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Imamichi T, Kusumoto N, Aoyama H, Takamatsu S, Honda Y, Muraoka S, Hagiwara-Komoda Y, Chiba Y, Onouchi H, Yamashita Y, Naito S. Phylogeny-linked occurrence of ribosome stalling on the mRNAs of Arabidopsis unfolded protein response factor bZIP60 orthologs in divergent plant species. Nucleic Acids Res 2024; 52:4276-4294. [PMID: 38366760 PMCID: PMC11077094 DOI: 10.1093/nar/gkae101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 01/28/2024] [Accepted: 02/01/2024] [Indexed: 02/18/2024] Open
Abstract
The bZIP60, XBP1 and HAC1 mRNAs encode transcription factors that mediate the unfolded protein response (UPR) in plants, animals and yeasts, respectively. Upon UPR, these mRNAs undergo unconventional cytoplasmic splicing on the endoplasmic reticulum (ER) to produce active transcription factors. Although cytoplasmic splicing is conserved, the ER targeting mechanism differs between XBP1 and HAC1. The ER targeting of HAC1 mRNA occurs before translation, whereas that of XBP1 mRNA involves a ribosome-nascent chain complex that is stalled when a hydrophobic peptide emerges from the ribosome; the corresponding mechanism is unknown for bZIP60. Here, we analyzed ribosome stalling on bZIP60 orthologs of plants. Using a cell-free translation system, we detected nascent peptide-mediated ribosome stalling during the translation elongation of the mRNAs of Arabidopsis, rice and Physcomitrium (moss) orthologs, and the termination-step stalling in the Selaginella (lycopod) ortholog, all of which occurred ∼50 amino acids downstream of a hydrophobic region. Transfection experiments showed that ribosome stalling contributes to cytoplasmic splicing in bZIP60u orthologs of Arabidopsis and Selaginella. In contrast, ribosome stalling was undetectable for liverwort, Klebsormidium (basal land plant), and green algae orthologs. This study highlights the evolutionary diversity of ribosome stalling and its contribution to ER targeting in plants.
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Affiliation(s)
- Tomoya Imamichi
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Nao Kusumoto
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Haruka Aoyama
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Seidai Takamatsu
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Yugo Honda
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Shiori Muraoka
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Yuka Hagiwara-Komoda
- Department of Sustainable Agriculture, Rakuno Gakuen University, Ebetsu 069-8501, Japan
| | - Yukako Chiba
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
- Division of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Hitoshi Onouchi
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
- Research Group of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Yui Yamashita
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
- Research Group of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Satoshi Naito
- Frontiers in Biosciences, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
- Division of Life Science, Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan
- Research Group of Applied Bioscience, Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
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Ma J, Dissanayaka Mudiyanselage SD, Hao J, Wang Y. Cellular roadmaps of viroid infection. Trends Microbiol 2023; 31:1179-1191. [PMID: 37349206 PMCID: PMC10592528 DOI: 10.1016/j.tim.2023.05.014] [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: 03/16/2023] [Revised: 05/28/2023] [Accepted: 05/31/2023] [Indexed: 06/24/2023]
Abstract
Viroids are single-stranded circular noncoding RNAs that infect plants. According to the International Committee on Taxonomy of Viruses, there are 44 viroids known to date. Notably, more than 20 000 distinct viroid-like RNA sequences have recently been identified in existing sequencing datasets, suggesting an unprecedented complexity in biological roles of viroids and viroid-like RNAs. Interestingly, a human pathogen, hepatitis delta virus (HDV), also replicates via a rolling circle mechanism like viroids. Therefore, knowledge of viroid infection is informative for research on HDV and other viroid-like RNAs reported from various organisms. Here, we summarize recent advancements in understanding viroid shuttling among subcellular compartments for completing replication cycles, emphasizing regulatory roles of RNA motifs and structural dynamics in diverse biological processes. We also compare the knowledge of viroid intracellular trafficking with known pathways governing cellular RNA movement in cells. Future investigations on regulatory RNA structures and cognate factors in regulating viroid subcellular trafficking and replication will likely provide new insights into RNA structure-function relationships and facilitate the development of strategies controlling RNA localization and function in cells.
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Affiliation(s)
- Junfei Ma
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA; Current address: Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA
| | | | - Jie Hao
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA; Current address: Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA
| | - Ying Wang
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA; Current address: Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA.
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