1
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Yuan S, Zhou G, Xu G. Translation machinery: the basis of translational control. J Genet Genomics 2024; 51:367-378. [PMID: 37536497 DOI: 10.1016/j.jgg.2023.07.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/23/2023] [Accepted: 07/23/2023] [Indexed: 08/05/2023]
Abstract
Messenger RNA (mRNA) translation consists of initiation, elongation, termination, and ribosome recycling, carried out by the translation machinery, primarily including tRNAs, ribosomes, and translation factors (TrFs). Translational regulators transduce signals of growth and development, as well as biotic and abiotic stresses, to the translation machinery, where global or selective translational control occurs to modulate mRNA translation efficiency (TrE). As the basis of translational control, the translation machinery directly determines the quality and quantity of newly synthesized peptides and, ultimately, the cellular adaption. Thus, regulating the availability of diverse machinery components is reviewed as the central strategy of translational control. We provide classical signaling pathways (e.g., integrated stress responses) and cellular behaviors (e.g., liquid-liquid phase separation) to exemplify this strategy within different physiological contexts, particularly during host-microbe interactions. With new technologies developed, further understanding this strategy will speed up translational medicine and translational agriculture.
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Affiliation(s)
- Shu Yuan
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, China
| | - Guilong Zhou
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, China
| | - Guoyong Xu
- State Key Laboratory of Hybrid Rice, Institute for Advanced Studies (IAS), Wuhan University, Wuhan, Hubei 430072, China; Hubei Hongshan Laboratory, Wuhan, Hubei 430070, China.
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2
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Truniger V, Pechar GS, Aranda MA. Advances in Understanding the Mechanism of Cap-Independent Cucurbit Aphid-Borne Yellows Virus Protein Synthesis. Int J Mol Sci 2023; 24:17598. [PMID: 38139425 PMCID: PMC10744285 DOI: 10.3390/ijms242417598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/07/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
Non-canonical translation mechanisms have been described for many viral RNAs. In the case of several plant viruses, their protein synthesis is controlled by RNA elements in their genomic 3'-ends that are able to enhance cap-independent translation (3'-CITE). The proposed general mechanism of 3'-CITEs includes their binding to eukaryotic translation initiation factors (eIFs) that reach the 5'-end and AUG start codon through 5'-3'-UTR-interactions. It was previously shown that cucurbit aphid-borne yellows virus (CABYV) has a 3'-CITE, which varies in sequence and structure depending on the phylogenetic group to which the isolate belongs, possibly as a result of adaptation to the different geographical regions. In this work, the cap-independent translation mechanisms of two CABYV 3'-CITEs belonging to the Mediterranean (CMTE) and Asian (CXTE) groups, respectively, were studied. In vivo cap-independent translation assays show that these 3'-CITEs require the presence of the CABYV short genomic 5'-UTR with at least 40% adenines in cis and an accessible 5'-end for its activity. Additionally, they suggest that the eIF4E-independent CABYV 3'-CITE activities may not require either eIF4A or the eIF4F complex, but may depend on eIF4G and PABP. By pulling down host proteins using RNA baits containing both 5'- and 3'-CABYV-UTRs, 80 RNA binding proteins were identified. These interacted preferentially with either CMTE, CXTE, or both. One of these proteins, specifically interacting with the RNA containing CMTE, was HSP70.2. Preliminary results suggested that HSP70.2 may be involved in CMTE- but not CXTE-mediated cap-independent translation activity.
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Affiliation(s)
- Verónica Truniger
- Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas (CEBAS-CSIC), 30100 Murcia, Spain; (G.S.P.); (M.A.A.)
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3
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Due Tankmar M, Reichel M, Arribas-Hernández L, Brodersen P. A YTHDF-PABP interaction is required for m 6 A-mediated organogenesis in plants. EMBO Rep 2023; 24:e57741. [PMID: 38009565 DOI: 10.15252/embr.202357741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 10/25/2023] [Accepted: 10/27/2023] [Indexed: 11/29/2023] Open
Abstract
N6-methyladenosine (m6 A) in mRNA is key to eukaryotic gene regulation. Many m6 A functions involve RNA-binding proteins that recognize m6 A via a YT521-B Homology (YTH) domain. YTH domain proteins contain long intrinsically disordered regions (IDRs) that may mediate phase separation and interaction with protein partners, but whose precise biochemical functions remain largely unknown. The Arabidopsis thaliana YTH domain proteins ECT2, ECT3, and ECT4 accelerate organogenesis through stimulation of cell division in organ primordia. Here, we use ECT2 to reveal molecular underpinnings of this function. We show that stimulation of leaf formation requires the long N-terminal IDR, and we identify two short IDR elements required for ECT2-mediated organogenesis. Of these two, a 19-amino acid region containing a tyrosine-rich motif conserved in both plant and metazoan YTHDF proteins is necessary for binding to the major cytoplasmic poly(A)-binding proteins PAB2, PAB4, and PAB8. Remarkably, overexpression of PAB4 in leaf primordia partially rescues the delayed leaf formation in ect2 ect3 ect4 mutants, suggesting that the ECT2-PAB2/4/8 interaction on target mRNAs of organogenesis-related genes may overcome limiting PAB concentrations in primordial cells.
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Affiliation(s)
| | - Marlene Reichel
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Peter Brodersen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
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4
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Sumitha MK, Kalimuthu M, Aarthy M, Paramasivan R, Kumar A, Gupta B. In silico identification, characterization, and expression analysis of RNA recognition motif (RRM) containing RNA-binding proteins in Aedes aegypti. Parasitol Res 2023; 122:2847-2857. [PMID: 37735272 DOI: 10.1007/s00436-023-07969-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 09/04/2023] [Indexed: 09/23/2023]
Abstract
RNA-binding proteins (RBPs) are the proteins that bind RNAs and regulate their functioning. RBPs in mosquitoes are gaining attention due to their ability to bind flaviviruses and regulate their replication and transmission. Despite their relevance, RBPs in mosquitoes are not explored much. In this study, we screened the whole genome of Aedes aegypti, the primary vector of several pathogenic viruses, and identified the proteins containing RNA recognition motif (RRM), the most abundant protein domain in eukaryotes. Using several in silico strategies, a total of 135 RRM-containing RBPs were identified in Ae. aegypti. The proteins were characterized based on their available annotations and the sequence similarity with Drosophila melanogaster. Ae. aegypti RRM-containing RBPs included serine/arginine-rich (SR) proteins, polyadenylate-binding proteins (PABP), heteronuclear ribonucleoproteins (hnRNP), small nuclear ribonucleoproteins (snRNP), splicing factors, eukaryotic initiation factors, transformers, and nucleolysins. Phylogenetic analysis revealed that the proteins and the domain organization are conserved among Ae. aegypti, Bombyx mori, and Drosophila melanogaster. However, the gene length and the intron-exon organization varied across the insect species. Expression analysis of the genes encoding RBPs using publicly available RNA sequencing data for different developmental time points of the mosquito life cycle starting from the ovary and eggs up to the adults revealed stage-specific expression with several genes preferentially expressed in early embryonic stages and blood-fed female ovaries. This is the first database for the Ae. aegypti RBPs that can serve as the reference base for future investigations. Stage-specific genes can be further explored to determine their role in mosquito growth and development with a focus on developing novel mosquito control strategies.
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Affiliation(s)
- Melveettil Kishor Sumitha
- ICMR-Vector Control Research Centre (VCRC), Field Station, 4, Sarojini Street Chinna Chokkikulam, Madurai, 625002, India
| | - Mariapillai Kalimuthu
- ICMR-Vector Control Research Centre (VCRC), Field Station, 4, Sarojini Street Chinna Chokkikulam, Madurai, 625002, India
| | - Murali Aarthy
- ICMR-Vector Control Research Centre (VCRC), Field Station, 4, Sarojini Street Chinna Chokkikulam, Madurai, 625002, India
| | - Rajaiah Paramasivan
- ICMR-Vector Control Research Centre (VCRC), Field Station, 4, Sarojini Street Chinna Chokkikulam, Madurai, 625002, India
| | - Ashwani Kumar
- ICMR-Vector Control Research Centre (VCRC), Puducherry, India
| | - Bhavna Gupta
- ICMR-Vector Control Research Centre (VCRC), Field Station, 4, Sarojini Street Chinna Chokkikulam, Madurai, 625002, India.
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Jia J, Lu W, Liu B, Fang H, Yu Y, Mo W, Zhang H, Jin X, Shu Y, Long Y, Pei Y, Zhai J. An atlas of plant full-length RNA reveals tissue-specific and monocots-dicots conserved regulation of poly(A) tail length. NATURE PLANTS 2022; 8:1118-1126. [PMID: 35982302 DOI: 10.1038/s41477-022-01224-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Accepted: 07/14/2022] [Indexed: 06/15/2023]
Abstract
Poly(A) tail is a hallmark of eukaryotic messenger RNA and its length plays an essential role in regulating mRNA metabolism. However, a comprehensive resource for plant poly(A) tail length has yet to be established. Here, we applied a poly(A)-enrichment-free, nanopore-based method to profile full-length RNA with poly(A) tail information in plants. Our atlas contains over 120 million polyadenylated mRNA molecules from seven different tissues of Arabidopsis, as well as the shoot tissue of maize, soybean and rice. In most tissues, the size of plant poly(A) tails shows peaks at approximately 20 and 45 nucleotides, while the poly(A) tails in pollen exhibit a distinct pattern with strong peaks centred at 55 and 80 nucleotides. Moreover, poly(A) tail length is regulated in a gene-specific manner-mRNAs with short half-lives in general have long poly(A) tails, while mRNAs with long half-lives are featured with relatively short poly(A) tails that peak at ~45 nucleotides. Across species, poly(A) tails in the nucleus are almost twice as long as in the cytoplasm. Our comprehensive dataset lays the groundwork for future functional and evolutionary studies on poly(A) tail length regulation in plants.
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Affiliation(s)
- Jinbu Jia
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
| | - Wenqin Lu
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
| | - Bo Liu
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
| | - Huihui Fang
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
- School of Life Science and Shanxi Key Laboratory for Research and Development of Regional Plants, Shanxi University, Taiyuan, China
| | - Yiming Yu
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
| | - Weipeng Mo
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
| | - Hong Zhang
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
| | - Xianhao Jin
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
| | - Yi Shu
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
| | - Yanping Long
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
| | - Yanxi Pei
- School of Life Science and Shanxi Key Laboratory for Research and Development of Regional Plants, Shanxi University, Taiyuan, China
| | - Jixian Zhai
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China.
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China.
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China.
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Expression analysis of plant intracellular Ras-group related leucine-rich repeat proteins (PIRLs) in Arabidopsis thaliana. Biochem Biophys Rep 2022; 30:101241. [PMID: 35280522 PMCID: PMC8904235 DOI: 10.1016/j.bbrep.2022.101241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/22/2022] [Accepted: 02/28/2022] [Indexed: 11/21/2022] Open
Abstract
Arabidopsis thaliana contains a family of nine genes known as plant intracellular Ras-group related leucine-rich repeat (LRR) proteins (PIRLs). These are structurally similar to animals and fungal LRR proteins and play important roles in developmental pathways. However, to date, no detailed tissue-specific expression analysis of these PIRLs has been performed. Therefore, in this study, we generated promoter:GUS transgenic plants for the nine A. thaliana PIRL genes and identified their expression patterns in seedlings and floral organs at different developmental stages. Most PIRL members showed expression in the root apical region and in the vascular tissue of primary and lateral roots. Shoot apex-specific expression was recorded for PIRL1 and PIRL8. Furthermore, PIRL1, PIRL3, PIRL5, PIRL6, and PIRL7 showed distinct expression patterns in flowers, especially in pollen and anthers. In addition, co-expression network analysis identified cases where PIRLs were co-expressed with other genes known to have specific functions related to growth and development. Taken together, the tissue-specific expression patterns of PIRL genes improve our understanding of the functions of this gene family in plant growth and development. PIRL constituting gene family in A. thaliana is widely distributed among plants. PIRL1, 2, 3, and 6 were strongly expressed in anther and/or pollen, consistent with their function in pollen development. PIRL7 was distinctively expressed in pollen and pollen tube, suggesting its role in pollen function.
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7
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Abstract
Viruses have evolved diverse strategies to hijack the cellular gene expression system for their replication. The poly(A) binding proteins (PABPs), a family of critical gene expression factors, are viruses' common targets. PABPs act not only as a translation factor but also as a key factor of mRNA metabolism. During viral infections, the activities of PABPs are manipulated by various viruses, subverting the host translation machinery or evading the cellular antiviral defense mechanism. Viruses harness PABPs by modifying their stability, complex formation with other translation initiation factors, or subcellular localization to promote viral mRNAs translation while shutting off or competing with host protein synthesis. For the past decade, many studies have demonstrated the PABPs' roles during viral infection. This review summarizes a comprehensive perspective of PABPs' roles during viral infection and how viruses evade host antiviral defense through the manipulations of PABPs.
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Affiliation(s)
- Jie Gao
- The State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot, China
| | - Yan-Dong Tang
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Wei Hu
- The State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot, China
- State Key Laboratory of Genetic Engineering, Ministry of Education Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Chunfu Zheng
- Department of Immunology, School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Alberta, Canada
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8
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Architectural and functional details of CF IA proteins involved in yeast 3'-end pre-mRNA processing and its significance for eukaryotes: A concise review. Int J Biol Macromol 2021; 193:387-400. [PMID: 34699898 DOI: 10.1016/j.ijbiomac.2021.10.129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/04/2021] [Accepted: 10/18/2021] [Indexed: 11/22/2022]
Abstract
In eukaryotes, maturation of pre-mRNA relies on its precise 3'-end processing. This processing involves co-transcriptional steps regulated by sequence elements and other proteins. Although, it holds tremendous importance, defect in the processing machinery will result in erroneous pre-mRNA maturation leading to defective translation. Remarkably, more than 20 proteins in humans and yeast share homology and execute this processing. The defects in this processing are associated with various diseases in humans. We shed light on the CF IA subunit of yeast Saccharomyces cerevisiae that contains four proteins (Pcf11, Clp1, Rna14 and Rna15) involved in this processing. Structural details of various domains of CF IA and their roles during 3'-end processing, like cleavage and polyadenylation at 3'-UTR of pre-mRNA and other cellular events are explained. Further, the chronological development and important discoveries associated with 3'-end processing are summarized. Moreover, the mammalian homologues of yeast CF IA proteins, along with their key roles are described. This knowledge would be helpful for better comprehension of the mechanism associated with this marvel; thus opening up vast avenues in this area.
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Billey E, Hafidh S, Cruz-Gallardo I, Litholdo CG, Jean V, Carpentier MC, Picart C, Kumar V, Kulichova K, Maréchal E, Honys D, Conte MR, Deragon JM, Bousquet-Antonelli C. LARP6C orchestrates posttranscriptional reprogramming of gene expression during hydration to promote pollen tube guidance. THE PLANT CELL 2021; 33:2637-2661. [PMID: 34124761 DOI: 10.1101/2020.11.27.401307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 05/06/2021] [Indexed: 05/19/2023]
Abstract
Increasing evidence suggests that posttranscriptional regulation is a key player in the transition between mature pollen and the progamic phase (from pollination to fertilization). Nonetheless, the actors in this messenger RNA (mRNA)-based gene expression reprogramming are poorly understood. We demonstrate that the evolutionarily conserved RNA-binding protein LARP6C is necessary for the transition from dry pollen to pollen tubes and the guided growth of pollen tubes towards the ovule in Arabidopsis thaliana. In dry pollen, LARP6C binds to transcripts encoding proteins that function in lipid synthesis and homeostasis, vesicular trafficking, and polarized cell growth. LARP6C also forms cytoplasmic granules that contain the poly(A) binding protein and possibly represent storage sites for translationally silent mRNAs. In pollen tubes, the loss of LARP6C negatively affects the quantities and distribution of storage lipids, as well as vesicular trafficking. In Nicotiana benthamiana leaf cells and in planta, analysis of reporter mRNAs designed from the LARP6C target MGD2 provided evidence that LARP6C can shift from a repressor to an activator of translation when the pollen grain enters the progamic phase. We propose that LARP6C orchestrates the timely posttranscriptional regulation of a subset of mRNAs in pollen during the transition from the quiescent to active state and along the progamic phase to promote male fertilization in plants.
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Affiliation(s)
- Elodie Billey
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
| | - Said Hafidh
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 16502 Prague 6, Czech Republic
| | - Isabel Cruz-Gallardo
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Celso G Litholdo
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
| | - Viviane Jean
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
| | - Marie-Christine Carpentier
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
| | - Claire Picart
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
| | - Vinod Kumar
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 16502 Prague 6, Czech Republic
| | - Katarina Kulichova
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 16502 Prague 6, Czech Republic
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRAE, Université Grenoble Alpes, IRIG, CEA Grenoble, 38054 Grenoble, France
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 16502 Prague 6, Czech Republic
| | - Maria R Conte
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Jean-Marc Deragon
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
- Institut Universitaire de France, 75231 Paris Cedex 5, France
| | - Cécile Bousquet-Antonelli
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
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10
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Billey E, Hafidh S, Cruz-Gallardo I, Litholdo CG, Jean V, Carpentier MC, Picart C, Kumar V, Kulichova K, Maréchal E, Honys D, Conte MR, Deragon JM, Bousquet-Antonelli C. LARP6C orchestrates posttranscriptional reprogramming of gene expression during hydration to promote pollen tube guidance. THE PLANT CELL 2021; 33:2637-2661. [PMID: 34124761 PMCID: PMC8408461 DOI: 10.1093/plcell/koab131] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 05/06/2021] [Indexed: 05/15/2023]
Abstract
Increasing evidence suggests that posttranscriptional regulation is a key player in the transition between mature pollen and the progamic phase (from pollination to fertilization). Nonetheless, the actors in this messenger RNA (mRNA)-based gene expression reprogramming are poorly understood. We demonstrate that the evolutionarily conserved RNA-binding protein LARP6C is necessary for the transition from dry pollen to pollen tubes and the guided growth of pollen tubes towards the ovule in Arabidopsis thaliana. In dry pollen, LARP6C binds to transcripts encoding proteins that function in lipid synthesis and homeostasis, vesicular trafficking, and polarized cell growth. LARP6C also forms cytoplasmic granules that contain the poly(A) binding protein and possibly represent storage sites for translationally silent mRNAs. In pollen tubes, the loss of LARP6C negatively affects the quantities and distribution of storage lipids, as well as vesicular trafficking. In Nicotiana benthamiana leaf cells and in planta, analysis of reporter mRNAs designed from the LARP6C target MGD2 provided evidence that LARP6C can shift from a repressor to an activator of translation when the pollen grain enters the progamic phase. We propose that LARP6C orchestrates the timely posttranscriptional regulation of a subset of mRNAs in pollen during the transition from the quiescent to active state and along the progamic phase to promote male fertilization in plants.
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Affiliation(s)
- Elodie Billey
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
| | - Said Hafidh
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 16502 Prague 6, Czech Republic
| | - Isabel Cruz-Gallardo
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Celso G. Litholdo
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
| | - Viviane Jean
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
| | - Marie-Christine Carpentier
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
| | - Claire Picart
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
| | - Vinod Kumar
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 16502 Prague 6, Czech Republic
| | - Katarina Kulichova
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 16502 Prague 6, Czech Republic
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRAE, Université Grenoble Alpes, IRIG, CEA Grenoble, 38054 Grenoble, France
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, 16502 Prague 6, Czech Republic
| | - Maria R. Conte
- Randall Centre for Cell and Molecular Biophysics, King's College London, London SE1 1UL, UK
| | - Jean-Marc Deragon
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
- Institut Universitaire de France, 75231 Paris Cedex 5, France
| | - Cécile Bousquet-Antonelli
- Laboratoire Génome et Développement des Plantes, UMR5096, CNRS, 66860 Perpignan, France
- Laboratoire Génome et Développement des Plantes, UMR5096, Université de Perpignan Via Domitia, 66860 Perpignan, France
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11
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Náprstková A, Malínská K, Záveská Drábková L, Billey E, Náprstková D, Sýkorová E, Bousquet-Antonelli C, Honys D. Characterization of ALBA Family Expression and Localization in Arabidopsis thaliana Generative Organs. Int J Mol Sci 2021; 22:1652. [PMID: 33562109 PMCID: PMC7914821 DOI: 10.3390/ijms22041652] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 01/31/2021] [Accepted: 02/03/2021] [Indexed: 12/21/2022] Open
Abstract
ALBA DNA/RNA-binding proteins form an ancient family, which in eukaryotes diversified into two Rpp25-like and Rpp20-like subfamilies. In most studied model organisms, their function remains unclear, but they are usually associated with RNA metabolism, mRNA translatability and stress response. In plants, the enriched number of ALBA family members remains poorly understood. Here, we studied ALBA dynamics during reproductive development in Arabidopsis at the levels of gene expression and protein localization, both under standard conditions and following heat stress. In generative tissues, ALBA proteins showed the strongest signal in mature pollen where they localized predominantly in cytoplasmic foci, particularly in regions surrounding the vegetative nucleus and sperm cells. Finally, we demonstrated the involvement of two Rpp25-like subfamily members ALBA4 and ALBA6 in RNA metabolism in mature pollen supported by their co-localization with poly(A)-binding protein 3 (PABP3). Collectively, we demonstrated the engagement of ALBA proteins in male reproductive development and the heat stress response, highlighting the involvement of ALBA4 and ALBA6 in RNA metabolism, storage and/or translational control in pollen upon heat stress. Such dynamic re-localization of ALBA proteins in a controlled, developmentally and environmentally regulated manner, likely reflects not only their redundancy but also their possible functional diversification in plants.
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Affiliation(s)
- Alena Náprstková
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6, Czech Republic; (A.N.); (L.Z.D.); (D.N.)
| | - Kateřina Malínská
- Imaging Facility, Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6, Czech Republic;
| | - Lenka Záveská Drábková
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6, Czech Republic; (A.N.); (L.Z.D.); (D.N.)
| | - Elodie Billey
- CNRS LGDP-UMR5096, 58 Av. Paul Alduy, 66860 Perpignan, France; (E.B.); (C.B.-A.)
- LGDP-UMR5096, Université de Perpignan via Domitia, 58 Av. Paul Alduy, 66860 Perpignan, France
| | - Dagmar Náprstková
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6, Czech Republic; (A.N.); (L.Z.D.); (D.N.)
| | - Eva Sýkorová
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská, 612 00 Brno, Czech Republic;
| | - Cécile Bousquet-Antonelli
- CNRS LGDP-UMR5096, 58 Av. Paul Alduy, 66860 Perpignan, France; (E.B.); (C.B.-A.)
- LGDP-UMR5096, Université de Perpignan via Domitia, 58 Av. Paul Alduy, 66860 Perpignan, France
| | - David Honys
- Laboratory of Pollen Biology, Institute of Experimental Botany of the Czech Academy of Sciences, Rozvojová 263, 165 02 Prague 6, Czech Republic; (A.N.); (L.Z.D.); (D.N.)
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12
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Mahalingam R, Walling JG. Genomic survey of RNA recognition motif (RRM) containing RNA binding proteins from barley (Hordeum vulgare ssp. vulgare). Genomics 2019; 112:1829-1839. [PMID: 31669702 DOI: 10.1016/j.ygeno.2019.10.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/29/2019] [Accepted: 10/25/2019] [Indexed: 01/25/2023]
Abstract
One of the major mechanisms of post-transcriptional gene regulation is achieved by proteins bearing well-defined sequence motifs involved in 'RNA binding'. In eukaryotes, RNA binding proteins (RBPs) are key players of RNA metabolism that includes synthesis, processing, editing, modifying, transport, storage and stability of RNA. In plants, the family of RBPs is vastly expanded compared to other eukaryotes including humans. In this study we identified 363 RBPs in the barley genome. Gene ontology enrichment analysis of barley RBPs indicated these proteins were in all the major cellular compartments and associated with key biological processes including translation, splicing, seed development and stress signaling. Members with the classical RNA binding motifs such as the RNA recognition motif (RRM), KH domain, Helicase, CRM, dsRNA and Pumilio were identified in the repertoire of barley RBPs. Similar to Arabidopsis, the RRM containing RBPs were the most abundant in barley genome. In-depth analysis of the RRM containing proteins - polyA binding proteins, Ser/Arg rich proteins and Glycine-rich RBPs were undertaken. Reanalysis of the proteome dataset of various stages during barley malting identified 38 RBPs suggesting an important role for these proteins during the malting process. This survey provides a systematic analysis of barley RBPs and serves as the basis for the further functional characterization of this important family of proteins.
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Affiliation(s)
| | - Jason G Walling
- 502 Walnut Street, Cereal Crops Research Unit, USDA-ARS, Madison, WI 53726, USA.
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13
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Mining for protein S-sulfenylation in Arabidopsis uncovers redox-sensitive sites. Proc Natl Acad Sci U S A 2019; 116:21256-21261. [PMID: 31578252 DOI: 10.1073/pnas.1906768116] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Hydrogen peroxide (H2O2) is an important messenger molecule for diverse cellular processes. H2O2 oxidizes proteinaceous cysteinyl thiols to sulfenic acid, also known as S-sulfenylation, thereby affecting the protein conformation and functionality. Although many proteins have been identified as S-sulfenylation targets in plants, site-specific mapping and quantification remain largely unexplored. By means of a peptide-centric chemoproteomics approach, we mapped 1,537 S-sulfenylated sites on more than 1,000 proteins in Arabidopsis thaliana cells. Proteins involved in RNA homeostasis and metabolism were identified as hotspots for S-sulfenylation. Moreover, S-sulfenylation frequently occurred on cysteines located at catalytic sites of enzymes or on cysteines involved in metal binding, hinting at a direct mode of action for redox regulation. Comparison of human and Arabidopsis S-sulfenylation datasets provided 155 conserved S-sulfenylated cysteines, including Cys181 of the Arabidopsis MITOGEN-ACTIVATED PROTEIN KINASE4 (AtMAPK4) that corresponds to Cys161 in the human MAPK1, which has been identified previously as being S-sulfenylated. We show that, by replacing Cys181 of recombinant AtMAPK4 by a redox-insensitive serine residue, the kinase activity decreased, indicating the importance of this noncatalytic cysteine for the kinase mechanism. Altogether, we quantitatively mapped the S-sulfenylated cysteines in Arabidopsis cells under H2O2 stress and thereby generated a comprehensive view on the S-sulfenylation landscape that will facilitate downstream plant redox studies.
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14
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Zhao T, Huan Q, Sun J, Liu C, Hou X, Yu X, Silverman IM, Zhang Y, Gregory BD, Liu CM, Qian W, Cao X. Impact of poly(A)-tail G-content on Arabidopsis PAB binding and their role in enhancing translational efficiency. Genome Biol 2019; 20:189. [PMID: 31481099 PMCID: PMC6724284 DOI: 10.1186/s13059-019-1799-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 08/22/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Polyadenylation plays a key role in producing mature mRNAs in eukaryotes. It is widely believed that the poly(A)-binding proteins (PABs) uniformly bind to poly(A)-tailed mRNAs, regulating their stability and translational efficiency. RESULTS We observe that the homozygous triple mutant of broadly expressed Arabidopsis thaliana PABs, AtPAB2, AtPAB4, and AtPAB8, is embryonic lethal. To understand the molecular basis, we characterize the RNA-binding landscape of these PABs. The AtPAB-binding efficiency varies over one order of magnitude among genes. To identify the sequences accounting for the variation, we perform poly(A)-seq that directly sequences the full-length poly(A) tails. More than 10% of poly(A) tails contain at least one guanosine (G); among them, the G-content varies from 0.8 to 28%. These guanosines frequently divide poly(A) tails into interspersed A-tracts and therefore cause the variation in the AtPAB-binding efficiency among genes. Ribo-seq and genome-wide RNA stability assays show that AtPAB-binding efficiency of a gene is positively correlated with translational efficiency rather than mRNA stability. Consistently, genes with stronger AtPAB binding exhibit a greater reduction in translational efficiency when AtPAB is depleted. CONCLUSIONS Our study provides a new mechanism that translational efficiency of a gene can be regulated through the G-content-dependent PAB binding, paving the way for a better understanding of poly(A) tail-associated regulation of gene expression.
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Affiliation(s)
- Taolan Zhao
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qing Huan
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jing Sun
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Chunyan Liu
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiuli Hou
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Xiang Yu
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Ian M Silverman
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Yi Zhang
- Laboratory for Genome Regulation and Human Health and Center for Genome Analysis, ABLife Inc, Wuhan, 430075, Hubei, China
| | - Brian D Gregory
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Chun-Ming Liu
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Wenfeng Qian
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
- Key Laboratory of Genetic Network Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Xiaofeng Cao
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
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15
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Roomi S, Masi A, Conselvan GB, Trevisan S, Quaggiotti S, Pivato M, Arrigoni G, Yasmin T, Carletti P. Protein Profiling of Arabidopsis Roots Treated With Humic Substances: Insights Into the Metabolic and Interactome Networks. FRONTIERS IN PLANT SCIENCE 2018; 9:1812. [PMID: 30619394 PMCID: PMC6299182 DOI: 10.3389/fpls.2018.01812] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 11/21/2018] [Indexed: 05/06/2023]
Abstract
Background and Aim: Humic substances (HSs) influence the chemical and physical properties of the soil, and are also known to affect plant physiology and nutrient uptake. This study aimed to elucidate plant metabolic pathways and physiological processes influenced by HS activity. Methods: Arabidopsis roots were treated with HS for 8 h. Quantitative mass spectrometry-based proteomics analysis of root proteins was performed using the iTRAQ (Isobaric Tag for Relative and Absolute Quantification) technique. Out of 902 protein families identified and quantified for HS treated vs. untreated roots, 92 proteins had different relative content. Bioinformatic tools such as STRING, KEGG, IIS and Cytoscape were used to interpret the biological function, pathway analysis and visualization of network amongst the identified proteins. Results: From this analysis it was possible to evaluate that all of the identified proteins were functionally classified into several categories, mainly redox homeostasis, response to inorganic substances, energy metabolism, protein synthesis, cell trafficking, and division. Conclusion: In the present study an overview of the metabolic pathways most modified by HS biological activity is provided. Activation of enzymes of the glycolytic pathway and up regulation of ribosomal protein indicated a stimulation in energy metabolism and protein synthesis. Regulation of the enzymes involved in redox homeostasis suggest a pivotal role of reactive oxygen species in the signaling and modulation of HS-induced responses.
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Affiliation(s)
- Sohaib Roomi
- Department of Biosciences, COMSATS University Islamabad, Islamabad, Pakistan
| | - Antonio Masi
- Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padua, Padua, Italy
| | | | - Sara Trevisan
- Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padua, Padua, Italy
| | - Silvia Quaggiotti
- Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padua, Padua, Italy
| | - Micaela Pivato
- Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padua, Padua, Italy
| | - Giorgio Arrigoni
- Proteomics Center, University of Padua and Azienda Ospedaliera di Padova, Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Tayyaba Yasmin
- Department of Biosciences, COMSATS University Islamabad, Islamabad, Pakistan
| | - Paolo Carletti
- Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padua, Padua, Italy
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16
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Zoltner M, Krienitz N, Field MC, Kramer S. Comparative proteomics of the two T. brucei PABPs suggests that PABP2 controls bulk mRNA. PLoS Negl Trop Dis 2018; 12:e0006679. [PMID: 30040867 PMCID: PMC6075789 DOI: 10.1371/journal.pntd.0006679] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 08/03/2018] [Accepted: 07/10/2018] [Indexed: 01/17/2023] Open
Abstract
Poly(A)-binding proteins (PABPs) regulate mRNA fate by controlling stability and translation through interactions with both the poly(A) tail and eIF4F complex. Many organisms have several paralogs of PABPs and eIF4F complex components and it is likely that different eIF4F/PABP complex combinations regulate distinct sets of mRNAs. Trypanosomes have five eIF4G paralogs, six of eIF4E and two PABPs, PABP1 and PABP2. Under starvation, polysomes dissociate and the majority of mRNAs, most translation initiation factors and PABP2 reversibly localise to starvation stress granules. To understand this more broadly we identified a protein interaction cohort for both T. brucei PABPs by cryo-mill/affinity purification-mass spectrometry. PABP1 very specifically interacts with the previously identified interactors eIF4E4 and eIF4G3 and few others. In contrast PABP2 is promiscuous, with a larger set of interactors including most translation initiation factors and most prominently eIF4G1, with its two partners TbG1-IP and TbG1-IP2. Only RBP23 was specific to PABP1, whilst 14 RNA-binding proteins were exclusively immunoprecipitated with PABP2. Significantly, PABP1 and associated proteins are largely excluded from starvation stress granules, but PABP2 and most interactors translocate to granules on starvation. We suggest that PABP1 regulates a small subpopulation of mainly small-sized mRNAs, as it interacts with a small and distinct set of proteins unable to enter the dominant pathway into starvation stress granules and localises preferentially to a subfraction of small polysomes. By contrast PABP2 likely regulates bulk mRNA translation, as it interacts with a wide range of proteins, enters stress granules and distributes over the full range of polysomes.
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Affiliation(s)
- Martin Zoltner
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Nina Krienitz
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany
| | - Mark C. Field
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Susanne Kramer
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Am Hubland, Würzburg, Germany
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17
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Gallie DR. Plant growth and fertility requires functional interactions between specific PABP and eIF4G gene family members. PLoS One 2018; 13:e0191474. [PMID: 29381712 PMCID: PMC5790229 DOI: 10.1371/journal.pone.0191474] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 01/07/2018] [Indexed: 11/19/2022] Open
Abstract
The initiation of protein synthesis requires the involvement of the eukaryotic translation initiation factor (eIF) 4G to promote assembly of the factors needed to recruit a 40S ribosomal subunit to an mRNA. Although many eukaryotes express two eIF4G isoforms that are highly similar, those in plants, referred to as eIF4G and eIFiso4G, are highly divergent in size, sequence, and domain organization. Species of the Brassicaceae and the Cleomaceae also express a divergent eIFiso4G isoform, referred to as eIFiso4G2, not found elsewhere in the plant kingdom. Despite their divergence, eIF4G and eIFiso4G interact with eIF4A, eIF4B, and eIF4E isoforms needed for binding an mRNA. eIF4G and eIFiso4G also interact with the poly(A)-binding protein (PABP) which promotes ribosome recruitment to an mRNA. Increasing the complexity of such an interaction, however, Arabidopsis also expresses three PABP isoforms (PAB2, PAB4, and PAB8) in vegetative and reproductive tissues. In this study, the functional interactions among the eIF4G and the widely-expressed PABP isoforms were examined. Loss of PAB2 or PAB8 in combination with loss of eIF4G or eIFiso4G had little to no effect on growth or fertility whereas pab2 pab8 eif4g or pab2 pab8 eifiso4g1/2 mutants exhibited smaller stature and reduced fertility. Although the pab4 eifiso4g1 mutant grows normally and is fertile, pab4 eif4g or pab4 eifiso4g2 mutants could not be isolated. Even pab4/PAB4 eif4g/eIF4G heterozygous plants exhibited growth defects and low fertility. Mutant co-inheritance analysis in reciprocal crosses with wild-type plants revealed that most ovaries and pollen from pab4/PAB4 eif4g/eIF4G plants were PAB4 eif4g. Similarly, co-inheritance studies with pab4/PAB4 eifiso4g2/eIFiso4G2 plants suggested most ovaries were PAB4 eifiso4g2. These results suggest that a functional interaction between PAB4 and eIF4G and between PAB4 and eIFiso4G2 is required for growth and normal fertility.
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Affiliation(s)
- Daniel R. Gallie
- Department of Biochemistry, University of California, Riverside, CA, United States of America
- * E-mail:
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18
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Gallie DR. Class II members of the poly(A) binding protein family exhibit distinct functions during Arabidopsis growth and development. ACTA ACUST UNITED AC 2017; 5:e1295129. [PMID: 28702277 DOI: 10.1080/21690731.2017.1295129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 01/20/2017] [Accepted: 02/09/2017] [Indexed: 10/20/2022]
Abstract
The poly(A)-binding protein (PABP) binds to the poly(A) tail of eukaryotic cellular mRNAs and contributes to their stability and translational efficiency. In plants, PABP is expressed from an unusually large gene family grouped into 3 classes that expanded during the evolution of land plants. Subsequent to expansion of the family, members diverged in their primary sequence and in expression. Further expansion of the family and divergence of its members in the Brassicaceae demonstrate the continued dynamic evolution of PABP in plants. In this study, the function of the widely-expressed class II PABP family members was examined to determine how individual class II members contribute to plant growth and development. Of the 3 class II PABP members, PAB2 and PAB4 contribute most to vegetative growth and vegetative-to-floral transition whereas PAB2, and the recently-evolved third class II member, PAB8, contribute to inflorescence and silique growth. Interestingly, although class I and class III PABP members are expressed specifically in reproductive organs, class II PABP members are also necessary for fertility in that the combinatorial loss of PAB2 and either PAB4 or PAB8 expression resulted in reduced fertility. Although all 3 class II members are required for protein expression, PAB4 contributes most to the steady-state level of a reporter mRNA and to protein expression. These findings suggest that class II PABP members are partially overlapping in function but also involved in distinct aspects of plant growth and development.
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Affiliation(s)
- Daniel R Gallie
- Department of Biochemistry, University of California, Riverside, CA, USA
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19
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Jang JC. Arginine-rich motif-tandem CCCH zinc finger proteins in plant stress responses and post-transcriptional regulation of gene expression. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 252:118-124. [PMID: 27717446 DOI: 10.1016/j.plantsci.2016.06.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/19/2016] [Accepted: 06/20/2016] [Indexed: 05/20/2023]
Abstract
Tandem CCCH zinc finger (TZF) proteins are evolutionarily conserved regulators of gene expression at the post-transcriptional level. TZFs target AU-rich RNA elements at 3' un-translated region and recruit catabolic machineries to trigger mRNA degradation. The plant TZF families are over-represented by a class of proteins with a unique TZF domain preceded by an arginine-rich motif (RR-TZF). RR-TZF proteins are mainly involved in hormone- and environmental cues-mediated plant growth and stress responses. Numerous reports have suggested that RR-TZF proteins control seed germination, plant size, flowering time, and biotic and abiotic stress responses via regulation of gene expression. Despite growing genetic evidence, the underlying molecular mechanisms are elusive. This review outlines the highly conserved roles of plant RR-TZFs in various stress responses and the potential involvements of RR-TZF proteins in transcriptional and post-transcriptional regulation of gene expression. The dynamic subcellular localization of RR-TZF proteins, implication of predominant protein-protein interactions between RR-TZF proteins and stress response mediators and future directions of this research field are also discussed.
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Affiliation(s)
- Jyan-Chyun Jang
- Department of Horticulture and Crop Science, Molecular Genetics, and Center for Applied Plant Sciences, The Ohio State University, Columbus, OH 43210, USA.
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20
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Bogamuwa S, Jang JC. Plant Tandem CCCH Zinc Finger Proteins Interact with ABA, Drought, and Stress Response Regulators in Processing-Bodies and Stress Granules. PLoS One 2016; 11:e0151574. [PMID: 26978070 PMCID: PMC4792416 DOI: 10.1371/journal.pone.0151574] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 03/01/2016] [Indexed: 12/22/2022] Open
Abstract
Although multiple lines of evidence have indicated that Arabidopsis thalianaTandem CCCH Zinc Finger proteins, AtTZF4, 5 and 6 are involved in ABA, GA and phytochrome mediated seed germination responses, the interacting proteins involved in these processes are unknown. Using yeast two-hybrid screens, we have identified 35 putative AtTZF5 interacting protein partners. Among them, Mediator of ABA-Regulated Dormancy 1 (MARD1) is highly expressed in seeds and involved in ABA signal transduction, while Responsive to Dehydration 21A (RD21A) is a well-documented stress responsive protein. Co-immunoprecipitation (Co-IP) and bimolecular fluorescence complementation (BiFC) assays were used to confirm that AtTZF5 can interact with MARD1 and RD21A in plant cells, and the interaction is mediated through TZF motif. In addition, AtTZF4 and 6 could also interact with MARD1 and RD21A in Y-2-H and BiFC assay, respectively. The protein-protein interactions apparently take place in processing bodies (PBs) and stress granules (SGs), because AtTZF5, MARD1 and RD21A could interact and co-localize with each other and they all can co-localize with the same PB and SG markers in plant cells.
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Affiliation(s)
- Srimathi Bogamuwa
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
| | - Jyan-Chyun Jang
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- Center for Applied Plant Sciences, The Ohio State University, Columbus, Ohio, United States of America
- Ohio Agriculture Research and Development Center, The Ohio State University, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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21
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Zuber H, Scheer H, Ferrier E, Sement FM, Mercier P, Stupfler B, Gagliardi D. Uridylation and PABP Cooperate to Repair mRNA Deadenylated Ends in Arabidopsis. Cell Rep 2016; 14:2707-17. [PMID: 26972004 DOI: 10.1016/j.celrep.2016.02.060] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/08/2015] [Accepted: 02/11/2016] [Indexed: 11/30/2022] Open
Abstract
Uridylation emerges as a key modification promoting mRNA degradation in eukaryotes. In addition, uridylation by URT1 prevents the accumulation of excessively deadenylated mRNAs in Arabidopsis. Here, we show that the extent of mRNA deadenylation is controlled by URT1. By using TAIL-seq analysis, we demonstrate the prevalence of mRNA uridylation and the existence, at lower frequencies, of mRNA cytidylation and guanylation in Arabidopsis. Both URT1-dependent and URT1-independent types of uridylation co-exist but only URT1-mediated uridylation prevents the accumulation of excessively deadenylated mRNAs. Importantly, uridylation repairs deadenylated extremities to restore the size distribution observed for non-uridylated oligo(A) tails. In vivo and in vitro data indicate that Poly(A) Binding Protein (PABP) binds to uridylated oligo(A) tails and determines the length of U-extensions added by URT1. Taken together, our results uncover a role for uridylation and PABP in repairing mRNA deadenylated ends and reveal that uridylation plays diverse roles in eukaryotic mRNA metabolism.
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Affiliation(s)
- Hélène Zuber
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 67000 Strasbourg, France
| | - Hélène Scheer
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 67000 Strasbourg, France
| | - Emilie Ferrier
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 67000 Strasbourg, France
| | - François Michaël Sement
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 67000 Strasbourg, France
| | - Pierre Mercier
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 67000 Strasbourg, France
| | - Benjamin Stupfler
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 67000 Strasbourg, France
| | - Dominique Gagliardi
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg, 67000 Strasbourg, France.
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Jiménez-López D, Bravo J, Guzmán P. Evolutionary history exposes radical diversification among classes of interaction partners of the MLLE domain of plant poly(A)-binding proteins. BMC Evol Biol 2015; 15:195. [PMID: 26377114 PMCID: PMC4574140 DOI: 10.1186/s12862-015-0475-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/03/2015] [Indexed: 11/16/2022] Open
Abstract
Background Poly(A)-binding proteins (PABPs) are evolutionarily conserved proteins that have important functions in the regulation of translation and the control of mRNA stability in eukaryotes. Most PABPs encode a C-terminal domain known as the MLLE domain (previously PABC or CTC), which can mediate protein interactions. In earlier work we identified and predicted that four classes of MLLE-interacting proteins were present in Arabidopsis thaliana, which we named CID A, B, C, and D. These proteins encode transcription-activating domains (CID A), the Lsm and LsmAD domains of ataxin-2 (CID B), the CUE and small MutS-related domains (CID C), and two RNA recognition domains (CID D). We recently found that a novel class that lacks the LsmAD domain is present in CID B proteins. Results We extended our analysis to other classes of CIDs present in the viridiplantae. We found that novel variants also evolved in classes CID A and CID C. A specific transcription factor domain is present in a distinct lineage in class A, and a variant that lacks at least two distinct domains was also identified in a divergent lineage in class C. We did not detect any variants in Class D CIDs. This class often consists of four to six highly conserved RNA-binding proteins, which suggests that major redundancy is present in this class. Conclusions CIDs are likely to operate as components of posttranscriptional regulatory assemblies. The evident diversification of CIDs may be neutral or may be important for plant adaptation to the environment and for acquisition of specific traits during evolution. The fact that CIDs subclasses are maintained in early lineages suggest that a presumed interference between duplicates was resolved, and a defined function for each subclass was achieved. Electronic supplementary material The online version of this article (doi:10.1186/s12862-015-0475-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Domingo Jiménez-López
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Unidad Irapuato, Apartado Postal 629, Irapuato, Gto., 36821, Mexico
| | - Jaime Bravo
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Unidad Irapuato, Apartado Postal 629, Irapuato, Gto., 36821, Mexico.,Present address: Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Plinio Guzmán
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Unidad Irapuato, Apartado Postal 629, Irapuato, Gto., 36821, Mexico.
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Domingues MN, Sforça ML, Soprano AS, Lee J, de Souza TDACB, Cassago A, Portugal RV, de Mattos Zeri AC, Murakami MT, Sadanandom A, de Oliveira PSL, Benedetti CE. Structure and Mechanism of Dimer-Monomer Transition of a Plant Poly(A)-Binding Protein upon RNA Interaction: Insights into Its Poly(A) Tail Assembly. J Mol Biol 2015; 427:2491-2506. [PMID: 26013164 DOI: 10.1016/j.jmb.2015.05.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 05/04/2015] [Accepted: 05/19/2015] [Indexed: 12/12/2022]
Abstract
Poly(A)-binding proteins (PABPs) play crucial roles in mRNA biogenesis, stability, transport and translational control in most eukaryotic cells. Although animal PABPs are well-studied proteins, the biological role, three-dimensional structure and RNA-binding mode of plant PABPs remain largely uncharacterized. Here, we report the structural features and RNA-binding mode of a Citrus sinensis PABP (CsPABPN1). CsPABPN1 has a domain architecture of nuclear PABPs (PABPNs) with a single RNA recognition motif (RRM) flanked by an acidic N-terminus and a GRPF-rich C-terminus. The RRM domain of CsPABPN1 displays virtually the same three-dimensional structure and poly(A)-binding mode of animal PABPNs. However, while the CsPABPN1 RRM domain specifically binds poly(A), the full-length protein also binds poly(U). CsPABPN1 localizes to the nucleus of plant cells and undergoes a dimer-monomer transition upon poly(A) interaction. We show that poly(A) binding by CsPABPN1 begins with the recognition of the RNA-binding sites RNP1 and RNP2, followed by interactions with residues of the β2 strands, which stabilize the dimer, thus leading to dimer dissociation. Like human PABPN1, CsPABPN1 also seems to form filaments in the presence of poly(A). Based on these data, we propose a structural model in which contiguous CsPABPN1 RRM monomers wrap around the RNA molecule creating a superhelical structure that could not only shield the poly(A) tail but also serve as a scaffold for the assembly of additional mRNA processing factors.
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Affiliation(s)
- Mariane Noronha Domingues
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP CP6192, Brazil
| | - Mauricio Luis Sforça
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP CP6192, Brazil
| | - Adriana Santos Soprano
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP CP6192, Brazil
| | - Jack Lee
- School of Biological and Biomedical Sciences, Durham University, Durham, County Durham DH1, United Kingdom
| | | | - Alexandre Cassago
- Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP CP6192, Brazil
| | - Rodrigo Villares Portugal
- Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP CP6192, Brazil
| | - Ana Carolina de Mattos Zeri
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP CP6192, Brazil
| | - Mario Tyago Murakami
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP CP6192, Brazil
| | - Ari Sadanandom
- School of Biological and Biomedical Sciences, Durham University, Durham, County Durham DH1, United Kingdom
| | | | - Celso Eduardo Benedetti
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP CP6192, Brazil.
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Browning KS, Bailey-Serres J. Mechanism of cytoplasmic mRNA translation. THE ARABIDOPSIS BOOK 2015; 13:e0176. [PMID: 26019692 PMCID: PMC4441251 DOI: 10.1199/tab.0176] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Protein synthesis is a fundamental process in gene expression that depends upon the abundance and accessibility of the mRNA transcript as well as the activity of many protein and RNA-protein complexes. Here we focus on the intricate mechanics of mRNA translation in the cytoplasm of higher plants. This chapter includes an inventory of the plant translational apparatus and a detailed review of the translational processes of initiation, elongation, and termination. The majority of mechanistic studies of cytoplasmic translation have been carried out in yeast and mammalian systems. The factors and mechanisms of translation are for the most part conserved across eukaryotes; however, some distinctions are known to exist in plants. A comprehensive understanding of the complex translational apparatus and its regulation in plants is warranted, as the modulation of protein production is critical to development, environmental plasticity and biomass yield in diverse ecosystems and agricultural settings.
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Affiliation(s)
- Karen S. Browning
- Department of Molecular Biosciences and Institute for Cell and Molecular Biology, University of Texas at Austin, Austin TX 78712-0165
- Both authors contributed equally to this work
| | - Julia Bailey-Serres
- Department of Botany and Plant Sciences and Center for Plant Cell Biology, University of California, Riverside, CA, 92521 USA
- Both authors contributed equally to this work
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25
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Gallie DR, Liu R. Phylogenetic analysis reveals dynamic evolution of the poly(A)-binding protein gene family in plants. BMC Evol Biol 2014; 14:238. [PMID: 25421536 PMCID: PMC4252990 DOI: 10.1186/s12862-014-0238-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 11/07/2014] [Indexed: 01/05/2023] Open
Abstract
Background The poly(A)-binding protein (PABP) binds the poly(A) tail of eukaryotic mRNAs and functions to maintain the integrity of the mRNA while promoting protein synthesis through its interaction with eukaryotic translation initiation factor (eIF) 4G and eIF4B. PABP is encoded by a single gene in yeast and marine algae but during plant evolution the PABP gene family expanded substantially, underwent sequence divergence into three subclasses, and acquired tissue-specificity in gene family member expression. Although such changes suggest functional specialization, the size of the family and its sequence divergence have complicated an understanding of which gene family members may be foundational and which may represent more recent expansions of the family to meet the specific needs of speciation. Here, we examine the evolution of the plant PABP gene family to provide insight into these aspects of the family that may yield clues into the function of individual family members. Results The PABP gene family had expanded to two members by the appearance of fresh water algae and four members in non-vascular plants. In lycophytes, the first sequence divergence yielding a specific class member occurs. The earliest members of the gene family share greatest similarity to those modern members whose expression is confined to reproductive tissues, suggesting that supporting reproductive-associated gene expression is the most conserved function of this family. A family member sharing similarity to modern vegetative-associated members first appears in gymnosperms. Further elaboration of the reproductive-associated and vegetative-associated members occurred during the evolution of flowering plants. Conclusions Expansion of the plant PABP gene family began prior to the colonization of land. By the evolution of lycophytes, the first class member whose expression is confined to reproductive tissues in higher plants had appeared. A second class member whose expression is vegetative-associated appeared in gymnosperms and all three modern classes had fully evolved by the appearance of the first known basal angiosperm. The size of each PABP class underwent further expansion during subsequent evolution, especially in the Brassicaceae, suggesting that the family is undergoing dynamic evolution. Electronic supplementary material The online version of this article (doi:10.1186/s12862-014-0238-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniel R Gallie
- Department of Biochemistry, University of California, Riverside, CA, 92521-0129, USA.
| | - Renyi Liu
- Department of Botany and Plant Sciences, University of California, Riverside, CA, 92521-0129, USA.
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26
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Tiruneh BS, Kim BH, Gallie DR, Roy B, von Arnim AG. The global translation profile in a ribosomal protein mutant resembles that of an eIF3 mutant. BMC Biol 2013; 11:123. [PMID: 24377433 PMCID: PMC3901033 DOI: 10.1186/1741-7007-11-123] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 12/17/2013] [Indexed: 01/15/2023] Open
Abstract
Background Genome-wide assays performed in Arabidopsis and other organisms have revealed that the translation status of mRNAs responds dramatically to different environmental stresses and genetic lesions in the translation apparatus. To identify additional features of the global landscape of translational control, we used microarray analysis of polysomal as well as non-polysomal mRNAs to examine the defects in translation in a poly(A) binding protein mutant, pab2 pab8, as well as in a mutant of a large ribosomal subunit protein, rpl24b/shortvalve1. Results The mutation of RPL24B stimulated the ribosome occupancy of mRNAs for nuclear encoded ribosomal proteins. Detailed analysis yielded new insights into the translational regulon containing the ribosomal protein mRNAs. First, the ribosome occupancy defects in the rpl24b mutant partially overlapped with those in a previously analyzed initiation factor mutant, eif3h. Second, a group of mRNAs with incomplete coding sequences appeared to be uncoupled from the regulon, since their dependence on RPL24B differed from regular mRNAs. Third, different sister paralogs of the ribosomal proteins differed in their translation state in the wild-type. Some sister paralogs also differed in their response to the rpl24b mutation. In contrast to rpl24b, the pab2 pab8 mutant revealed few gene specific translational defects, but a group of seed storage protein mRNAs were stimulated in their ribosome occupancy. In the course of this work, while optimizing the statistical analysis of ribosome occupancy data, we collected 12 biological replicates of translation states from wild-type seedlings. We defined 20% of mRNAs as having a high variance in their translation state. Many of these mRNAs were functionally associated with responses to the environment, suggesting that subtle variation in the environmental conditions is sensed by plants and transduced to affect the translational efficiency of hundreds of mRNAs. Conclusions These data represent the first genome-wide analysis of translation in a eukaryote defective in the large ribosomal subunit. RPL24 and eIF3h play similar but non-identical roles in eukaryotic translation. The data also shed light on the fine structure of the regulon of ribosomal protein mRNAs.
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Affiliation(s)
| | | | | | | | - Albrecht G von Arnim
- Department of Biochemistry, Cellular and Molecular Biology, M407 Walters Life Sciences, The University of Tennessee, Knoxville, TN 37996-0840, USA.
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Roy B, von Arnim AG. Translational Regulation of Cytoplasmic mRNAs. THE ARABIDOPSIS BOOK 2013; 11:e0165. [PMID: 23908601 PMCID: PMC3727577 DOI: 10.1199/tab.0165] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Translation of the coding potential of a messenger RNA into a protein molecule is a fundamental process in all living cells and consumes a large fraction of metabolites and energy resources in growing cells. Moreover, translation has emerged as an important control point in the regulation of gene expression. At the level of gene regulation, translational control is utilized to support the specific life histories of plants, in particular their responses to the abiotic environment and to metabolites. This review summarizes the diversity of translational control mechanisms in the plant cytoplasm, focusing on specific cases where mechanisms of translational control have evolved to complement or eclipse other levels of gene regulation. We begin by introducing essential features of the translation apparatus. We summarize early evidence for translational control from the pre-Arabidopsis era. Next, we review evidence for translation control in response to stress, to metabolites, and in development. The following section emphasizes RNA sequence elements and biochemical processes that regulate translation. We close with a chapter on the role of signaling pathways that impinge on translation.
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Affiliation(s)
- Bijoyita Roy
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996-0840
- Current address: University of Massachussetts Medical School, Worcester, MA 01655-0122, USA
| | - Albrecht G. von Arnim
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996-0840
- Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN 37996-0840
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Kramer S, Bannerman-Chukualim B, Ellis L, Boulden EA, Kelly S, Field MC, Carrington M. Differential localization of the two T. brucei poly(A) binding proteins to the nucleus and RNP granules suggests binding to distinct mRNA pools. PLoS One 2013; 8:e54004. [PMID: 23382864 PMCID: PMC3559699 DOI: 10.1371/journal.pone.0054004] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 12/06/2012] [Indexed: 12/30/2022] Open
Abstract
The number of paralogs of proteins involved in translation initiation is larger in trypanosomes than in yeasts or many metazoan and includes two poly(A) binding proteins, PABP1 and PABP2, and four eIF4E variants. In many cases, the paralogs are individually essential and are thus unlikely to have redundant functions although, as yet, distinct functions of different isoforms have not been determined. Here, trypanosome PABP1 and PABP2 have been further characterised. PABP1 and PABP2 diverged subsequent to the differentiation of the Kinetoplastae lineage, supporting the existence of specific aspects of translation initiation regulation. PABP1 and PABP2 exhibit major differences in intracellular localization and distribution on polysome fractionation under various conditions that interfere with mRNA metabolism. Most striking are differences in localization to the four known types of inducible RNP granules. Moreover, only PABP2 but not PABP1 can accumulate in the nucleus. Taken together, these observations indicate that PABP1 and PABP2 likely associate with distinct populations of mRNAs. The differences in localization to inducible RNP granules also apply to paralogs of components of the eIF4F complex: eIF4E1 showed similar localization pattern to PABP2, whereas the localisation of eIF4E4 and eIF4G3 resembled that of PABP1. The grouping of translation initiation as either colocalizing with PABP1 or with PABP2 can be used to complement interaction studies to further define the translation initiation complexes in kinetoplastids.
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Affiliation(s)
- Susanne Kramer
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | | | - Louise Ellis
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | | | - Steve Kelly
- Department of Plant Sciences, University of Oxford, and Oxford Centre for Integrative Systems Biology, Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Mark C. Field
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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29
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Goss DJ, Kleiman FE. Poly(A) binding proteins: are they all created equal? WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 4:167-79. [PMID: 23424172 DOI: 10.1002/wrna.1151] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The PABP family of proteins were originally thought of as a simple shield for the mRNA poly(A) tail. Years of research have shown that PABPs interact not only with the poly(A) tail, but also with specific sequences in the mRNA, having a general and specific role on the metabolism of different mRNAs. The complexity of PABPs function is increased by the interactions of PABPs with factors involved in different cellular functions. PABPs participate in all the metabolic pathways of the mRNA: polyadenylation/deadenylation, mRNA export, mRNA surveillance, translation, mRNA degradation, microRNA-associated regulation, and regulation of expression during development. In this review, we update information on the roles of PABPs and emerging data on the specific interactions of PABP homologs. Specific functions of individual members of PABPC family in development and viral infection are beginning to be elucidated. However, the interactions are complex and recent evidence for exchange of nuclear and cytoplasmic forms of the proteins, as well as post-translational modifications, emphasize the possibilities for fine-tuning the PABP metabolic network.
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Affiliation(s)
- Dixie J Goss
- Chemistry Department, Hunter College CUNY, New York, NY, USA.
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Poly(A)-binding protein facilitates translation of an uncapped/nonpolyadenylated viral RNA by binding to the 3' untranslated region. J Virol 2012; 86:7836-49. [PMID: 22593149 DOI: 10.1128/jvi.00538-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Viruses employ an alternative translation mechanism to exploit cellular resources at the expense of host mRNAs and to allow preferential translation. Plant RNA viruses often lack both a 5' cap and a 3' poly(A) tail in their genomic RNAs. Instead, cap-independent translation enhancer elements (CITEs) located in the 3' untranslated region (UTR) mediate their translation. Although eukaryotic translation initiation factors (eIFs) or ribosomes have been shown to bind to the 3'CITEs, our knowledge is still limited for the mechanism, especially for cellular factors. Here, we searched for cellular factors that stimulate the 3'CITE-mediated translation of Red clover necrotic mosaic virus (RCNMV) RNA1 using RNA aptamer-based one-step affinity chromatography, followed by mass spectrometry analysis. We identified the poly(A)-binding protein (PABP) as one of the key players in the 3'CITE-mediated translation of RCNMV RNA1. We found that PABP binds to an A-rich sequence (ARS) in the viral 3' UTR. The ARS is conserved among dianthoviruses. Mutagenesis and a tethering assay revealed that the PABP-ARS interaction stimulates 3'CITE-mediated translation of RCNMV RNA1. We also found that both the ARS and 3'CITE are important for the recruitment of the plant eIF4F and eIFiso4F factors to the 3' UTR and of the 40S ribosomal subunit to the viral mRNA. Our results suggest that dianthoviruses have evolved the ARS and 3'CITE as substitutes for the 3' poly(A) tail and the 5' cap of eukaryotic mRNAs for the efficient recruitment of eIFs, PABP, and ribosomes to the uncapped/nonpolyadenylated viral mRNA.
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Meier I. mRNA export and sumoylation-Lessons from plants. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1819:531-7. [PMID: 22306659 DOI: 10.1016/j.bbagrm.2012.01.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 01/15/2012] [Accepted: 01/19/2012] [Indexed: 01/22/2023]
Abstract
SUMO is a small ubiquitin-related protein modifier that is involved in a number of biological processes, including transcription, DNA repair, genome stability, and chromatin organization. Its potential role in mRNA biogenesis is less well investigated. The biogenesis of mRNA is closely coupled to transcription as well as mRNA nuclear export and several of the involved proteins have dual roles and appear in several complexes. Recently, SUMO-proteome analyses have discovered a number of these proteins as putative targets of SUMO regulation. In the model plant Arabidopsis thaliana, several mutants as well as environmental conditions have been identified that show a close correlation between over- and under-sumoylation of nuclear proteins and mRNA export retention. Three new plant SUMO-proteome studies add to the list of potentially sumoylated RNA-related proteins. Here, the emerging connection between SUMO and mRNA export is compared across kingdoms and its potential mechanistic role is discussed. This article is part of a Special Issue entitled: Nuclear Transport and RNA Processing.
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Affiliation(s)
- Iris Meier
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA.
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Aalto MK, Helenius E, Kariola T, Pennanen V, Heino P, Hõrak H, Puzõrjova I, Kollist H, Palva ET. ERD15--an attenuator of plant ABA responses and stomatal aperture. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 182:19-28. [PMID: 22118612 DOI: 10.1016/j.plantsci.2011.08.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2010] [Revised: 04/10/2011] [Accepted: 08/23/2011] [Indexed: 05/24/2023]
Abstract
Plants are continuously challenged by abiotic and biotic stress factors and need to mount appropriate responses to ensure optimal growth and survival. We have identified ERD15 as a central component in several stress responses in Arabidopsis thaliana. Comparative genomics demonstrates that ERD15 is a member of a small but highly conserved protein family ubiquitous but specific to the plant kingdom. The origin of ERD15 family of proteins can be traced to the time of emergence of land plants. The presence of the conserved PAM2 motif in ERD15 proteins is indicative of a possible interaction with poly(A) binding proteins and could suggest a role in posttranscriptional regulation of gene expression. The function of the other highly conserved motifs in ERD15 remains to be elucidated. The biological role of all ERD15 family members studied so far appears associated to stress responses and stress adaptation. Studies in Arabidopsis demonstrate a role in abiotic stress tolerance where ERD15 is a negative regulator of ABA signaling. The role in ABA signaling may also explain how ERD15 regulates stomatal aperture and consequently controls plant water relations.
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Affiliation(s)
- Markku K Aalto
- Department of Biosciences, Division of Genetics, POB 56, Viikki Biocenter, University of Helsinki, FI-00014 Helsinki, Finland.
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Ruwe H, Kupsch C, Teubner M, Schmitz-Linneweber C. The RNA-recognition motif in chloroplasts. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:1361-71. [PMID: 21330002 DOI: 10.1016/j.jplph.2011.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 01/25/2011] [Accepted: 01/26/2011] [Indexed: 05/10/2023]
Abstract
Chloroplast RNA metabolism is characterized by multiple RNA processing steps that require hundreds of RNA binding proteins. A growing number of RNA binding proteins have been shown to mediate specific RNA processing steps in the chloroplast, but little do we know about their regulatory importance or mode of molecular action. This review summarizes knowledge on chloroplast proteins that contain an RNA recognition motif, a classical RNA binding domain widespread in pro- and eukaryotes. Several members of this family respond to external and internal stimuli by changes in their expression levels and protein modification state. They therefore appear as ideal candidates for regulating chloroplast RNA processing under shifting environmental conditions.
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Affiliation(s)
- Hannes Ruwe
- Institute of Biology, Humboldt University of Berlin, Chausseestrasse 117, Berlin, Germany
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Li H, Yuan Z, Vizcay-Barrena G, Yang C, Liang W, Zong J, Wilson ZA, Zhang D. PERSISTENT TAPETAL CELL1 encodes a PHD-finger protein that is required for tapetal cell death and pollen development in rice. PLANT PHYSIOLOGY 2011; 156:615-30. [PMID: 21515697 PMCID: PMC3177263 DOI: 10.1104/pp.111.175760] [Citation(s) in RCA: 207] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In higher plants, timely degradation of tapetal cells, the innermost sporophytic cells of the anther wall layer, is a prerequisite for the development of viable pollen grains. However, relatively little is known about the mechanism underlying programmed tapetal cell development and degradation. Here, we report a key regulator in monocot rice (Oryza sativa), PERSISTANT TAPETAL CELL1 (PTC1), which controls programmed tapetal development and functional pollen formation. The evolutionary significance of PTC1 was revealed by partial genetic complementation of the homologous mutation MALE STERILITY1 (MS1) in the dicot Arabidopsis (Arabidopsis thaliana). PTC1 encodes a PHD-finger (for plant homeodomain) protein, which is expressed specifically in tapetal cells and microspores during anther development in stages 8 and 9, when the wild-type tapetal cells initiate a typical apoptosis-like cell death. Even though ptc1 mutants show phenotypic similarity to ms1 in a lack of tapetal DNA fragmentation, delayed tapetal degeneration, as well as abnormal pollen wall formation and aborted microspore development, the ptc1 mutant displays a previously unreported phenotype of uncontrolled tapetal proliferation and subsequent commencement of necrosis-like tapetal death. Microarray analysis indicated that 2,417 tapetum- and microspore-expressed genes, which are principally associated with tapetal development, degeneration, and pollen wall formation, had changed expression in ptc1 anthers. Moreover, the regulatory role of PTC1 in anther development was revealed by comparison with MS1 and other rice anther developmental regulators. These findings suggest a diversified and conserved switch of PTC1/MS1 in regulating programmed male reproductive development in both dicots and monocots, which provides new insights in plant anther development.
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Merkle T. Nucleo-cytoplasmic transport of proteins and RNA in plants. PLANT CELL REPORTS 2011; 30:153-76. [PMID: 20960203 PMCID: PMC3020307 DOI: 10.1007/s00299-010-0928-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 09/30/2010] [Indexed: 05/19/2023]
Abstract
Transport of macromolecules between the nucleus and the cytoplasm is an essential necessity in eukaryotic cells, since the nuclear envelope separates transcription from translation. In the past few years, an increasing number of components of the plant nuclear transport machinery have been characterised. This progress, although far from being completed, confirmed that the general characteristics of nuclear transport are conserved between plants and other organisms. However, plant-specific components were also identified. Interestingly, several mutants in genes encoding components of the plant nuclear transport machinery were investigated, revealing differential sensitivity of plant-specific pathways to impaired nuclear transport. These findings attracted attention towards plant-specific cargoes that are transported over the nuclear envelope, unravelling connections between nuclear transport and components of signalling and developmental pathways. The current state of research in plants is summarised in comparison to yeast and vertebrate systems, and special emphasis is given to plant nuclear transport mutants.
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Affiliation(s)
- Thomas Merkle
- Faculty of Biology, Institute for Genome Research and Systems Biology, University of Bielefeld, 33594 Bielefeld, Germany.
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da Costa Lima TD, Moura DMN, Reis CRS, Vasconcelos JRC, Ellis L, Carrington M, Figueiredo RCBQ, de Melo Neto OP. Functional characterization of three leishmania poly(a) binding protein homologues with distinct binding properties to RNA and protein partners. EUKARYOTIC CELL 2010; 9:1484-94. [PMID: 20675580 PMCID: PMC2950419 DOI: 10.1128/ec.00148-10] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Accepted: 07/19/2010] [Indexed: 11/20/2022]
Abstract
Trypanosomatid protozoans are reliant on posttranscriptional processes to control gene expression. Regulation occurs at the levels of mRNA processing, stability, and translation, events that may require the participation of the poly(A) binding protein (PABP). Here, we have undertaken a functional study of the three distinct Leishmania major PABP (LmPABP) homologues: the previously described LmPABP1; LmPABP2, orthologous to the PABP described from Trypanosoma species; and LmPABP3, unique to Leishmania. Sequence identity between the three PABPs is no greater than 40%. In assays measuring binding to A-rich sequences, LmPABP1 binding was poly(A) sensitive but heparin insensitive; LmPABP2 binding was heparin sensitive and less sensitive to poly(A), compatible with unique substitutions observed in residues implicated in poly(A) binding; and LmPABP3 displayed intermediate properties. All three homologues are simultaneously expressed as abundant cytoplasmic proteins in L. major promastigotes, but only LmPABP1 is present as multiple isoforms. Upon transcription inhibition, LmPABP2 and -3 migrated to the nucleus, while LmPABP1 remained predominantly cytoplasmic. Immunoprecipitation assays showed an association between LmPABP2 and -3. Although the three proteins bound to a Leishmania homologue of the translation initiation factor eukaryotic initiation factor 4G (eIF4G) (LmEIF4G3) in vitro, LmPABP1 was the only one to copurify with native LmEIF4G3 from cytoplasmic extracts. Functionality was tested using RNA interference (RNAi) in Trypanosoma brucei, where both orthologues to LmPABP1 and -2 are required for cellular viability. Our results indicate that these homologues have evolved divergent functions, some of which may be unique to the trypanosomatids, and reinforces a role for LmPABP1 in translation through its interaction with the eIF4G homologue.
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Affiliation(s)
- Tamara D. da Costa Lima
- Departamento de Microbiologia, Centro de Pesquisas Aggeu Magalhães/Fiocruz, Av. Moraes Rego s/n, Campus UFPE, Recife, PE 50670-420, Brazil
| | - Danielle M. N. Moura
- Departamento de Microbiologia, Centro de Pesquisas Aggeu Magalhães/Fiocruz, Av. Moraes Rego s/n, Campus UFPE, Recife, PE 50670-420, Brazil
| | - Christian R. S. Reis
- Departamento de Microbiologia, Centro de Pesquisas Aggeu Magalhães/Fiocruz, Av. Moraes Rego s/n, Campus UFPE, Recife, PE 50670-420, Brazil
| | - J. Ronnie C. Vasconcelos
- Departamento de Microbiologia, Centro de Pesquisas Aggeu Magalhães/Fiocruz, Av. Moraes Rego s/n, Campus UFPE, Recife, PE 50670-420, Brazil
| | - Louise Ellis
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA, United Kingdom
| | - Regina C. B. Q. Figueiredo
- Departamento de Microbiologia, Centro de Pesquisas Aggeu Magalhães/Fiocruz, Av. Moraes Rego s/n, Campus UFPE, Recife, PE 50670-420, Brazil
| | - Osvaldo P. de Melo Neto
- Departamento de Microbiologia, Centro de Pesquisas Aggeu Magalhães/Fiocruz, Av. Moraes Rego s/n, Campus UFPE, Recife, PE 50670-420, Brazil
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Baena-González E. Energy signaling in the regulation of gene expression during stress. MOLECULAR PLANT 2010; 3:300-13. [PMID: 20080814 DOI: 10.1093/mp/ssp113] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Maintenance of homeostasis is pivotal to all forms of life. In the case of plants, homeostasis is constantly threatened by the inability to escape environmental fluctuations, and therefore sensitive mechanisms must have evolved to allow rapid perception of environmental cues and concomitant modification of growth and developmental patterns for adaptation and survival. Re-establishment of homeostasis in response to environmental perturbations requires reprogramming of metabolism and gene expression to shunt energy sources from growth-related biosynthetic processes to defense, acclimation, and, ultimately, adaptation. Failure to mount an initial 'emergency' response may result in nutrient deprivation and irreversible senescence and cell death. Early signaling events largely determine the capacity of plants to orchestrate a successful adaptive response. Early events, on the other hand, are likely to be shared by different conditions through the generation of similar signals and before more specific responses are elaborated. Recent studies lend credence to this hypothesis, underpinning the importance of a shared energy signal in the transcriptional response to various types of stress. Energy deficiency is associated with most environmental perturbations due to their direct or indirect deleterious impact on photosynthesis and/or respiration. Several systems are known to have evolved for monitoring the available resources and triggering metabolic, growth, and developmental decisions accordingly. In doing so, energy-sensing systems regulate gene expression at multiple levels to allow flexibility in the diversity and the kinetics of the stress response.
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Affiliation(s)
- Elena Baena-González
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande, 6, 2780-156 Oeiras, Portugal.
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Meier I, Brkljacic J. The Arabidopsis nuclear pore and nuclear envelope. THE ARABIDOPSIS BOOK 2010; 8:e0139. [PMID: 22303264 PMCID: PMC3244964 DOI: 10.1199/tab.0139] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The nuclear envelope is a double membrane structure that separates the eukaryotic cytoplasm from the nucleoplasm. The nuclear pores embedded in the nuclear envelope are the sole gateways for macromolecular trafficking in and out of the nucleus. The nuclear pore complexes assembled at the nuclear pores are large protein conglomerates composed of multiple units of about 30 different nucleoporins. Proteins and RNAs traffic through the nuclear pore complexes, enabled by the interacting activities of nuclear transport receptors, nucleoporins, and elements of the Ran GTPase cycle. In addition to directional and possibly selective protein and RNA nuclear import and export, the nuclear pore gains increasing prominence as a spatial organizer of cellular processes, such as sumoylation and desumoylation. Individual nucleoporins and whole nuclear pore subcomplexes traffic to specific mitotic locations and have mitotic functions, for example at the kinetochores, in spindle assembly, and in conjunction with the checkpoints. Mutants of nucleoporin genes and genes of nuclear transport components lead to a wide array of defects from human diseases to compromised plant defense responses. The nuclear envelope acts as a repository of calcium, and its inner membrane is populated by functionally unique proteins connected to both chromatin and-through the nuclear envelope lumen-the cytoplasmic cytoskeleton. Plant nuclear pore and nuclear envelope research-predominantly focusing on Arabidopsis as a model-is discovering both similarities and surprisingly unique aspects compared to the more mature model systems. This chapter gives an overview of our current knowledge in the field and of exciting areas awaiting further exploration.
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Affiliation(s)
- Iris Meier
- Department of Plant Cellular and Molecular Biology and Plant Biotechnology Center, The Ohio State University, 520 Aronoff Laboratory, 318 W 12th Avenue, Columbus, OH 43210
- Address correspondence to
| | - Jelena Brkljacic
- Department of Plant Cellular and Molecular Biology and Plant Biotechnology Center, The Ohio State University, 520 Aronoff Laboratory, 318 W 12th Avenue, Columbus, OH 43210
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Van Der Kelen K, Beyaert R, Inzé D, De Veylder L. Translational control of eukaryotic gene expression. Crit Rev Biochem Mol Biol 2009; 44:143-68. [PMID: 19604130 DOI: 10.1080/10409230902882090] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Translational control mechanisms are, besides transcriptional control and mRNA stability, the most determining for final protein levels. A large number of accessory factors that assist the ribosome during initiation, elongation, and termination of translation are required for protein synthesis. Cap-dependent translational control occurs mainly during the initiation step, involving eukaryotic initiation factors (eIFs) and accessory proteins. Initiation is affected by various stimuli that influence the phosphorylation status of both eIF4E and eIF2 and through binding of 4E-binding proteins to eIF4E, which finally inhibits cap- dependent translation. Under conditions where cap-dependent translation is hampered, translation of transcripts containing an internal ribosome entry site can still be supported in a cap-independent manner. An interesting example of translational control is the switch between cap-independent and cap-dependent translation during the eukaryotic cell cycle. At the G1-to-S transition, translation occurs predominantly in a cap-dependent manner, while during the G2-to-M transition, cap-dependent translation is inhibited and transcripts are predominantly translated through a cap-independent mechanism.
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Mayberry LK, Allen ML, Dennis MD, Browning KS. Evidence for variation in the optimal translation initiation complex: plant eIF4B, eIF4F, and eIF(iso)4F differentially promote translation of mRNAs. PLANT PHYSIOLOGY 2009; 150:1844-54. [PMID: 19493973 PMCID: PMC2719132 DOI: 10.1104/pp.109.138438] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 05/28/2009] [Indexed: 05/17/2023]
Abstract
Eukaryotic initiation factor (eIF) 4B is known to interact with multiple initiation factors, mRNA, rRNA, and poly(A) binding protein (PABP). To gain a better understanding of the function of eIF4B, the two isoforms from Arabidopsis (Arabidopsis thaliana) were expressed and analyzed using biophysical and biochemical methods. Plant eIF4B was found by ultracentrifugation and light scattering analysis to most likely be a monomer with an extended structure. An extended structure would facilitate the multiple interactions of eIF4B with mRNA as well as other initiation factors (eIF4A, eIF4G, PABP, and eIF3). Eight mRNAs, barley (Hordeum vulgare) alpha-amylase mRNA, rabbit beta-hemoglobin mRNA, Arabidopsis heat shock protein 21 (HSP21) mRNA, oat (Avena sativa) globulin, wheat (Triticum aestivum) germin, maize (Zea mays) alcohol dehydrogenase, satellite tobacco necrosis virus RNA, and alfalfa mosaic virus (AMV) 4, were used in wheat germ in vitro translation assays to measure their dependence on eIF4B and eIF4F isoforms. The two Arabidopsis eIF4B isoforms, as well as native and recombinant wheat eIF4B, showed similar responses in the translation assay. AMV RNA 4 and Arabidopsis HSP21 showed only a slight dependence on the presence of eIF4B isoforms, whereas rabbit beta-hemoglobin mRNA and wheat germin mRNA showed modest dependence. Barley alpha-amylase, oat globulin, and satellite tobacco necrosis virus RNA displayed the strongest dependence on eIF4B. These results suggest that eIF4B has some effects on mRNA discrimination during initiation of translation. Barley alpha-amylase, oat globulin, and rabbit beta-hemoglobin mRNA showed the highest activity with eIF4F, whereas Arabidopsis HSP21 and AMV RNA 4 used both eIF4F and eIF(iso)4F equally well. These results suggest that differential or optimal translation of mRNAs may require initiation complexes composed of specific isoforms of initiation factor gene products. Thus, individual mRNAs or classes of mRNAs may respond to the relative abundance of a particular initiation factor(s), which in turn may affect the amount of protein translated. It is likely that optimal multifactor initiation complexes exist that allow for optimal translation of mRNAs under a variety of cellular conditions.
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Affiliation(s)
- Laura K Mayberry
- Department of Chemistry and Biochemistry and the Institute for Cell and Molecular Biology, University of Texas, Austin, Texas 78712, USA
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Bailey-Serres J, Sorenson R, Juntawong P. Getting the message across: cytoplasmic ribonucleoprotein complexes. TRENDS IN PLANT SCIENCE 2009; 14:443-53. [PMID: 19616989 DOI: 10.1016/j.tplants.2009.05.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2009] [Revised: 05/29/2009] [Accepted: 05/29/2009] [Indexed: 05/20/2023]
Abstract
mRNA-ribonucleoprotein (mRNP) complexes mediate post-transcriptional control mechanisms in the cell nucleus and cytoplasm. Transcriptional control is paramount to gene expression but is followed by regulated nuclear pre-mRNA maturation and quality control processes that culminate in the export of a functional transcript to the cytoplasm. Once in the cytosol, mRNPs determine the activity of individual mRNAs through regulation of localization, translation, sequestration and turnover. Here, we review how quantitative assessment of mRNAs in distinct cytoplasmic mRNPs, such as polyribosomes (polysomes), has provided new perspectives on post-transcriptional regulation from the global to gene-specific level. In addition, we explore recent genetic and biochemical studies of cytoplasmic mRNPs that have begun to expose RNA-binding proteins in an integrated network that fine-tunes gene expression.
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Affiliation(s)
- J Bailey-Serres
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, CA 92521-0124, USA
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42
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Grobei MA, Qeli E, Brunner E, Rehrauer H, Zhang R, Roschitzki B, Basler K, Ahrens CH, Grossniklaus U. Deterministic protein inference for shotgun proteomics data provides new insights into Arabidopsis pollen development and function. Genome Res 2009; 19:1786-800. [PMID: 19546170 DOI: 10.1101/gr.089060.108] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Pollen, the male gametophyte of flowering plants, represents an ideal biological system to study developmental processes, such as cell polarity, tip growth, and morphogenesis. Upon hydration, the metabolically quiescent pollen rapidly switches to an active state, exhibiting extremely fast growth. This rapid switch requires relevant proteins to be stored in the mature pollen, where they have to retain functionality in a desiccated environment. Using a shotgun proteomics approach, we unambiguously identified approximately 3500 proteins in Arabidopsis pollen, including 537 proteins that were not identified in genetic or transcriptomic studies. To generate this comprehensive reference data set, which extends the previously reported pollen proteome by a factor of 13, we developed a novel deterministic peptide classification scheme for protein inference. This generally applicable approach considers the gene model-protein sequence-protein accession relationships. It allowed us to classify and eliminate ambiguities inherently associated with any shotgun proteomics data set, to report a conservative list of protein identifications, and to seamlessly integrate data from previous transcriptomics studies. Manual validation of proteins unambiguously identified by a single, information-rich peptide enabled us to significantly reduce the false discovery rate, while keeping valuable identifications of shorter and lower abundant proteins. Bioinformatic analyses revealed a higher stability of pollen proteins compared to those of other tissues and implied a protein family of previously unknown function in vesicle trafficking. Interestingly, the pollen proteome is most similar to that of seeds, indicating physiological similarities between these developmentally distinct tissues.
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Affiliation(s)
- Monica A Grobei
- Center for Model Organism Proteomes, University of Zürich, Switzerland
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Abstract
RNA-protein interactions profoundly impact organismal development and function through their contributions to the basal gene expression machineries and their regulation of post-transcriptional processes. The repertoire of predicted RNA binding proteins (RBPs) in plants is particularly large, suggesting that the RNA-protein interactome in plants may be more complex and dynamic even than that in metazoa. To dissect RNA-protein interaction networks, it is necessary to identify the RNAs with which each RBP interacts and to determine how those interactions influence RNA fate and downstream processes. Identification of the native RNA ligands of RBPs remains a challenge, but several high-throughput methods for the analysis of RNAs that copurify with specific RBPs from cell extract have been reported recently. This chapter reviews approaches for defining the native RNA ligands of RBPs on a genome-wide scale and provides a protocol for a method that has been used to this end for RBPs that localize to the chloroplast.
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Affiliation(s)
- Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, OR, USA
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45
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Dufresne PJ, Ubalijoro E, Fortin MG, Laliberté JF. Arabidopsis thaliana class II poly(A)-binding proteins are required for efficient multiplication of turnip mosaic virus. J Gen Virol 2008; 89:2339-2348. [PMID: 18753244 DOI: 10.1099/vir.0.2008/002139-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The poly(A)-binding protein (PABP) is an important translation initiation factor that binds to the polyadenylated 3' end of mRNA. We have previously shown that PABP2 interacts with the RNA-dependent RNA polymerase (RdRp) and VPg-Pro of turnip mosaic virus (TuMV) within virus-induced vesicles. At least eight PABP isoforms are produced in Arabidopsis thaliana, three of which (PABP2, PABP4 and PABP8) are highly and broadly expressed and probably constitute the bulk of PABP required for cellular functions. Upon TuMV infection, an increase in protein and mRNA expression from PAB2, PAB4 and PAB8 genes was recorded. In vitro binding assays revealed that RdRp and the viral genome-linked protein (VPg-Pro) interact preferentially with PABP2 but are also capable of interaction with one or both of the other class II PABPs (i.e. PABP4 and PABP8). To assess whether PABP is required for potyvirus replication, A. thaliana single and double pab knockouts were isolated and inoculated with TuMV. All lines showed susceptibility to TuMV. However, when precise monitoring of viral RNA accumulation was performed, it was found to be reduced by 2.2- and 3.5-fold in pab2 pab4 and pab2 pab8 mutants, respectively, when compared with wild-type plants. PABP levels were most significantly reduced in the membrane-associated fraction in both of these mutants. TuMV mRNA levels thus correlated with cellular PABP concentrations in these A. thaliana knockout lines. These data provide further support for a role of PABP in potyvirus replication.
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Affiliation(s)
- Philippe J Dufresne
- Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, Québec H9X 3V9, Canada
| | - Eliane Ubalijoro
- Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, Québec H9X 3V9, Canada
| | - Marc G Fortin
- Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, Québec H9X 3V9, Canada
| | - Jean-François Laliberté
- Institut national de la recherche scientifique, Institut Armand-Frappier, Laval, Québec H7V 1B7, Canada
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Tiwari S, Schulz R, Ikeda Y, Dytham L, Bravo J, Mathers L, Spielman M, Guzmán P, Oakey RJ, Kinoshita T, Scott RJ. MATERNALLY EXPRESSED PAB C-TERMINAL, a novel imprinted gene in Arabidopsis, encodes the conserved C-terminal domain of polyadenylate binding proteins. THE PLANT CELL 2008; 20:2387-98. [PMID: 18796636 PMCID: PMC2570725 DOI: 10.1105/tpc.108.061929] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 08/18/2008] [Accepted: 09/01/2008] [Indexed: 05/18/2023]
Abstract
Parental imprinting is important for seed development, but few imprinted genes have been identified in plants. The four known imprinted genes in Arabidopsis thaliana encode transcriptional regulators. Here, we describe a novel imprinted gene, MATERNALLY EXPRESSED PAB C-TERMINAL (MPC), which encodes the C-terminal domain of poly(A) binding proteins (PABPs). PABPs play roles in mRNA stability and translation. MPC interacts with proteins that also interact with the C-terminal domain of typical PABPs, suggesting that MPC may regulate translation by modulating PABP activity. In the endosperm, MPC is expressed only from the maternal allele. Reduction of MPC expression affects seed development. In dna methyltransferase1 (met1) mutants, MPC is ectopically expressed, and the paternal allele is active in the endosperm. CGs in the 5' flanking region and gene body of MPC lose methylation in a met1 background. Both regions are required to confer imprinted reporter expression, suggesting that the gene body contains imprinting control region elements. In Arabidopsis, DEMETER (DME) activates expression of maternal alleles. MPC expression is reduced in flowers and seeds in a dme-4 mutant but only after fertilization in dme-1. We conclude that other factors along with DME promote MPC expression and that DME has indirect effects on imprinted gene expression in endosperm.
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Affiliation(s)
- Sushma Tiwari
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, United Kingdom
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Kariola T, Brader G, Helenius E, Li J, Heino P, Palva ET. EARLY RESPONSIVE TO DEHYDRATION 15, a negative regulator of abscisic acid responses in Arabidopsis. PLANT PHYSIOLOGY 2006; 142:1559-73. [PMID: 17056758 PMCID: PMC1676049 DOI: 10.1104/pp.106.086223] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Accepted: 10/12/2006] [Indexed: 05/12/2023]
Abstract
EARLY RESPONSIVE TO DEHYDRATION 15 (ERD15) is rapidly induced in response to various abiotic and biotic stress stimuli in Arabidopsis (Arabidopsis thaliana). Modulation of ERD15 levels by overexpression or RNAi silencing altered the responsiveness of the transgenic plants to the phytohormone abscisic acid (ABA). Overexpression of ERD15 reduced the ABA sensitivity of Arabidopsis manifested in decreased drought tolerance and in impaired ability of the plants to increase their freezing tolerance in response to this hormone. In contrast, RNAi silencing of ERD15 resulted in plants that were hypersensitive to ABA and showed improved tolerance to both drought and freezing, as well as impaired seed germination in the presence of ABA. The modulation of ERD15 levels not only affected abiotic stress tolerance but also disease resistance: ERD15 overexpression plants showed improved resistance to the bacterial necrotroph Erwinia carotovora subsp. carotovora accompanied with enhanced induction of marker genes for systemic acquired resistance. We propose that ERD15 is a novel mediator of stress-related ABA signaling in Arabidopsis.
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Affiliation(s)
- Tarja Kariola
- Viikki Biocenter, Department of Biological and Environmental Sciences, Division of Genetics, University of Helsinki, FIN-00014, Helsinki, Finland
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Abstract
POGs/PlantRBP (http://plantrbp.uoregon.edu/) is a relational database that integrates data from rice, Arabidopsis, and maize by placing the complete Arabidopsis and rice proteomes and available maize sequences into 'putative orthologous groups' (POGs). Annotation efforts will focus on predicted RNA binding proteins (RBPs): i.e. those with known RNA binding domains or otherwise implicated in RNA function. POGs form the heart of the database, and were assigned using a mutual-best-hit-strategy after performing BLAST comparisons of the predicted Arabidopsis and rice proteomes. Each POG entry includes orthologs in Arabidopsis and rice, annotated with domain organization, gene models, phylogenetic trees, and multiple intracellular targeting predictions. A graphical display maps maize sequences on to their most similar rice gene model. The database can be queried using any combination of gene name, accession, domain, and predicted intracellular location, or using BLAST. Useful features of the database include the ability to search for proteins with both a specified domain content and intracellular location, the concurrent display of mutual best hits and phylogenetic trees which facilitates evaluation of POG assignments, the association of maize sequences with POGs, and the display of targeting predictions and domain organization for all POG members, which reveals consistency, or lack thereof, of those predictions.
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Affiliation(s)
| | | | - Alice Barkan
- To whom correspondence should be addressed. Tel: +1 541 346 5145; Fax: +1 541 346 5891;
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50
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Schmitz-Linneweber C, Williams-Carrier R, Barkan A. RNA immunoprecipitation and microarray analysis show a chloroplast Pentatricopeptide repeat protein to be associated with the 5' region of mRNAs whose translation it activates. THE PLANT CELL 2005; 17:2791-804. [PMID: 16141451 PMCID: PMC1242273 DOI: 10.1105/tpc.105.034454] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 07/25/2005] [Accepted: 08/17/2005] [Indexed: 05/04/2023]
Abstract
Plant nuclear genomes encode hundreds of predicted organellar RNA binding proteins, few of which have been connected with their physiological RNA substrates and functions. In fact, among the largest family of putative RNA binding proteins in plants, the pentatricopeptide repeat (PPR) family, no physiologically relevant RNA ligands have been firmly established. We used the chloroplast-splicing factor CAF1 to demonstrate the fidelity of a microarray-based method for identifying RNAs associated with specific proteins in chloroplast extract. We then used the same method to identify RNAs associated with the maize (Zea mays) PPR protein CRP1. Two mRNAs whose translation is CRP1-dependent were strongly and specifically enriched in CRP1 coimmunoprecipitations. These interactions establish CRP1 as a translational regulator by showing that the translation defects in crp1 mutants are a direct consequence of the absence of CRP1. Additional experiments localized these interactions to the 5' untranslated regions and suggested a possible CRP1 interaction motif. These results enhance understanding of the PPR protein family by showing that a PPR protein influences gene expression through association with specific mRNAs in vivo, suggesting an unusual mode of RNA binding for PPR proteins, and highlighting the possibility that translational regulation may be a particularly common function of PPR proteins. Analogous methods should have broad application for the study of native RNA-protein interactions in both mitochondria and chloroplasts.
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