1
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Small I, Melonek J, Bohne AV, Nickelsen J, Schmitz-Linneweber C. Plant organellar RNA maturation. THE PLANT CELL 2023; 35:1727-1751. [PMID: 36807982 PMCID: PMC10226603 DOI: 10.1093/plcell/koad049] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/05/2023] [Accepted: 01/17/2023] [Indexed: 05/30/2023]
Abstract
Plant organellar RNA metabolism is run by a multitude of nucleus-encoded RNA-binding proteins (RBPs) that control RNA stability, processing, and degradation. In chloroplasts and mitochondria, these post-transcriptional processes are vital for the production of a small number of essential components of the photosynthetic and respiratory machinery-and consequently for organellar biogenesis and plant survival. Many organellar RBPs have been functionally assigned to individual steps in RNA maturation, often specific to selected transcripts. While the catalog of factors identified is ever-growing, our knowledge of how they achieve their functions mechanistically is far from complete. This review summarizes the current knowledge of plant organellar RNA metabolism taking an RBP-centric approach and focusing on mechanistic aspects of RBP functions and the kinetics of the processes they are involved in.
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Affiliation(s)
- Ian Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley 6009, Australia
| | - Joanna Melonek
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley 6009, Australia
| | | | - Jörg Nickelsen
- Department of Molecular Plant Sciences, LMU Munich, 82152 Martinsried, Germany
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2
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Ghandour R, Gao Y, Laskowski J, Barahimipour R, Ruf S, Bock R, Zoschke R. Transgene insertion into the plastid genome alters expression of adjacent native chloroplast genes at the transcriptional and translational levels. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:711-725. [PMID: 36529916 PMCID: PMC10037153 DOI: 10.1111/pbi.13985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 11/14/2022] [Accepted: 12/13/2022] [Indexed: 06/17/2023]
Abstract
In plant biotechnology and basic research, chloroplasts have been used as chassis for the expression of various transgenes. However, potential unintended side effects of transgene insertion and high-level transgene expression on the expression of native chloroplast genes are often ignored and have not been studied comprehensively. Here, we examined expression of the chloroplast genome at both the transcriptional and translational levels in five transplastomic tobacco (Nicotiana tabacum) lines carrying the identical aadA resistance marker cassette in diverse genomic positions. Although none of the lines exhibits a pronounced visible phenotype, the analysis of three lines that contain the aadA insertion in different locations within the petL-petG-psaJ-rpl33-rps18 transcription unit demonstrates that transcriptional read-through from the aadA resistance marker is unavoidable, and regularly causes overexpression of downstream sense-oriented chloroplast genes at the transcriptional and translational levels. Investigation of additional lines that harbour the aadA intergenically and outside of chloroplast transcription units revealed that expression of the resistance marker can also cause antisense effects by interference with transcription/transcript accumulation and/or translation of downstream antisense-oriented genes. In addition, we provide evidence for a previously suggested role of genomically encoded tRNAs in chloroplast transcription termination and/or transcript processing. Together, our data uncover principles of neighbouring effects of chloroplast transgenes and suggest general strategies for the choice of transgene insertion sites and expression elements to minimize unintended consequences of transgene expression on the transcription and translation of native chloroplast genes.
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Affiliation(s)
- Rabea Ghandour
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Yang Gao
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | | | | | - Stephanie Ruf
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Reimo Zoschke
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
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3
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Yang T, Sahu SK, Yang L, Liu Y, Mu W, Liu X, Strube ML, Liu H, Zhong B. Comparative Analyses of 3,654 Plastid Genomes Unravel Insights Into Evolutionary Dynamics and Phylogenetic Discordance of Green Plants. FRONTIERS IN PLANT SCIENCE 2022; 13:808156. [PMID: 35498716 PMCID: PMC9038950 DOI: 10.3389/fpls.2022.808156] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/07/2022] [Indexed: 05/03/2023]
Abstract
The plastid organelle is essential for many vital cellular processes and the growth and development of plants. The availability of a large number of complete plastid genomes could be effectively utilized to understand the evolution of the plastid genomes and phylogenetic relationships among plants. We comprehensively analyzed the plastid genomes of Viridiplantae comprising 3,654 taxa from 298 families and 111 orders and compared the genomic organizations in their plastid genomic DNA among major clades, which include gene gain/loss, gene copy number, GC content, and gene blocks. We discovered that some important genes that exhibit similar functions likely formed gene blocks, such as the psb family presumably showing co-occurrence and forming gene blocks in Viridiplantae. The inverted repeats (IRs) in plastid genomes have doubled in size across land plants, and their GC content is substantially higher than non-IR genes. By employing three different data sets [all nucleotide positions (nt123), only the first and second codon positions (nt12), and amino acids (AA)], our phylogenomic analyses revealed Chlorokybales + Mesostigmatales as the earliest-branching lineage of streptophytes. Hornworts, mosses, and liverworts forming a monophylum were identified as the sister lineage of tracheophytes. Based on nt12 and AA data sets, monocots, Chloranthales and magnoliids are successive sister lineages to the eudicots + Ceratophyllales clade. The comprehensive taxon sampling and analysis of different data sets from plastid genomes recovered well-supported relationships of green plants, thereby contributing to resolving some long-standing uncertainties in the plant phylogeny.
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Affiliation(s)
- Ting Yang
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Sunil Kumar Sahu
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
- *Correspondence: Sunil Kumar Sahu,
| | - Lingxiao Yang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Yang Liu
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
| | - Weixue Mu
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
| | - Xin Liu
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
| | - Mikael Lenz Strube
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Huan Liu
- Beijing Genomics Institute Shenzhen, Yantian Beishan Industrial Zone, Shenzhen, China
- State Key Laboratory of Agricultural Genomics, Beijing Genomics Institute Shenzhen, Shenzhen, China
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Bojian Zhong
- College of Life Sciences, Nanjing Normal University, Nanjing, China
- Bojian Zhong,
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4
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Oliver T, Sánchez-Baracaldo P, Larkum AW, Rutherford AW, Cardona T. Time-resolved comparative molecular evolution of oxygenic photosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2021; 1862:148400. [PMID: 33617856 PMCID: PMC8047818 DOI: 10.1016/j.bbabio.2021.148400] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 02/01/2021] [Accepted: 02/12/2021] [Indexed: 12/15/2022]
Abstract
Oxygenic photosynthesis starts with the oxidation of water to O2, a light-driven reaction catalysed by photosystem II. Cyanobacteria are the only prokaryotes capable of water oxidation and therefore, it is assumed that the origin of oxygenic photosynthesis is a late innovation relative to the origin of life and bioenergetics. However, when exactly water oxidation originated remains an unanswered question. Here we use phylogenetic analysis to study a gene duplication event that is unique to photosystem II: the duplication that led to the evolution of the core antenna subunits CP43 and CP47. We compare the changes in the rates of evolution of this duplication with those of some of the oldest well-described events in the history of life: namely, the duplication leading to the Alpha and Beta subunits of the catalytic head of ATP synthase, and the divergence of archaeal and bacterial RNA polymerases and ribosomes. We also compare it with more recent events such as the duplication of Cyanobacteria-specific FtsH metalloprotease subunits and the radiation leading to Margulisbacteria, Sericytochromatia, Vampirovibrionia, and other clades containing anoxygenic phototrophs. We demonstrate that the ancestral core duplication of photosystem II exhibits patterns in the rates of protein evolution through geological time that are nearly identical to those of the ATP synthase, RNA polymerase, or the ribosome. Furthermore, we use ancestral sequence reconstruction in combination with comparative structural biology of photosystem subunits, to provide additional evidence supporting the premise that water oxidation had originated before the ancestral core duplications. Our work suggests that photosynthetic water oxidation originated closer to the origin of life and bioenergetics than can be documented based on phylogenetic or phylogenomic species trees alone.
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Affiliation(s)
- Thomas Oliver
- Department of Life Sciences, Imperial College London, London, UK
| | | | | | | | - Tanai Cardona
- Department of Life Sciences, Imperial College London, London, UK.
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5
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Fu HY, Ghandour R, Ruf S, Zoschke R, Bock R, Schöttler MA. The availability of neither D2 nor CP43 limits the biogenesis of photosystem II in tobacco. PLANT PHYSIOLOGY 2021; 185:1111-1130. [PMID: 33793892 PMCID: PMC8133689 DOI: 10.1093/plphys/kiaa052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
The pathway of photosystem II (PSII) assembly is well understood, and multiple auxiliary proteins supporting it have been identified, but little is known about rate-limiting steps controlling PSII biogenesis. In the cyanobacterium Synechocystis PCC6803 and the green alga Chlamydomonas reinhardtii, indications exist that the biosynthesis of the chloroplast-encoded D2 reaction center subunit (PsbD) limits PSII accumulation. To determine the importance of D2 synthesis for PSII accumulation in vascular plants and elucidate the contributions of transcriptional and translational regulation, we modified the 5'-untranslated region of psbD via chloroplast transformation in tobacco (Nicotiana tabacum). A drastic reduction in psbD mRNA abundance resulted in a strong decrease in PSII content, impaired photosynthetic electron transport, and retarded growth under autotrophic conditions. Overexpression of the psbD mRNA also increased transcript abundance of psbC (the CP43 inner antenna protein), which is co-transcribed with psbD. Because translation efficiency remained unaltered, translation output of pbsD and psbC increased with mRNA abundance. However, this did not result in increased PSII accumulation. The introduction of point mutations into the Shine-Dalgarno-like sequence or start codon of psbD decreased translation efficiency without causing pronounced effects on PSII accumulation and function. These data show that neither transcription nor translation of psbD and psbC are rate-limiting for PSII biogenesis in vascular plants and that PSII assembly and accumulation in tobacco are controlled by different mechanisms than in cyanobacteria or in C. reinhardtii.
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Affiliation(s)
- Han-Yi Fu
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Rabea Ghandour
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Stephanie Ruf
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Reimo Zoschke
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Mark Aurel Schöttler
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
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6
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Yu Q, Tungsuchat-Huang T, Verma K, Radler MR, Maliga P. Independent translation of ORFs in dicistronic operons, synthetic building blocks for polycistronic chloroplast gene expression. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:2318-2329. [PMID: 32497322 DOI: 10.1111/tpj.14864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 05/13/2020] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
We designed a dicistronic plastid marker system that relies on the plastid's ability to translate polycistronic mRNAs. The identification of transplastomic clones is based on selection for antibiotic resistance encoded in the first open reading frame (ORF) and accumulation of the reporter gene product in tobacco chloroplasts encoded in the second ORF. The antibiotic resistance gene may encode spectinomycin or kanamycin resistance based on the expression of aadA or neo genes, respectively. The reporter gene used in the study is the green fluorescent protein (GFP). The mRNA level depends on the 5'-untranslated region of the first ORF. The protein output depends on the strengths of the ribosome binding, and is proportional with the level of translatable mRNA. Because the dicistronic mRNA is not processed, we could show that protein output from the second ORF is independent from the first ORF. High-level GFP accumulation from the second ORF facilitates identification of transplastomic events under ultraviolet light. Expression of multiple proteins from an unprocessed mRNA is an experimental design that enables predictable protein output from polycistronic mRNAs, expanding the toolkit of plant synthetic biology.
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Affiliation(s)
- Qiguo Yu
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA
| | | | - Kanak Verma
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Megan R Radler
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Pal Maliga
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ, 08854, USA
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, 08901, USA
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7
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Hamsher SE, Keepers KG, Pogoda CS, Stepanek JG, Kane NC, Kociolek JP. Extensive chloroplast genome rearrangement amongst three closely related Halamphora spp. (Bacillariophyceae), and evidence for rapid evolution as compared to land plants. PLoS One 2019; 14:e0217824. [PMID: 31269054 PMCID: PMC6608930 DOI: 10.1371/journal.pone.0217824] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 05/21/2019] [Indexed: 01/08/2023] Open
Abstract
Diatoms are the most diverse lineage of algae, but the diversity of their chloroplast genomes, particularly within a genus, has not been well documented. Herein, we present three chloroplast genomes from the genus Halamphora (H. americana, H. calidilacuna, and H. coffeaeformis), the first pennate diatom genus to be represented by more than one species. Halamphora chloroplast genomes ranged in size from ~120 to 150 kb, representing a 24% size difference within the genus. Differences in genome size were due to changes in the length of the inverted repeat region, length of intergenic regions, and the variable presence of ORFs that appear to encode as-yet-undescribed proteins. All three species shared a set of 161 core features but differed in the presence of two genes, serC and tyrC of foreign and unknown origin, respectively. A comparison of these data to three previously published chloroplast genomes in the non-pennate genus Cyclotella (Thalassiosirales) revealed that Halamphora has undergone extensive chloroplast genome rearrangement compared to other genera, as well as containing variation within the genus. Finally, a comparison of Halamphora chloroplast genomes to those of land plants indicates diatom chloroplast genomes within this genus may be evolving at least ~4–7 times faster than those of land plants. Studies such as these provide deeper insights into diatom chloroplast evolution and important genetic resources for future analyses.
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Affiliation(s)
- Sarah E. Hamsher
- Department of Biology, Grand Valley State University, Allendale, Michigan, United States of America
- Annis Water Resources Institute, Grand Valley State University, Muskegon, Michigan, United States of America
- * E-mail:
| | - Kyle G. Keepers
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, United States of America
| | - Cloe S. Pogoda
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, United States of America
| | - Joshua G. Stepanek
- Department of Biology, Colorado Mountain College, Edwards, Colorado, United States of America
| | - Nolan C. Kane
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, United States of America
| | - J. Patrick Kociolek
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, United States of America
- Museum of Natural History, University of Colorado, Boulder, Colorado, United States of America
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8
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Wang L, Zhang H, Jiang M, Chen H, Huang L, Liu C. Complete plastome sequence of Iodes cirrhosa Turcz., the first in the Icacinaceae, comparative genomic analyses and possible split of Idoes species in response to climate changes. PeerJ 2019; 7:e6663. [PMID: 30972252 PMCID: PMC6448556 DOI: 10.7717/peerj.6663] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 02/20/2019] [Indexed: 11/20/2022] Open
Abstract
Plastome-based phylogenetic study has largely resolved the phylogeny of Icacinaceae. However, no single complete plastome sequence is available for Icacinaceae species, thereby limiting the further phylogenomics analysis of the members of this family. Here, we obtained the complete plastome sequence of Iodes cirrhosa Turcz., which is the first in Icacinaceae, by using the next-generation sequencing technology. The genome was annotated and compared with other closely related plastomes by using mVISTA. The divergence time of six Iodes species was analyzed using the BEAST software. The plastome of I. cirrhosa was 151,994 bp long, with a pair of inverted repeats (IRs, 24,973 bp) separated by a large single-copy (LSC, 84,527 bp) region and a small single-copy (SSC, 17,521 bp) region. The plastome encoded 112 unique genes, including 80 protein-coding, 28 tRNA, and four rRNA genes. Approximately 59 repeat sequences and 188 simple sequence repeats were identified. Four pairs of partially overlapped genes, namely, psbD/psbC, ndhF/Ψycf1, atpB/atpE, and rpl22/rps3, were observed. A comparison of the boundaries of the LSC, SSC, and IR regions with four other plastomes from Aquifoliales and Sapindales exhibited a high overall degree of sequence similarity. Four most highly variable regions, namely, trnH-GUG/psbA, psbM/trnD-GUC, petA/psbJ, and rps16/trnQ-UUG, were found. Using the plastome of I. cirrhosa as reference, we reassembled the plastomes of five Iodes species. K a/K s ratio analyses revealed that 27 genes and 52 amino acid residue sites from 11 genes had undergone strong positive selection in the Iodes branch, with the most abundant proteins being the NDH and ribosomal proteins. Divergence-time analysis indicated that Iodes species were first formed 34.40 million years ago. Results revealed that the ancestor of the six species was likely to have split in the late Eocene epoch. In summary, the first complete plastome sequence of I. cirrhosa provided valuable information regarding the evolutionary processes of Iodes species.
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Affiliation(s)
- Liqiang Wang
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine from Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui Zhang
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine from Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Mei Jiang
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine from Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Haimei Chen
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine from Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Linfang Huang
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine from Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chang Liu
- Key Laboratory of Bioactive Substances and Resource Utilization of Chinese Herbal Medicine from Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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9
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Khan AL, Asaf S, Lee IJ, Al-Harrasi A, Al-Rawahi A. First chloroplast genomics study of Phoenix dactylifera (var. Naghal and Khanezi): A comparative analysis. PLoS One 2018; 13:e0200104. [PMID: 30063732 PMCID: PMC6067692 DOI: 10.1371/journal.pone.0200104] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 06/19/2018] [Indexed: 12/16/2022] Open
Abstract
Date palm (Phoenix dactylifera L.) is one of the oldest fruit crops in the arid regions of the Middle East. However, little information is available regarding its plastid genomes. In this study, we sequenced the chloroplast (cp) genomes of two economically important but genomically unexplored date palm cultivars of Phoenix dactylifera (var. Naghal and Khanezi). The data assembly and genome annotation revealed a typical quadripartite structure similar to Arecaceae, and the genome sizes of Naghal and Khanezi were 158,210 bp and 158,211 bp, respectively. Structurally, both cp genomes were comprised of four regions: a pair of inverted repeats (27,273 bp for Khanezi and for Naghal 27,272 bp), a large single-copy region (86,090 bp and 86,092 bp) and a small single-copy region (17,575 bp and 17,574 bp). Both genomes had 138 representative genes, whereas 227 and 229 randomly distributed microsatellites were also observed in Khanezi and Naghal, respectively. Phylogenetic analysis based on the whole cp genomes and 68 shared genes showed identical phylogenetic trees of Khanezi and Naghal forming clades with Khalas and Aseel cultivars, respectively. The current study showed detailed comparative cp genome analysis, which could be essential for broader population genetics and molecular studies of these four date palm cultivars.
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Affiliation(s)
- Abdul Latif Khan
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa, Oman
| | - Sajjad Asaf
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa, Oman
| | - In-Jung Lee
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - Ahmed Al-Harrasi
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa, Oman
| | - Ahmed Al-Rawahi
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa, Oman
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10
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Zoschke R, Bock R. Chloroplast Translation: Structural and Functional Organization, Operational Control, and Regulation. THE PLANT CELL 2018; 30:745-770. [PMID: 29610211 PMCID: PMC5969280 DOI: 10.1105/tpc.18.00016] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/26/2018] [Accepted: 04/01/2018] [Indexed: 05/20/2023]
Abstract
Chloroplast translation is essential for cellular viability and plant development. Its positioning at the intersection of organellar RNA and protein metabolism makes it a unique point for the regulation of gene expression in response to internal and external cues. Recently obtained high-resolution structures of plastid ribosomes, the development of approaches allowing genome-wide analyses of chloroplast translation (i.e., ribosome profiling), and the discovery of RNA binding proteins involved in the control of translational activity have greatly increased our understanding of the chloroplast translation process and its regulation. In this review, we provide an overview of the current knowledge of the chloroplast translation machinery, its structure, organization, and function. In addition, we summarize the techniques that are currently available to study chloroplast translation and describe how translational activity is controlled and which cis-elements and trans-factors are involved. Finally, we discuss how translational control contributes to the regulation of chloroplast gene expression in response to developmental, environmental, and physiological cues. We also illustrate the commonalities and the differences between the chloroplast and bacterial translation machineries and the mechanisms of protein biosynthesis in these two prokaryotic systems.
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Affiliation(s)
- Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
| | - Ralph Bock
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
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11
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Stable Membrane-Association of mRNAs in Etiolated, Greening and Mature Plastids. Int J Mol Sci 2017; 18:ijms18091881. [PMID: 28858216 PMCID: PMC5618530 DOI: 10.3390/ijms18091881] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 08/25/2017] [Accepted: 08/28/2017] [Indexed: 12/24/2022] Open
Abstract
Chloroplast genes are transcribed as polycistronic precursor RNAs that give rise to a multitude of processing products down to monocistronic forms. Translation of these mRNAs is realized by bacterial type 70S ribosomes. A larger fraction of these ribosomes is attached to chloroplast membranes. This study analyzed transcriptome-wide distribution of plastid mRNAs between soluble and membrane fractions of purified plastids using microarray analyses and validating RNA gel blot hybridizations. To determine the impact of light on mRNA localization, we used etioplasts, greening plastids and mature chloroplasts from Zea mays as a source for membrane and soluble extracts. The results show that the three plastid types display an almost identical distribution of RNAs between the two organellar fractions, which is confirmed by quantitative RNA gel blot analyses. Furthermore, they reveal that different RNAs processed from polycistronic precursors show transcript-autonomous distribution between stroma and membrane fractions. Disruption of ribosomes leads to release of mRNAs from membranes, demonstrating that attachment is likely a direct consequence of translation. We conclude that plastid mRNA distribution is a stable feature of different plastid types, setting up rapid chloroplast translation in any plastid type.
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12
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Asaf S, Khan AL, Aaqil Khan M, Muhammad Imran Q, Kang SM, Al-Hosni K, Jeong EJ, Lee KE, Lee IJ. Comparative analysis of complete plastid genomes from wild soybean (Glycine soja) and nine other Glycine species. PLoS One 2017; 12:e0182281. [PMID: 28763486 PMCID: PMC5538705 DOI: 10.1371/journal.pone.0182281] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 07/14/2017] [Indexed: 11/19/2022] Open
Abstract
The plastid genomes of different plant species exhibit significant variation, thereby providing valuable markers for exploring evolutionary relationships and population genetics. Glycine soja (wild soybean) is recognized as the wild ancestor of cultivated soybean (G. max), representing a valuable genetic resource for soybean breeding programmes. In the present study, the complete plastid genome of G. soja was sequenced using Illumina paired-end sequencing and then compared it for the first time with previously reported plastid genome sequences from nine other Glycine species. The G. soja plastid genome was 152,224 bp in length and possessed a typical quadripartite structure, consisting of a pair of inverted repeats (IRa/IRb; 25,574 bp) separated by small (178,963 bp) and large (83,181 bp) single-copy regions, with a 51-kb inversion in the large single-copy region. The genome encoded 134 genes, including 87 protein-coding genes, eight ribosomal RNA genes, and 39 transfer RNA genes, and possessed 204 randomly distributed microsatellites, including 15 forward, 25 tandem, and 34 palindromic repeats. Whole-plastid genome comparisons revealed an overall high degree of sequence similarity between G. max and G. gracilis and some divergence in the intergenic spacers of other species. Greater numbers of indels and SNP substitutions were observed compared with G. cyrtoloba. The sequence of the accD gene from G. soja was highly divergent from those of the other species except for G. max and G. gracilis. Phylogenomic analyses of the complete plastid genomes and 76 shared genes yielded an identical topology and indicated that G. soja is closely related to G. max and G. gracilis. The complete G. soja genome sequenced in the present study is a valuable resource for investigating the population and evolutionary genetics of Glycine species and can be used to identify related species.
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Affiliation(s)
- Sajjad Asaf
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - Abdul Latif Khan
- Chair of Oman's Medicinal Plants & Marine Natural Products, University of Nizwa, Nizwa, Oman
| | - Muhammad Aaqil Khan
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - Qari Muhammad Imran
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - Sang-Mo Kang
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - Khdija Al-Hosni
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - Eun Ju Jeong
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - Ko Eun Lee
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
| | - In-Jung Lee
- School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea
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Martin Avila E, Gisby MF, Day A. Seamless editing of the chloroplast genome in plants. BMC PLANT BIOLOGY 2016; 16:168. [PMID: 27474038 PMCID: PMC4966725 DOI: 10.1186/s12870-016-0857-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 07/20/2016] [Indexed: 05/13/2023]
Abstract
BACKGROUND Gene editing technologies enable the precise insertion of favourable mutations and performance enhancing trait genes into chromosomes whilst excluding all excess DNA from modified genomes. The technology gives rise to a new class of biotech crops which is likely to have widespread applications in agriculture. Despite progress in the nucleus, the seamless insertions of point mutations and non-selectable foreign genes into the organelle genomes of crops have not been described. The chloroplast genome is an attractive target to improve photosynthesis and crop performance. Current chloroplast genome engineering technologies for introducing point mutations into native chloroplast genes leave DNA scars, such as the target sites for recombination enzymes. Seamless editing methods to modify chloroplast genes need to address reversal of site-directed point mutations by template mediated repair with the vast excess of wild type chloroplast genomes that are present early in the transformation process. RESULTS Using tobacco, we developed an efficient two-step method to edit a chloroplast gene by replacing the wild type sequence with a transient intermediate. This was resolved to the final edited gene by recombination between imperfect direct repeats. Six out of 11 transplastomic plants isolated contained the desired intermediate and at the second step this was resolved to the edited chloroplast gene in five of six plants tested. Maintenance of a single base deletion mutation in an imperfect direct repeat of the native chloroplast rbcL gene showed the limited influence of biased repair back to the wild type sequence. The deletion caused a frameshift, which replaced the five C-terminal amino acids of the Rubisco large subunit with 16 alternative residues resulting in a ~30-fold reduction in its accumulation. We monitored the process in vivo by engineering an overlapping gusA gene downstream of the edited rbcL gene. Translational coupling between the overlapping rbcL and gusA genes resulted in relatively high GUS accumulation (~0.5 % of leaf protein). CONCLUSIONS Editing chloroplast genomes using transient imperfect direct repeats provides an efficient method for introducing point mutations into chloroplast genes. Moreover, we describe the first synthetic operon allowing expression of a downstream overlapping gene by translational coupling in chloroplasts. Overlapping genes provide a new mechanism for co-ordinating the translation of foreign proteins in chloroplasts.
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Affiliation(s)
- Elena Martin Avila
- Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT UK
- Present address: Research School of Biology, The Australian National University, Acton, ACT 2601 Australia
| | - Martin F. Gisby
- Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT UK
| | - Anil Day
- Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT UK
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Nakamura M, Hibi Y, Okamoto T, Sugiura M. Cooperation between the chloroplast psbA 5'-untranslated region and coding region is important for translational initiation: the chloroplast translation machinery cannot read a human viral gene coding region. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:772-80. [PMID: 26931095 DOI: 10.1111/tpj.13150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 02/15/2016] [Accepted: 02/17/2016] [Indexed: 06/05/2023]
Abstract
Chloroplast mRNA translation is regulated by the 5'-untranslated region (5'-UTR). Chloroplast 5'-UTRs also support translation of the coding regions of heterologous genes. Using an in vitro translation system from tobacco chloroplasts, we detected no translation from a human immunodeficiency virus tat coding region fused directly to the tobacco chloroplast psbA 5'-UTR. This lack of apparent translation could have been due to rapid degradation of mRNA templates or synthesized protein products. Replacing the psbA 5'-UTR with the E. coli phage T7 gene 10 5'-UTR, a highly active 5'-UTR, and substituting synonymous codons led to some translation of the tat coding region. The Tat protein thus synthesized was stable during translation reactions. No significant degradation of the added tat mRNAs was observed after translation reactions. These results excluded the above two possibilities and confirmed that the tat coding region prevented its own translation. The tat coding region was then fused to the psbA 5'-UTR with a cognate 5'-coding segment. Significant translation was detected from the tat coding region when fused after 10 or more codons. That is, translation could be initiated from the tat coding region once translation had started, indicating that the tat coding region inhibits translational initiation but not elongation. Hence, cooperation/compatibility between the 5'-UTR and its coding region is important for translational initiation.
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Affiliation(s)
- Masayuki Nakamura
- Graduate School of Natural Sciences, Nagoya City University, Yamanohata, Mizuho-ku, Nagoya, 467-8501, Japan
| | - Yurina Hibi
- Department of Molecular and Cellular Biology, Graduate School of Medical Sciences, Nagoya City University, Kawasumi, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Takashi Okamoto
- Department of Molecular and Cellular Biology, Graduate School of Medical Sciences, Nagoya City University, Kawasumi, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Masahiro Sugiura
- Graduate School of Natural Sciences, Nagoya City University, Yamanohata, Mizuho-ku, Nagoya, 467-8501, Japan
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15
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Liang C, Cheng S, Zhang Y, Sun Y, Fernie AR, Kang K, Panagiotou G, Lo C, Lim BL. Transcriptomic, proteomic and metabolic changes in Arabidopsis thaliana leaves after the onset of illumination. BMC PLANT BIOLOGY 2016; 16:43. [PMID: 26865323 PMCID: PMC4750186 DOI: 10.1186/s12870-016-0726-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 01/28/2016] [Indexed: 05/19/2023]
Abstract
BACKGROUND Light plays an important role in plant growth and development. In this study, the impact of light on physiology of 20-d-old Arabidopsis leaves was examined through transcriptomic, proteomic and metabolomic analysis. Since the energy-generating electron transport chains in chloroplasts and mitochondria are encoded by both nuclear and organellar genomes, sequencing total RNA after removal of ribosomal RNAs provides essential information on transcription of organellar genomes. The changes in the levels of ADP, ATP, NADP(+), NADPH and 41 metabolites upon illumination were also quantified. RESULTS Upon illumination, while the transcription of the genes encoded by the plastid genome did not change significantly, the transcription of nuclear genes encoding different functional complexes in the photosystem are differentially regulated whereas members of the same complex are co-regulated with each other. The abundance of mRNAs and proteins encoded by all three genomes are, however, not always positively correlated. One such example is the negative correlation between mRNA and protein abundances of the photosystem components, which reflects the importance of post-transcriptional regulation in plant physiology. CONCLUSION This study provides systems-wide datasets which allow plant researchers to examine the changes in leaf transcriptomes, proteomes and key metabolites upon illumination and to determine whether there are any correlations between changes in transcript and protein abundances of a particular gene or pathway upon illumination. The integration of data of the organelles and the photosystems, Calvin-Benson cycle, carbohydrate metabolism, glycolysis, the tricarboxylic acid cycle and respiratory chain, thereby provides a more complete picture to the changes in plant physiology upon illumination than has been attained to date.
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Affiliation(s)
- Chao Liang
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
| | - Shifeng Cheng
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
| | - Youjun Zhang
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
| | - Yuzhe Sun
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
| | - Alisdair R Fernie
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
| | - Kang Kang
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
| | - Gianni Panagiotou
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
| | - Clive Lo
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
| | - Boon Leong Lim
- School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China.
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
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16
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Kuroda H, Sugiura M. Processing of the 5'-UTR and existence of protein factors that regulate translation of tobacco chloroplast psbN mRNA. PLANT MOLECULAR BIOLOGY 2014; 86:585-93. [PMID: 25201100 DOI: 10.1007/s11103-014-0248-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/31/2014] [Indexed: 05/28/2023]
Abstract
The chloroplast psbB operon includes five genes encoding photosystem II and cytochrome b 6 /f complex components. The psbN gene is located on the opposite strand. PsbN is localized in the thylakoid and is present even in the dark, although its level increases upon illumination and then decreases. However, the translation mechanism of the psbN mRNA remains unclear. Using an in vitro translation system from tobacco chloroplasts and a green fluorescent protein as a reporter protein, we show that translation occurs from a tobacco primary psbN 5'-UTR of 47 nucleotides (nt). Unlike many other chloroplast 5'-UTRs, the psbN 5'-UTR has two processing sites, at -39 and -24 upstream from the initiation site. Processing at -39 enhanced the translation rate fivefold. In contrast, processing at -24 did not affect the translation rate. These observations suggest that the two distinct processing events regulate, at least in part, the level of PsbN during development. The psbN 5'-UTR has no Shine-Dalgarno (SD)-like sequence. In vitro translation assays with excess amounts of the psbN 5'-UTR or with deleted psbN 5'-UTR sequences demonstrated that protein factors are required for translation and that their binding site is an 18 nt sequence in the 5'-UTR. Mobility shift assays using 10 other chloroplast 5'-UTRs suggested that common or similar proteins are involved in translation of a set of mRNAs lacking SD-like sequences.
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Affiliation(s)
- Hiroshi Kuroda
- Graduate School of Natural Sciences, Nagoya City University, Yamanohata, Mizuho-ku, Nagoya, 467-8501, Japan,
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17
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Abstract
Overall translational machinery in plastids is similar to that of E. coli. Initiation is the crucial step for translation and this step in plastids is somewhat different from that of E. coli. Unlike the Shine-Dalgarno sequence in E. coli, cis-elements for translation initiation are not well conserved in plastid mRNAs. Specific trans-acting factors are generally required for translation initiation and its regulation in plastids. During translation elongation, ribosomes pause sometimes on photosynthesis-related mRNAs due probably to proper insertion of nascent polypeptides into membrane complexes. Codon usage of plastid mRNAs is different from that of E. coli and mammalian cells. Plastid mRNAs do not have the so-called rare codons. Translation efficiencies of several synonymous codons are not always correlated with codon usage in plastid mRNAs.
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Yukawa M, Sugiura M. Additional pathway to translate the downstream ndhK cistron in partially overlapping ndhC-ndhK mRNAs in chloroplasts. Proc Natl Acad Sci U S A 2013; 110:5701-6. [PMID: 23509265 PMCID: PMC3619338 DOI: 10.1073/pnas.1219914110] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The chloroplast NAD(P)H dehydrogenase (NDH) C (ndhC) and ndhK genes partially overlap and are cotranscribed in many plants. We previously reported that the tobacco ndhC/K genes are translationally coupled but produce NdhC and NdhK, subunits of the NDH complex, in similar amounts. Generally, translation of the downstream cistron in overlapping mRNAs is very low. Hence, these findings suggested that the ndhK cistron is translated not only from the ndhC 5'UTR but also by an additional pathway. Using an in vitro translation system from tobacco chloroplasts, we report here that free ribosomes enter, with formylmethionyl-tRNA(fMet), at an internal AUG start codon that is located in frame in the middle of the upstream ndhC cistron, translate the 3' half of the ndhC cistron, reach the ndhK start codon, and that, at that point, some ribosomes resume ndhK translation. We detected a peptide corresponding to a 57-amino-acid product encoded by the sequence from the internal AUG to the ndhC stop codon. We propose a model in which the internal initiation site AUG is not designed for synthesizing a functional isoform but for delivering additional ribosomes to the ndhK cistron to produce NdhK in the amount required for the assembly of the NDH complex. This pathway is a unique type of translation to produce protein in the needed amount with the cost of peptide synthesis.
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Affiliation(s)
- Maki Yukawa
- Graduate School of Natural Sciences, Nagoya City University, Nagoya 467-8501, Japan; and
- Center for Gene Research, Nagoya University, Nagoya 464-8602, Japan
| | - Masahiro Sugiura
- Graduate School of Natural Sciences, Nagoya City University, Nagoya 467-8501, Japan; and
- Center for Gene Research, Nagoya University, Nagoya 464-8602, Japan
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