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Akagi C, Kurihara Y, Makita Y, Kawauchi M, Tsuge T, Aoyama T, Matsui M. Translational activation of ribosome-related genes at initial photoreception is dependent on signals derived from both the nucleus and the chloroplasts in Arabidopsis thaliana. JOURNAL OF PLANT RESEARCH 2023; 136:227-238. [PMID: 36658292 DOI: 10.1007/s10265-022-01430-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Light is one of the indispensable elements that plants need in order to grow and develop. In particular, it is essential for inducing morphogenesis, such as suppression of hypocotyl elongation and cotyledon expansion, that plants undergo when they first emerge after germination. However, there is a lack of knowledge about the gene expression and, in particular, the translational levels that induce a response upon light exposure. We have investigated the translational expression of nuclear genes in Arabidopsis thaliana seedlings germinated in the dark and then exposed to blue monochromatic light. In this study, ribosome profiling analysis was performed in the blue-light-receptor mutant cry1cry2 and the light-signaling mutant hy5 to understand which signaling pathways are responsible for the changes in gene expression at the translational level after blue-light exposure. The analysis showed that the expression of certain chloroplast- and ribosome-related genes was up-regulated at the translational level in the wild type. However, in both mutants the translational up-regulation of ribosome-related genes was apparently compromised. This suggests that light signaling through photoreceptors and the HY5 transcription factor are responsible for translation of ribosome-related genes. To further understand the effect of photoreception by chloroplasts on nuclear gene expression, chloroplast function was inhibited by adding a photosynthesis inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), and a carotenoid synthesis inhibitor, norflurazon. The results show that inhibition of chloroplast function did not lead to an increase in the expression of ribosome-related genes at the translational level. These results suggest that signals from both the nucleus and chloroplasts are required to activate translation of ribosome-related genes during blue-light reception.
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Affiliation(s)
- Chika Akagi
- Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Yukio Kurihara
- Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo, 153-8902, Japan
| | - Yuko Makita
- Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Faculty of Engineering, Maebashi Institute of Technology, Kamisadori 460-1, Maebashi, Gunma, 371-0816, Japan
| | - Masaharu Kawauchi
- Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Tomohiko Tsuge
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Takashi Aoyama
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Minami Matsui
- Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.
- Graduate School of Nanobioscience Department of Life and Environmental System Science, Yokohama City University, Yokohama, Kanagawa, 236-0027, Japan.
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Orth C, Niemann N, Hennig L, Essen LO, Batschauer A. Hyperactivity of the Arabidopsis cryptochrome (cry1) L407F mutant is caused by a structural alteration close to the cry1 ATP-binding site. J Biol Chem 2017. [PMID: 28634231 DOI: 10.1074/jbc.m117.788869] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Plant cryptochromes (cry) act as UV-A/blue light receptors. The prototype, Arabidopsis thaliana cry1, regulates several light responses during the life cycle, including de-etiolation, and is also involved in regulating flowering time. The cry1 photocycle is initiated by light absorption by its FAD chromophore, which is most likely fully oxidized (FADox) in the dark state and photoreduced to the neutral flavin semiquinone (FADH°) in its lit state. Cryptochromes lack the DNA-repair activity of the closely related DNA photolyases, but they retain the ability to bind nucleotides such as ATP. The previously characterized L407F mutant allele of Arabidopsis cry1 is biologically hyperactive and seems to mimic the ATP-bound state of cry1, but the reason for this phenotypic change is unclear. Here, we show that cry1L407F can still bind ATP, has less pronounced photoreduction and formation of FADH° than wild-type cry1, and has a dark reversion rate 1.7 times lower than that of the wild type. The hyperactivity of cry1L407F is not related to a higher FADH° occupancy of the photoreceptor but is caused by a structural alteration close to the ATP-binding site. Moreover, we show that ATP binds to cry1 in both the dark and the lit states. This binding was not affected by cry1's C-terminal extension, which is important for signal transduction. Finally, we show that a recently discovered chemical inhibitor of cry1, 3-bromo-7-nitroindazole, competes for ATP binding and thereby diminishes FADH° formation, which demonstrates that both processes are important for cry1 function.
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Affiliation(s)
- Christian Orth
- Faculty of Biology, Department of Plant Physiology and Photobiology, Philipps-Universität, 35032 Marburg, Germany
| | - Nils Niemann
- Faculty of Biology, Department of Plant Physiology and Photobiology, Philipps-Universität, 35032 Marburg, Germany
| | - Lars Hennig
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden
| | - Lars-Oliver Essen
- Faculty of Chemistry, Department of Biochemistry, Philipps-Universität, 35032 Marburg, Germany
| | - Alfred Batschauer
- Faculty of Biology, Department of Plant Physiology and Photobiology, Philipps-Universität, 35032 Marburg, Germany.
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