depletion chlorophyll a (Chl a) and/or phycocyanin autofluorescence intensities were identified. These nonbleaching candidate strains were sorted via a cell sorter, isolated on solid medium, and their post-N-depletion Chl a and phycocyanin levels were analyzed. Chl a levels of these nonbleaching candidate strains were lower at 1-4 weeks of N-depletion similar to the control strains, however, their phycocyanin levels were unchanged. Thus, we successfully isolated nonbleaching C. merolae strains in which phycocyanin was not degraded under N-depletion, via autofluorescence spectroscopy and cell sorting. This versatile method will help to elucidate the mechanisms regulating pigments in microalgae.
Collapse
Affiliation(s)
- Nozomi Takeue
- School of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Ayaka Kuroyama
- Product and Business Planning Section, Planning and Marketing Department, Life Science Business Division, Medical Business Group, Sony Corporation, Nishi-ku, Yokohama, Japan
| | - Yoshiharu Hayashi
- Product and Business Planning Section, Planning and Marketing Department, Life Science Business Division, Medical Business Group, Sony Corporation, Nishi-ku, Yokohama, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Midori-ku, Yokohama, Japan
- Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, Musashino-shi, Tokyo, Japan
| |
Collapse
|
3
|
Murakami M, Osanai T. Biochemical Properties of β-Amylase from Red Algae and Improvement of Its Thermostability through Immobilization. ACS OMEGA 2022; 7:36195-36205. [PMID: 36278071 PMCID: PMC9583313 DOI: 10.1021/acsomega.2c03315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 09/16/2022] [Indexed: 06/16/2023]
Abstract
β-Amylase hydrolyzes polysaccharides, such as starch, into maltose. It is used as an industrial enzyme in the production of food and pharmaceuticals. The eukaryotic red alga Cyanidioschyzon merolae is a unicellular alga that grows at an optimum pH of 2.0-3.0 and an optimum temperature of 40-50 °C. By focusing on the thermostability and acid resistance of the proteins of C. merolae, we investigated the properties of β-amylase from C. merolae (hereafter CmBAM) and explored the possibility of using CmBAM as an industrial enzyme. CmBAM showed the highest activity at 47 °C and pH 6.0. CmBAM had a relatively higher specificity for amylose as a substrate than for starch. Immobilization of CmBAM on a silica gel carrier improved storage stability and thermostability, allowing the enzyme to be reused. The optimum temperature and pH of CmBAM were comparable to those of existing β-amylases from barley and wheat. C. merolae does not use amylose, but CmBAM has a substrate specificity for both amylose and amylopectin but not for glycogen. Among the several β-amylases reported, CmBAM was unique, with a higher specificity for amylose than for starch. The high specificity of CmBAM for amylose suggests that isoamylase and pullulanase, which cleave the α-1,6 bonds of starch, may act together in vivo. Compared with several reported immobilized plant-derived β-amylases, immobilized CmBAM was comparable to β-amylase, with the highest reusability and the third-highest storage stability at 30 days of storage. In addition, immobilized CmBAM has improved thermostability by 15-20 °C, which can lead to wider applications and easier handling.
Collapse
|
4
|
Zhou B, Shima H, Igarashi K, Tanaka K, Imamura S. CmNDB1 and a Specific Domain of CmMYB1 Negatively Regulate CmMYB1-Dependent Transcription of Nitrate Assimilation Genes Under Nitrogen-Repleted Condition in a Unicellular Red Alga. FRONTIERS IN PLANT SCIENCE 2022; 13:821947. [PMID: 35360310 PMCID: PMC8962646 DOI: 10.3389/fpls.2022.821947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 02/07/2022] [Indexed: 06/02/2023]
Abstract
Nitrogen assimilation is an essential process that controls plant growth and development. Plant cells adjust the transcription of nitrogen assimilation genes through transcription factors (TFs) to acclimatize to changing nitrogen levels in nature. However, the regulatory mechanisms of these TFs under nitrogen-repleted (+N) conditions in plant lineages remain largely unknown. Here, we identified a negative domain (ND) of CmMYB1, the nitrogen-depleted (-N)-activated TF, in a unicellular red alga Cyanidioschyzon merolae. The ND deletion changed the localization of CmMYB1 from the cytoplasm to the nucleus, enhanced the binding efficiency of CmMYB1 to promoters of nitrate assimilation genes, and increased the transcripts of nitrate assimilation genes under +N condition. A pull-down assay using an ND-overexpressing strain combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis helped us to screen and identify an unknown-function protein, the CmNDB1. Yeast two-hybrid analysis demonstrated that CmNDB1 interacts with ND. Similar to ND deletion, CmNDB1 deletion also led to the nucleus localization of CmMYB1, enhanced the promoter-binding ratio of CmMYB1 to the promoter regions of nitrate assimilation genes, and increased transcript levels of nitrate assimilation genes under +N condition. Thus, these presented results indicated that ND and CmNDB1 negatively regulate CmMYB1 functions under the +N condition in C. merolae.
Collapse
Affiliation(s)
- Baifeng Zhou
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Hiroki Shima
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kazuhiko Igarashi
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- NTT Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, Tokyo, Japan
| |
Collapse
|
5
|
Abstract
Apicomplexan parasites, such as Toxoplasma gondii and Plasmodium falciparum, are the cause of many important human and animal diseases. While T. gondii tachyzoites replicate through endodyogeny, during which two daughter cells are formed within the parental cell, P. falciparum replicates through schizogony, where up to 32 parasites are formed in a single infected red blood cell and even thousands of daughter cells during mosquito- or liver-stage development. These processes require a tightly orchestrated division and distribution over the daughter parasites of one-per-cell organelles such as the mitochondrion and apicoplast. Although proper organelle segregation is highly essential, the molecular mechanism and the key proteins involved remain largely unknown. In this review, we describe organelle dynamics during cell division in T. gondii and P. falciparum, summarize the current understanding of the molecular mechanisms underlying organelle fission in these parasites, and introduce candidate fission proteins.
Collapse
|
6
|
Izzo M, Jacquet M, Fujiwara T, Harputlu E, Mazur R, Wróbel P, Góral T, Unlu CG, Ocakoglu K, Miyagishima S, Kargul J. Development of a Novel Nanoarchitecture of the Robust Photosystem I from a Volcanic Microalga Cyanidioschyzon merolae on Single Layer Graphene for Improved Photocurrent Generation. Int J Mol Sci 2021; 22:8396. [PMID: 34445103 PMCID: PMC8395140 DOI: 10.3390/ijms22168396] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/22/2021] [Accepted: 08/02/2021] [Indexed: 11/17/2022] Open
Abstract
Here, we report the development of a novel photoactive biomolecular nanoarchitecture based on the genetically engineered extremophilic photosystem I (PSI) biophotocatalyst interfaced with a single layer graphene via pyrene-nitrilotriacetic acid self-assembled monolayer (SAM). For the oriented and stable immobilization of the PSI biophotocatalyst, an His6-tag was genetically engineered at the N-terminus of the stromal PsaD subunit of PSI, allowing for the preferential binding of this photoactive complex with its reducing side towards the graphene monolayer. This approach yielded a novel robust and ordered nanoarchitecture designed to generate an efficient direct electron transfer pathway between graphene, the metal redox center in the organic SAM and the photo-oxidized PSI biocatalyst. The nanosystem yielded an overall current output of 16.5 µA·cm-2 for the nickel- and 17.3 µA·cm-2 for the cobalt-based nanoassemblies, and was stable for at least 1 h of continuous standard illumination. The novel green nanosystem described in this work carries the high potential for future applications due to its robustness, highly ordered and simple architecture characterized by the high biophotocatalyst loading as well as simplicity of manufacturing.
Collapse
Affiliation(s)
- Miriam Izzo
- Solar Fuels Laboratory, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland; (M.I.); (M.J.)
| | - Margot Jacquet
- Solar Fuels Laboratory, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland; (M.I.); (M.J.)
| | - Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Yata 111, Mishima 411-8540, Japan; (T.F.); (S.M.)
| | - Ersan Harputlu
- Department of Engineering Fundamental Sciences, Faculty of Engineering, Tarsus University, Tarsus 33400, Turkey; (E.H.); (K.O.)
| | - Radosław Mazur
- Department of Metabolic Regulation, Faculty of Biology, Institute of Biochemistry, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland;
| | - Piotr Wróbel
- Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland;
| | - Tomasz Góral
- Cryomicroscopy and Electron Diffraction Core Facility, Center of New Technologies, University of Warsaw, 02-097 Warsaw, Poland;
| | - C. Gokhan Unlu
- Department of Biomedical Engineering, Pamukkale University, Denizli 20070, Turkey;
| | - Kasim Ocakoglu
- Department of Engineering Fundamental Sciences, Faculty of Engineering, Tarsus University, Tarsus 33400, Turkey; (E.H.); (K.O.)
| | - Shinya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Yata 111, Mishima 411-8540, Japan; (T.F.); (S.M.)
| | - Joanna Kargul
- Solar Fuels Laboratory, Center of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland; (M.I.); (M.J.)
| |
Collapse
|
7
|
Pancha I, Takaya K, Tanaka K, Imamura S. The Unicellular Red Alga Cyanidioschyzon merolae, an Excellent Model Organism for Elucidating Fundamental Molecular Mechanisms and Their Applications in Biofuel Production. PLANTS 2021; 10:plants10061218. [PMID: 34203949 PMCID: PMC8232737 DOI: 10.3390/plants10061218] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/11/2021] [Accepted: 06/11/2021] [Indexed: 11/16/2022]
Abstract
Microalgae are considered one of the best resources for the production of biofuels and industrially important compounds. Various models have been developed to understand the fundamental mechanism underlying the accumulation of triacylglycerols (TAGs)/starch and to enhance its content in cells. Among various algae, the red alga Cyanidioschyzonmerolae has been considered an excellent model system to understand the fundamental mechanisms behind the accumulation of TAG/starch in the microalga, as it has a smaller genome size and various biotechnological methods are available for it. Furthermore, C. merolae can grow and survive under high temperature (40 °C) and low pH (2–3) conditions, where most other organisms would die, thus making it a choice alga for large-scale production. Investigations using this alga has revealed that the target of rapamycin (TOR) kinase is involved in the accumulation of carbon-reserved molecules, TAGs, and starch. Furthermore, detailed molecular mechanisms of the role of TOR in controlling the accumulation of TAGs and starch were uncovered via omics analyses. Based on these findings, genetic engineering of the key gene and proteins resulted in a drastic increment of the amount of TAGs and starch. In addition to these studies, other trials that attempted to achieve the TAG increment in C. merolae have been summarized in this article.
Collapse
Affiliation(s)
- Imran Pancha
- Department of Biological Sciences, SRM University-AP, Amaravati, Andhra Pradesh 522502, India
- Correspondence: (I.P.); (S.I.); Tel.: +81-422-59-6179 (S.I.)
| | - Kazuhiro Takaya
- NTT Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, 3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan;
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1-29 Nagatsuta, Midori-ku, Yokohama-shi, Kanagawa 226-8503, Japan;
| | - Sousuke Imamura
- NTT Space Environment and Energy Laboratories, Nippon Telegraph and Telephone Corporation, 3-9-11 Midori-cho, Musashino-shi, Tokyo 180-8585, Japan;
- Correspondence: (I.P.); (S.I.); Tel.: +81-422-59-6179 (S.I.)
| |
Collapse
|
8
|
Morano AA, Dvorin JD. The Ringleaders: Understanding the Apicomplexan Basal Complex Through Comparison to Established Contractile Ring Systems. Front Cell Infect Microbiol 2021; 11:656976. [PMID: 33954122 PMCID: PMC8089483 DOI: 10.3389/fcimb.2021.656976] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/19/2021] [Indexed: 12/02/2022] Open
Abstract
The actomyosin contractile ring is a key feature of eukaryotic cytokinesis, conserved across many eukaryotic kingdoms. Recent research into the cell biology of the divergent eukaryotic clade Apicomplexa has revealed a contractile ring structure required for asexual division in the medically relevant genera Toxoplasma and Plasmodium; however, the structure of the contractile ring, known as the basal complex in these parasites, remains poorly characterized and in the absence of a myosin II homolog, it is unclear how the force required of a cytokinetic contractile ring is generated. Here, we review the literature on the basal complex in Apicomplexans, summarizing what is known about its formation and function, and attempt to provide possible answers to this question and suggest new avenues of study by comparing the Apicomplexan basal complex to well-studied, established cytokinetic contractile rings and their mechanisms in organisms such as S. cerevisiae and D. melanogaster. We also compare the basal complex to structures formed during mitochondrial and plastid division and cytokinetic mechanisms of organisms beyond the Opisthokonts, considering Apicomplexan diversity and divergence.
Collapse
Affiliation(s)
- Alexander A Morano
- Biological and Biomedical Sciences, Harvard Medical School, Boston, MA, United States.,Division of Infectious Diseases, Boston Children's Hospital, Boston, MA, United States
| | - Jeffrey D Dvorin
- Division of Infectious Diseases, Boston Children's Hospital, Boston, MA, United States.,Department of Pediatrics, Harvard Medical School, Boston, MA, United States
| |
Collapse
|
9
|
Imoto Y, Itoh K, Fujiki Y. Molecular Basis of Mitochondrial and Peroxisomal Division Machineries. Int J Mol Sci 2020; 21:E5452. [PMID: 32751702 PMCID: PMC7432047 DOI: 10.3390/ijms21155452] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/28/2020] [Accepted: 07/28/2020] [Indexed: 12/20/2022] Open
Abstract
Mitochondria and peroxisomes are ubiquitous subcellular organelles that are highly dynamic and possess a high degree of plasticity. These organelles proliferate through division of pre-existing organelles. Studies on yeast, mammalian cells, and unicellular algae have led to a surprising finding that mitochondria and peroxisomes share the components of their division machineries. At the heart of the mitochondrial and peroxisomal division machineries is a GTPase dynamin-like protein, Dnm1/Drp1, which forms a contractile ring around the neck of the dividing organelles. During division, Dnm1/Drp1 functions as a motor protein and constricts the membrane. This mechanochemical work is achieved by utilizing energy from GTP hydrolysis. Over the last two decades, studies have focused on the structure and assembly of Dnm1/Drp1 molecules around the neck. However, the regulation of GTP during the division of mitochondrion and peroxisome is not well understood. Here, we review the current understanding of Dnm1/Drp1-mediated divisions of mitochondria and peroxisomes, exploring the mechanisms of GTP regulation during the Dnm1/Drp1 function, and provide new perspectives on their potential contribution to mitochondrial and peroxisomal biogenesis.
Collapse
Grants
- 14J04556 Japan Society for the Promotion of Science Fellowships
- P24247038, JP25112518, JP25116717, JP26116007, JP15K14511, JP15K21743, JP17H03675 Ministry of Education, Culture, Sports, Science, and Technology of Japan, Grants-in-Aid for Scientific Research
Collapse
Affiliation(s)
- Yuuta Imoto
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA;
| | - Kie Itoh
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205, USA;
| | - Yukio Fujiki
- Division of Organelle Homeostasis, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
- Institute of Rheological Functions of Food, Hisayama-cho, Fukuoka 811-2501, Japan
| |
Collapse
|
10
|
Nonogaki H, Nishiyama E, Ohshima K, Nonogaki M. Ancient Memories of Seeds: ABA-Dependent Growth Arrest and Reserve Accumulation. Trends Genet 2020; 36:464-473. [DOI: 10.1016/j.tig.2020.04.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/22/2020] [Accepted: 04/27/2020] [Indexed: 11/30/2022]
|
11
|
Yagisawa F, Fujiwara T, Takemura T, Kobayashi Y, Sumiya N, Miyagishima SY, Nakamura S, Imoto Y, Misumi O, Tanaka K, Kuroiwa H, Kuroiwa T. ESCRT Machinery Mediates Cytokinetic Abscission in the Unicellular Red Alga Cyanidioschyzon merolae. Front Cell Dev Biol 2020; 8:169. [PMID: 32346536 PMCID: PMC7169423 DOI: 10.3389/fcell.2020.00169] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/29/2020] [Indexed: 12/17/2022] Open
Abstract
In many eukaryotes, cytokinesis proceeds in two successive steps: first, ingression of the cleavage furrow and second, abscission of the intercellular bridge. In animal cells, the actomyosin contractile ring is involved in the first step, while the endosomal sorting complex required for transport (ESCRT), which participates in various membrane fusion/fission events, mediates the second step. Intriguingly, in archaea, ESCRT is involved in cytokinesis, raising the hypothesis that the function of ESCRT in eukaryotic cytokinesis descended from the archaeal ancestor. In eukaryotes other than in animals, the roles of ESCRT in cytokinesis are poorly understood. To explore the primordial core mechanisms for eukaryotic cytokinesis, we investigated ESCRT functions in the unicellular red alga Cyanidioschyzon merolae that diverged early in eukaryotic evolution. C. merolae provides an excellent experimental system. The cell has a simple organelle composition. The genome (16.5 Mb, 5335 genes) has been completely sequenced, transformation methods are established, and the cell cycle is synchronized by a light and dark cycle. Similar to animal and fungal cells, C. merolae cells divide by furrowing at the division site followed by abscission of the intercellular bridge. However, they lack an actomyosin contractile ring. The proteins that comprise ESCRT-I-IV, the four subcomplexes of ESCRT, are partially conserved in C. merolae. Immunofluorescence of native or tagged proteins localized the homologs of the five ESCRT-III components [charged multivesicular body protein (CHMP) 1, 2, and 4-6], apoptosis-linked gene-2-interacting protein X (ALIX), the ESCRT-III adapter, and the main ESCRT-IV player vacuolar protein sorting (VPS) 4, to the intercellular bridge. In addition, ALIX was enriched around the cleavage furrow early in cytokinesis. When the ESCRT function was perturbed by expressing dominant-negative VPS4, cells with an elongated intercellular bridge accumulated-a phenotype resulting from abscission failure. Our results show that ESCRT mediates cytokinetic abscission in C. merolae. The fact that ESCRT plays a role in cytokinesis in archaea, animals, and early diverged alga C. merolae supports the hypothesis that the function of ESCRT in cytokinesis descended from archaea to a common ancestor of eukaryotes.
Collapse
Affiliation(s)
- Fumi Yagisawa
- Center for Research Advancement and Collaboration, University of the Ryukyus, Okinawa, Japan
- Graduate School of Engineering and Science, University of the Ryukyus, Okinawa, Japan
| | - Takayuki Fujiwara
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
- JST-Mirai Program, Japan Science and Technology Agency, Saitama, Japan
- Department of Genetics, The Graduate University for Advanced Studies, Shizuoka, Japan
| | - Tokiaki Takemura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- School of Life Sciences and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Yuki Kobayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Nobuko Sumiya
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
| | - Shin-ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, Shizuoka, Japan
- JST-Mirai Program, Japan Science and Technology Agency, Saitama, Japan
- Department of Genetics, The Graduate University for Advanced Studies, Shizuoka, Japan
| | - Soichi Nakamura
- Laboratory of Cell and Functional Biology, Faculty of Science, University of the Ryukyus, Okinawa, Japan
| | - Yuuta Imoto
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Osami Misumi
- Department of Biological Science and Chemistry, Faculty of Science, Yamaguchi University, Yamaguchi, Japan
- Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Haruko Kuroiwa
- Department of Chemical and Biological Science, Japan Women’s University, Tokyo, Japan
| | - Tsuneyoshi Kuroiwa
- Department of Chemical and Biological Science, Japan Women’s University, Tokyo, Japan
| |
Collapse
|
12
|
Yoshida Y, Mogi Y. How do plastids and mitochondria divide? Microscopy (Oxf) 2019; 68:45-56. [PMID: 30476140 DOI: 10.1093/jmicro/dfy132] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/16/2018] [Indexed: 12/30/2022] Open
Abstract
Plastids and mitochondria are thought to have originated from free-living cyanobacterial and alpha-proteobacterial ancestors, respectively, via endosymbiosis. Their evolutionary origins dictate that these organelles do not multiply de novo but through the division of pre-existing plastids and mitochondria. Over the past three decades, studies have shown that plastid and mitochondrial division are performed by contractile ring-shaped structures, broadly termed the plastid and mitochondrial-division machineries. Interestingly, the division machineries are hybrid forms of the bacterial cell division system and eukaryotic membrane fission system. The structure and function of the plastid and mitochondrial-division machineries are similar to each other, implying that the division machineries evolved in parallel since their establishment in primitive eukaryotes. Compared with our knowledge of their structures, our understanding of the mechanical details of how these division machineries function is still quite limited. Here, we review and compare the structural frameworks of the plastid and mitochondrial-division machineries in both lower and higher eukaryotes. Then, we highlight fundamental issues that need to be resolved to reveal the underlying mechanisms of plastid and mitochondrial division. Finally, we highlight related studies that point to an exciting future for the field.
Collapse
Affiliation(s)
- Yamato Yoshida
- Department of Science, College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, Japan
| | - Yuko Mogi
- Department of Science, College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki, Japan
| |
Collapse
|
13
|
Johnston IG. Tension and Resolution: Dynamic, Evolving Populations of Organelle Genomes within Plant Cells. MOLECULAR PLANT 2019; 12:764-783. [PMID: 30445187 DOI: 10.1016/j.molp.2018.11.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/25/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
Mitochondria and plastids form dynamic, evolving populations physically embedded in the fluctuating environment of the plant cell. Their evolutionary heritage has shaped how the cell controls the genetic structure and the physical behavior of its organelle populations. While the specific genes involved in these processes are gradually being revealed, the governing principles underlying this controlled behavior remain poorly understood. As the genetic and physical dynamics of these organelles are central to bioenergetic performance and plant physiology, this challenges both fundamental biology and strategies to engineer better-performing plants. This article reviews current knowledge of the physical and genetic behavior of mitochondria and chloroplasts in plant cells. An overarching hypothesis is proposed whereby organelles face a tension between genetic robustness and individual control and responsiveness, and different species resolve this tension in different ways. As plants are immobile and thus subject to fluctuating environments, their organelles are proposed to favor individual responsiveness, sacrificing genetic robustness. Several notable features of plant organelles, including large genomes, mtDNA recombination, fragmented organelles, and plastid/mitochondrial differences may potentially be explained by this hypothesis. Finally, the ways that quantitative and systems biology can help shed light on the plethora of open questions in this field are highlighted.
Collapse
Affiliation(s)
- Iain G Johnston
- School of Biosciences, University of Birmingham, Birmingham, UK; Birmingham Institute for Forest Research, University of Birmingham, Birmingham, UK.
| |
Collapse
|
14
|
Identification of a chloroplast fatty acid exporter protein, CmFAX1, and triacylglycerol accumulation by its overexpression in the unicellular red alga Cyanidioschyzon merolae. ALGAL RES 2019. [DOI: 10.1016/j.algal.2018.101396] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
15
|
Kobayashi Y, Tanaka K. Lability in sulfur acidic cultivation medium explains unstable effects of CDK inhibitors on Cyanidioschyzon merolae cell proliferation. J GEN APPL MICROBIOL 2019; 64:299-302. [PMID: 29899184 DOI: 10.2323/jgam.2018.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We previously showed that nuclear DNA replication (NDR) is regulated by a checkpoint monitoring the occurrence of organelle DNA replication (ODR) in a unicellular red alga Cyanidioschyzon merolae. These analyses depended on the use of chemical CDK inhibitors such as CDK2 inhibitor II and roscovitine, but subsequent analyses yielded conflicting results depending on the experimental conditions. In the present study, we identified significantly short half-lives of the used chemicals in the sulfur acidic cultivation medium, which reconciles the discrepancy among these results.
Collapse
Affiliation(s)
- Yuki Kobayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency
| |
Collapse
|
16
|
Takemura T, Imamura S, Kobayashi Y, Tanaka K. Construction of a Selectable Marker Recycling System and the Use in Epitope Tagging of Multiple Nuclear Genes in the Unicellular Red Alga Cyanidioschyzon merolae. PLANT & CELL PHYSIOLOGY 2018; 59:2308-2316. [PMID: 30099537 DOI: 10.1093/pcp/pcy156] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 07/30/2018] [Indexed: 06/08/2023]
Abstract
The nuclear genome of the unicellular red alga Cyanidioschyzon merolae can be modified by homologous recombination with exogenously introduced DNA. However, it is presently difficult to modify multiple chromosome loci because of the limited number of available positive selectable markers. In this study, we constructed a modified URA5.3 gene (URA5.3T), which can be repeatedly used for nuclear genome transformation, as well as two plasmid vectors for 3× FLAG- or 3× Myc-epitope tagging of nuclear-encoded proteins using URA5.3T. In the URA5.3T marker, the promoter region and open reading frame were located between directly repeated URA5.3 terminator sequences, and the URA5.3 gene can be eliminated by 5-fluoroorotic acid selection through homologous recombination. To demonstrate the utility of the constructed system, a 3× FLAG-tag and 3× Myc-tag were introduced at the C-termini of two of the six Rab proteins in C. merolae, CmRab18 and CmRab7, respectively, and the differential expression levels were successfully monitored by immunoblot analysis using these epitope tags. The URA5.3T marker's introduction and elimination cycle can be repeated. Thus, we have constructed a marker recycling system for C. merolae nuclear transformation. A novel procedure to obtain a high plating efficiency of C. merolae cells on solid gellan gum plates is also presented.
Collapse
Affiliation(s)
- Tokiaki Takemura
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, Nagatsuta, Yokohama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta, Yokohama, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, Nagatsuta, Yokohama, Japan
| | - Yuki Kobayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, Nagatsuta, Yokohama, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Science, Tokyo Institute of Technology, Nagatsuta, Yokohama, Japan
| |
Collapse
|
17
|
Yoshida Y. The cellular machineries responsible for the division of endosymbiotic organelles. JOURNAL OF PLANT RESEARCH 2018; 131:727-734. [PMID: 29948488 PMCID: PMC6424925 DOI: 10.1007/s10265-018-1050-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Accepted: 05/29/2018] [Indexed: 06/08/2023]
Abstract
Chloroplasts (plastids) and mitochondria evolved from endosymbiotic bacteria. These organelles perform vital functions in photosynthetic eukaryotes, such as harvesting and converting energy for use in biological processes. Consistent with their evolutionary origins, plastids and mitochondria proliferate by the binary fission of pre-existing organelles. Here, I review the structures and functions of the supramolecular machineries driving plastid and mitochondrial division, which were discovered and first studied in the primitive red alga Cyanidioschyzon merolae. In the past decade, intact division machineries have been isolated from plastids and mitochondria and examined to investigate their underlying structure and molecular mechanisms. A series of studies has elucidated how these division machineries assemble and transform during the fission of these organelles, and which of the component proteins generate the motive force for their contraction. Plastid- and mitochondrial-division machineries have important similarities in their structures and mechanisms despite sharing no component proteins, implying that these division machineries evolved in parallel. The establishment of these division machineries might have enabled the host eukaryotic ancestor to permanently retain these endosymbiotic organelles by regulating their binary fission and the equal distribution of resources to daughter cells. These findings provide key insights into the establishment of endosymbiotic organelles and have opened new avenues of research into their evolution and mechanisms of proliferation.
Collapse
Affiliation(s)
- Yamato Yoshida
- Department of Science, College of Science, Ibaraki University, Ibaraki, 310-8512, Japan.
| |
Collapse
|
18
|
Yoshida Y. Insights into the Mechanisms of Chloroplast Division. Int J Mol Sci 2018; 19:ijms19030733. [PMID: 29510533 PMCID: PMC5877594 DOI: 10.3390/ijms19030733] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 02/28/2018] [Accepted: 03/01/2018] [Indexed: 02/08/2023] Open
Abstract
The endosymbiosis of a free-living cyanobacterium into an ancestral eukaryote led to the evolution of the chloroplast (plastid) more than one billion years ago. Given their independent origins, plastid proliferation is restricted to the binary fission of pre-existing plastids within a cell. In the last 25 years, the structure of the supramolecular machinery regulating plastid division has been discovered, and some of its component proteins identified. More recently, isolated plastid-division machineries have been examined to elucidate their structural and mechanistic details. Furthermore, complex studies have revealed how the plastid-division machinery morphologically transforms during plastid division, and which of its component proteins play a critical role in generating the contractile force. Identifying the three-dimensional structures and putative functional domains of the component proteins has given us hints about the mechanisms driving the machinery. Surprisingly, the mechanisms driving plastid division resemble those of mitochondrial division, indicating that these division machineries likely developed from the same evolutionary origin, providing a key insight into how endosymbiotic organelles were established. These findings have opened new avenues of research into organelle proliferation mechanisms and the evolution of organelles.
Collapse
Affiliation(s)
- Yamato Yoshida
- Department of Science, College of Science, Ibaraki University, Ibaraki 310-8512, Japan.
| |
Collapse
|
19
|
Imamura S, Taki K, Tanaka K. Construction of a rapamycin-susceptible strain of the unicellular red alga Cyanidioschyzon merolae for analysis of the target of rapamycin (TOR) function. J GEN APPL MICROBIOL 2017; 63:305-309. [PMID: 28954966 DOI: 10.2323/jgam.2017.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| | - Keiko Taki
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| |
Collapse
|
20
|
Kawase Y, Imamura S, Tanaka K. A MYB-type transcription factor, MYB2, represses light-harvesting protein genes in Cyanidioschyzon merolae. FEBS Lett 2017; 591:2439-2448. [PMID: 28748638 DOI: 10.1002/1873-3468.12763] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 07/18/2017] [Accepted: 07/19/2017] [Indexed: 11/07/2022]
Abstract
While searching for transcriptional regulators that respond to changes in light regimes, we identified a MYB domain-containing protein, MYB2, that accumulates under dark and other conditions in the unicellular red alga Cyanidioschyzon merolae. The isolation and analysis of a MYB2 mutant revealed that MYB2 represses the expression of the nuclear-encoded chloroplast RNA polymerase sigma factor gene SIG2, which results in the repression of the chloroplast-encoded phycobilisome genes that are under its control. Since nuclear-encoded phycobilisome and other light-harvesting protein genes are also repressed by MYB2, we conclude that MYB2 has a role in repressing the expression of light-harvesting genes. The MYB2 mutant is sensitive to a prolonged dark incubation, indicating the importance of MYB2 for cell viability in the dark.
Collapse
Affiliation(s)
- Yasuko Kawase
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan.,Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Yokohama, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| |
Collapse
|
21
|
Yamaguchi S, Kawada Y, Yuge H, Tanaka K, Imamura S. Development of New Carbon Resources: Production of Important Chemicals from Algal Residue. Sci Rep 2017; 7:855. [PMID: 28405002 PMCID: PMC5429806 DOI: 10.1038/s41598-017-00979-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/17/2017] [Indexed: 12/19/2022] Open
Abstract
Algal biomass has received attention as an alternative carbon resource owing not only to its high oil production efficiency but also, unlike corn starch, to its lack of demand in foods. However, algal residue is commonly discarded after the abstraction of oil. The utilization of the residue to produce chemicals will therefore increase the value of using algal biomass instead of fossil fuels. Here, we report the use of algal residue as a new carbon resource to produce important chemicals. The application of different homogeneous catalysts leads to the selective production of methyl levulinate or methyl lactate. These results demonstrate the successful development of new carbon resources as a solution for the depletion of fossil fuels.
Collapse
Affiliation(s)
- Sho Yamaguchi
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259-G1-14 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8502, Japan.
| | - Yuuki Kawada
- Department of Chemistry, School of Science, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Hidetaka Yuge
- Department of Chemistry, School of Science, Kitasato University, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1-30 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8502, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, 332-0012, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259-R1-30 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8502, Japan.,Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, 332-0012, Japan
| |
Collapse
|
22
|
Zhang Y, Avalos JL. Traditional and novel tools to probe the mitochondrial metabolism in health and disease. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2017; 9. [PMID: 28067471 DOI: 10.1002/wsbm.1373] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 11/07/2016] [Accepted: 11/09/2016] [Indexed: 02/06/2023]
Abstract
Mitochondrial metabolism links energy production to other essential cellular processes such as signaling, cellular differentiation, and apoptosis. In addition to producing adenosine triphosphate (ATP) as an energy source, mitochondria are responsible for the synthesis of a myriad of important metabolites and cofactors such as tetrahydrofolate, α-ketoacids, steroids, aminolevulinic acid, biotin, lipoic acid, acetyl-CoA, iron-sulfur clusters, heme, and ubiquinone. Furthermore, mitochondria and their metabolism have been implicated in aging and several human diseases, including inherited mitochondrial disorders, cardiac dysfunction, heart failure, neurodegenerative diseases, diabetes, and cancer. Therefore, there is great interest in understanding mitochondrial metabolism and the complex relationship it has with other cellular processes. A large number of studies on mitochondrial metabolism have been conducted in the last 50 years, taking a broad range of approaches. In this review, we summarize and discuss the most commonly used tools that have been used to study different aspects of the metabolism of mitochondria: ranging from dyes that monitor changes in the mitochondrial membrane potential and pharmacological tools to study respiration or ATP synthesis, to more modern tools such as genetically encoded biosensors and trans-omic approaches enabled by recent advances in mass spectrometry, computation, and other technologies. These tools have allowed the large number of studies that have shaped our current understanding of mitochondrial metabolism. WIREs Syst Biol Med 2017, 9:e1373. doi: 10.1002/wsbm.1373 For further resources related to this article, please visit the WIREs website.
Collapse
Affiliation(s)
- Yanfei Zhang
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - José L Avalos
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA.,Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| |
Collapse
|
23
|
Kobayashi Y, Tanaka K. Transcriptional Regulation of Tetrapyrrole Biosynthetic Genes Explains Abscisic Acid-Induced Heme Accumulation in the Unicellular Red Alga Cyanidioschyzon merolae. FRONTIERS IN PLANT SCIENCE 2016; 7:1300. [PMID: 27621743 PMCID: PMC5002421 DOI: 10.3389/fpls.2016.01300] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 08/15/2016] [Indexed: 06/06/2023]
Abstract
Abscisic acid (ABA), a pivotal phytohormone that is synthesized in response to abiotic stresses and other environmental changes, induces various physiological responses. Heme, in its unbound form, has a positive signaling role in cell-cycle initiation in Cyanidioschyzon merolae. ABA induces heme accumulation, but also prevents cell-cycle initiation through the titration of the unbound heme by inducing the heme scavenging protein tryptophan-rich sensory protein-related protein O. In this study, we analyzed the accumulation of tetrapyrrole biosynthetic gene transcripts after the addition of ABA to the medium and found that transcripts of a ferrochelatase and a magnesium-chelatase subunit increased, while other examined transcripts decreased. Under the same conditions, the heme and magnesium-protoporphyrin IX contents increased, while the protoporphyrin IX content decreased. Thus, ABA may regulate the intracellular heme and other tetrapyrrole contents through the transcriptional regulation of biosynthetic genes.
Collapse
Affiliation(s)
- Yuki Kobayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, YokohamaJapan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, YokohamaJapan
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, SaitamaJapan
| |
Collapse
|
24
|
Kobayashi Y, Ando H, Hanaoka M, Tanaka K. Abscisic Acid Participates in the Control of Cell Cycle Initiation Through Heme Homeostasis in the Unicellular Red Alga Cyanidioschyzon merolae. PLANT & CELL PHYSIOLOGY 2016; 57:953-60. [PMID: 27044672 DOI: 10.1093/pcp/pcw054] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 03/09/2016] [Indexed: 05/08/2023]
Abstract
ABA is a phytohormone that is synthesized in response to abiotic stresses and other environmental changes, inducing various physiological responses. While ABA has been found in unicellular photosynthetic organisms, such as cyanobacteria and eukaryotic algae, its function in these organisms is poorly understood. Here, we found that ABA accumulated in the unicellular red alga Cyanidioschyzon merolae under conditions of salt stress and that the cell cycle G1/S transition was inhibited when ABA was added to the culture medium. A gene encoding heme-scavenging tryptophan-rich sensory protein-related protein (CmTSPO; CMS231C) was positively regulated by ABA, as in Arabidopsis, and CmTSPO bound heme in vitro. The intracellular content of total heme was increased by addition of ABA, but unfettered heme decreased, presumably due to scavenging by CmTSPO. The inhibition of DNA replication by ABA was negated by addition of heme to the culture medium. Thus, we propose a regulatory role for ABA and heme in algal cell cycle initiation. Finally, we found that a C. merolae mutant that is defective in ABA production was more susceptible to salt stress, indicating the importance of ABA to stress resistance in red algae.
Collapse
Affiliation(s)
- Yuki Kobayashi
- Chemical Resources Laboratory, Tokyo Institute of Technology, 4259-R1-29 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
| | - Hiroyuki Ando
- Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo, Chiba, 271-8510 Japan
| | - Mitsumasa Hanaoka
- Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo, Chiba, 271-8510 Japan
| | - Kan Tanaka
- Chemical Resources Laboratory, Tokyo Institute of Technology, 4259-R1-29 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, 332-0012 Japan
| |
Collapse
|
25
|
Yagisawa F, Kuroiwa H, Fujiwara T, Kuroiwa T. Intracellular Structure of the Unicellular Red Alga Cyanidioschyzon merolae in Response to Phosphate Depletion and Resupplementation. CYTOLOGIA 2016. [DOI: 10.1508/cytologia.81.341] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Fumi Yagisawa
- Instrumental Research Center, University of the Ryukyus
| | - Haruko Kuroiwa
- Department of Chemical and Biological Science, Faculty of Science, Japan Women’s University
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency
| | | | - Tsuneyoshi Kuroiwa
- Department of Chemical and Biological Science, Faculty of Science, Japan Women’s University
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency
| |
Collapse
|
26
|
|
27
|
Kanesaki Y, Imamura S, Matsuzaki M, Tanaka K. Identification of centromere regions in chromosomes of a unicellular red alga,Cyanidioschyzon merolae. FEBS Lett 2015; 589:1219-24. [DOI: 10.1016/j.febslet.2015.04.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 04/07/2015] [Accepted: 04/09/2015] [Indexed: 01/20/2023]
|
28
|
Watanabe S, Sato J, Imamura S, Ohnuma M, Ohoba Y, Chibazakura T, Tanaka K, Yoshikawa H. Stable expression of a GFP-reporter gene in the red alga Cyanidioschyzon merolae. Biosci Biotechnol Biochem 2014; 78:175-7. [PMID: 25036501 DOI: 10.1080/09168451.2014.877823] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The unicellular red alga Cyanidioschyzon merolae is used as a model organism to investigate the basic architecture of photosynthetic eukaryotes. We established a stable expression system for the green fluorescent protein fused with the phycocyanin-associated rod linker (APCC) protein in C. merolae, which was clearly localized on the plastid. This system should be useful in the genetic engineering of C. merolae.
Collapse
Affiliation(s)
- Satoru Watanabe
- a Department of Bioscience , Tokyo University of Agriculture , Tokyo , Japan
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Soma A, Sugahara J, Onodera A, Yachie N, Kanai A, Watanabe S, Yoshikawa H, Ohnuma M, Kuroiwa H, Kuroiwa T, Sekine Y. Identification of highly-disrupted tRNA genes in nuclear genome of the red alga, Cyanidioschyzon merolae 10D. Sci Rep 2014; 3:2321. [PMID: 23900518 PMCID: PMC3728597 DOI: 10.1038/srep02321] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 07/10/2013] [Indexed: 12/03/2022] Open
Abstract
The limited locations of tRNA introns are crucial for eukaryal tRNA-splicing endonuclease recognition. However, our analysis of the nuclear genome of an early-diverged red alga, Cyanidioschyzon merolae, demonstrated the first evidence of nuclear-encoded tRNA genes that contain ectopic and/or multiple introns. Some genes exhibited both intronic and permuted structures in which the 3′-half of the tRNA coding sequence lies upstream of the 5′-half, and an intron is inserted into either half. These highly disrupted tRNA genes, which account for 63% of all nuclear tRNA genes, are expressed via the orderly and sequential processing of bulge-helix-bulge (BHB) motifs at intron-exon junctions and termini of permuted tRNA precursors, probably by a C. merolae tRNA-splicing endonuclease with an unidentified subunit architecture. The results revealed a considerable diversity in eukaryal tRNA intron properties and endonuclease architectures, which will help to elucidate the acquisition mechanism of the BHB-mediated disrupted tRNA genes.
Collapse
Affiliation(s)
- Akiko Soma
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Fujii G, Imamura S, Hanaoka M, Tanaka K. Nuclear-encoded chloroplast RNA polymerase sigma factor SIG2 activates chloroplast-encoded phycobilisome genes in a red alga, Cyanidioschyzon merolae. FEBS Lett 2013; 587:3354-9. [PMID: 24036445 DOI: 10.1016/j.febslet.2013.08.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 08/23/2013] [Accepted: 08/23/2013] [Indexed: 10/26/2022]
Abstract
The phycobilisome (PBS) is a photosynthetic light-harvesting complex in red algae, whose structural genes are separately encoded by both the nuclear and chloroplast genomes. While the expression of PBS genes in both genomes is responsive to environmental changes to modulate light-harvesting efficiency, little is known about how gene expression of the two genomes is coordinated. In this study, we focused on the four nuclear-encoded chloroplast sigma factors to understand aspects of this coordination, and found that SIG2 directs the expression of chloroplast PBS genes in the red alga Cyanidioschyzon merolae.
Collapse
Affiliation(s)
- Gaku Fujii
- Chemical Resources Laboratory, Tokyo Institute of Technology, 4259-R1-29 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan; Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo, Chiba 271-8510, Japan
| | | | | | | |
Collapse
|
31
|
Watanabe S, Hanaoka M, Ohba Y, Ono T, Ohnuma M, Yoshikawa H, Taketani S, Tanaka K. Mitochondrial localization of ferrochelatase in a red alga Cyanidioschyzon merolae. PLANT & CELL PHYSIOLOGY 2013; 54:1289-95. [PMID: 23700350 DOI: 10.1093/pcp/pct077] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Ferrochelatase (FECH) is an essential enzyme for the final step of heme biosynthesis. In green plants, its activity has been reported in both plastids and mitochondria. However, the precise subcellular localization of FECH remains uncertain. In this study, we analyzed the localization of FECH in the unicellular red alga, Cyanidioschyzon merolae. Immunoblot and enzyme activity analyses of subcellular fractions localized little FECH in the plastid. In addition, immunofluorescence microscopy identified that both intrinsic and hemagglutinin (HA)-tagged FECH are localized in the mitochondrion. We therefore conclude that FECH is localized in the mitochondrion in C. merolae.
Collapse
Affiliation(s)
- Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Yagisawa F, Fujiwara T, Ohnuma M, Kuroiwa H, Nishida K, Imoto Y, Yoshida Y, Kuroiwa T. Golgi inheritance in the primitive red alga, Cyanidioschyzon merolae. PROTOPLASMA 2013. [PMID: 23197134 DOI: 10.1007/s00709-012-0467-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The Golgi body has important roles in modifying, sorting, and transport of proteins and lipids. Eukaryotic cells have evolved in various ways to inherit the Golgi body from mother to daughter cells, which allows the cells to function properly immediately after mitosis. Here we used Cyanidioschyzon merolae, one of the most suitable systems for studies of organelle dynamics, to investigate the inheritance of the Golgi. Two proteins, Sed5 and Got1, were used as Golgi markers. Using immunofluorescence microscopy, we demonstrated that C. merolae contains one to two Golgi bodies per cell. The Golgi body was localized to the perinuclear region during the G1 and S phases and next to the spindle poles in a microtubule-dependent manner during M phase. It was inherited together with spindle poles upon cytokinesis. These observations suggested that Golgi inheritance is dependent on microtubules in C. merolae.
Collapse
Affiliation(s)
- Fumi Yagisawa
- Research Information Center for Extremophiles, Rikkyo (St. Paul's) University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Vlachakis D, Pavlopoulou A, Kazazi D, Kossida S. Unraveling microalgal molecular interactions using evolutionary and structural bioinformatics. Gene 2013; 528:109-19. [PMID: 23900196 DOI: 10.1016/j.gene.2013.07.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 07/08/2013] [Accepted: 07/18/2013] [Indexed: 10/26/2022]
Abstract
Microalgae are unicellular microorganisms indispensible for environmental stability and life on earth, because they produce approximately half of the atmospheric oxygen, with simultaneously feeding on the harmful greenhouse gas carbon dioxide. Using gene fusion analysis, a series of five fusion/fission events was identified, that provided the basis for critical insights to their evolutionary history. Moreover, the three-dimensional structures of both the fused and the component proteins were predicted, allowing us to envisage putative protein-protein interactions that are invaluable for the efficient usage, handling and exploitation of microalgae. Collectively, our proposed approach on the five fusion/fission alga protein events contributes towards the expansion of the microalgae knowledgebase, bridging protein evolution of the ancient microalgal species and the rapidly evolving, modern, bioinformatics field.
Collapse
Affiliation(s)
- Dimitrios Vlachakis
- Bioinformatics & Medical Informatics Team, Biomedical Research Foundation, Academy of Athens, Soranou Efessiou 4, Athens 11527, Greece
| | | | | | | |
Collapse
|
34
|
Yagisawa F, Fujiwara T, Kuroiwa H, Nishida K, Imoto Y, Kuroiwa T. Mitotic inheritance of endoplasmic reticulum in the primitive red alga Cyanidioschyzon merolae. PROTOPLASMA 2012; 249:1129-35. [PMID: 22160190 DOI: 10.1007/s00709-011-0359-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 11/28/2011] [Indexed: 05/03/2023]
Abstract
Endoplasmic reticulum (ER) is a major site for secretory protein folding and lipid synthesis. Since ER cannot be synthesized de novo, it must be inherited during the cell cycle. Studying ER inheritance can however be difficult because the ER of typical plant and animal cells is morphologically complex. Therefore, our study used Cyanidioschyzon merolae, a species that has a simple ER structure, to investigate the inheritance of this organelle. Using immunofluorescence microscopy, we demonstrated that C. merolae contains a nuclear ER (nuclear envelope) and a small amount of peripheral ER extending from the nuclear ER. During mitosis, the nuclear ER became dumbbell-shaped and underwent division. Peripheral ER formed ring-like structures during the G1 and S phases, and extended toward the mitochondria and cell division planes during the M phase. These observations indicated that C. merolae undergoes closed mitosis, whereby the nuclear ER does not diffuse, and the peripheral ER contains cell cycle-specific structures.
Collapse
Affiliation(s)
- Fumi Yagisawa
- Research Information Center for Extremophiles, Rikkyo (St. Paul's) University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan.
| | | | | | | | | | | |
Collapse
|
35
|
Kanesaki Y, Imamura S, Minoda A, Tanaka K. External light conditions and internal cell cycle phases coordinate accumulation of chloroplast and mitochondrial transcripts in the red alga Cyanidioschyzon merolae. DNA Res 2012; 19:289-303. [PMID: 22518007 PMCID: PMC3372377 DOI: 10.1093/dnares/dss013] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 03/14/2012] [Indexed: 01/08/2023] Open
Abstract
The mitochondria and chloroplasts in plant cells are originated from bacterial endosymbioses, and they still replicate their own genome and divide in a similar manner as their ancestors did. It is thus likely that the organelle transcription is coordinated with its proliferation cycle. However, this possibility has not extensively been explored to date, because in most plant cells there are many mitochondria and chloroplasts that proliferate asynchronously. It is generally believed that the gene transfer from the organellar to nuclear genome has enabled nuclear control of the organelle functions during the evolution of eukaryotic plant cells. Nevertheless, no significant relationship has been reported between the organelle transcriptome and the host cell cycle even in Chlamydomonas reinhardtii. While the organelle proliferation cycle is not coordinated with the cell cycle in vascular plants, in the unicellular red alga Cyanidioschyzon merolae that contains only one mitochondrion, one chloroplast, and one nucleus per cell, each of the organelles is known to proliferate at a specific phase of the cell cycle. Here, we show that the expression of most of the organelle genes is highly coordinated with the cell cycle phases as well as with light regimes in clustering analyses. In addition, a strong correlation was observed between the gene expression profiles in the mitochondrion and chloroplast, resulting in the identification of a network of functionally related genes that are co-expressed during organelle proliferation.
Collapse
Affiliation(s)
- Yu Kanesaki
- Genome Research Center, Nodai Research Institute, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo156-8502, Japan
- Laboratory of Molecular Genetics, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Sousuke Imamura
- Laboratory of Molecular Genetics, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo112-8551, Japan
- Chemical Resources Laboratory, Tokyo Institute of Technology, 4259-R1-29 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Ayumi Minoda
- Laboratory of Molecular Genetics, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Horinouchi, Tokyo192-0392, Japan
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Japan
| | - Kan Tanaka
- Laboratory of Molecular Genetics, Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
- Chemical Resources Laboratory, Tokyo Institute of Technology, 4259-R1-29 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
- Graduate School of Horticulture, Chiba University, 648 Matsudo, Matsudo, Chiba 271-8510, Japan
| |
Collapse
|
36
|
A tetrapyrrole-regulated ubiquitin ligase controls algal nuclear DNA replication. Nat Cell Biol 2011; 13:483-7. [PMID: 21378982 DOI: 10.1038/ncb2203] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 01/06/2011] [Indexed: 11/08/2022]
Abstract
In plant cells, organelle DNA replication (ODR) is coordinated with nuclear DNA replication (NDR), with ODR preceding NDR during cell cycle progression. We previously showed that the occurrence of ODR is signalled by a tetrapyrrole compound, most likely Mg-protoporphyrin IX (Mg-ProtoIX), resulting in the activation of cyclin-dependent kinase A (CDKA) and consequent initiation of NDR (refs 1, 2, 3). Here we identify an F-box protein of SCF-type E3 ubiquitin ligase (Fbx3) in the red alga Cyanidioschyzon merolae, which inhibits CDKA by ubiquitylating the relevant cyclin and inducing its degradation. Mg-ProtoIX binds to Fbx3 and inhibits cyclin ubiquitylation. Thus, these observations indicate that Fbx3 serves as the receptor for the plastid-to-nucleus retrograde signal Mg-ProtoIX and thereby contributes to a checkpoint mechanism ensuring coordination of ODR and NDR.
Collapse
|
37
|
Retrograde signaling pathway from plastid to nucleus. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 290:167-204. [PMID: 21875565 DOI: 10.1016/b978-0-12-386037-8.00002-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Plastids are a diverse group of organelles found in plants and some parasites. Because genes encoding plastid proteins are divided between the nuclear and plastid genomes, coordinated expression of genes in two separate genomes is indispensable for plastid function. To coordinate nuclear gene expression with the functional or metabolic state of plastids, plant cells have acquired a retrograde signaling pathway from plastid to nucleus, also known as the plastid signaling pathway. To date, several metabolic processes within plastids have been shown to affect the expression of nuclear genes. Recent progress in this field has also revealed that the plastid signaling pathway interacts and shares common components with other intracellular signaling pathways. This review summarizes our current knowledge on retrograde signaling from plastid to nucleus in plant cells and its role in plant growth and development.
Collapse
|
38
|
Kuroiwa T. Review of cytological studies on cellular and molecular mechanisms of uniparental (maternal or paternal) inheritance of plastid and mitochondrial genomes induced by active digestion of organelle nuclei (nucleoids). JOURNAL OF PLANT RESEARCH 2010; 123:207-230. [PMID: 20145972 DOI: 10.1007/s10265-009-0306-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Accepted: 12/07/2009] [Indexed: 05/28/2023]
Abstract
In most sexual organisms, including isogamous, anisogamous and oogamous organisms, uniparental transmission is a striking and universal characteristic of the transmission of organelle (plastid and mitochondrial) genomes (DNA). Using genetic, biochemical and molecular biological techniques, mechanisms of uniparental (maternal and parental) and biparental transmission of organelle genomes have been studied and reviewed. Although to date there has been no cytological review of the transmission of organelle genomes, cytology offers advantages in terms of direct evidence and can enhance global studies of the transmission of organelle genomes. In this review, I focus on the cytological mechanism of uniparental inheritance by "active digestion of male or female organelle nuclei (nucleoids, DNA)" which is universal among isogamous, anisogamous, and oogamous organisms. The global existence of uniparental transmission since the evolution of sexual eukaryotes may imply that the cell nuclear genome continues to inhibit quantitative evolution of organelles by organelle recombination.
Collapse
Affiliation(s)
- Tsuneyoshi Kuroiwa
- Research Information Center for Extremophile, Graduate School of Science, Rikkyo University, Tokyo 171-8501, Japan.
| |
Collapse
|
39
|
Fujiwara T, Kuroiwa H, Yagisawa F, Ohnuma M, Yoshida Y, Yoshida M, Nishida K, Misumi O, Watanabe S, Tanaka K, Kuroiwa T. The coiled-coil protein VIG1 is essential for tethering vacuoles to mitochondria during vacuole inheritance of Cyanidioschyzon merolae. THE PLANT CELL 2010; 22:772-81. [PMID: 20348431 PMCID: PMC2861457 DOI: 10.1105/tpc.109.070227] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Vacuoles/lysosomes function in endocytosis and in storage and digestion of metabolites. These organelles are inherited by the daughter cells in eukaryotes. However, the mechanisms of this inheritance are poorly understood because the cells contain multiple vacuoles that behave randomly. The primitive red alga Cyanidioschyzon merolae has a minimum set of organelles. Here, we show that C. merolae contains about four vacuoles that are distributed equally between the daughter cells by binding to dividing mitochondria. Binding is mediated by VIG1, a 30-kD coiled-coil protein identified by microarray analyses and immunological assays. VIG1 appears on the surface of free vacuoles in the cytosol and then tethers the vacuoles to the mitochondria. The vacuoles are released from the mitochondrion in the daughter cells following VIG1 digestion. Suppression of VIG1 by antisense RNA disrupted the migration of vacuoles. Thus, VIG1 is essential for tethering vacuoles to mitochondria during vacuole inheritance in C. merolae.
Collapse
Affiliation(s)
- Takayuki Fujiwara
- Research Information Center for Extremophile, Rikkyo University, Toshima-ku 171-8501, Japan
| | - Haruko Kuroiwa
- Research Information Center for Extremophile, Rikkyo University, Toshima-ku 171-8501, Japan
| | - Fumi Yagisawa
- Research Information Center for Extremophile, Rikkyo University, Toshima-ku 171-8501, Japan
| | - Mio Ohnuma
- Research Information Center for Extremophile, Rikkyo University, Toshima-ku 171-8501, Japan
| | - Yamato Yoshida
- Research Information Center for Extremophile, Rikkyo University, Toshima-ku 171-8501, Japan
| | - Masaki Yoshida
- Research Information Center for Extremophile, Rikkyo University, Toshima-ku 171-8501, Japan
| | - Keiji Nishida
- Research Information Center for Extremophile, Rikkyo University, Toshima-ku 171-8501, Japan
| | - Osami Misumi
- Research Information Center for Extremophile, Rikkyo University, Toshima-ku 171-8501, Japan
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo 156-8502, Japan
| | - Kan Tanaka
- Graduate School of Horticulture, Chiba University, Matsudo, Chiba 271-8510, Japan
| | - Tsuneyoshi Kuroiwa
- Research Information Center for Extremophile, Rikkyo University, Toshima-ku 171-8501, Japan
- Address correspondence to
| |
Collapse
|
40
|
Kanesaki Y, Kobayashi Y, Hanaoka M, Tanaka K. Mg-protoporphyrin IX signaling in Cyanidioschyzon merolae: multiple pathways may involve the retrograde signaling in plant cells. PLANT SIGNALING & BEHAVIOR 2009; 4:1190-2. [PMID: 20514244 PMCID: PMC2819454 DOI: 10.4161/psb.4.12.10061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 08/26/2009] [Indexed: 05/09/2023]
Abstract
Plastids and mitochondria are organelles in plant cells, which are considered to have evolved from endosymbiotic associations of bacteria. These organelles have their own genomes descended from their ancestors, and the organelle DNA replications (ODR) of plant cells are coordinated with the nuclear DNA replication (NDR) as ODR precedes NDR during a cell cycle progression. However, the underlying mechanism for this coordination remains largely to be determined. Recently, we identified that a tetrapyrrole compound, Mg-Protoporphyrin IX (Mg-Proto), is a cell cycle coordinator from organelle to NDR in plant cells.1 While Mg-Proto has been suggested to be a retrograde plastid signal to modulate transcription of nuclear genes for plastid proteins, our results indicated that nuclear transcriptional regulation is not involved in the NDR induction in C. merolae. Thus, our finding for the NDR control is likely to represent a novel signaling mechanism independent of the conventional plastid signal, which we named "parasitic signal", and suggests multiple Mg-Protoinvolved pathways for the plastid-nucleus retrograde signaling.
Collapse
Affiliation(s)
- Yu Kanesaki
- Nodai Genome Research Center; Tokyo University of Agriculture; Setagaya-ku, Tokyo Japan
| | - Yuki Kobayashi
- Graduate School of Horticulture; Chiba University, Matsudo, Chiba Japan
| | - Mitsumasa Hanaoka
- Graduate School of Horticulture; Chiba University, Matsudo, Chiba Japan
| | - Kan Tanaka
- Graduate School of Horticulture; Chiba University, Matsudo, Chiba Japan
| |
Collapse
|
41
|
R2R3-type MYB transcription factor, CmMYB1, is a central nitrogen assimilation regulator in Cyanidioschyzon merolae. Proc Natl Acad Sci U S A 2009; 106:12548-53. [PMID: 19592510 DOI: 10.1073/pnas.0902790106] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Plant cells sense environmental nitrogen levels and alter their gene expression accordingly to survive; however, the underlying regulatory mechanisms still remains to be elucidated. Here, we identified and characterized a transcription factor that is responsible for expression of nitrogen assimilation genes in a unicellular red alga Cyanidioschyzon merolae. DNA microarray and Northern blot analyses revealed that transcript of the gene encoding CmMYB1, an R2R3-type MYB transcription factor, increased 1 h after nitrogen depletion. The CmMYB1 protein started to accumulate after 2 h and reached a peak after 4 h after nitrogen depletion, correlating with the expression of key nitrogen assimilation genes, such as CmNRT, CmNAR, CmNIR, CmAMT, and CmGS. Although the transcripts of these nitrogen assimilation genes were detected in nitrate-grown cells, they disappeared upon the addition of preferred nitrogen source such as ammonium or glutamine, suggesting the presence of a nitrogen catabolite repression (NCR) mechanism. The nitrogen depletion-induced gene expression disappeared in a CmMYB1-null mutant, and the mutant showed decreased cell viability after exposure to the nitrogen-depleted conditions compared with the parental strain. Chromatin immunoprecipitation analysis demonstrated that CmMYB1 specifically occupied these nitrogen-responsive promoter regions only under nitrogen-depleted conditions, and electrophoretic mobility shift assays using crude cell extract revealed specific binding of CmMYB1, or a complex containing CmMYB1, to these promoters. Thus, the presented results indicated that CmMYB1 is a central nitrogen regulator in C. merolae.
Collapse
|
42
|
The plant-specific TFIIB-related protein, pBrp, is a general transcription factor for RNA polymerase I. EMBO J 2009; 27:2317-27. [PMID: 18668124 DOI: 10.1038/emboj.2008.151] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Accepted: 07/07/2008] [Indexed: 01/19/2023] Open
Abstract
TFIIB and BRF are general transcription factors (GTFs) for eukaryotic RNA polymerases II and III, respectively, and have important functions in transcriptional initiation. In this study, the third type of TFIIB-related protein, pBrp, found in plant lineages was characterized in the red alga Cyanidioschyzon merolae. Chromatin immunoprecipitation analysis revealed that CmpBrp specifically occupied the rDNA promoter region in vivo, and the occupancy was proportional to de novo 18S rRNA synthesis. Consistently, CmpBrp and CmTBP cooperatively bound the rDNA promoter region in vitro, and the binding site was identified at a proximal downstream region of the transcription start point. alpha-Amanitin-resistant transcription from the rDNA promoter in crude cell lysate was severely inhibited by the CmpBrp antibody and was also inhibited when DNA template with a mutated CmpBrp-CmTBP binding site was used. CmpBrp was shown to co-immunoprecipitate and co-localize with the RNA polymerase I subunit, CmRPA190, in the cell. Thus, together with comparative studies of Arabidopsis pBrp, we concluded that pBrp is a GTF for RNA polymerase I in plant cells.
Collapse
|
43
|
Fujiwara T, Misumi O, Tashiro K, Yoshida Y, Nishida K, Yagisawa F, Imamura S, Yoshida M, Mori T, Tanaka K, Kuroiwa H, Kuroiwa T. Periodic gene expression patterns during the highly synchronized cell nucleus and organelle division cycles in the unicellular red alga Cyanidioschyzon merolae. DNA Res 2009; 16:59-72. [PMID: 19147531 PMCID: PMC2646357 DOI: 10.1093/dnares/dsn032] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Previous cell cycle studies have been based on cell-nuclear proliferation only. Eukaryotic cells, however, have double membranes-bound organelles, such as the cell nucleus, mitochondrion, plastids and single-membrane-bound organelles such as ER, the Golgi body, vacuoles (lysosomes) and microbodies. Organelle proliferations, which are very important for cell functions, are poorly understood. To clarify this, we performed a microarray analysis during the cell cycle of Cyanidioschyzon merolae. C. merolae cells contain a minimum set of organelles that divide synchronously. The nuclear, mitochondrial and plastid genomes were completely sequenced. The results showed that, of 158 genes induced during the S or G2-M phase, 93 were known and contained genes related to mitochondrial division, ftsZ1-1, ftsz1-2 and mda1, and plastid division, ftsZ2-1, ftsZ2-2 and cmdnm2. Moreover, three genes, involved in vesicle trafficking between the single-membrane organelles such as vps29 and the Rab family protein, were identified and might be related to partitioning of single-membrane-bound organelles. In other genes, 46 were hypothetical and 19 were hypothetical conserved. The possibility of finding novel organelle division genes from hypothetical and hypothetical conserved genes in the S and G2-M expression groups is discussed.
Collapse
Affiliation(s)
- Takayuki Fujiwara
- Research Information Center for Extremophile, Rikkyo University, 3-34-1 Nishiikebukuro, Toshima, Tokyo 171-8501, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Tetrapyrrole signal as a cell-cycle coordinator from organelle to nuclear DNA replication in plant cells. Proc Natl Acad Sci U S A 2009; 106:803-7. [PMID: 19141634 DOI: 10.1073/pnas.0804270105] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Eukaryotic cells arose from an ancient endosymbiotic association of prokaryotes, with plant cells harboring 3 genomes as the remnants of such evolution. In plant cells, plastid and mitochondrial DNA replication [organelle DNA replication (ODR)] occurs in advance of the subsequent cell cycles composed of nuclear DNA replication (NDR) and cell division. However, the mechanism by which replication of these genomes with different origins is coordinated is largely unknown. Here, we show that NDR is regulated by a tetrapyrrole signal in plant cells, which has been suggested as an organelle-to-nucleus retrograde signal. In synchronized cultures of the primitive red alga Cyanidioschyzon merolae, specific inhibition of A-type cyclin-dependent kinase (CDKA) prevented NDR but not ODR after onset of the cell cycle. In contrast, inhibition of ODR by nalidixic acid also resulted in inhibition of NDR, indicating a strict dependence of NDR on ODR. The requirement of ODR for NDR was bypassed by addition of the tetrapyrrole intermediates protoporphyrin IX (ProtoIX) or Mg-ProtoIX, both of which activated CDKA without inducing ODR. This scheme was also observed in cultured tobacco cells (BY-2), where inhibition of ODR by nalidixic acid prevented CDKA activation and NDR, and these inhibitions were circumvented by Mg-ProtoIX without inducing ODR. We thus show that tetrapyrrole-mediated organelle-nucleus replicational coupling is an evolutionary conserved process among plant cells.
Collapse
|
45
|
Di Giulio M. Permuted tRNA genes of Cyanidioschyzon merolae, the origin of the tRNA molecule and the root of the Eukarya domain. J Theor Biol 2008; 253:587-92. [PMID: 18513750 DOI: 10.1016/j.jtbi.2008.04.022] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 04/17/2008] [Accepted: 04/17/2008] [Indexed: 11/19/2022]
Abstract
An evolutionary analysis is conducted on the permuted tRNA genes of Cyanidioschyzon merolae, in which the 5' half of the tRNA molecule is codified at the 3' end of the gene and its 3' half is codified at the 5' end. This analysis has shown that permuted genes cannot be considered as derived traits but seem to possess characteristics that suggest they are ancestral traits, i.e. they originated when tRNA molecule genes originated for the first time. In particular, if the hypothesis that permuted genes are a derived trait were true, then we should not have been able to observe that the most frequent class of permuted genes is that of the anticodon loop type, for the simple reason that this class would derive by random permutation from a class of non-permuted tRNA genes, which instead is the rarest. This would not explain the high frequency with which permuted tRNA genes with perfectly separate 5' and 3' halves were observed. Clearly the mechanism that produced this class of permuted genes would envisage the existence, in an advanced stage of evolution, of minigenes codifying for the 5' and 3' halves of tRNAs which were assembled in a permuted way at the origin of the tRNA molecule, thus producing a high frequency of permuted genes of the class here referred. Therefore, this evidence supports the hypothesis that the genes of the tRNA molecule were assembled by minigenes codifying for hairpin-like RNA molecules, as suggested by one model for the origin of tRNA [Di Giulio, M., 1992. On the origin of the transfer RNA molecule. J. Theor. Biol. 159, 199-214; Di Giulio, M., 1999. The non-monophyletic origin of tRNA molecule. J. Theor. Biol. 197, 403-414]. Moreover, the late assembly of the permuted genes of C. merolae, as well as their ancestrality, strengthens the hypothesis of the polyphyletic origins of these genes. Finally, on the basis of the uniqueness and the ancestrality of these permuted genes, I suggest that the root of the Eukarya domain is in the super-ensemble of the Plantae and that the Rhodophyta to which C. merolae belongs are the first line of divergence.
Collapse
Affiliation(s)
- Massimo Di Giulio
- Laboratory for Molecular Evolution, Institute of Genetics and Biophysics 'Adriano Buzzati Traverso', CNR, Via P. Castellino, 111, 80131 Naples, Napoli, Italy.
| |
Collapse
|
46
|
Misumi O, Yoshida Y, Nishida K, Fujiwara T, Sakajiri T, Hirooka S, Nishimura Y, Kuroiwa T. Genome analysis and its significance in four unicellular algae, Cyanidioschyzon [corrected] merolae, Ostreococcus tauri, Chlamydomonas reinhardtii, and Thalassiosira pseudonana. JOURNAL OF PLANT RESEARCH 2008; 121:3-17. [PMID: 18074102 DOI: 10.1007/s10265-007-0133-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Accepted: 10/30/2007] [Indexed: 05/19/2023]
Abstract
Algae play a more important role than land plants in the maintenance of the global environment and productivity. Progress in genome analyses of these organisms means that we can now obtain information on algal genomes, global annotation and gene expression. The full genome information for several algae has already been analyzed. Whole genomes of the red alga Cyanidioschyzon [corrected] merolae, the green algae Ostreococcus tauri and Chlamydomonas reinhardtii, and the diatom Thalassiosira pseudonana have been sequenced. Genome composition and the features of cells among the four algae were compared. Each alga maintains basic genes as photosynthetic eukaryotes and possesses additional gene groups to represent their particular characteristics. This review discusses and introduces the latest research that makes the best use of the particular features of each organism and the significance of genome analysis to study biological phenomena. In particular, examples of post-genome studies of organelle multiplication in C. merolae based on analyzed genome information are presented.
Collapse
Affiliation(s)
- Osami Misumi
- Department of Life Science, Graduate School of Science, Rikkyo University, Tokyo 171-8501, Japan
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Maple J, Mateo* A, Møller SG. Plastid Division Regulation and Interactions with the Environment. PLANT CELL MONOGRAPHS 2008. [DOI: 10.1007/7089_2008_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
|
48
|
Soma A, Onodera A, Sugahara J, Kanai A, Yachie N, Tomita M, Kawamura F, Sekine Y. Permuted tRNA genes expressed via a circular RNA intermediate in Cyanidioschyzon merolae. Science 2007; 318:450-3. [PMID: 17947580 DOI: 10.1126/science.1145718] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A computational analysis of the nuclear genome of a red alga, Cyanidioschyzon merolae, identified 11 transfer RNA (tRNA) genes in which the 3' half of the tRNA lies upstream of the 5' half in the genome. We verified that these genes are expressed and produce mature tRNAs that are aminoacylated. Analysis of tRNA-processing intermediates for these genes indicates an unusual processing pathway in which the termini of the tRNA precursor are ligated, resulting in formation of a characteristic circular RNA intermediate that is then processed at the acceptor stem to generate the correct termini.
Collapse
Affiliation(s)
- Akiko Soma
- Department of Life Science, College of Science, Rikkyo (St. Paul's) University, Toshima, Tokyo 171-8501, Japan
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Yagisawa F, Nishida K, Kuroiwa H, Nagata T, Kuroiwa T. Identification and mitotic partitioning strategies of vacuoles in the unicellular red alga Cyanidioschyzon merolae. PLANTA 2007; 226:1017-29. [PMID: 17574474 DOI: 10.1007/s00425-007-0550-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Accepted: 05/07/2007] [Indexed: 05/15/2023]
Abstract
Cyanidioschyzon merolae is considered as a suitable model system for studies of organelle differentiation, proliferation and partitioning. Here, we have identified and characterized vacuoles in this organism and examined the partitioning of vacuoles using fluorescence and electron microscopy. Vacuoles were stained with the fluorescent aminopeptidase substrate 7-amino-4-chloromethylcoumarin L: -arginine amide, acidotrophic dyes quinacrine and LysoTracker, and 4',6-diamidino-2-phenyl indole, which, at a high concentration, stains polyphosphate. Vacuoles have been shown to be approximately 500 nm in diameter with a mean of around five per interphase cell. The vacuolar H(+)-ATPase inhibitor concanamycin A blocked the accumulation of quinacrine in the vacuoles, suggesting the presence of the enzyme on these membranes. Electron microscopy revealed that the vacuoles were single membrane-bound organelles with an electron-dense substance, often containing a thick layer surrounding the membrane. Immunoelectron microscopy using an anti-vacuolar-H(+)-pyrophosphatase antibody revealed the presence of the enzyme on these membranes. In interphase cells, vacuoles were distributed in the cytoplasm, while in mitotic cells they were localized adjacent to the mitochondria. Filamentous structures were observed between vacuoles and mitochondria. Vacuoles were distributed almost evenly to daughter cells and redistributed in the cytoplasm after cytokinesis. The change in localization of vacuoles also happened in microtubule-disrupted cells. Since no actin protein or filaments have been detected in C. merolae, this result suggests an intrinsic mechanism for the movement of vacuoles that differs from commonly known mechanisms mediated by microtubules and actin filaments.
Collapse
Affiliation(s)
- Fumi Yagisawa
- Department of Life Science, College of Science, Rikkyo (St Paul's) University, Nishiikebukuro, Tokyo 171-8501, Japan.
| | | | | | | | | |
Collapse
|
50
|
Sato N, Moriyama T. Genomic and biochemical analysis of lipid biosynthesis in the unicellular rhodophyte Cyanidioschyzon merolae: lack of a plastidic desaturation pathway results in the coupled pathway of galactolipid synthesis. EUKARYOTIC CELL 2007; 6:1006-17. [PMID: 17416897 PMCID: PMC1951526 DOI: 10.1128/ec.00393-06] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Accepted: 03/20/2007] [Indexed: 11/20/2022]
Abstract
The acyl lipids making up the plastid membranes in plants and algae are highly enriched in polyunsaturated fatty acids and are synthesized by two distinct pathways, known as the prokaryotic and eukaryotic pathways, which are located within the plastids and the endoplasmic reticulum, respectively. Here we report the results of biochemical as well as genomic analyses of lipids and fatty acids in the unicellular rhodophyte Cyanidioschyzon merolae. All of the glycerolipids usually found in photosynthetic algae were found, such as mono- and digalactosyl diacylglycerol, sulfolipid, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol. However, the fatty acid composition was extremely simple. Only palmitic, stearic, oleic, and linoleic acids were found as major acids. In addition, 3-trans-hexadecanoic acid was found as a very minor component in phosphatidylglycerol. Unlike the case for most other photosynthetic eukaryotes, polyenoic fatty acids having three or more double bonds were not detected. These results suggest that polyunsaturated fatty acids are not necessary for photosynthesis in eukaryotes. Genomic analysis suggested that C. merolae lacks acyl lipid desaturases of cyanobacterial origin as well as stearoyl acyl carrier protein desaturase, both of which are major desaturases in plants and green algae. The results of labeling experiments with radioactive acetate showed that the desaturation leading to linoleic acid synthesis occurs on phosphatidylcholine located outside the plastids. Monogalactosyl diacylglycerol is therefore synthesized by the coupled pathway, using plastid-derived palmitic acid and endoplasmic reticulum-derived linoleic acid. These results highlight essential differences in lipid biosynthetic pathways between the red algae and the green lineage, which includes plants and green algae.
Collapse
Affiliation(s)
- Naoki Sato
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan.
| | | |
Collapse
|