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Hasegawa H, Kanesaki Y, Watanabe S, Tanaka K. A high-temperature sensitivity of Synechococcus elongatus PCC 7942 due to a tRNA-Leu mutation. J GEN APPL MICROBIOL 2023; 69:167-174. [PMID: 36805585 DOI: 10.2323/jgam.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Certain mutations of the model cyanobacterium Synechococcus elongatus PCC 7942 during laboratory storage have resulted in some divergent phenotypes. One laboratory-stored strain (H1) shows a temperature-sensitive (ts) growth phenotype at 40 °C. Here, we investigated the reason for this temperature sensitivity. Whole genome sequencing of H1 identified a single nucleotide mutation in synpcc7942_R0040 encoding tRNA-Leu(CAA). The mutation decreases the length of the tRNA-Leu t-arm from 5 to 4 base pairs, and this explains the ts phenotype. Secondary mutations suppressing the ts phenotype were identified in synpcc7942_1640, which putatively encodes a NYN domain-containing protein (nynA). The NYN domain is thought to be involved in tRNA/rRNA degradation. Thus, the structural stability of tRNA-Leu is critical for growth at 40 °C in Synechococcus elongatus PCC 7942.
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Affiliation(s)
- Hazuki Hasegawa
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology
- School of Life Science and Technology, Tokyo Institute of Technology
| | - Yu Kanesaki
- Research Institute of Green Science and Technology, Shizuoka University
| | | | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology
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Bairagi N, Watanabe S, Nimura-Matsune K, Tanaka K, Tsurumaki T, Nakanishi S, Tanaka K. Conserved Two-component Hik2-Rre1 Signaling Is Activated Under Temperature Upshift and Plastoquinone-reducing Conditions in the Cyanobacterium Synechococcus elongatus PCC 7942. PLANT & CELL PHYSIOLOGY 2022; 63:176-188. [PMID: 34750635 DOI: 10.1093/pcp/pcab158] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/25/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
The highly conserved Hik2-Rre1 two-component system is a multi-stress responsive signal-transducing module that controls the expression of hsp and other genes in cyanobacteria. Previously, we found in Synechococcus elongatus PCC 7942 that the heat-inducible phosphorylation of Rre1 was alleviated in a hik34 mutant, suggesting that Hik34 positively regulates signaling. In this study, we examined the growth of the hik34 deletion mutant in detail, and newly identified suppressor mutations located in rre1 or sasA gene negating the phenotype. Subsequent analyses indicated that heat-inducible Rre1 phosphorylation is dependent on Hik2 and that Hik34 modulates this Hik2-dependent response. In the following part of this study, we focused on the mechanism to control the Hik2 activity. Other recent studies reported that Hik2 activity is regulated by the redox status of plastoquinone (PQ) through the 3Fe-4S cluster attached to the cyclic GMP, adenylyl cyclase, FhlA (GAF) domain. Consistent with this, Rre1 phosphorylation occurred after the addition of 2,5-dibromo-6-isopropyl-3-methyl-1,4-benzoquinone but not after the addition of 3-(3,4-dichlorophenyl)-1,1-dimethylurea to the culture medium, which corresponded to PQ-reducing or -oxidizing conditions, respectively, suggesting that the Hik2-to-Rre1 phosphotransfer was activated under PQ-reducing conditions. However, there was no correlation between the measured PQ redox status and Rre1 phosphorylation during the temperature upshift. Therefore, changes in the PQ redox status are not the direct reason for the heat-inducible Rre1 phosphorylation, while some redox regulation is likely involved as oxidation events dependent on 2,6-dichloro-1,4-benzoquinone prevented heat-inducible Rre1 phosphorylation. On the basis of these results, we propose a model for the control of Hik2-dependent Rre1 phosphorylation.
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Affiliation(s)
- Nachiketa Bairagi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
| | - Satoru Watanabe
- Department of Bioscience, Tokyo University of Agriculture, Sakuragaoka, Setagaya-ku, Tokyo, 156-8502 Japan
| | - Kaori Nimura-Matsune
- Department of Bioscience, Tokyo University of Agriculture, Sakuragaoka, Setagaya-ku, Tokyo, 156-8502 Japan
| | - Kenya Tanaka
- Research Center for Solar Energy Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531 Japan
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, 657-8501 Japan
| | - Tatsuhiro Tsurumaki
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
| | - Shuji Nakanishi
- Research Center for Solar Energy Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka, 560-8531 Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503 Japan
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Hasegawa H, Tsurumaki T, Imamura S, Sonoike K, Tanaka K. The circadian rhythm regulator RpaA modulates photosynthetic electron transport and alters the preferable temperature range for growth in a cyanobacterium. FEBS Lett 2021; 595:1480-1492. [PMID: 33728661 DOI: 10.1002/1873-3468.14075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 11/07/2022]
Abstract
Cyanobacterial strains can grow within a specific temperature range that approximately corresponds to their natural habitat. However, how the preferable temperature range for growth (PTRG) is determined at the molecular level remains unclear. In this study, we detected a PTRG upshift in a mutant strain of Synechococcus elongatus PCC 7942 lacking the circadian rhythm regulator RpaA. Subsequent analyses revealed that RpaA decreases the electron transport from photosystem I to NADPH. The change in electron transport likely inhibits H2 O2 generation under high-temperature conditions and contributes to the observed PTRG upshift in rpaA-deficient cells. The importance of the effects of the circadian rhythm regulator on the PTRG is discussed.
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Affiliation(s)
- Hazuki Hasegawa
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Tatsuhiro Tsurumaki
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Sousuke Imamura
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Kintake Sonoike
- Faculty of Education and Integrated Arts and Sciences, Waseda University, Tokyo, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
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Rachedi R, Foglino M, Latifi A. Stress Signaling in Cyanobacteria: A Mechanistic Overview. Life (Basel) 2020; 10:life10120312. [PMID: 33256109 PMCID: PMC7760821 DOI: 10.3390/life10120312] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 11/22/2020] [Accepted: 11/25/2020] [Indexed: 12/22/2022] Open
Abstract
Cyanobacteria are highly diverse, widely distributed photosynthetic bacteria inhabiting various environments ranging from deserts to the cryosphere. Throughout this range of niches, they have to cope with various stresses and kinds of deprivation which threaten their growth and viability. In order to adapt to these stresses and survive, they have developed several global adaptive responses which modulate the patterns of gene expression and the cellular functions at work. Sigma factors, two-component systems, transcriptional regulators and small regulatory RNAs acting either separately or collectively, for example, induce appropriate cyanobacterial stress responses. The aim of this review is to summarize our current knowledge about the diversity of the sensors and regulators involved in the perception and transduction of light, oxidative and thermal stresses, and nutrient starvation responses. The studies discussed here point to the fact that various stresses affecting the photosynthetic capacity are transduced by common mechanisms.
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Ikeuchi M. Molecular biology of cyanobacteria and microalgae from atom to ecology. J GEN APPL MICROBIOL 2020; 66:51-52. [PMID: 32554950 DOI: 10.2323/jgam.2020.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Masahiko Ikeuchi
- Department of Life Sciences (Biology), The University of Tokyo.,Faculty of Education and Integrated Arts and Sciences, Waseda University
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