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Schmid LM, Manavski N, Chi W, Meurer J. Chloroplast Ribosome Biogenesis Factors. PLANT & CELL PHYSIOLOGY 2024; 65:516-536. [PMID: 37498958 DOI: 10.1093/pcp/pcad082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/13/2023] [Accepted: 07/25/2023] [Indexed: 07/29/2023]
Abstract
The formation of chloroplasts can be traced back to an ancient event in which a eukaryotic host cell containing mitochondria ingested a cyanobacterium. Since then, chloroplasts have retained many characteristics of their bacterial ancestor, including their transcription and translation machinery. In this review, recent research on the maturation of rRNA and ribosome assembly in chloroplasts is explored, along with their crucial role in plant survival and their implications for plant acclimation to changing environments. A comparison is made between the ribosome composition and auxiliary factors of ancient and modern chloroplasts, providing insights into the evolution of ribosome assembly factors. Although the chloroplast contains ancient proteins with conserved functions in ribosome assembly, newly evolved factors have also emerged to help plants acclimate to changes in their environment and internal signals. Overall, this review offers a comprehensive analysis of the molecular mechanisms underlying chloroplast ribosome assembly and highlights the importance of this process in plant survival, acclimation and adaptation.
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Affiliation(s)
- Lisa-Marie Schmid
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Street 2-4, Planegg-Martinsried 82152, Germany
| | - Nikolay Manavski
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Street 2-4, Planegg-Martinsried 82152, Germany
| | - Wei Chi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jörg Meurer
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Street 2-4, Planegg-Martinsried 82152, Germany
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2
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Wang C, Quadrado M, Mireau H. Interplay of endonucleolytic and exonucleolytic processing in the 3'-end formation of a mitochondrial nad2 RNA precursor in Arabidopsis. Nucleic Acids Res 2023; 51:7619-7630. [PMID: 37293952 PMCID: PMC10415111 DOI: 10.1093/nar/gkad493] [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: 03/24/2023] [Revised: 05/17/2023] [Accepted: 05/31/2023] [Indexed: 06/10/2023] Open
Abstract
Initiation and termination of plant mitochondrial transcription are poorly controlled steps. Precursor transcripts are thus often longer than necessary, and 3'-end processing as well as control of RNA stability are essential to produce mature mRNAs in plant mitochondria. Plant mitochondrial 3' ends are determined by 3'-to-5' exonucleolytic trimming until the progression of mitochondrial exonucleases along transcripts is stopped by stable RNA structures or RNA binding proteins. In this analysis, we investigated the function of the endonucleolytic mitochondrial stability factor 1 (EMS1) pentatricopeptide repeat (PPR) protein and showed that it is essential for the production and the stabilization of the mature form of the nad2 exons 1-2 precursor transcript, whose 3' end corresponds to the 5' half of the nad2 trans-intron 2. The accumulation of an extended rather than a truncated form of this transcript in ems1 mutant plants suggests that the role of EMS1 in 3' end formation is not strictly limited to blocking the passage of 3'-5' exonucleolytic activity, but that 3' end formation of the nad2 exons 1-2 transcript involves an EMS1-dependent endonucleolytic cleavage. This study demonstrates that the formation of the 3' end of mitochondrial transcripts may involve an interplay of endonucleolytic and exonucleolytic processing mediated by PPR proteins.
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Affiliation(s)
- Chuande Wang
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Martine Quadrado
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Hakim Mireau
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
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3
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Liu K, Lee KP, Duan J, Kim EY, Singh RM, Di M, Meng Z, Kim C. Cooperative role of AtRsmD and AtRimM proteins in modification and maturation of 16S rRNA in plastids. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 114:310-324. [PMID: 36752655 DOI: 10.1111/tpj.16135] [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: 08/12/2022] [Accepted: 02/01/2023] [Indexed: 05/10/2023]
Abstract
Chloroplast pre-ribosomal RNA (rRNA) undergoes maturation, which is critical for ribosome assembly. While the central and auxiliary factors in rRNA maturation have been elucidated in bacteria, their mode of action remains largely unexplored in chloroplasts. We now reveal chloroplast-specific factors involved in 16S rRNA maturation, Arabidopsis thaliana orthologs of bacterial RsmD methyltransferase (AtRsmD) and ribosome maturation factor RimM (AtRimM). A forward genetic screen aimed to find suppressors of the Arabidopsis yellow variegated 2 (var2) mutant defective in photosystem II quality control found a causal nonsense mutation in AtRsmD. The substantially impaired 16S rRNA maturation and translation due to the mutation rescued the leaf variegation phenotype by lowering the levels of chloroplast-encoded proteins, including photosystem II core proteins, in var2. The subsequent co-immunoprecipitation coupled with mass spectrometry analyses and bimolecular fluorescence complementation assay found that AtRsmD interacts with AtRimM. Consistent with their interaction, loss of AtRimM also considerably impairs 16S rRNA maturation with decelerated m2 G915 modification in 16S rRNA catalyzed by AtRsmD. The atrimM mutation also rescued var2 mutant phenotypes, corroborating the functional interplay between AtRsmD and AtRimM towards modification and maturation of 16S rRNA and chloroplast proteostasis. The maturation and post-transcriptional modifications of rRNA are critical to assembling ribosomes responsible for protein translation. Here, we revealed that the cooperative regulation of 16S rRNA m2 G915 modifications by AtRsmD methyltransferase and ribosome assembly factor AtRimM contributes to 16S rRNA maturation, ribosome assembly, and proteostasis in chloroplasts.
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Affiliation(s)
- Kaiwei Liu
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Keun Pyo Lee
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Jianli Duan
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Eun Yu Kim
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Chinese Academy of Sciences, Shanghai, 200032, China
| | - Rahul Mohan Singh
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Minghui Di
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhuoling Meng
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Chanhong Kim
- Shanghai Center for Plant Stress Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
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4
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Abula A, Yang T, Zhang Y, Li T, Ji X. Enhancement of Escherichia coli Ribonuclease R Cytosine-Sensitive Activity by Single Amino Acid Substitution. Mol Biotechnol 2023; 65:108-115. [PMID: 35838865 DOI: 10.1007/s12033-022-00533-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 06/30/2022] [Indexed: 02/07/2023]
Abstract
Exoribonucleases are frequently used as nuclei acids detection tools for their sequences, modifications, and structures. Escherichia coli ribonuclease R (EcR) is the prototypical exoribonuclease of the RNase II/RNB family degrading RNA in the 3'-5' direction. Different from RNase II, EcR is capable of degrading structured RNA efficiently, which makes it a potential analysis tool for various RNA species. In this work, we examined the nuclease activity of EcR degrading a series of RNA substrates with various sequences. Our biochemical work reveals that EcR is significantly sensitive to cytosine compared with other bases when catalyzing RNA degradation. EcR shows higher cytosine sensitivity compared to its homolog RNase II when degrading RNAs, and the hydrolysis process of EcR is transiently halted and produces apparent intermediate product when the 1-nt upstream of C is A or U, or G. Furthermore, the substitution of glycine with proline (G273P) in EcR enhances its cytosine sensitivity. These findings expand our understanding of EcR enzymatic activities. The EcR G273P mutant bearing higher cytosine sensitivity could help enrich cytosine trails in RNAs and will have potential implications in the detection and analysis of various RNA species especially small RNAs in biological and clinical samples.
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Affiliation(s)
- Abudureyimu Abula
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu, People's Republic of China.,School of Basic Medical Sciences, Xinjiang Medical University, Urumqi, 830054, Xinjiang, China
| | - Tingting Yang
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu, People's Republic of China
| | - Yingxin Zhang
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu, People's Republic of China
| | - Tinghan Li
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu, People's Republic of China
| | - Xiaoyun Ji
- The State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, Jiangsu, People's Republic of China. .,Institute of Artificial Intelligence Biomedicine, Nanjing University, Nanjing, China. .,Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, 163 Xianlin Avenue, Nanjing, 210023, China. .,Ministry of Education, Engineering Research Center of Protein and Peptide Medicine, Nanjing, China.
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5
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Chen W, Huang J, Chen S, Zhang L, Rochaix JD, Peng L, Xin Q. Stromal Protein Chloroplast Development and Biogenesis1 Is Essential for Chloroplast Development and Biogenesis in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2022; 13:815859. [PMID: 35222475 PMCID: PMC8866770 DOI: 10.3389/fpls.2022.815859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
Although numerous studies have been carried out on chloroplast development and biogenesis, the underlying regulatory mechanisms are still largely elusive. Here, we characterized a chloroplast stromal protein Chloroplast Development and Biogenesis1 (CDB1). The knockout cdb1 mutant exhibits a seedling-lethal and ivory leaf phenotype. Immunoblot and RNA blot analyses show that accumulation of chloroplast ribosomes is compromised in cdb1, resulting in an almost complete loss of plastid-encoded proteins including the core subunits of the plastid-encoded RNA polymerase (PEP) RpoB and RpoC2, and therefore in impaired PEP activity. Orthologs of CDB1 are found in green algae and land plants. Moreover, a protein shows high similarity with CDB1, designated as CDB1-Like (CDB1L), is present in angiosperms. Absence of CDB1L results in impaired embryo development. While CDB1 is specifically located in the chloroplast stroma, CDB1L is localized in both chloroplasts and mitochondria in Arabidopsis. Thus, our results demonstrate that CDB1 is indispensable for chloroplast development and biogenesis through its involvement in chloroplast ribosome assembly whereas CDB1L may fulfill a similar function in both mitochondria and chloroplasts.
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Affiliation(s)
- Weijie Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Jingang Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Shiwei Chen
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Lin Zhang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Jean-David Rochaix
- Departments of Molecular Biology and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Lianwei Peng
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Qiang Xin
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
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Kong M, Wu Y, Wang Z, Qu W, Lan Y, Chen X, Liu Y, Shahnaz P, Yang Z, Yu Q, Mi H. A Novel Chloroplast Protein RNA Processing 8 Is Required for the Expression of Chloroplast Genes and Chloroplast Development in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2021; 12:700975. [PMID: 34956248 PMCID: PMC8695849 DOI: 10.3389/fpls.2021.700975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 11/03/2021] [Indexed: 06/14/2023]
Abstract
Chloroplast development involves the coordinated expression of both plastids- and nuclear-encoded genes in higher plants. However, the underlying mechanism still remains largely unknown. In this study, we isolated and characterized an Arabidopsis mutant with an albino lethality phenotype named RNA processing 8 (rp8). Genetic complementation analysis demonstrated that the gene AT4G37920 (RP8) was responsible for the mutated phenotype. The RP8 gene was strongly expressed in photosynthetic tissues at both transcription and translation protein levels. The RP8 protein is localized in the chloroplast and associated with the thylakoid. Disruption of the RP8 gene led to a defect in the accumulation of the rpoA mature transcript, which reduced the level of the RpoA protein, and affected the transcription of PEP-dependent genes. The abundance of the chloroplast rRNA, including 23S, 16S, 4.5S, and 5S rRNA, were reduced in the rp8 mutant, respectively, and the amounts of chloroplast ribosome proteins, such as, PRPS1(uS1c), PRPS5(uS5c), PRPL2 (uL2c), and PRPL4 (uL4c), were substantially decreased in the rp8 mutant, which indicated that knockout of RP8 seriously affected chloroplast translational machinery. Accordingly, the accumulation of photosynthetic proteins was seriously reduced. Taken together, these results indicate that the RP8 protein plays an important regulatory role in the rpoA transcript processing, which is required for the expression of chloroplast genes and chloroplast development in Arabidopsis.
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Affiliation(s)
- Mengmeng Kong
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yaozong Wu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Ziyuan Wang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Wantong Qu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Yixin Lan
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Xin Chen
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Yanyun Liu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Perveen Shahnaz
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Zhongnan Yang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Qingbo Yu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, China
| | - Hualing Mi
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
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Hirayama T. PARN-like Proteins Regulate Gene Expression in Land Plant Mitochondria by Modulating mRNA Polyadenylation. Int J Mol Sci 2021; 22:ijms221910776. [PMID: 34639116 PMCID: PMC8509313 DOI: 10.3390/ijms221910776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/21/2021] [Accepted: 10/02/2021] [Indexed: 11/20/2022] Open
Abstract
Mitochondria have their own double-stranded DNA genomes and systems to regulate transcription, mRNA processing, and translation. These systems differ from those operating in the host cell, and among eukaryotes. In recent decades, studies have revealed several plant-specific features of mitochondrial gene regulation. The polyadenylation status of mRNA is critical for its stability and translation in mitochondria. In this short review, I focus on recent advances in understanding the mechanisms regulating mRNA polyadenylation in plant mitochondria, including the role of poly(A)-specific ribonuclease-like proteins (PARNs). Accumulating evidence suggests that plant mitochondria have unique regulatory systems for mRNA poly(A) status and that PARNs play pivotal roles in these systems.
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Affiliation(s)
- Takashi Hirayama
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurahiki 710-0046, Okayama, Japan
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8
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DeTar RA, Barahimipour R, Manavski N, Schwenkert S, Höhner R, Bölter B, Inaba T, Meurer J, Zoschke R, Kunz HH. Loss of inner-envelope K+/H+ exchangers impairs plastid rRNA maturation and gene expression. THE PLANT CELL 2021; 33:2479-2505. [PMID: 34235544 PMCID: PMC8364240 DOI: 10.1093/plcell/koab123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/30/2021] [Indexed: 05/08/2023]
Abstract
The inner-envelope K+ EFFLUX ANTIPORTERS (KEA) 1 and 2 are critical for chloroplast development, ion homeostasis, and photosynthesis. However, the mechanisms by which changes in ion flux across the envelope affect organelle biogenesis remained elusive. Chloroplast development requires intricate coordination between the nuclear genome and the plastome. Many mutants compromised in plastid gene expression (PGE) display a virescent phenotype, that is delayed greening. The phenotypic appearance of Arabidopsis thaliana kea1 kea2 double mutants fulfills this criterion, yet a link to PGE has not been explored. Here, we show that a simultaneous loss of KEA1 and KEA2 results in maturation defects of the plastid ribosomal RNAs. This may be caused by secondary structure changes of rRNA transcripts and concomitant reduced binding of RNA-processing proteins, which we documented in the presence of skewed ion homeostasis in kea1 kea2. Consequently, protein synthesis and steady-state levels of plastome-encoded proteins remain low in mutants. Disturbance in PGE and other signs of plastid malfunction activate GENOMES UNCOUPLED 1-dependent retrograde signaling in kea1 kea2, resulting in a dramatic downregulation of GOLDEN2-LIKE transcription factors to halt expression of photosynthesis-associated nuclear-encoded genes (PhANGs). PhANG suppression delays the development of fully photosynthesizing kea1 kea2 chloroplasts, probably to avoid progressing photo-oxidative damage. Overall, our results reveal that KEA1/KEA2 function impacts plastid development via effects on RNA-metabolism and PGE.
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Affiliation(s)
- Rachael Ann DeTar
- Plant Physiology, School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236, USA
| | - Rouhollah Barahimipour
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Nikolay Manavski
- Plant Sciences, Department I, LMU Munich, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Serena Schwenkert
- Plant Sciences, Department I, LMU Munich, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Ricarda Höhner
- Plant Physiology, School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236, USA
| | - Bettina Bölter
- Plant Sciences, Department I, LMU Munich, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Takehito Inaba
- Department of Agricultural and Environmental Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan
| | - Jörg Meurer
- Plant Sciences, Department I, LMU Munich, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
| | - Reimo Zoschke
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Am Mühlenberg 1, 14476 Potsdam, Germany
| | - Hans-Henning Kunz
- Plant Physiology, School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236, USA
- Plant Sciences, Department I, LMU Munich, Großhaderner Str. 2-4, 82152 Planegg-Martinsried, Germany
- Author for correspondence:
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Chen J, Wang L, Jin X, Wan J, Zhang L, Je BI, Zhao K, Kong F, Huang J, Tian M. Oryza sativa ObgC1 Acts as a Key Regulator of DNA Replication and Ribosome Biogenesis in Chloroplast Nucleoids. RICE (NEW YORK, N.Y.) 2021; 14:65. [PMID: 34251486 PMCID: PMC8275814 DOI: 10.1186/s12284-021-00498-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Accepted: 05/30/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND The Spo0B-associated GTP-binding protein (Obg) GTPase, has diverse and important functions in bacteria, including morphological development, DNA replication and ribosome maturation. Homologs of the Bacillus subtilis Obg have been also found in chloroplast of Oryza sativa, but their primary roles remain unknown. RESULTS We clarify that OsObgC1 is a functional homolog of AtObgC. The mutant obgc1-d1 exhibited hypersensitivity to the DNA replication inhibitor hydroxyurea. Quantitative PCR results showed that the ratio of chloroplast DNA to nuclear DNA in the mutants was higher than that of the wild-type plants. After DAPI staining, OsObgC1 mutants showed abnormal nucleoid architectures. The specific punctate staining pattern of OsObgC1-GFP signal suggests that this protein localizes to the chloroplast nucleoids. Furthermore, loss-of-function mutation in OsObgC1 led to a severe suppression of protein biosynthesis by affecting plastid rRNA processing. It was also demonstrated through rRNA profiling that plastid rRNA processing was decreased in obgc1-d mutants, which resulted in impaired ribosome biogenesis. The sucrose density gradient profiles revealed a defective chloroplast ribosome maturation of obgc1-d1 mutants. CONCLUSION Our findings here indicate that the OsObgC1 retains the evolutionarily biological conserved roles of prokaryotic Obg, which acts as a signaling hub that regulates DNA replication and ribosome biogenesis in chloroplast nucleoids.
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Affiliation(s)
- Ji Chen
- College of Agronomy, Sichuan Agricultural University, Chengdu, 611130, China
- Division of Applied Life Sciences (BK21+), Graduate School of Gyeongsang National University, Jinju, 660-701, Republic of Korea
| | - Li Wang
- College of Agronomy, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xiaowan Jin
- College of Agronomy, Sichuan Agricultural University, Chengdu, 611130, China
| | - Jian Wan
- College of Agronomy, Sichuan Agricultural University, Chengdu, 611130, China
| | - Lang Zhang
- College of Agronomy, Sichuan Agricultural University, Chengdu, 611130, China
| | - Byoung Il Je
- College of Ecology and Environment, Chengdu University of Technology, Chengdu, 61005, China
| | - Ke Zhao
- College of Agronomy, Sichuan Agricultural University, Chengdu, 611130, China
| | - Fanlei Kong
- College of Agronomy, Sichuan Agricultural University, Chengdu, 611130, China
| | - Jin Huang
- Division of Applied Life Sciences (BK21+), Graduate School of Gyeongsang National University, Jinju, 660-701, Republic of Korea.
- College of Ecology and Environment, Chengdu University of Technology, Chengdu, 61005, China.
| | - Mengliang Tian
- Institute for New Rural Development, Sichuan Agricultural University, Yaan, 625000, China.
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Genome-Wide Association Mapping Unravels the Genetic Control of Seed Vigor under Low-Temperature Conditions in Rapeseed ( Brassica napus L.). PLANTS 2021; 10:plants10030426. [PMID: 33668258 PMCID: PMC7996214 DOI: 10.3390/plants10030426] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/15/2021] [Accepted: 02/15/2021] [Indexed: 11/16/2022]
Abstract
Low temperature inhibits rapid germination and successful seedling establishment of rapeseed (Brassica napus L.), leading to significant productivity losses. Little is known about the genetic diversity for seed vigor under low-temperature conditions in rapeseed, which motivated our investigation of 13 seed germination- and emergence-related traits under normal and low-temperature conditions for 442 diverse rapeseed accessions. The stress tolerance index was calculated for each trait based on performance under non-stress and low-temperature stress conditions. Principal component analysis of the low-temperature stress tolerance indices identified five principal components that captured 100% of the seedling response to low temperature. A genome-wide association study using ~8 million SNP (single-nucleotide polymorphism) markers identified from genome resequencing was undertaken to uncover the genetic basis of seed vigor related traits in rapeseed. We detected 22 quantitative trait loci (QTLs) significantly associated with stress tolerance indices regarding seed vigor under low-temperature stress. Scrutiny of the genes in these QTL regions identified 62 candidate genes related to specific stress tolerance indices of seed vigor, and the majority were involved in DNA repair, RNA translation, mitochondrial activation and energy generation, ubiquitination and degradation of protein reserve, antioxidant system, and plant hormone and signal transduction. The high effect variation and haplotype-based effect of these candidate genes were evaluated, and high priority could be given to the candidate genes BnaA03g40290D, BnaA06g07530D, BnaA09g06240D, BnaA09g06250D, and BnaC02g10720D in further study. These findings should be useful for marker-assisted breeding and genomic selection of rapeseed to increase seed vigor under low-temperature stress.
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11
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Gawroński P, Burdiak P, Scharff LB, Mielecki J, Górecka M, Zaborowska M, Leister D, Waszczak C, Karpiński S. CIA2 and CIA2-LIKE are required for optimal photosynthesis and stress responses in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 105:619-638. [PMID: 33119927 DOI: 10.1111/tpj.15058] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 10/05/2020] [Accepted: 10/12/2020] [Indexed: 05/22/2023]
Abstract
Chloroplast-to-nucleus retrograde signaling is essential for cell function, acclimation to fluctuating environmental conditions, plant growth and development. The vast majority of chloroplast proteins are nuclear-encoded, and must be imported into the organelle after synthesis in the cytoplasm. This import is essential for the development of fully functional chloroplasts. On the other hand, functional chloroplasts act as sensors of environmental changes and can trigger acclimatory responses that influence nuclear gene expression. Signaling via mobile transcription factors (TFs) has been recently recognized as a way of communication between organelles and the nucleus. In this study, we performed a targeted reverse genetic screen to identify dual-localized TFs involved in chloroplast retrograde signaling during stress responses. We found that CHLOROPLAST IMPORT APPARATUS 2 (CIA2) has a functional plastid transit peptide, and can be located both in chloroplasts and the nucleus. Further, we found that CIA2, along with its homolog CIA2-like (CIL) are involved in the regulation of Arabidopsis responses to UV-AB, high light and heat shock. Finally, our results suggest that both CIA2 and CIL are crucial for chloroplast translation. Our results contribute to a deeper understanding of signaling events in the chloroplast-nucleus cross-talk.
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Affiliation(s)
- Piotr Gawroński
- Department of Plant Genetics, Breeding, and Biotechnology, Warsaw University of Life Sciences, Warsaw, 02-776, Poland
| | - Paweł Burdiak
- Department of Plant Genetics, Breeding, and Biotechnology, Warsaw University of Life Sciences, Warsaw, 02-776, Poland
| | - Lars B Scharff
- Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg C, 1871, Denmark
| | - Jakub Mielecki
- Department of Plant Genetics, Breeding, and Biotechnology, Warsaw University of Life Sciences, Warsaw, 02-776, Poland
| | - Magdalena Górecka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, Warsaw, 02-106, Poland
| | - Magdalena Zaborowska
- Department of Plant Genetics, Breeding, and Biotechnology, Warsaw University of Life Sciences, Warsaw, 02-776, Poland
| | - Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhadernerstraße 2-4, Planegg-Martinsried, 82152, Germany
| | - Cezary Waszczak
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Finland
| | - Stanisław Karpiński
- Department of Plant Genetics, Breeding, and Biotechnology, Warsaw University of Life Sciences, Warsaw, 02-776, Poland
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12
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Yang Z, Li M, Sun Q. RHON1 Co-transcriptionally Resolves R-Loops for Arabidopsis Chloroplast Genome Maintenance. Cell Rep 2021; 30:243-256.e5. [PMID: 31914390 DOI: 10.1016/j.celrep.2019.12.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/24/2019] [Accepted: 12/02/2019] [Indexed: 01/10/2023] Open
Abstract
Preventing transcription-replication head-on conflict (HO-TRC)-triggered R-loop formation is essential for maintaining genome integrity in bacteria, plants, and mammals. The R-loop eraser RNase H can efficiently relax HO-TRCs. However, it is not clear how organisms resist HO-TRC-triggered R-loops when RNase H proteins are deficient. By screening factors that may relieve R-loop accumulation in the Arabidopsis atrnh1c mutant, we find that overexpression of the R-loop helicase RHON1 can rescue the defects of aberrantly accumulated HO-TRC-triggered R-loops co-transcriptionally. In addition, we find that RHON1 interacts with and orchestrates the transcriptional activity of plastid-encoded RNA polymerases to release the conflicts between transcription and replication. Our study illustrates that organisms employ multiple mechanisms to escape HO-TRC-triggered R-loop accumulation and thus maintain genome integrity.
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Affiliation(s)
- Zhuo Yang
- Tsinghua-Peking Joint Center for Life Sciences and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Mengmeng Li
- Tsinghua-Peking Joint Center for Life Sciences and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qianwen Sun
- Tsinghua-Peking Joint Center for Life Sciences and Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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13
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MacIntosh GC, Castandet B. Organellar and Secretory Ribonucleases: Major Players in Plant RNA Homeostasis. PLANT PHYSIOLOGY 2020; 183:1438-1452. [PMID: 32513833 PMCID: PMC7401137 DOI: 10.1104/pp.20.00076] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 05/31/2020] [Indexed: 05/05/2023]
Abstract
Organellar and secretory RNases, associated with different cellular compartments, are essential to maintain cellular homeostasis during development and in stress responses.
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Affiliation(s)
- Gustavo C MacIntosh
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, 50011
| | - Benoît Castandet
- Université Paris-Saclay, Centre National de la Recherche Scientifique, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Univ Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
- Université de Paris, Centre National de la Recherche Scientifique, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Institute of Plant Sciences Paris-Saclay (IPS2), 91405, Orsay, France
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14
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Wu S, Guo Y, Adil MF, Sehar S, Cai B, Xiang Z, Tu Y, Zhao D, Shamsi IH. Comparative Proteomic Analysis by iTRAQ Reveals that Plastid Pigment Metabolism Contributes to Leaf Color Changes in Tobacco ( Nicotiana tabacum) during Curing. Int J Mol Sci 2020; 21:E2394. [PMID: 32244294 PMCID: PMC7178154 DOI: 10.3390/ijms21072394] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/27/2020] [Accepted: 03/30/2020] [Indexed: 01/21/2023] Open
Abstract
Tobacco (Nicotiana tabacum), is a world's major non-food agricultural crop widely cultivated for its economic value. Among several color change associated biological processes, plastid pigment metabolism is of trivial importance in postharvest plant organs during curing and storage. However, the molecular mechanisms involved in carotenoid and chlorophyll metabolism, as well as color change in tobacco leaves during curing, need further elaboration. Here, proteomic analysis at different curing stages (0 h, 48 h, 72 h) was performed in tobacco cv. Bi'na1 with an aim to investigate the molecular mechanisms of pigment metabolism in tobacco leaves as revealed by the iTRAQ proteomic approach. Our results displayed significant differences in leaf color parameters and ultrastructural fingerprints that indicate an acceleration of chloroplast disintegration and promotion of pigment degradation in tobacco leaves due to curing. In total, 5931 proteins were identified, of which 923 (450 up-regulated, 452 down-regulated, and 21 common) differentially expressed proteins (DEPs) were obtained from tobacco leaves. To elucidate the molecular mechanisms of pigment metabolism and color change, 19 DEPs involved in carotenoid metabolism and 12 DEPs related to chlorophyll metabolism were screened. The results exhibited the complex regulation of DEPs in carotenoid metabolism, a negative regulation in chlorophyll biosynthesis, and a positive regulation in chlorophyll breakdown, which delayed the degradation of xanthophylls and accelerated the breakdown of chlorophylls, promoting the formation of yellow color during curing. Particularly, the up-regulation of the chlorophyllase-1-like isoform X2 was the key protein regulatory mechanism responsible for chlorophyll metabolism and color change. The expression pattern of 8 genes was consistent with the iTRAQ data. These results not only provide new insights into pigment metabolism and color change underlying the postharvest physiological regulatory networks in plants, but also a broader perspective, which prompts us to pay attention to further screen key proteins in tobacco leaves during curing.
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Affiliation(s)
- Shengjiang Wu
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Guizhou University, Guiyang 550025, China;
- Key Laboratory of Molecular Genetics/Upland Flue-cured Tobacco Quality and Ecology Key Laboratory, Guizhou Academy of Tobacco Science, CNTC, Guiyang 550081, China; (Y.G.); (B.C.); (Z.X.); (Y.T.)
| | - Yushuang Guo
- Key Laboratory of Molecular Genetics/Upland Flue-cured Tobacco Quality and Ecology Key Laboratory, Guizhou Academy of Tobacco Science, CNTC, Guiyang 550081, China; (Y.G.); (B.C.); (Z.X.); (Y.T.)
| | - Muhammad Faheem Adil
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, China; (M.F.A.); (S.S.)
| | - Shafaque Sehar
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, China; (M.F.A.); (S.S.)
| | - Bin Cai
- Key Laboratory of Molecular Genetics/Upland Flue-cured Tobacco Quality and Ecology Key Laboratory, Guizhou Academy of Tobacco Science, CNTC, Guiyang 550081, China; (Y.G.); (B.C.); (Z.X.); (Y.T.)
| | - Zhangmin Xiang
- Key Laboratory of Molecular Genetics/Upland Flue-cured Tobacco Quality and Ecology Key Laboratory, Guizhou Academy of Tobacco Science, CNTC, Guiyang 550081, China; (Y.G.); (B.C.); (Z.X.); (Y.T.)
| | - Yonggao Tu
- Key Laboratory of Molecular Genetics/Upland Flue-cured Tobacco Quality and Ecology Key Laboratory, Guizhou Academy of Tobacco Science, CNTC, Guiyang 550081, China; (Y.G.); (B.C.); (Z.X.); (Y.T.)
| | - Degang Zhao
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, The Key Laboratory of Plant Resources Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Guizhou University, Guiyang 550025, China;
- Guizhou Academy of Agricultural Sciences, Guiyang 550006, China
| | - Imran Haider Shamsi
- Department of Agronomy, College of Agriculture and Biotechnology, Zijingang Campus, Zhejiang University, Hangzhou 310058, China; (M.F.A.); (S.S.)
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15
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Nagashima Y, Ohshiro K, Iwase A, Nakata MT, Maekawa S, Horiguchi G. The bRPS6-Family Protein RFC3 Prevents Interference by the Splicing Factor CFM3b during Plastid rRNA Biogenesis in Arabidopsis thaliana. PLANTS 2020; 9:plants9030328. [PMID: 32143506 PMCID: PMC7154815 DOI: 10.3390/plants9030328] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/24/2020] [Accepted: 03/03/2020] [Indexed: 01/03/2023]
Abstract
Plastid ribosome biogenesis is important for plant growth and development. REGULATOR OF FATTY ACID COMPOSITION3 (RFC3) is a member of the bacterial ribosomal protein S6 family and is important for lateral root development. rfc3-2 dramatically reduces the plastid rRNA level and produces lateral roots that lack stem cells. In this study, we isolated a suppressor of rfc three2 (sprt2) mutant that enabled recovery of most rfc3 mutant phenotypes, including abnormal primary and lateral root development and reduced plastid rRNA level. Northern blotting showed that immature and mature plastid rRNA levels were reduced, with the exception of an early 23S rRNA intermediate, in rfc3-2 mutants. These changes were recovered in rfc3-2 sprt2-1 mutants, but a second defect in the processing of 16S rRNA appeared in this line. The results suggest that rfc3 mutants may be defective in at least two steps of plastid rRNA processing, one of which is specifically affected by the sprt2-1 mutation. sprt2-1 mutants had a mutation in CRM FAMILY MEMBER 3b (CFM3b), which encodes a plastid-localized splicing factor. A bimolecular fluorescence complementation (BiFC) assay suggested that RFC3 and SPRT2/CFM3b interact with each other in plastids. These results suggest that RFC3 suppresses the nonspecific action of SPRT2/CFM3b and improves the accuracy of plastid rRNA processing.
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Affiliation(s)
- Yumi Nagashima
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - Katsutomo Ohshiro
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - Akiyasu Iwase
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - Miyuki T Nakata
- Research Center for Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
- Current address: Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Shugo Maekawa
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
- Research Center for Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
| | - Gorou Horiguchi
- Department of Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
- Research Center for Life Science, College of Science, Rikkyo University, Toshima, Tokyo 171-8501, Japan
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16
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Reis FP, Bárria C, Gomez‐Puertas P, Gomes CM, Arraiano CM. Identification of temperature‐sensitive mutations and characterization of thermolabile
RN
ase
II
variants. FEBS Lett 2018; 593:352-360. [DOI: 10.1002/1873-3468.13313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 11/12/2018] [Indexed: 01/06/2023]
Affiliation(s)
- Filipa P. Reis
- Instituto de Tecnologia Química e Biológica António Xavier Universidade Nova de Lisboa Oeiras Portugal
| | - Cátia Bárria
- Instituto de Tecnologia Química e Biológica António Xavier Universidade Nova de Lisboa Oeiras Portugal
| | - Paulino Gomez‐Puertas
- Centro de Biologia Molecular ‘Severo Ochoa’ (CSIC‐UAM) Campus Universidad Autonoma de Madrid Spain
| | - Cláudio M. Gomes
- Biosystems and Integrative Sciences Institute Faculdade de Ciências Universidade de Lisboa Portugal
- Departamento de Química e Bioquímica Universidade de Lisboa Portugal
| | - Cecília M. Arraiano
- Instituto de Tecnologia Química e Biológica António Xavier Universidade Nova de Lisboa Oeiras Portugal
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17
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Ji D, Manavski N, Meurer J, Zhang L, Chi W. Regulated chloroplast transcription termination. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1860:69-77. [PMID: 30414934 DOI: 10.1016/j.bbabio.2018.11.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 10/15/2018] [Accepted: 11/07/2018] [Indexed: 11/16/2022]
Abstract
Transcription termination by the RNA polymerase (RNAP) is a fundamental step of gene expression that involves the release of the nascent transcript and dissociation of the RNAP from the DNA template. However, the functional importance of termination extends beyond the mere definition of the gene borders. Chloroplasts originate from cyanobacteria and possess their own gene expression system. Plastids have a unique hybrid transcription system consisting of two different types of RNAPs of dissimilar phylogenetic origin together with several additional nuclear encoded components. Although the basic components involved in chloroplast transcription have been identified, little attention has been paid to the chloroplast transcription termination. Recent identification and functional characterization of novel factors in regulating transcription termination in Arabidopsis chloroplasts via genetic and biochemical approaches have provided insights into the mechanisms and significance of transcription termination in chloroplast gene expression. This review provides an overview of the current knowledge of the transcription termination in chloroplasts.
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Affiliation(s)
- Daili Ji
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Nikolay Manavski
- Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Moleculaire des Plantes, 12 rue du General Zimmer, 67084 Strasbourg, France
| | - Jörg Meurer
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University Munich, D-82152 Planegg-Martinsried, Germany
| | - Lixin Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Wei Chi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
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18
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Dos Santos RF, Quendera AP, Boavida S, Seixas AF, Arraiano CM, Andrade JM. Major 3'-5' Exoribonucleases in the Metabolism of Coding and Non-coding RNA. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 159:101-155. [PMID: 30340785 DOI: 10.1016/bs.pmbts.2018.07.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
3'-5' exoribonucleases are key enzymes in the degradation of superfluous or aberrant RNAs and in the maturation of precursor RNAs into their functional forms. The major bacterial 3'-5' exoribonucleases responsible for both these activities are PNPase, RNase II and RNase R. These enzymes are of ancient nature with widespread distribution. In eukaryotes, PNPase and RNase II/RNase R enzymes can be found in the cytosol and in mitochondria and chloroplasts; RNase II/RNase R-like enzymes are also found in the nucleus. Humans express one PNPase (PNPT1) and three RNase II/RNase R family members (Dis3, Dis3L and Dis3L2). These enzymes take part in a multitude of RNA surveillance mechanisms that are critical for translation accuracy. Although active against a wide range of both coding and non-coding RNAs, the different 3'-5' exoribonucleases exhibit distinct substrate affinities. The latest studies on these RNA degradative enzymes have contributed to the identification of additional homologue proteins, the uncovering of novel RNA degradation pathways, and to a better comprehension of several disease-related processes and response to stress, amongst many other exciting findings. Here, we provide a comprehensive and up-to-date overview on the function, structure, regulation and substrate preference of the key 3'-5' exoribonucleases involved in RNA metabolism.
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Affiliation(s)
- Ricardo F Dos Santos
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ana P Quendera
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Sofia Boavida
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - André F Seixas
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Cecília M Arraiano
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - José M Andrade
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
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19
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Paieri F, Tadini L, Manavski N, Kleine T, Ferrari R, Morandini P, Pesaresi P, Meurer J, Leister D. The DEAD-box RNA Helicase RH50 Is a 23S-4.5S rRNA Maturation Factor that Functionally Overlaps with the Plastid Signaling Factor GUN1. PLANT PHYSIOLOGY 2018; 176:634-648. [PMID: 29138350 PMCID: PMC5761802 DOI: 10.1104/pp.17.01545] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 11/11/2017] [Indexed: 05/04/2023]
Abstract
DEAD-box RNA helicases (DBRHs) modulate RNA secondary structure, allowing RNA molecules to adopt the conformations required for interaction with their target proteins. RH50 is a chloroplast-located DBRH that colocalizes and is coexpressed with GUN1, a central factor in chloroplast-to-nucleus signaling. When combined with mutations that impair plastid gene expression (prors1-1, prpl11-1, prps1-1, prps21-1, prps17-1, and prpl24-1), rh50 and gun1 mutations evoke similar patterns of epistatic effects. These observations, together with the synergistic growth phenotype of the double mutant rh50-1 gun1-102, suggest that RH50 and GUN1 are functionally related and that this function is associated with plastid gene expression, in particular ribosome functioning. However, rh50-1 itself is not a gun mutant, although-like gun1-102-the rh50-1 mutation suppresses the down-regulation of nuclear genes for photosynthesis induced by the prors1-1 mutation. The RH50 protein comigrates with ribosomal particles, and is required for efficient translation of plastid proteins. RH50 binds to transcripts of the 23S-4.5S intergenic region and, in its absence, levels of the corresponding rRNA processing intermediate are strongly increased, implying that RH50 is required for the maturation of the 23S and 4.5S rRNAs. This inference is supported by the finding that loss of RH50 renders chloroplast protein synthesis sensitive to erythromycin and exposure to cold. Based on these results, we conclude that RH50 is a plastid rRNA maturation factor.
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Affiliation(s)
- Francesca Paieri
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
- Centro Ricerca e Innovazione, Fondazione Edmund Mach, I-38010, San Michele all'Adige, Italy
| | - Luca Tadini
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
| | | | - Tatjana Kleine
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
| | - Roberto Ferrari
- Department of Biosciences, I-20133 Milano, Università degli studi di Milano, Italy
| | - Piero Morandini
- Department of Biosciences, I-20133 Milano, Università degli studi di Milano, Italy
| | - Paolo Pesaresi
- Department of Agricultural and Environmental Sciences - Production, Landscape, Agroenergy, I-20133 Milano, Università degli studi di Milano, Italy
| | - Jörg Meurer
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
| | - Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
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20
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Chu LY, Hsieh TJ, Golzarroshan B, Chen YP, Agrawal S, Yuan HS. Structural insights into RNA unwinding and degradation by RNase R. Nucleic Acids Res 2017; 45:12015-12024. [PMID: 29036353 PMCID: PMC5714204 DOI: 10.1093/nar/gkx880] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 09/25/2017] [Indexed: 11/13/2022] Open
Abstract
RNase R is a conserved exoribonuclease in the RNase II family that primarily participates in RNA decay in all kingdoms of life. RNase R degrades duplex RNA with a 3′ overhang, suggesting that it has RNA unwinding activity in addition to its 3′-to-5′ exoribonuclease activity. However, how RNase R coordinates RNA binding with unwinding to degrade RNA remains elusive. Here, we report the crystal structure of a truncated form of Escherichia coli RNase R (residues 87–725) at a resolution of 1.85 Å. Structural comparisons with other RNase II family proteins reveal two open RNA-binding channels in RNase R and suggest a tri-helix ‘wedge’ region in the RNB domain that may induce RNA unwinding. We constructed two tri-helix wedge mutants and they indeed lost their RNA unwinding but not RNA binding or degrading activities. Our results suggest that the duplex RNA with an overhang is bound in the two RNA-binding channels in RNase R. The 3′ overhang is threaded into the active site and the duplex RNA is unwound upon reaching the wedge region during RNA degradation. Thus, RNase R is a proficient enzyme, capable of concurrently binding, unwinding and degrading structured RNA in a highly processive manner during RNA decay.
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Affiliation(s)
- Lee-Ya Chu
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC.,Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, ROC.,Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsin Chu, Taiwan 30013, ROC
| | - Tung-Ju Hsieh
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC
| | - Bagher Golzarroshan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC.,Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, ROC.,Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsin Chu, Taiwan 30013, ROC
| | - Yi-Ping Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC
| | - Sashank Agrawal
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC.,Molecular and Cell Biology Program, Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan 11529, ROC.,Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan 11490, ROC
| | - Hanna S Yuan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 11529, ROC.,Graduate Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan 10048, ROC
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21
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Jeon Y, Ahn HK, Kang YW, Pai HS. Functional characterization of chloroplast-targeted RbgA GTPase in higher plants. PLANT MOLECULAR BIOLOGY 2017; 95:463-479. [PMID: 29038916 DOI: 10.1007/s11103-017-0664-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 10/01/2017] [Indexed: 06/07/2023]
Abstract
KEY MESSAGE Plant RbgA GTPase is targeted to chloroplasts and co-fractionated with chloroplast ribosomes, and plays a role in chloroplast rRNA processing and/or ribosome biogenesis. Ribosome Biogenesis GTPase A (RbgA) homologs are evolutionarily conserved GTPases that are widely distributed in both prokaryotes and eukaryotes. In this study, we investigated functions of chloroplast-targeted RbgA. Nicotiana benthamiana RbgA (NbRbgA) and Arabidopsis thaliana RbgA (AtRbgA) contained a conserved GTP-binding domain and a plant-specific C-terminal domain. NbRbgA and AtRbgA were mainly localized in chloroplasts, and possessed GTPase activity. Since Arabidopsis rbgA null mutants exhibited an embryonic lethal phenotype, virus-induced gene silencing (VIGS) of NbRbgA was performed in N. benthamiana. NbRbgA VIGS resulted in a leaf-yellowing phenotype caused by disrupted chloroplast development. NbRbgA was mainly co-fractionated with 50S/70S ribosomes and interacted with the chloroplast ribosomal proteins cpRPL6 and cpRPL35. NbRbgA deficiency lowered the levels of mature 23S and 16S rRNAs in chloroplasts and caused processing defects. Sucrose density gradient sedimentation revealed that NbRbgA-deficient chloroplasts contained reduced levels of mature 23S and 16S rRNAs and diverse plastid-encoded mRNAs in the polysomal fractions, suggesting decreased protein translation activity in the chloroplasts. Interestingly, NbRbgA protein was highly unstable under high light stress, suggesting its possible involvement in the control of chloroplast ribosome biogenesis under environmental stresses. Collectively, these results suggest a role for RbgA GTPase in chloroplast rRNA processing/ribosome biogenesis, affecting chloroplast protein translation in higher plants.
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Affiliation(s)
- Young Jeon
- Department of Systems Biology, Yonsei University, Seoul, 03722, South Korea
| | - Hee-Kyung Ahn
- Department of Systems Biology, Yonsei University, Seoul, 03722, South Korea
| | - Yong Won Kang
- R&D Center, Morechem Co., Ltd., Yongin, Gyeonggi-do, 16954, South Korea
| | - Hyun-Sook Pai
- Department of Systems Biology, Yonsei University, Seoul, 03722, South Korea.
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22
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Meurer J, Schmid LM, Stoppel R, Leister D, Brachmann A, Manavski N. PALE CRESS binds to plastid RNAs and facilitates the biogenesis of the 50S ribosomal subunit. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:400-413. [PMID: 28805278 DOI: 10.1111/tpj.13662] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/04/2017] [Accepted: 08/08/2017] [Indexed: 05/11/2023]
Abstract
The plant-specific PALE CRESS (PAC) protein has previously been shown to be essential for photoautotrophic growth. Here we further investigated the molecular function of the PAC protein. PAC localizes to plastid nucleoids and forms large proteinaceous and RNA-containing megadalton complexes. It co-immunoprecipitates with a specific subset of chloroplast RNAs including psbK-psbI, ndhF, ndhD, and 23S ribosomal RNA (rRNA), as demonstrated by RNA immunoprecipitation in combination with high throughput RNA sequencing (RIP-seq) analyses. Furthermore, it co-migrates with premature 50S ribosomal particles and specifically binds to 23S rRNA in vitro. This coincides with severely reduced levels of 23S rRNA in pac leading to translational deficiencies and related alterations of plastid transcript patterns and abundance similar to plants treated with the translation inhibitor lincomycin. Thus, we conclude that deficiency in plastid ribosomes accounts for the pac phenotype. Moreover, the absence or reduction of PAC levels in the corresponding mutants induces structural changes of the 23S rRNA, as demonstrated by in vivo RNA structure probing. Our results indicate that PAC binds to the 23S rRNA to promote the biogenesis of the 50S subunit.
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Affiliation(s)
- Jörg Meurer
- Plant Sciences, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Lisa-Marie Schmid
- Plant Sciences, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Rhea Stoppel
- Plant Sciences, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Dario Leister
- Plant Sciences, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Andreas Brachmann
- Genetics, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
| | - Nikolay Manavski
- Plant Sciences, Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Straße 2-4, 82152, Planegg-Martinsried, Germany
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23
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Plötner B, Nurmi M, Fischer A, Watanabe M, Schneeberger K, Holm S, Vaid N, Schöttler MA, Walther D, Hoefgen R, Weigel D, Laitinen RAE. Chlorosis caused by two recessively interacting genes reveals a role of RNA helicase in hybrid breakdown in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:251-262. [PMID: 28378460 DOI: 10.1111/tpj.13560] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/24/2017] [Accepted: 03/30/2017] [Indexed: 05/28/2023]
Abstract
Hybrids often differ in fitness from their parents. They may be superior, translating into hybrid vigour or heterosis, but they may also be markedly inferior, because of hybrid weakness or incompatibility. The underlying genetic causes for the latter can often be traced back to genes that evolve rapidly because of sexual or host-pathogen conflicts. Hybrid weakness may manifest itself only in later generations, in a phenomenon called hybrid breakdown. We have characterized a case of hybrid breakdown among two Arabidopsis thaliana accessions, Shahdara (Sha, Tajikistan) and Lövvik-5 (Lov-5, Northern Sweden). In addition to chlorosis, a fraction of the F2 plants have defects in leaf and embryo development, and reduced photosynthetic efficiency. Hybrid chlorosis is due to two major-effect loci, of which one, originating from Lov-5, appears to encode an RNA helicase (AtRH18). To examine the role of the chlorosis allele in the Lövvik area, in addition to eight accessions collected in 2009, we collected another 240 accessions from 15 collections sites, including Lövvik, from Northern Sweden in 2015. Genotyping revealed that Lövvik collection site is separated from the rest. Crosses between 109 accessions from this area and Sha revealed 85 cases of hybrid chlorosis, indicating that the chlorosis-causing allele is common in this area. These results suggest that hybrid breakdown alleles not only occur at rapidly evolving loci, but also at genes that code for conserved processes.
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Affiliation(s)
- Björn Plötner
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Markus Nurmi
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Axel Fischer
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Mutsumi Watanabe
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | | | | | - Neha Vaid
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | | | - Dirk Walther
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Rainer Hoefgen
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Detlef Weigel
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Roosa A E Laitinen
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
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24
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Abstract
Numerous attempts have been made to identify and engineer sequence-specific RNA endonucleases, as these would allow for efficient RNA manipulation. However, no natural RNA endonuclease that recognizes RNA in a sequence-specific manner has been described to date. Here, we report that SUPPRESSOR OF THYLAKOID FORMATION 1 (SOT1), an Arabidopsis pentatricopeptide repeat (PPR) protein with a small MutS-related (SMR) domain, has RNA endonuclease activity. We show that the SMR moiety of SOT1 performs the endonucleolytic maturation of 23S and 4.5S rRNA through the PPR domain, specifically recognizing a 13-nucleotide RNA sequence in the 5' end of the chloroplast 23S-4.5S rRNA precursor. In addition, we successfully engineered the SOT1 protein with altered PPR motifs to recognize and cleave a predicted RNA substrate. Our findings point to SOT1 as an exciting tool for RNA manipulation.
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25
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Köhler D, Helm S, Agne B, Baginsky S. Importance of Translocon Subunit Tic56 for rRNA Processing and Chloroplast Ribosome Assembly. PLANT PHYSIOLOGY 2016; 172:2429-2444. [PMID: 27733515 PMCID: PMC5129725 DOI: 10.1104/pp.16.01393] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 10/11/2016] [Indexed: 05/20/2023]
Abstract
Toc159-containing complexes at the outer chloroplast envelope membrane form stable supercomplexes with a 1-MD translocon at the inner chloroplast envelope membrane of which Tic56 is one essential subunit. While the single mutants tic56-1 and ppi2 (toc159) have an albino phenotype and are able to grow heterotrophically, we find the double mutant to be embryo lethal. Comprehensive quantitative proteome profiling with both single mutants in combination with GeneChip analyses identified a posttranscriptional defect in the accumulation of plastid ribosomal proteins and diminished expression of plastid encoded proteins. In the tic56-1 mutant, the assembly of functional ribosomes is furthermore hampered by a processing defect of the plastid 23S rRNA. Spectinomycin-treatment of wild-type plants phenocopies the molecular phenotype of plastid proteome accumulation in tic56-1 and to a smaller degree also ppi2 plastids, suggesting that a defect in plastid translation is largely responsible for the phenotype of both import mutants. Import experiments with the tic56-3 mutant revealed no significant defect in the import of small ribosomal protein 16 in the absence of full-length Tic56, suggesting that the defect in ribosome assembly in tic56-1 may be independent of a function of Tic56 in protein import. Our data establish a previously unknown link between plastid protein import, the processing of plastid rRNAs, and the assembly of plastid ribosomes and provide further knowledge on the function of the translocon components and the molecular basis for their albino phenotype.
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Affiliation(s)
- Daniel Köhler
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, 06120 Halle (Saale), Germany
| | - Stefan Helm
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, 06120 Halle (Saale), Germany
| | - Birgit Agne
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, 06120 Halle (Saale), Germany
| | - Sacha Baginsky
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Biozentrum, 06120 Halle (Saale), Germany
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26
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Mermigka G, Helm JM, Vlatakis I, Schumacher HT, Vamvaka E, Kalantidis K. ERIL1, the plant homologue of ERI-1, is involved in the processing of chloroplastic rRNAs. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:839-853. [PMID: 27531275 DOI: 10.1111/tpj.13304] [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: 07/08/2015] [Revised: 08/05/2016] [Accepted: 08/09/2016] [Indexed: 06/06/2023]
Abstract
Proteins belonging to the enhancer of RNA interference-1 subfamily of 3'-5' exoribonucleases participate in divergent RNA pathways. They degrade small interfering RNAs (siRNAs), thus suppressing RNA interference, and are involved in the maturation of ribosomal RNAs and the degradation of histone messenger RNAs (mRNAs). Here, we report evidence for the role of the plant homologue of these proteins, which we termed ENHANCED RNA INTERFERENCE-1-LIKE-1 (ERIL1), in chloroplast function. In vitro assays with AtERIL1 proved that the conserved 3'-5' exonuclease activity is shared among all homologues studied. Confocal microscopy revealed that ERL1, a nucleus-encoded protein, is targeted to the chloroplast. To gain insight into its role in plants, we used Nicotiana benthamiana and Arabidopsis thaliana plants that constitutively overexpress or suppress ERIL1. In the mutant lines of both species we observed malfunctions in photosynthetic ability. Molecular analysis showed that ERIL1 participates in the processing of chloroplastic ribosomal RNAs (rRNAs). Lastly, our results suggest that the missexpression of ERIL1 may have an indirect effect on the microRNA (miRNA) pathway. Altogether our data point to an additional piece of the puzzle in the complex RNA metabolism of chloroplasts.
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Affiliation(s)
- Glykeria Mermigka
- Department of Biology, University of Crete, Vassilika Vouton, Heraklion/Crete, GR-71409, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion/Crete, GR-71110, Greece
| | - Jutta Maria Helm
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion/Crete, GR-71110, Greece
| | - Ioannis Vlatakis
- Department of Biology, University of Crete, Vassilika Vouton, Heraklion/Crete, GR-71409, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion/Crete, GR-71110, Greece
| | - Heiko Tobias Schumacher
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion/Crete, GR-71110, Greece
| | - Evgenia Vamvaka
- Department of Biology, University of Crete, Vassilika Vouton, Heraklion/Crete, GR-71409, Greece
| | - Kriton Kalantidis
- Department of Biology, University of Crete, Vassilika Vouton, Heraklion/Crete, GR-71409, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion/Crete, GR-71110, Greece
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27
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Binder S, Stoll K, Stoll B. Maturation of 5' ends of plant mitochondrial RNAs. PHYSIOLOGIA PLANTARUM 2016; 157:280-8. [PMID: 26833432 DOI: 10.1111/ppl.12423] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 12/11/2015] [Accepted: 12/15/2015] [Indexed: 05/26/2023]
Abstract
The generation of mature RNAs, i.e. mRNAs, rRNAs or tRNAs, is a complex process in all genetic systems. RNA-internal processes such as splicing or RNA editing, but also posttranscriptional processes modulating 5' and 3' termini of transcripts, contribute to RNA maturation. In this article, we focus on the posttranscriptional formation of 5' termini of mitochondrial RNAs in seed plants, with particular emphasis on the model plant species Arabidopsis thaliana (Arabidopsis). We will summarize the progress made in recent studies of proteins involved in this process. In addition, we will evaluate whether 5' processing proceeds endo- or exo-nucleolytically. Despite the considerable progress made, many details of this process remain unsolved. In particular, it is still unclear why there is frequent 5' processing of many mRNAs although impaired processing does not interfere with mitochondrial function and plant fitness. Thus, the importance of 5' processing for plant mitochondria is still puzzling.
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Affiliation(s)
- Stefan Binder
- Institut Molekulare Botanik, Universität Ulm, Ulm, D-89069, Germany
| | - Katrin Stoll
- Institut Molekulare Botanik, Universität Ulm, Ulm, D-89069, Germany
| | - Birgit Stoll
- Institut Molekulare Botanik, Universität Ulm, Ulm, D-89069, Germany
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28
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Chloroplast RNA-Binding Protein RBD1 Promotes Chilling Tolerance through 23S rRNA Processing in Arabidopsis. PLoS Genet 2016; 12:e1006027. [PMID: 27138552 PMCID: PMC4854396 DOI: 10.1371/journal.pgen.1006027] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 04/14/2016] [Indexed: 01/17/2023] Open
Abstract
Plants have varying abilities to tolerate chilling (low but not freezing temperatures), and it is largely unknown how plants such as Arabidopsis thaliana achieve chilling tolerance. Here, we describe a genome-wide screen for genes important for chilling tolerance by their putative knockout mutants in Arabidopsis thaliana. Out of 11,000 T-DNA insertion mutant lines representing half of the genome, 54 lines associated with disruption of 49 genes had a drastic chilling sensitive phenotype. Sixteen of these genes encode proteins with chloroplast localization, suggesting a critical role of chloroplast function in chilling tolerance. Study of one of these proteins RBD1 with an RNA binding domain further reveals the importance of chloroplast translation in chilling tolerance. RBD1 is expressed in the green tissues and is localized in the chloroplast nucleoid. It binds directly to 23S rRNA and the binding is stronger under chilling than at normal growth temperatures. The rbd1 mutants are defective in generating mature 23S rRNAs and deficient in chloroplast protein synthesis especially under chilling conditions. Together, our study identifies RBD1 as a regulator of 23S rRNA processing and reveals the importance of chloroplast function especially protein translation in chilling tolerance. Compared to cold acclimation (enhancement of freezing tolerance by a prior exposure to low non-freezing temperature), the tolerance mechanism to non-freezing chilling temperatures is not well understood. Here, we performed a genome-wide mutant screen for chilling sensitive phenotype and identified 49 candidate genes important for chilling tolerance in Arabidopsis. Among the proteins encoded by these 49 genes, 16 are annotated as having chloroplast localization, suggesting a critical role of chloroplast function in chilling tolerance. We further studied RBD1, one of the four RNA-binding proteins localized to chloroplast. RBD1 is only expressed in the green photosynthetic tissues and is localized to nucleoid of chloroplasts. Furthermore, RBD1 is found to be a regulator of 23S rRNA processing likely through direct binding to the precursor of 23S rRNA in a temperature dependent manner. Our study thus reveals the importance of chloroplast function especially protein translation in chilling tolerance at genome-wide scale and suggests an adaptive mechanism involving low temperature enhanced activities from proteins such as RBD1 in chilling tolerance.
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29
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Wu W, Liu S, Ruwe H, Zhang D, Melonek J, Zhu Y, Hu X, Gusewski S, Yin P, Small ID, Howell KA, Huang J. SOT1, a pentatricopeptide repeat protein with a small MutS-related domain, is required for correct processing of plastid 23S-4.5S rRNA precursors in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:607-21. [PMID: 26800847 DOI: 10.1111/tpj.13126] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 01/12/2016] [Indexed: 05/22/2023]
Abstract
Ribosomal RNA processing is essential for plastid ribosome biogenesis, but is still poorly understood in higher plants. Here, we show that SUPPRESSOR OF THYLAKOID FORMATION1 (SOT1), a plastid-localized pentatricopeptide repeat (PPR) protein with a small MutS-related domain, is required for maturation of the 23S-4.5S rRNA dicistron. Loss of SOT1 function leads to slower chloroplast development, suppression of leaf variegation, and abnormal 23S and 4.5S processing. Predictions based on the PPR motif sequences identified the 5' end of the 23S-4.5S rRNA dicistronic precursor as a putative SOT1 binding site. This was confirmed by electrophoretic mobility shift assay, and by loss of the abundant small RNA 'footprint' associated with this site in sot1 mutants. We found that more than half of the 23S-4.5S rRNA dicistrons in sot1 mutants contain eroded and/or unprocessed 5' and 3' ends, and that the endonucleolytic cleavage product normally released from the 5' end of the precursor is absent in a sot1 null mutant. We postulate that SOT1 binding protects the 5' extremity of the 23S-4.5S rRNA dicistron from exonucleolytic attack, and favours formation of the RNA structure that allows endonucleolytic processing of its 5' and 3' ends.
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MESH Headings
- Arabidopsis/genetics
- Arabidopsis/metabolism
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Base Sequence
- Binding Sites/genetics
- Blotting, Western
- Gene Expression Regulation, Plant
- Mutation
- Plants, Genetically Modified
- Plastids/genetics
- Plastids/metabolism
- Protein Binding
- RNA Precursors/genetics
- RNA Precursors/metabolism
- RNA Processing, Post-Transcriptional
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Ribosomal, 23S/genetics
- RNA, Ribosomal, 23S/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Nucleic Acid
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Affiliation(s)
- Wenjuan Wu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Sheng Liu
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Hannes Ruwe
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Delin Zhang
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, 430070, China
| | - Joanna Melonek
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Yajuan Zhu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Xupeng Hu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Sandra Gusewski
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Ping Yin
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ian D Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
- Centre of Excellence in Computational Systems Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Katharine A Howell
- Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Crawley, Western Australia, 6009, Australia
| | - Jirong Huang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
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30
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Stoll B, Binder S. Two NYN domain containing putative nucleases are involved in transcript maturation in Arabidopsis mitochondria. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 85:278-288. [PMID: 26711866 DOI: 10.1111/tpj.13111] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/11/2015] [Accepted: 12/14/2015] [Indexed: 06/05/2023]
Abstract
Plant mitochondrial transcripts frequently undergo maturation processes at their 5' ends. This almost completely enigmatic process requires the function of several proteins such as RNA processing factors, which are selectively involved in distinct 5' processing events. As RNA processing factors represent pentatricopeptide repeat proteins without apparent enzymatic function, it is hypothesized that a ribonuclease, most likely with endonucleolytic activity is involved in the 5' end maturation. We have now applied a reverse genetic approach to analyze the role of two potential mitochondrial nucleases, MNU1 and MNU2, in Arabidopsis thaliana. Both proteins contain several RNA-binding domains and NYN domains found in other endonucleases. A thorough analysis of various mitochondrial transcripts in MNU1 and MNU2 mutants revealed aberrant transcript pattern characterized by a decrease in mature RNA species often accompanied by an accumulation of larger, 5' extended precursor molecules. In addition, severely reduced amounts of nad9 mRNAs in the rpf2-1/mnu2-1 double mutant indicate a corporate function of RNA processing factor 2 and MNU2 in the maturation of these transcripts. However, the dramatic reduction of the nad9 mRNA is not reflected by the level of the corresponding Nad9 protein, which is found to be only moderately lowered. Collectively, our analysis strongly suggests a function of MNU1 and MNU2 in 5' processing of plant mitochondrial transcripts.
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Affiliation(s)
- Birgit Stoll
- Institut Molekulare Botanik, Universität Ulm, Ulm, D-89069, Germany
| | - Stefan Binder
- Institut Molekulare Botanik, Universität Ulm, Ulm, D-89069, Germany
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31
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Romani I, Manavski N, Morosetti A, Tadini L, Maier S, Kühn K, Ruwe H, Schmitz-Linneweber C, Wanner G, Leister D, Kleine T. A Member of the Arabidopsis Mitochondrial Transcription Termination Factor Family Is Required for Maturation of Chloroplast Transfer RNAIle(GAU). PLANT PHYSIOLOGY 2015; 169:627-46. [PMID: 26152711 PMCID: PMC4577433 DOI: 10.1104/pp.15.00964] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 07/07/2015] [Indexed: 05/20/2023]
Abstract
Plastid gene expression is crucial for organelle function, but the factors that control it are still largely unclear. Members of the so-called mitochondrial transcription termination factor (mTERF) family are found in metazoans and plants and regulate organellar gene expression at different levels. Arabidopsis (Arabidopsis thaliana) mTERF6 is localized in chloroplasts and mitochondria, and its knockout perturbs plastid development and results in seedling lethality. In the leaky mterf6-1 mutant, a defect in photosynthesis is associated with reduced levels of photosystem subunits, although corresponding messenger RNA levels are unaffected, whereas translational capacity and maturation of chloroplast ribosomal RNAs (rRNAs) are perturbed in mterf6-1 mutants. Bacterial one-hybrid screening, electrophoretic mobility shift assays, and coimmunoprecipitation experiments reveal a specific interaction between mTERF6 and an RNA sequence in the chloroplast isoleucine transfer RNA gene (trnI.2) located in the rRNA operon. In vitro, recombinant mTERF6 bound to its plastid DNA target site can terminate transcription. At present, it is unclear whether disturbed rRNA maturation is a primary or secondary defect. However, it is clear that mTERF6 is required for the maturation of trnI.2. This points to an additional function of mTERFs.
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MESH Headings
- 5' Untranslated Regions/genetics
- Aminoacylation
- Arabidopsis/genetics
- Arabidopsis/metabolism
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Base Sequence
- Basic-Leucine Zipper Transcription Factors/genetics
- Basic-Leucine Zipper Transcription Factors/metabolism
- Chloroplasts/metabolism
- DNA, Bacterial/genetics
- Gene Expression Regulation, Plant
- Genetic Loci
- Mitochondria/metabolism
- Mitochondrial Proteins/genetics
- Mitochondrial Proteins/metabolism
- Molecular Sequence Data
- Mutagenesis, Insertional/genetics
- Mutation
- Phenotype
- Photosynthesis
- Protein Binding
- Protein Transport
- RNA Processing, Post-Transcriptional
- RNA, Ribosomal/genetics
- RNA, Transfer, Ile/chemistry
- RNA, Transfer, Ile/genetics
- RNA, Transfer, Ile/metabolism
- Ribosomes/metabolism
- Seedlings/metabolism
- Seeds/ultrastructure
- Transcription Termination, Genetic
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Affiliation(s)
- Isidora Romani
- Plant Molecular Biology (Botany), Department Biology I (I.R., N.M., A.M., L.T., D.L., T.K.), and Ultrastrukturforschung, Department Biology I (G.W.), Ludwig-Maximilians-Universität München, 81252 Planegg-Martinsried, Germany;Mathematisch-Naturwissenschaftliche Fakultät I/Biologie, Molekulare Zellbiologie der Pflanzen, Humboldt-Universität zu Berlin, 10099 Berlin, Germany (S.M., K.K.); andInstitute of Biology, Molecular Genetics, Humboldt-University of Berlin, 10115 Berlin, Germany (H.R., C.S.-L.)
| | - Nikolay Manavski
- Plant Molecular Biology (Botany), Department Biology I (I.R., N.M., A.M., L.T., D.L., T.K.), and Ultrastrukturforschung, Department Biology I (G.W.), Ludwig-Maximilians-Universität München, 81252 Planegg-Martinsried, Germany;Mathematisch-Naturwissenschaftliche Fakultät I/Biologie, Molekulare Zellbiologie der Pflanzen, Humboldt-Universität zu Berlin, 10099 Berlin, Germany (S.M., K.K.); andInstitute of Biology, Molecular Genetics, Humboldt-University of Berlin, 10115 Berlin, Germany (H.R., C.S.-L.)
| | - Arianna Morosetti
- Plant Molecular Biology (Botany), Department Biology I (I.R., N.M., A.M., L.T., D.L., T.K.), and Ultrastrukturforschung, Department Biology I (G.W.), Ludwig-Maximilians-Universität München, 81252 Planegg-Martinsried, Germany;Mathematisch-Naturwissenschaftliche Fakultät I/Biologie, Molekulare Zellbiologie der Pflanzen, Humboldt-Universität zu Berlin, 10099 Berlin, Germany (S.M., K.K.); andInstitute of Biology, Molecular Genetics, Humboldt-University of Berlin, 10115 Berlin, Germany (H.R., C.S.-L.)
| | - Luca Tadini
- Plant Molecular Biology (Botany), Department Biology I (I.R., N.M., A.M., L.T., D.L., T.K.), and Ultrastrukturforschung, Department Biology I (G.W.), Ludwig-Maximilians-Universität München, 81252 Planegg-Martinsried, Germany;Mathematisch-Naturwissenschaftliche Fakultät I/Biologie, Molekulare Zellbiologie der Pflanzen, Humboldt-Universität zu Berlin, 10099 Berlin, Germany (S.M., K.K.); andInstitute of Biology, Molecular Genetics, Humboldt-University of Berlin, 10115 Berlin, Germany (H.R., C.S.-L.)
| | - Swetlana Maier
- Plant Molecular Biology (Botany), Department Biology I (I.R., N.M., A.M., L.T., D.L., T.K.), and Ultrastrukturforschung, Department Biology I (G.W.), Ludwig-Maximilians-Universität München, 81252 Planegg-Martinsried, Germany;Mathematisch-Naturwissenschaftliche Fakultät I/Biologie, Molekulare Zellbiologie der Pflanzen, Humboldt-Universität zu Berlin, 10099 Berlin, Germany (S.M., K.K.); andInstitute of Biology, Molecular Genetics, Humboldt-University of Berlin, 10115 Berlin, Germany (H.R., C.S.-L.)
| | - Kristina Kühn
- Plant Molecular Biology (Botany), Department Biology I (I.R., N.M., A.M., L.T., D.L., T.K.), and Ultrastrukturforschung, Department Biology I (G.W.), Ludwig-Maximilians-Universität München, 81252 Planegg-Martinsried, Germany;Mathematisch-Naturwissenschaftliche Fakultät I/Biologie, Molekulare Zellbiologie der Pflanzen, Humboldt-Universität zu Berlin, 10099 Berlin, Germany (S.M., K.K.); andInstitute of Biology, Molecular Genetics, Humboldt-University of Berlin, 10115 Berlin, Germany (H.R., C.S.-L.)
| | - Hannes Ruwe
- Plant Molecular Biology (Botany), Department Biology I (I.R., N.M., A.M., L.T., D.L., T.K.), and Ultrastrukturforschung, Department Biology I (G.W.), Ludwig-Maximilians-Universität München, 81252 Planegg-Martinsried, Germany;Mathematisch-Naturwissenschaftliche Fakultät I/Biologie, Molekulare Zellbiologie der Pflanzen, Humboldt-Universität zu Berlin, 10099 Berlin, Germany (S.M., K.K.); andInstitute of Biology, Molecular Genetics, Humboldt-University of Berlin, 10115 Berlin, Germany (H.R., C.S.-L.)
| | - Christian Schmitz-Linneweber
- Plant Molecular Biology (Botany), Department Biology I (I.R., N.M., A.M., L.T., D.L., T.K.), and Ultrastrukturforschung, Department Biology I (G.W.), Ludwig-Maximilians-Universität München, 81252 Planegg-Martinsried, Germany;Mathematisch-Naturwissenschaftliche Fakultät I/Biologie, Molekulare Zellbiologie der Pflanzen, Humboldt-Universität zu Berlin, 10099 Berlin, Germany (S.M., K.K.); andInstitute of Biology, Molecular Genetics, Humboldt-University of Berlin, 10115 Berlin, Germany (H.R., C.S.-L.)
| | - Gerhard Wanner
- Plant Molecular Biology (Botany), Department Biology I (I.R., N.M., A.M., L.T., D.L., T.K.), and Ultrastrukturforschung, Department Biology I (G.W.), Ludwig-Maximilians-Universität München, 81252 Planegg-Martinsried, Germany;Mathematisch-Naturwissenschaftliche Fakultät I/Biologie, Molekulare Zellbiologie der Pflanzen, Humboldt-Universität zu Berlin, 10099 Berlin, Germany (S.M., K.K.); andInstitute of Biology, Molecular Genetics, Humboldt-University of Berlin, 10115 Berlin, Germany (H.R., C.S.-L.)
| | - Dario Leister
- Plant Molecular Biology (Botany), Department Biology I (I.R., N.M., A.M., L.T., D.L., T.K.), and Ultrastrukturforschung, Department Biology I (G.W.), Ludwig-Maximilians-Universität München, 81252 Planegg-Martinsried, Germany;Mathematisch-Naturwissenschaftliche Fakultät I/Biologie, Molekulare Zellbiologie der Pflanzen, Humboldt-Universität zu Berlin, 10099 Berlin, Germany (S.M., K.K.); andInstitute of Biology, Molecular Genetics, Humboldt-University of Berlin, 10115 Berlin, Germany (H.R., C.S.-L.)
| | - Tatjana Kleine
- Plant Molecular Biology (Botany), Department Biology I (I.R., N.M., A.M., L.T., D.L., T.K.), and Ultrastrukturforschung, Department Biology I (G.W.), Ludwig-Maximilians-Universität München, 81252 Planegg-Martinsried, Germany;Mathematisch-Naturwissenschaftliche Fakultät I/Biologie, Molekulare Zellbiologie der Pflanzen, Humboldt-Universität zu Berlin, 10099 Berlin, Germany (S.M., K.K.); andInstitute of Biology, Molecular Genetics, Humboldt-University of Berlin, 10115 Berlin, Germany (H.R., C.S.-L.)
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Liu J, Zhou W, Liu G, Yang C, Sun Y, Wu W, Cao S, Wang C, Hai G, Wang Z, Bock R, Huang J, Cheng Y. The conserved endoribonuclease YbeY is required for chloroplast ribosomal RNA processing in Arabidopsis. PLANT PHYSIOLOGY 2015; 168:205-21. [PMID: 25810095 PMCID: PMC4424013 DOI: 10.1104/pp.114.255000] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 03/23/2015] [Indexed: 05/20/2023]
Abstract
Maturation of chloroplast ribosomal RNAs (rRNAs) comprises several endoribonucleolytic and exoribonucleolytic processing steps. However, little is known about the specific enzymes involved and the cleavage steps they catalyze. Here, we report the functional characterization of the single Arabidopsis (Arabidopsis thaliana) gene encoding a putative YbeY endoribonuclease. AtYbeY null mutants are seedling lethal, indicating that AtYbeY function is essential for plant growth. Knockdown plants display slow growth and show pale-green leaves. Physiological and ultrastructural analyses of atybeY mutants revealed impaired photosynthesis and defective chloroplast development. Fluorescent microcopy analysis showed that, when fused with the green fluorescence protein, AtYbeY is localized in chloroplasts. Immunoblot and RNA gel-blot assays revealed that the levels of chloroplast-encoded subunits of photosynthetic complexes are reduced in atybeY mutants, but the corresponding transcripts accumulate normally. In addition, atybeY mutants display defective maturation of both the 5' and 3' ends of 16S, 23S, and 4.5S rRNAs as well as decreased accumulation of mature transcripts from the transfer RNA genes contained in the chloroplast rRNA operon. Consequently, mutant plants show a severe deficiency in ribosome biogenesis, which, in turn, results in impaired plastid translational activity. Furthermore, biochemical assays show that recombinant AtYbeY is able to cleave chloroplast rRNAs as well as messenger RNAs and transfer RNAs in vitro. Taken together, our findings indicate that AtYbeY is a chloroplast-localized endoribonuclease that is required for chloroplast rRNA processing and thus for normal growth and development.
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Affiliation(s)
- Jinwen Liu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Wenbin Zhou
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Guifeng Liu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Chuanping Yang
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Yi Sun
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Wenjuan Wu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Shenquan Cao
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Chong Wang
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Guanghui Hai
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Zhifeng Wang
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Ralph Bock
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Jirong Huang
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
| | - Yuxiang Cheng
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China (J.L., G.L., C.Y., S.C., C.W., G.H., Z.W., Y.C.);College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China (J.L.);National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Science, Chinese Academy of Sciences, Shanghai 200032, China (W.Z., Y.S., W.W., J.H.); andMax-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany (R.B.)
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Hotto AM, Castandet B, Gilet L, Higdon A, Condon C, Stern DB. Arabidopsis chloroplast mini-ribonuclease III participates in rRNA maturation and intron recycling. THE PLANT CELL 2015; 27:724-40. [PMID: 25724636 PMCID: PMC4558656 DOI: 10.1105/tpc.114.134452] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 12/24/2014] [Accepted: 02/09/2015] [Indexed: 05/21/2023]
Abstract
RNase III proteins recognize double-stranded RNA structures and catalyze endoribonucleolytic cleavages that often regulate gene expression. Here, we characterize the functions of RNC3 and RNC4, two Arabidopsis thaliana chloroplast Mini-RNase III-like enzymes sharing 75% amino acid sequence identity. Whereas rnc3 and rnc4 null mutants have no visible phenotype, rnc3/rnc4 (rnc3/4) double mutants are slightly smaller and chlorotic compared with the wild type. In Bacillus subtilis, the RNase Mini-III is integral to 23S rRNA maturation. In Arabidopsis, we observed imprecise maturation of 23S rRNA in the rnc3/4 double mutant, suggesting that exoribonucleases generated staggered ends in the absence of specific Mini-III-catalyzed cleavages. A similar phenotype was found at the 3' end of the 16S rRNA, and the primary 4.5S rRNA transcript contained 3' extensions, suggesting that Mini-III catalyzes several processing events of the polycistronic rRNA precursor. The rnc3/4 mutant showed overaccumulation of a noncoding RNA complementary to the 4.5S-5S rRNA intergenic region, and its presence correlated with that of the extended 4.5S rRNA precursor. Finally, we found rnc3/4-specific intron degradation intermediates that are probable substrates for Mini-III and show that B. subtilis Mini-III is also involved in intron regulation. Overall, this study extends our knowledge of the key role of Mini-III in intron and noncoding RNA regulation and provides important insight into plastid rRNA maturation.
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MESH Headings
- Amino Acid Sequence
- Arabidopsis/metabolism
- Arabidopsis Proteins/chemistry
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Bacillus subtilis/metabolism
- Base Sequence
- Chloroplasts/metabolism
- Evolution, Molecular
- Exons/genetics
- Genetic Complementation Test
- Introns/genetics
- Models, Biological
- Molecular Sequence Data
- Mutation/genetics
- Polyribosomes/metabolism
- Protein Structure, Tertiary
- RNA Stability
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Ribosomal, 23S/genetics
- RNA, Untranslated/genetics
- Ribonuclease III/metabolism
- Ribosomes/metabolism
- Sequence Analysis, RNA
- Sequence Homology, Amino Acid
- Transgenes
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Affiliation(s)
- Amber M Hotto
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853
| | - Benoît Castandet
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853
| | - Laetitia Gilet
- Centre National de la Recherche Scientifique FRE3630, Université de Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Andrea Higdon
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853
| | - Ciarán Condon
- Centre National de la Recherche Scientifique FRE3630, Université de Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - David B Stern
- Boyce Thompson Institute for Plant Research, Ithaca, New York 14853
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Tiller N, Bock R. The translational apparatus of plastids and its role in plant development. MOLECULAR PLANT 2014; 7:1105-20. [PMID: 24589494 PMCID: PMC4086613 DOI: 10.1093/mp/ssu022] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 02/26/2014] [Indexed: 05/18/2023]
Abstract
Chloroplasts (plastids) possess a genome and their own machinery to express it. Translation in plastids occurs on bacterial-type 70S ribosomes utilizing a set of tRNAs that is entirely encoded in the plastid genome. In recent years, the components of the chloroplast translational apparatus have been intensely studied by proteomic approaches and by reverse genetics in the model systems tobacco (plastid-encoded components) and Arabidopsis (nucleus-encoded components). This work has provided important new insights into the structure, function, and biogenesis of chloroplast ribosomes, and also has shed fresh light on the molecular mechanisms of the translation process in plastids. In addition, mutants affected in plastid translation have yielded strong genetic evidence for chloroplast genes and gene products influencing plant development at various levels, presumably via retrograde signaling pathway(s). In this review, we describe recent progress with the functional analysis of components of the chloroplast translational machinery and discuss the currently available evidence that supports a significant impact of plastid translational activity on plant anatomy and morphology.
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Affiliation(s)
- Nadine Tiller
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Ralph Bock
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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35
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Bohne AV. The nucleoid as a site of rRNA processing and ribosome assembly. FRONTIERS IN PLANT SCIENCE 2014; 5:257. [PMID: 24926303 PMCID: PMC4046486 DOI: 10.3389/fpls.2014.00257] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 05/19/2014] [Indexed: 05/08/2023]
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36
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Jeon Y, Ahn CS, Jung HJ, Kang H, Park GT, Choi Y, Hwang J, Pai HS. DER containing two consecutive GTP-binding domains plays an essential role in chloroplast ribosomal RNA processing and ribosome biogenesis in higher plants. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:117-30. [PMID: 24272962 PMCID: PMC3883289 DOI: 10.1093/jxb/ert360] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
This study investigated protein characteristics and physiological functions of DER (Double Era-like GTPase) of higher plants. Nicotiana benthamiana DER (NbDER) contained two tandemly repeated GTP-binding domains (GD) and a C-terminal domain (CTD) that was similar to the K-homology domain involved in RNA binding. Both GDs possessed GTPase activity and contributed to the maximum GTPase activity of NbDER. NbDER fused to green fluorescent protein was localized primarily to chloroplast nucleoids. Arabidopsis der null mutants exhibited an embryonic lethal phenotype, indicating an essential function of DER during plant embryogenesis. Virus-induced gene silencing of NbDER resulted in a leaf-yellowing phenotype caused by disrupted chloroplast biogenesis. NbDER was associated primarily with the chloroplast 50S ribosomal subunit in vivo, and both the CTD and the two GD contributed to the association. Recombinant proteins of NbDER and its CTD could bind to 23S and 16S ribosomal RNAs in vitro. Depletion of NbDER impaired processing of plastid-encoded ribosomal RNAs, resulting in accumulation of the precursor rRNAs in the chloroplasts. NbDER-deficient chloroplasts contained significantly reduced levels of mature 23S and 16S rRNAs and diverse mRNAs in the polysomal fractions, suggesting decreased translation in chloroplasts. These results suggest that DER is involved in chloroplast rRNA processing and ribosome biogenesis in higher plants.
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Affiliation(s)
- Young Jeon
- Department of Systems Biology, Yonsei University, Seoul 120-749, Korea
| | - Chang Sook Ahn
- Department of Systems Biology, Yonsei University, Seoul 120-749, Korea
| | - Hyun Ju Jung
- Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Korea
| | - Hunseung Kang
- Department of Plant Biotechnology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Korea
| | - Guen Tae Park
- School of Biological Sciences, Seoul National University, Seoul 151-;747, Korea
| | - Yeonhee Choi
- School of Biological Sciences, Seoul National University, Seoul 151-;747, Korea
| | - Jihwan Hwang
- Department of Microbiology, Pusan National University, Busan 609-735, Korea
| | - Hyun-Sook Pai
- Department of Systems Biology, Yonsei University, Seoul 120-749, Korea
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37
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Fristedt R, Scharff LB, Clarke CA, Wang Q, Lin C, Merchant SS, Bock R. RBF1, a plant homolog of the bacterial ribosome-binding factor RbfA, acts in processing of the chloroplast 16S ribosomal RNA. PLANT PHYSIOLOGY 2014; 164:201-15. [PMID: 24214533 PMCID: PMC3875801 DOI: 10.1104/pp.113.228338] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 11/07/2013] [Indexed: 05/20/2023]
Abstract
Plastids (chloroplasts) possess 70S ribosomes that are very similar in structure and function to the ribosomes of their bacterial ancestors. While most components of the bacterial ribosome (ribosomal RNAs [rRNAs] and ribosomal proteins) are well conserved in the plastid ribosome, little is known about the factors mediating the biogenesis of plastid ribosomes. Here, we have investigated a putative homolog of the bacterial RbfA (for ribosome-binding factor A) protein that was identified as a cold-shock protein and an auxiliary factor acting in the 5' maturation of the 16S rRNA. The unicellular green alga Chlamydomonas reinhardtii and the vascular plant Arabidopsis (Arabidopsis thaliana) both encode a single RbfA-like protein in their nuclear genomes. By generating specific antibodies against this protein, we show that the plant RbfA-like protein functions exclusively in the plastid, where it is associated with thylakoid membranes. Analysis of mutants for the corresponding gene (termed RBF1) reveals that the gene function is essential for photoautotrophic growth. Weak mutant alleles display reduced levels of plastid ribosomes, a specific depletion in 30S ribosomal subunits, and reduced activity of plastid protein biosynthesis. Our data suggest that, while the function in ribosome maturation and 16S rRNA 5' end processing is conserved, the RBF1 protein has assumed an additional role in 3' end processing. Together with the apparent absence of a homologous protein from plant mitochondria, our findings illustrate that the assembly process of the 70S ribosome is not strictly conserved and has undergone some modifications during organelle evolution.
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Reis FP, Barbas A, Klauer-King AA, Tsanova B, Schaeffer D, López-Viñas E, Gómez-Puertas P, van Hoof A, Arraiano CM. Modulating the RNA processing and decay by the exosome: altering Rrp44/Dis3 activity and end-product. PLoS One 2013; 8:e76504. [PMID: 24265673 PMCID: PMC3827031 DOI: 10.1371/journal.pone.0076504] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 08/27/2013] [Indexed: 01/02/2023] Open
Abstract
In eukaryotes, the exosome plays a central role in RNA maturation, turnover, and quality control. In Saccharomyces cerevisiae, the core exosome is composed of nine catalytically inactive subunits constituting a ring structure and the active nuclease Rrp44, also known as Dis3. Rrp44 is a member of the ribonuclease II superfamily of exoribonucleases which include RNase R, Dis3L1 and Dis3L2. In this work we have functionally characterized three residues located in the highly conserved RNB catalytic domain of Rrp44: Y595, Q892 and G895. To address their precise role in Rrp44 activity, we have constructed Rrp44 mutants and compared their activity to the wild-type Rrp44. When we mutated residue Q892 and tested its activity in vitro, the enzyme became slightly more active. We also showed that when we mutated Y595, the final degradation product of Rrp44 changed from 4 to 5 nucleotides. This result confirms that this residue is responsible for the stacking of the RNA substrate in the catalytic cavity, as was predicted from the structure of Rrp44. Furthermore, we also show that a strain with a mutation in this residue has a growth defect and affects RNA processing and degradation. These results lead us to hypothesize that this residue has an important biological role. Molecular dynamics modeling of these Rrp44 mutants and the wild-type enzyme showed changes that extended beyond the mutated residues and helped to explain these results.
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Affiliation(s)
- Filipa P. Reis
- Instituto de Tecnologia Química e Biológica - ITQB, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ana Barbas
- Instituto de Tecnologia Química e Biológica - ITQB, Universidade Nova de Lisboa, Oeiras, Portugal
| | - A. A. Klauer-King
- Department of Microbiology and Molecular Genetics, and The University of Texas Graduate School of Biomedical Sciences, University of Texas Health Science Center-Houston, Houston, Texas, United States of America
| | - Borislava Tsanova
- Department of Microbiology and Molecular Genetics, and The University of Texas Graduate School of Biomedical Sciences, University of Texas Health Science Center-Houston, Houston, Texas, United States of America
| | - Daneen Schaeffer
- Department of Microbiology and Molecular Genetics, and The University of Texas Graduate School of Biomedical Sciences, University of Texas Health Science Center-Houston, Houston, Texas, United States of America
| | - Eduardo López-Viñas
- Centro de Biologia Molecular “Severo Ochoa” (CSIC-UAM), Campus Universidad Autonoma de Madrid, Madrid, Spain
- Biomol-Informatics SL, Madrid, Spain
| | - Paulino Gómez-Puertas
- Centro de Biologia Molecular “Severo Ochoa” (CSIC-UAM), Campus Universidad Autonoma de Madrid, Madrid, Spain
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics, and The University of Texas Graduate School of Biomedical Sciences, University of Texas Health Science Center-Houston, Houston, Texas, United States of America
| | - Cecília M. Arraiano
- Instituto de Tecnologia Química e Biológica - ITQB, Universidade Nova de Lisboa, Oeiras, Portugal
- * E-mail:
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39
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Liu X, Zheng M, Wang R, Wang R, An L, Rodermel SR, Yu F. Genetic interactions reveal that specific defects of chloroplast translation are associated with the suppression of var2-mediated leaf variegation. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:979-93. [PMID: 23721655 DOI: 10.1111/jipb.12078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 05/21/2013] [Indexed: 05/09/2023]
Abstract
Arabidopsis thaliana L. yellow variegated (var2) mutant is defective in a chloroplast FtsH family metalloprotease, AtFtsH2/VAR2, and displays an intriguing green and white leaf variegation. This unique var2-mediated leaf variegation offers a simple yet powerful tool for dissecting the genetic regulation of chloroplast development. Here, we report the isolation and characterization of a new var2 suppressor gene, SUPPRESSOR OF VARIEGATION8 (SVR8), which encodes a putative chloroplast ribosomal large subunit protein, L24. Mutations in SVR8 suppress var2 leaf variegation at ambient temperature and partially suppress the cold-induced chlorosis phenotype of var2. Loss of SVR8 causes unique chloroplast rRNA processing defects, particularly the 23S-4.5S dicistronic precursor. The recovery of the major abnormal processing site in svr8 23S-4.5S precursor indicate that it does not lie in the same position where SVR8/L24 binds on the ribosome. Surprisingly, we found that the loss of a chloroplast ribosomal small subunit protein, S21, results in aberrant chloroplast rRNA processing but not suppression of var2 variegation. These findings suggest that the disruption of specific aspects of chloroplast translation, rather than a general impairment in chloroplast translation, suppress var2 variegation and the existence of complex genetic interactions in chloroplast development.
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Affiliation(s)
- Xiayan Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, 712100, China
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40
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Germain A, Hotto AM, Barkan A, Stern DB. RNA processing and decay in plastids. WILEY INTERDISCIPLINARY REVIEWS-RNA 2013; 4:295-316. [PMID: 23536311 DOI: 10.1002/wrna.1161] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Plastids were derived through endosymbiosis from a cyanobacterial ancestor, whose uptake was followed by massive gene transfer to the nucleus, resulting in the compact size and modest coding capacity of the extant plastid genome. Plastid gene expression is essential for plant development, but depends on nucleus-encoded proteins recruited from cyanobacterial or host-cell origins. The plastid genome is heavily transcribed from numerous promoters, giving posttranscriptional events a critical role in determining the quantity and sizes of accumulating RNA species. The major events reviewed here are RNA editing, which restores protein conservation or creates correct open reading frames by converting C residues to U, RNA splicing, which occurs both in cis and trans, and RNA cleavage, which relies on a variety of exoribonucleases and endoribonucleases. Because the RNases have little sequence specificity, they are collectively able to remove extraneous RNAs whose ends are not protected by RNA secondary structures or sequence-specific RNA-binding proteins (RBPs). Other plastid RBPs, largely members of the helical-repeat superfamily, confer specificity to editing and splicing reactions. The enzymes that catalyze RNA processing are also the main actors in RNA decay, implying that these antagonistic roles are optimally balanced. We place the actions of RBPs and RNases in the context of a recent proteomic analysis that identifies components of the plastid nucleoid, a protein-DNA complex with multiple roles in gene expression. These results suggest that sublocalization and/or concentration gradients of plastid proteins could underpin the regulation of RNA maturation and degradation.
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41
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Sulthana S, Deutscher MP. Multiple exoribonucleases catalyze maturation of the 3' terminus of 16S ribosomal RNA (rRNA). J Biol Chem 2013; 288:12574-9. [PMID: 23532845 DOI: 10.1074/jbc.c113.459172] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Processing of ribosomal RNA (rRNA) precursors is an important component of RNA metabolism in all cells. However, in no system have we yet identified all the RNases involved in this process. Here, we show that four 3'→5'-exoribonucleases, RNases II, R, and PH, and polynucleotide phosphorylase (PNPase), participate in maturation of the 3' end of 16S rRNA. In their absence, 16S precursor molecules with 33 extra 3'-nt accumulate; however, the presence of any one of the four RNases is sufficient to allow processing to occur, although with different efficiencies. Additionally, we find that in the absence of 3' maturation, 5' processing proceeds much less efficiently. Moreover, mutant 30S particles, containing immature 16S rRNA, form 70S ribosomes very poorly. These findings, together with the earlier discovery that RNases E and G are the 5'-processing enzymes, completes the catalogue of RNases involved in maturation of Escherichia coli 16S rRNA.
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Affiliation(s)
- Shaheen Sulthana
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33101, USA
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42
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Missbach S, Weis BL, Martin R, Simm S, Bohnsack MT, Schleiff E. 40S ribosome biogenesis co-factors are essential for gametophyte and embryo development. PLoS One 2013; 8:e54084. [PMID: 23382868 PMCID: PMC3559688 DOI: 10.1371/journal.pone.0054084] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 12/05/2012] [Indexed: 12/13/2022] Open
Abstract
Ribosome biogenesis is well described in Saccharomyces cerevisiae. In contrast only very little information is available on this pathway in plants. This study presents the characterization of five putative protein co-factors of ribosome biogenesis in Arabidopsis thaliana, namely Rrp5, Pwp2, Nob1, Enp1 and Noc4. The characterization of the proteins in respect to localization, enzymatic activity and association with pre-ribosomal complexes is shown. Additionally, analyses of T-DNA insertion mutants aimed to reveal an involvement of the plant co-factors in ribosome biogenesis. The investigated proteins localize mainly to the nucleolus or the nucleus, and atEnp1 and atNob1 co-migrate with 40S pre-ribosomal complexes. The analysis of T-DNA insertion lines revealed that all proteins are essential in Arabidopsis thaliana and mutant plants show alterations of rRNA intermediate abundance already in the heterozygous state. The most significant alteration was observed in the NOB1 T-DNA insertion line where the P-A3 fragment, a 23S-like rRNA precursor, accumulated. The transmission of the T-DNA through the male and female gametophyte was strongly inhibited indicating a high importance of ribosome co-factor genes in the haploid stages of plant development. Additionally impaired embryogenesis was observed in some mutant plant lines. All results support an involvement of the analyzed proteins in ribosome biogenesis but differences in rRNA processing, gametophyte and embryo development suggested an alternative regulation in plants.
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Affiliation(s)
- Sandra Missbach
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Frankfurt/Main, Germany
| | - Benjamin L. Weis
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Frankfurt/Main, Germany
| | - Roman Martin
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Frankfurt/Main, Germany
| | - Stefan Simm
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Frankfurt/Main, Germany
| | - Markus T. Bohnsack
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Frankfurt/Main, Germany
- Cluster of Excellence Frankfurt; Goethe University, Frankfurt/Main, Germany
| | - Enrico Schleiff
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, Frankfurt/Main, Germany
- Cluster of Excellence Frankfurt; Goethe University, Frankfurt/Main, Germany
- Center of Membrane Proteomics, Goethe University, Frankfurt/Main, Germany
- * E-mail:
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43
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Conserved bacterial RNase YbeY plays key roles in 70S ribosome quality control and 16S rRNA maturation. Mol Cell 2012; 49:427-38. [PMID: 23273979 DOI: 10.1016/j.molcel.2012.11.025] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 10/18/2012] [Accepted: 11/21/2012] [Indexed: 12/29/2022]
Abstract
Quality control of ribosomes is critical for cellular function since protein mistranslation leads to severe physiological consequences. We report evidence of a previously unrecognized ribosome quality control system in bacteria that operates at the level of 70S to remove defective ribosomes. YbeY, a previously unidentified endoribonuclease, and the exonuclease RNase R act together by a process mediated specifically by the 30S ribosomal subunit, to degrade defective 70S ribosomes but not properly matured 70S ribosomes or individual subunits. Furthermore, there is essentially no fully matured 16S rRNA in a ΔybeY mutant at 45°C, making YbeY the only endoribonuclease to be implicated in the critically important processing of the 16S rRNA 3' terminus. These key roles in ribosome quality control and maturation indicate why YbeY is a member of the minimal bacterial gene set and suggest that it could be a potential target for antibacterial drugs.
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44
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Hotto AM, Germain A, Stern DB. Plastid non-coding RNAs: emerging candidates for gene regulation. TRENDS IN PLANT SCIENCE 2012; 17:737-44. [PMID: 22981395 DOI: 10.1016/j.tplants.2012.08.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 07/27/2012] [Accepted: 08/05/2012] [Indexed: 05/08/2023]
Abstract
Recent advances in transcriptomics and bioinformatics, specifically strand-specific RNA sequencing, have allowed high-throughput, comprehensive detection of low-abundance transcripts typical of the non-coding RNAs studied in bacteria and eukaryotes. Before this, few plastid non-coding RNAs (pncRNAs) had been identified, and even fewer had been investigated for any functional role in gene regulation. Relaxed plastid transcription initiation and termination result in full transcription of both chloroplast DNA strands. Following this, post-transcriptional processing produces a pool of metastable RNA species, including distinct pncRNAs. Here we review pncRNA biogenesis and possible functionality, and speculate that this RNA class may have an underappreciated role in plastid gene regulation.
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Affiliation(s)
- Amber M Hotto
- Boyce Thompson Institute for Plant Research, Tower Road, Ithaca, NY 14853, USA
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45
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Germain A, Kim SH, Gutierrez R, Stern DB. Ribonuclease II preserves chloroplast RNA homeostasis by increasing mRNA decay rates, and cooperates with polynucleotide phosphorylase in 3' end maturation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 72:960-971. [PMID: 23061883 DOI: 10.1111/tpj.12006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Ribonuclease R (RNR1) and polynucleotide phosphorylase (cpPNPase) are the two known 3'→5' exoribonucleases in Arabidopsis chloroplasts, and are involved in several aspects of rRNA and mRNA metabolism. In this work, we show that mutants lacking both RNR1 and cpPNPase exhibit embryo lethality, akin to the non-viability of the analogous double mutant in Escherichia coli. We were successful, however, in combining an rnr1 null mutation with weak pnp mutant alleles, and show that the resulting chlorotic plants display a global reduction in RNA abundance. Such a counterintuitive outcome following the loss of RNA degradation activity suggests a major importance of RNA maturation as a determinant of RNA stability. Detailed analysis of the double mutant demonstrates that the enzymes catalyze a two-step maturation of mRNA 3' ends, with RNR1 polishing 3' termini created by cpPNPase. The bulky quaternary structure of cpPNPase compared with RNR1 could explain this activity split between the two enzymes. In contrast to the double mutants, the rnr1 single mutant overaccumulates most mRNA species when compared with the wild type. The excess mRNAs in rnr1 are often present in non-polysomal fractions, and half-life measurements demonstrate a substantial increase in the stability of most mRNA species tested. Together, our data reveal the cooperative activity of two 3'→5' exoribonucleases in chloroplast mRNA 3' end maturation, and support the hypothesis that RNR1 plays a significant role in the destabilization of mRNAs unprotected by ribosomes.
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Affiliation(s)
- Arnaud Germain
- Boyce Thompson Institute for Plant Research, Tower Road, Ithaca, NY 14853, USA
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46
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Kim BH, Malec P, Waloszek A, von Arnim AG. Arabidopsis BPG2: a phytochrome-regulated gene whose protein product binds to plastid ribosomal RNAs. PLANTA 2012; 236:677-90. [PMID: 22526496 DOI: 10.1007/s00425-012-1638-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 03/22/2012] [Indexed: 05/08/2023]
Abstract
BPG2 (Brz-insensitive pale green 2) is a dark-repressible and light-inducible gene that is required for the greening process in Arabidopsis. Light pulse experiments suggested that light-regulated gene expression of BPG2 is mediated by phytochrome. The T-DNA insertion mutant bpg2-2 exhibited a reduced level of chlorophyll and carotenoid pigmentation in the plastids. Measurements of time resolved chlorophyll fluorescence and of fluorescence emission at 77 K indicated defective photosystem II and altered photosystem I functions in bpg2 mutants. Kinetic analysis of chlorophyll fluorescence induction suggested that the reduction of the primary acceptor (QA) is impaired in bpg2. The observed alterations resulted in reduced photosynthetic efficiency as measured by the electron transfer rate. BPG2 protein is localized in the plastid stroma fraction. Co-immunoprecipitation of a formaldehyde cross-linked RNA-protein complex indicated that BPG2 protein binds with specificity to chloroplast 16S and 23S ribosomal RNAs. The direct physical interaction with the plastid rRNAs supports an emerging model whereby BPG2 provides light-regulated ribosomal RNA processing functions, which are rate limiting for development of the plastid and its photosynthetic apparatus.
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Affiliation(s)
- Byung-Hoon Kim
- Department of Natural Sciences, Albany State University, 504 College Drive, Albany, GA 31705, USA.
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47
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Asakura Y, Galarneau E, Watkins KP, Barkan A, van Wijk KJ. Chloroplast RH3 DEAD box RNA helicases in maize and Arabidopsis function in splicing of specific group II introns and affect chloroplast ribosome biogenesis. PLANT PHYSIOLOGY 2012; 159:961-74. [PMID: 22576849 PMCID: PMC3387720 DOI: 10.1104/pp.112.197525] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 05/08/2012] [Indexed: 05/18/2023]
Abstract
Chloroplasts in angiosperms contain at least seven nucleus-encoded members of the DEAD box RNA helicase family. Phylogenetic analysis shows that five of these plastid members (RH22, -39, -47, -50, and -58) form a single clade and that RH3 forms a clade with two mitochondrial RH proteins (PMH1 and -2) functioning in intron splicing. The function of chloroplast RH3 in maize (Zea mays; ZmRH3) and Arabidopsis (Arabidopsis thaliana; AtRH3) was determined. ZmRH3 and AtRH3 are both under strong developmental control, and ZmRH3 abundance sharply peaked in the sink-source transition zone of developing maize leaves, coincident with the plastid biogenesis machinery. ZmRH3 coimmunoprecipitated with a specific set of plastid RNAs, including several group II introns, as well as pre23S and 23S ribosomal RNA (rRNA), but not 16S rRNA. Furthermore, ZmRH3 associated with 50S preribosome particles as well as nucleoids. AtRH3 null mutants are embryo lethal, whereas a weak allele (rh3-4) results in pale-green seedlings with defects in splicing of several group II introns and rRNA maturation as well as reduced levels of assembled ribosomes. These results provide strong evidence that RH3 functions in the splicing of group II introns and possibly also contributes to the assembly of the 50S ribosomal particle. Previously, we observed 5- to 10-fold up-regulation of AtRH3 in plastid Caseinolytic protease mutants. The results shown here indicate that AtRH3 up-regulation was not a direct consequence of reduced proteolysis but constituted a compensatory response at both RH3 transcript and protein levels to impaired chloroplast biogenesis; this response demonstrates that cross talk between the chloroplast and the nucleus is used to regulate RH3 levels.
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Affiliation(s)
- Yukari Asakura
- Department of Plant Biology, Cornell University, Ithaca, New York 14853, USA
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48
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Stoppel R, Manavski N, Schein A, Schuster G, Teubner M, Schmitz-Linneweber C, Meurer J. RHON1 is a novel ribonucleic acid-binding protein that supports RNase E function in the Arabidopsis chloroplast. Nucleic Acids Res 2012; 40:8593-606. [PMID: 22735703 PMCID: PMC3458557 DOI: 10.1093/nar/gks613] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The Arabidopsis endonuclease RNase E (RNE) is localized in the chloroplast and is involved in processing of plastid ribonucleic acids (RNAs). By expression of a tandem affinity purification-tagged version of the plastid RNE in the Arabidopsis rne mutant background in combination with mass spectrometry, we identified the novel vascular plant-specific and co-regulated interaction partner of RNE, designated RHON1. RHON1 is essential for photoautotrophic growth and together with RNE forms a distinct ∼800 kDa complex. Additionally, RHON1 is part of various smaller RNA-containing complexes. RIP-chip and other association studies revealed that a helix-extended-helix-structured Rho-N motif at the C-terminus of RHON1 binds to and supports processing of specific plastid RNAs. In all respects, such as plastid RNA precursor accumulation, protein pattern, increased number and decreased size of chloroplasts and defective chloroplast development, the phenotype of rhon1 knockout mutants resembles that of rne lines. This strongly suggests that RHON1 supports RNE functions presumably by conferring sequence specificity to the endonuclease.
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Affiliation(s)
- Rhea Stoppel
- Department Biology 1, Biocenter of the Ludwig-Maximilians-University Munich, Chair of Plant Molecular Biology, Planegg-Martinsried D-82152, Germany
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49
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Stoppel R, Meurer J. The cutting crew - ribonucleases are key players in the control of plastid gene expression. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1663-73. [PMID: 22140236 DOI: 10.1093/jxb/err401] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Chloroplast biogenesis requires constant adjustment of RNA homeostasis under conditions of on-going developmental and environmental change and its regulation is achieved mainly by post-transcriptional control mechanisms mediated by various nucleus-encoded ribonucleases. More than 180 ribonucleases are annotated in Arabidopsis, but only 17 are predicted to localize to the chloroplast. Although different ribonucleases act at different RNA target sites in vivo, most nucleases that attack RNA are thought to lack intrinsic cleavage specificity and show non-specific activity in vitro. In vivo, specificity is thought to be imposed by auxiliary RNA-binding proteins, including members of the huge pentatricopeptide repeat family, which protect RNAs from non-specific nucleolytic attack by masking otherwise vulnerable sites. RNA stability is also influenced by secondary structure, polyadenylation, and ribosome binding. Ribonucleases may cleave at internal sites (endonucleases) or digest successively from the 5' or 3' end of the polynucleotide chain (exonucleases). In bacteria, RNases act in the maturation of rRNA and tRNA precursors, as well as in initiating the degradation of mRNAs and small non-coding RNAs. Many ribonucleases in the chloroplasts of higher plants possess homologies to their bacterial counterparts, but their precise functions have rarely been described. However, many ribonucleases present in the chloroplast process polycistronic rRNAs, tRNAs, and mRNAs. The resulting production of monocistronic, translationally competent mRNAs may represent an adaptation to the eukaryotic cellular environment. This review provides a basic overview of the current knowledge of RNases in plastids and highlights gaps to stimulate future studies.
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Affiliation(s)
- Rhea Stoppel
- Biozentrum der Ludwig-Maximilians-Universität, Plant Molecular Biology/Botany, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany
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50
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Chi W, He B, Mao J, Li Q, Ma J, Ji D, Zou M, Zhang L. The function of RH22, a DEAD RNA helicase, in the biogenesis of the 50S ribosomal subunits of Arabidopsis chloroplasts. PLANT PHYSIOLOGY 2012; 158:693-707. [PMID: 22170977 PMCID: PMC3271760 DOI: 10.1104/pp.111.186775] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 12/12/2011] [Indexed: 05/18/2023]
Abstract
The chloroplast ribosome is a large and dynamic ribonucleoprotein machine that is composed of the 30S and 50S subunits. Although the components of the chloroplast ribosome have been identified in the last decade, the molecular mechanisms driving chloroplast ribosome biogenesis remain largely elusive. Here, we show that RNA helicase 22 (RH22), a putative DEAD RNA helicase, is involved in chloroplast ribosome assembly in Arabidopsis (Arabidopsis thaliana). A loss of RH22 was lethal, whereas a knockdown of RH22 expression resulted in virescent seedlings with clear defects in chloroplast ribosomal RNA (rRNA) accumulation. The precursors of 23S and 4.5S, but not 16S, rRNA accumulated in rh22 mutants. Further analysis showed that RH22 was associated with the precursors of 50S ribosomal subunits. These results suggest that RH22 may function in the assembly of 50S ribosomal subunits in chloroplasts. In addition, RH22 interacted with the 50S ribosomal protein RPL24 through yeast two-hybrid and pull-down assays, and it was also bound to a small 23S rRNA fragment encompassing RPL24-binding sites. This action of RH22 may be similar to, but distinct from, that of SrmB, a DEAD RNA helicase that is involved in the ribosomal assembly in Escherichia coli, which suggests that DEAD RNA helicases and rRNA structures may have coevolved with respect to ribosomal assembly and function.
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Affiliation(s)
| | | | | | | | | | | | | | - Lixin Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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