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Wu HYL, Jen J, Hsu PY. What, where, and how: Regulation of translation and the translational landscape in plants. THE PLANT CELL 2024; 36:1540-1564. [PMID: 37437121 PMCID: PMC11062462 DOI: 10.1093/plcell/koad197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/14/2023] [Accepted: 06/15/2023] [Indexed: 07/14/2023]
Abstract
Translation is a crucial step in gene expression and plays a vital role in regulating various aspects of plant development and environmental responses. It is a dynamic and complex program that involves interactions between mRNAs, transfer RNAs, and the ribosome machinery through both cis- and trans-regulation while integrating internal and external signals. Translational control can act in a global (transcriptome-wide) or mRNA-specific manner. Recent advances in genome-wide techniques, particularly ribosome profiling and proteomics, have led to numerous exciting discoveries in both global and mRNA-specific translation. In this review, we aim to provide a "primer" that introduces readers to this fascinating yet complex cellular process and provide a big picture of how essential components connect within the network. We begin with an overview of mRNA translation, followed by a discussion of the experimental approaches and recent findings in the field, focusing on unannotated translation events and translational control through cis-regulatory elements on mRNAs and trans-acting factors, as well as signaling networks through 3 conserved translational regulators TOR, SnRK1, and GCN2. Finally, we briefly touch on the spatial regulation of mRNAs in translational control. Here, we focus on cytosolic mRNAs; translation in organelles and viruses is not covered in this review.
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Affiliation(s)
- Hsin-Yen Larry Wu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Joey Jen
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Polly Yingshan Hsu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
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Chang HH, Huang LC, Browning KS, Huq E, Cheng MC. The phosphorylation of carboxyl-terminal eIF2α by SPA kinases contributes to enhanced translation efficiency during photomorphogenesis. Nat Commun 2024; 15:3467. [PMID: 38658612 PMCID: PMC11043401 DOI: 10.1038/s41467-024-47848-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 04/11/2024] [Indexed: 04/26/2024] Open
Abstract
Light triggers an enhancement of global translation during photomorphogenesis in Arabidopsis, but little is known about the underlying mechanisms. The phosphorylation of the α-subunit of eukaryotic initiation factor 2 (eIF2α) at a conserved serine residue in the N-terminus has been shown as an important mechanism for the regulation of protein synthesis in mammalian and yeast cells. However, whether the phosphorylation of this residue in plant eIF2α plays a role in regulation of translation remains elusive. Here, we show that the quadruple mutant of SUPPRESSOR OF PHYA-105 family members (SPA1-SPA4) display repressed translation efficiency after light illumination. Moreover, SPA1 directly phosphorylates the eIF2α C-terminus under light conditions. The C-term-phosphorylated eIF2α promotes translation efficiency and photomorphogenesis, whereas the C-term-unphosphorylated eIF2α results in a decreased translation efficiency. We also demonstrate that the phosphorylated eIF2α enhances ternary complex assembly by promoting its affinity to eIF2β and eIF2γ. This study reveals a unique mechanism by which light promotes translation via SPA1-mediated phosphorylation of the C-terminus of eIF2α in plants.
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Affiliation(s)
- Hui-Hsien Chang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Lin-Chen Huang
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan
| | - Karen S Browning
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | - Enamul Huq
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | - Mei-Chun Cheng
- Department of Biochemical Science and Technology, National Taiwan University, Taipei, 10617, Taiwan.
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Xu Y, Li Y, Li Y, Zhai C, Zhang K. Transcriptome Analysis Reveals the Stress Tolerance Mechanisms of Cadmium in Zoysia japonica. PLANTS (BASEL, SWITZERLAND) 2023; 12:3833. [PMID: 38005730 PMCID: PMC10674853 DOI: 10.3390/plants12223833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 11/09/2023] [Accepted: 11/10/2023] [Indexed: 11/26/2023]
Abstract
Cadmium (Cd) is a severe heavy metal pollutant globally. Zoysia japonica is an important perennial warm-season turf grass that potentially plays a role in phytoremediation in Cd-polluted soil areas; however, the molecular mechanisms underlying its Cd stress response are unknown. To further investigate the early gene response pattern in Z. japonica under Cd stress, plant leaves were harvested 0, 6, 12, and 24 h after Cd stress (400 μM CdCl2) treatment and used for a time-course RNA-sequencing analysis. Twelve cDNA libraries were constructed and sequenced, and high-quality data were obtained, whose mapped rates were all higher than 94%, and more than 601 million bp of sequence were generated. A total of 5321, 6526, and 4016 differentially expressed genes were identified 6, 12, and 24 h after Cd stress treatment, respectively. A total of 1660 genes were differentially expressed at the three time points, and their gene expression profiles over time were elucidated. Based on the analysis of these genes, the important mechanisms for the Cd stress response in Z. japonica were identified. Specific genes participating in glutathione metabolism, plant hormone signal and transduction, members of protein processing in the endoplasmic reticulum, transporter proteins, transcription factors, and carbohydrate metabolism pathways were further analyzed in detail. These genes may contribute to the improvement of Cd tolerance in Z. japonica. In addition, some candidate genes were highlighted for future studies on Cd stress resistance in Z. japonica and other plants. Our results illustrate the early gene expression response of Z. japonica leaves to Cd and provide some new understanding of the molecular mechanisms of Cd stress in Zosia and Gramineae species.
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Affiliation(s)
- Yi Xu
- College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China; (Y.X.); (Y.L.); (Y.L.); (C.Z.)
- College of Life Sciences, Qingdao Agricultural University, Qingdao 266109, China
| | - Yonglong Li
- College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China; (Y.X.); (Y.L.); (Y.L.); (C.Z.)
| | - Yan Li
- College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China; (Y.X.); (Y.L.); (Y.L.); (C.Z.)
| | - Chenyuan Zhai
- College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China; (Y.X.); (Y.L.); (Y.L.); (C.Z.)
| | - Kun Zhang
- College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China; (Y.X.); (Y.L.); (Y.L.); (C.Z.)
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Fang JC, Liu MJ. Translation initiation at AUG and non-AUG triplets in plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 335:111822. [PMID: 37574140 DOI: 10.1016/j.plantsci.2023.111822] [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: 12/15/2022] [Revised: 07/22/2023] [Accepted: 08/07/2023] [Indexed: 08/15/2023]
Abstract
In plants and other eukaryotes, precise selection of translation initiation site (TIS) on mRNAs shapes the proteome in response to cellular events or environmental cues. The canonical translation of mRNAs initiates at a 5' proximal AUG codon in a favorable context. However, the coding and non-coding regions of plant genomes contain numerous unannotated alternative AUG and non-AUG TISs. Determining how and why these unexpected and prevalent TISs are activated in plants has emerged as an exciting research area. In this review, we focus on the selection of plant TISs and highlight studies that revealed previously unannotated TISs used in vivo via comparative genomics and genome-wide profiling of ribosome positioning and protein N-terminal ends. The biological signatures of non-AUG TIS-initiated open reading frames (ORFs) in plants are also discussed. We describe what is understood about cis-regulatory RNA elements and trans-acting eukaryotic initiation factors (eIFs) in the site selection for translation initiation by featuring the findings in plants along with supporting findings in non-plant species. The prevalent, unannotated TISs provide a hidden reservoir of ORFs that likely help reshape plant proteomes in response to developmental or environmental cues. These findings underscore the importance of understanding the mechanistic basis of TIS selection to functionally annotate plant genomes, especially for crops with large genomes.
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Affiliation(s)
- Jhen-Cheng Fang
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 711, Taiwan
| | - Ming-Jung Liu
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan 711, Taiwan; Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan.
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Sasaki S, Murakami T, Yasumuro M, Makita A, Oi Y, Hiragori Y, Watanabe S, Kudo R, Hayashi N, Ohbayashi I, Sugiyama M, Yamashita Y, Naito S, Onouchi H. Upstream open reading frame-mediated upregulation of ANAC082 expression in response to nucleolar stress in Arabidopsis. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2023; 40:21-30. [PMID: 38213914 PMCID: PMC10777128 DOI: 10.5511/plantbiotechnology.22.1215a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 12/15/2022] [Indexed: 01/13/2024]
Abstract
Perturbations in ribosome biogenesis cause a type of cellular stress called nucleolar or ribosomal stress, which triggers adaptive responses in both animal and plant cells. The Arabidopsis ANAC082 transcription factor has been identified as a key mediator of the plant nucleolar stress response. The 5'-untranslated region (5'-UTR) of ANAC082 mRNA contains an upstream ORF (uORF) encoding an evolutionarily conserved amino acid sequence. Here, we report that this uORF mediates the upregulation of ANAC082 expression in response to nucleolar stress. When transgenic Arabidopsis plants containing a luciferase reporter gene under the control of the ANAC082 promoter and 5'-UTR were treated with reagents that induced nucleolar stress, expression of the reporter gene was enhanced in a uORF sequence-dependent manner. Additionally, we examined the effect of an endoplasmic reticulum (ER) stress-inducing reagent on reporter gene expression because the closest homolog of ANAC082 in Arabidopsis, ANAC103, is involved in the ER stress response. However, the ANAC082 uORF did not respond to ER stress. Interestingly, although ANAC103 has a uORF with an amino acid sequence similar to that of the ANAC082 uORF, the C-terminal sequence critical for regulation is not well conserved among ANAC103 homologs in Brassicaceae. Transient expression assays revealed that unlike the ANAC082 uORF, the ANAC103 uORF does not exert a sequence-dependent repressive effect. Altogether, our findings suggest that the ANAC082 uORF is important for the nucleolar stress response but not for the ER stress response, and that for this reason, the uORF sequence-dependent regulation was lost in ANAC103 during evolution.
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Affiliation(s)
- Shun Sasaki
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Toru Murakami
- Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Miharu Yasumuro
- Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Ayaka Makita
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Yutaro Oi
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Yuta Hiragori
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Shun Watanabe
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Rin Kudo
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Noriya Hayashi
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Iwai Ohbayashi
- Department of Life Sciences, National Cheng Kung University, Tainan 701, Taiwan R.O.C
- Institute of Tropical Plant Sciences and Microbiology, National Cheng Kung University, Tainan 701, Taiwan R.O.C
| | - Munetaka Sugiyama
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yui Yamashita
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
| | - Satoshi Naito
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
- Graduate School of Life Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Hitoshi Onouchi
- Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
- Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan
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Son S, Park SR. Plant translational reprogramming for stress resilience. FRONTIERS IN PLANT SCIENCE 2023; 14:1151587. [PMID: 36909402 PMCID: PMC9998923 DOI: 10.3389/fpls.2023.1151587] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
Organisms regulate gene expression to produce essential proteins for numerous biological processes, from growth and development to stress responses. Transcription and translation are the major processes of gene expression. Plants evolved various transcription factors and transcriptome reprogramming mechanisms to dramatically modulate transcription in response to environmental cues. However, even the genome-wide modulation of a gene's transcripts will not have a meaningful effect if the transcripts are not properly biosynthesized into proteins. Therefore, protein translation must also be carefully controlled. Biotic and abiotic stresses threaten global crop production, and these stresses are seriously deteriorating due to climate change. Several studies have demonstrated improved plant resistance to various stresses through modulation of protein translation regulation, which requires a deep understanding of translational control in response to environmental stresses. Here, we highlight the translation mechanisms modulated by biotic, hypoxia, heat, and drought stresses, which are becoming more serious due to climate change. This review provides a strategy to improve stress tolerance in crops by modulating translational regulation.
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Lokdarshi A, von Arnim AG, Akuoko TK. Modulation of GCN2 activity under excess light stress by osmoprotectants and amino acids. PLANT SIGNALING & BEHAVIOR 2022; 17:2115747. [PMID: 36093942 PMCID: PMC9481134 DOI: 10.1080/15592324.2022.2115747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
The protein kinase GCN2 (General Control Nonderepressible2) and its phosphorylation target, the eukaryotic translation initiation factor (eIF)2α represent the core module of the plant's integrated stress response, a signaling pathway widely conserved in eukaryotes that can rapidly regulate translation in response to stressful conditions. Recent findings indicate that the Arabidopsis thaliana GCN2 protein operates under the command of reactive oxygen species (ROS) emanating from the chloroplast under a variety of abiotic stresses such as excess light. To get deeper insights into the mechanism of GCN2 activation under excess light, we assessed the role of amino acids in view of the classic function of GCN2 as a sensor of amino acid status. Additionally, given that osmoprotectants can counteract ROS-related stresses, we tested their ability to mitigate GCN2 activity. Our results demonstrate that certain amino acids and osmoprotectants attenuate eIF2α-phosphorylation under excess light stress to some degree. Future investigations into the biochemical mechanisms of these natural compounds on GCN2 signaling activity will provide better insights into the GCN2-eIF2α regulation.
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Affiliation(s)
- Ansul Lokdarshi
- Department of Biology, Valdosta State University, Valdosta, GA, USA
| | - Albrecht G von Arnim
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
- UT-ORNL Graduate School of Genome Science and Technology, the University of Tennessee, Knoxville, TN, USA
| | - Teressa K Akuoko
- Department of Biology, Valdosta State University, Valdosta, GA, USA
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