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Granot G, Morgenstern Y, Khan A, Rapp YG, Pesok A, Nevo E, Grafi G. Internucleosomal DNA fragmentation in wild emmer wheat is catalyzed by S1-type endonucleases translocated to the nucleus upon induction of cell death. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1849:239-46. [PMID: 25497371 DOI: 10.1016/j.bbagrm.2014.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/25/2014] [Accepted: 12/03/2014] [Indexed: 11/17/2022]
Abstract
Leaves of cereal plants display nucleosomal fragmentation of DNA attributed to the action of nucleases induced during program cell death (PCD). Yet, the specific nuclease activity responsible for generating double strand DNA breaks (DSBs) that lead to DNA fragmentation has not been fully described. Here, we characterized a Ca2+/Mg2+-dependent S1-type endonuclease activity in leaves of wild emmer wheat (Triticum dicoccoides Köern.) capable of introducing DSBs as demonstrated by the conversion of supercoiled plasmid DNA into a linear duplex DNA. In-gel nuclease assay revealed a nuclease of about 35 kDa capable of degrading both single stranded DNA and RNA. We further showed that the endonuclease activity can be purified on Concanavalin A and treatment with peptide-N-glycosidase F (PNGase F) did not abolish its activity. Furthermore, ConA-associated endonuclease was capable of generating nucleosomal DNA fragmentation in tobacco nuclei. Since S1-type endonucleases lack canonical nuclear localization signal it was necessary to determine their subcellular localization. To this end, a cDNA encoding for a putative 34 kDa S1-type nuclease, designated TaS1-like (TaS1L) was synthesized based on available sequence data of Triticum aestivum and fused with RFP. Introduction into protoplasts showed that TaS1L-RFP is cytoplasmic 24h post transformation but gradually turn nuclear at 48 h concomitantly with induction of cell death. Our results suggest that DNA fragmentation occurring in leaves of wild emmer wheat may be attributed to S1-type endonuclease(s) that reside in the cytoplasm but translocate to the nucleus upon induction of cell death.
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Affiliation(s)
- Gila Granot
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
| | - Yaakov Morgenstern
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
| | - Asif Khan
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
| | - Yemima Givaty Rapp
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
| | - Anat Pesok
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel
| | - Eviatar Nevo
- Institute of Evolution, University of Haifa, 199 Aba-Hushi Avenue Mount Carmel, Haifa 3498838, Israel
| | - Gideon Grafi
- French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel.
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Abstract
How is a rapid cellular turnover of the lateral root cap achieved in plants to control cap size in the growing root tips? Downstream of ANAC033/SOMBRERO, a highly organized and temporally coordinated cell death program involving BFN1 nuclease-mediated rapid corpse clearance eliminates these cells.
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Affiliation(s)
- Shri Ram Yadav
- Institute of Biotechnology, University of Helsinki, FIN-00014, Finland
| | - Ykä Helariutta
- Institute of Biotechnology, University of Helsinki, FIN-00014, Finland.
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Structural insights of the ssDNA binding site in the multifunctional endonuclease AtBFN2 from Arabidopsis thaliana. PLoS One 2014; 9:e105821. [PMID: 25157844 PMCID: PMC4144908 DOI: 10.1371/journal.pone.0105821] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/14/2014] [Indexed: 12/02/2022] Open
Abstract
The multi S1/P1 nuclease AtBFN2 (EC 3.1.30.1) encoded by the Arabidopsis thaliana At1g68290 gene is a glycoprotein that digests RNA, ssDNA, and dsDNA. AtBFN2 depends on three zinc ions for cleaving DNA and RNA at 3′-OH to yield 5′-nucleotides. In addition, AtBFN2′s enzymatic activity is strongly glycan dependent. Plant Zn2+-dependent endonucleases present a unique fold, and belong to the Phospholipase C (PLC)/P1 nuclease superfamily. In this work, we present the first complete, ligand-free, AtBFN2 crystal structure, along with sulfate, phosphate and ssDNA co-crystal structures. With these, we were able to provide better insight into the glycan structure and possible enzymatic mechanism. In comparison with other nucleases, the AtBFN2/ligand-free and AtBFN2/PO4 models suggest a similar, previously proposed, catalytic mechanism. Our data also confirm that the phosphate and vanadate can inhibit the enzyme activity by occupying the active site. More importantly, the AtBFN2/A5T structure reveals a novel and conserved secondary binding site, which seems to be important for plant Zn2+-dependent endonucleases. Based on these findings, we propose a rational ssDNA binding model, in which the ssDNA wraps itself around the protein and the attached surface glycan, in turn, reinforces the binding complex.
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Sakamoto W, Takami T. Nucleases in higher plants and their possible involvement in DNA degradation during leaf senescence. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3835-43. [PMID: 24634485 DOI: 10.1093/jxb/eru091] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
During leaf senescence, macromolecules such as proteins and lipids are known to be degraded for redistribution into upper tissues. Similarly, nucleic acids appear to undergo fragmentation or degradation during senescence, but the physiological role of nucleic acid degradation, particularly of genomic DNA degradation, remains unclear. To date, more than a dozen of plant deoxyribonucleases have been reported, whereas it remains to be verified whether any of them degrade DNA during leaf senescence. This review summarizes current knowledge related to the plant nucleases that are induced developmentally or in a tissue-specific manner and are known to degrade DNA biochemically. Of these, several endonucleases (BFN1, CAN1, and CAN2) and an exonuclease (DPD1) in Arabidopsis seem to act in leaf senescence because they were shown to be inducible at the transcript level. This review specifically examines DPD1, which is dual-targeted to chloroplasts and mitochondria. Results show that, among the exonuclease family to which DPD1 belongs, DPD1 expression is extraordinary when estimated using a microarray database. DPD1 is the only example among the nucleases in which DNA degradation has been confirmed in vivo in pollen by mutant analysis. These data imply a significant role of organelle DNA degradation during leaf senescence and implicate DPD1 as a potential target for deciphering nucleotide salvage in plants.
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Affiliation(s)
- Wataru Sakamoto
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
| | - Tsuneaki Takami
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
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Lambert R, Quiles FA, Cabello-Díaz JM, Piedras P. Purification and identification of a nuclease activity in embryo axes from French bean. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 224:137-143. [PMID: 24908514 DOI: 10.1016/j.plantsci.2014.04.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 04/02/2014] [Accepted: 04/28/2014] [Indexed: 06/03/2023]
Abstract
Plant nucleases are involved in nucleic acid degradation associated to programmed cell death processes as well as in DNA restriction, repair and recombination processes. However, the knowledge about the function of plant nucleases is limited. A major nuclease activity was detected by in-gel assay with whole embryonic axes of common bean by using ssDNA or RNA as substrate, whereas this activity was minimal in cotyledons. The enzyme has been purified to electrophoretic homogeneity from embryonic axes. The main biochemical properties of the purified enzyme indicate that it belongs to the S1/P1 family of nucleases. This was corroborated when this protein, after SDS-electrophoresis, was excised from the gel and further analysis by MALDI TOF/TOF allowed identification of the gene (PVN1) that codes this protein. The gene that codes the purified protein was identified. The expression of PVN1 gene was induced at the specific moment of radicle protrusion. The inclusion of inorganic phosphate to the imbibition media reduced the level of expression of this gene and the nuclease activity suggesting a relationship with the phosphorous status in French bean seedlings.
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Affiliation(s)
- Rocío Lambert
- Departamento de Botánica, Ecología y Fisiología Vegetal, Grupo de Fisiología Molecular y Biotecnología de Plantas, Campus Rabanales, Edif. Severo Ochoa, 1ª Planta, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Francisco Antonio Quiles
- Departamento de Botánica, Ecología y Fisiología Vegetal, Grupo de Fisiología Molecular y Biotecnología de Plantas, Campus Rabanales, Edif. Severo Ochoa, 1ª Planta, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Juan Miguel Cabello-Díaz
- Departamento de Botánica, Ecología y Fisiología Vegetal, Grupo de Fisiología Molecular y Biotecnología de Plantas, Campus Rabanales, Edif. Severo Ochoa, 1ª Planta, Universidad de Córdoba, 14071 Córdoba, Spain
| | - Pedro Piedras
- Departamento de Botánica, Ecología y Fisiología Vegetal, Grupo de Fisiología Molecular y Biotecnología de Plantas, Campus Rabanales, Edif. Severo Ochoa, 1ª Planta, Universidad de Córdoba, 14071 Córdoba, Spain.
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Hierl G, Höwing T, Isono E, Lottspeich F, Gietl C. Ex vivo processing for maturation of Arabidopsis KDEL-tailed cysteine endopeptidase 2 (AtCEP2) pro-enzyme and its storage in endoplasmic reticulum derived organelles. PLANT MOLECULAR BIOLOGY 2014; 84:605-20. [PMID: 24287716 PMCID: PMC3950626 DOI: 10.1007/s11103-013-0157-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 11/19/2013] [Indexed: 05/24/2023]
Abstract
Ricinosomes are specialized ER-derived organelles that store the inactive pro-forms of KDEL-tailed cysteine endopeptidases (KDEL-CysEP) associated with programmed cell death (PCD). The Arabidopsis genome encodes three KDEL-CysEP (AtCEP1, AtCEP2, and AtCEP3) that are differentially expressed in vegetative and generative tissues undergoing PCD. These Arabidopsis proteases have not been characterized at a biochemical level, nor have they been localized intracellularly. In this study, we characterized AtCEP2. A 3xHA-mCherry-AtCEP2 gene fusion including pro-peptide and KDEL targeting sequences expressed under control of the endogenous promoter enabled us to isolate AtCEP2 "ex vivo". The purified protein was shown to be activated in a pH-dependent manner. After activation, however, protease activity was pH-independent. Analysis of substrate specificity showed that AtCEP2 accepts proline near the cleavage site, which is a rare feature specific for KDEL-CysEPs. mCherry-AtCEP2 was detected in the epidermal layers of leaves, hypocotyls and roots; in the root, it was predominantly found in the elongation zone and root cap. Co-localization with an ER membrane marker showed that mCherry-AtCEP2 was stored in two different types of ER-derived organelles: 10 μm long spindle shaped organelles as well as round vesicles with a diameter of approximately 1 μm. The long organelles appear to be ER bodies, which are found specifically in Brassicacae. The round vesicles strongly resemble the ricinosomes first described in castor bean. This study provides a first evidence for the existence of ricinosomes in Arabidopsis, and may open up new avenues of research in the field of PCD and developmental tissue remodeling.
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Affiliation(s)
- Georg Hierl
- Center of Life and Food Sciences Weihenstephan, Lehrstuhl fuer Botanik, Technische Universitaet Muenchen, Emil-Ramann-Str. 4, 85350 Freising, Germany
| | - Timo Höwing
- Center of Life and Food Sciences Weihenstephan, Lehrstuhl fuer Botanik, Technische Universitaet Muenchen, Emil-Ramann-Str. 4, 85350 Freising, Germany
| | - Erika Isono
- Center of Life and Food Sciences Weihenstephan, Department of Plant Systems Biology, Technische Universitaet Muenchen, Emil-Ramann-Str. 4, 85350 Freising, Germany
| | - Friedrich Lottspeich
- Max Planck Institute of Biochemistry, Protein Analysis, 82152 Martinsried, Germany
| | - Christine Gietl
- Center of Life and Food Sciences Weihenstephan, Lehrstuhl fuer Botanik, Technische Universitaet Muenchen, Emil-Ramann-Str. 4, 85350 Freising, Germany
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57
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Shahri W, Tahir I. Flower senescence: some molecular aspects. PLANTA 2014; 239:277-97. [PMID: 24178586 DOI: 10.1007/s00425-013-1984-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 10/14/2013] [Indexed: 05/08/2023]
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58
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Sánchez-Pons N, Vicient CM. Identification of a type I Ca2+/Mg2+-dependent endonuclease induced in maize cells exposed to camptothecin. BMC PLANT BIOLOGY 2013; 13:186. [PMID: 24256432 PMCID: PMC4225560 DOI: 10.1186/1471-2229-13-186] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 11/16/2013] [Indexed: 05/24/2023]
Abstract
BACKGROUND Camptothecin is a plant alkaloid that specifically binds topoisomerase I, inhibiting its activity and inducing double stranded breaks in DNA and activating the cell responses to DNA damage. RESULTS Maize cultured cells were incubated in the presence of different concentrations of camptothecin. Camptothecin inhibits cultured cell growth, induces genomic DNA degradation, and induces a 32 kDa Ca2+/Mg2+-dependent nuclease activity. This nuclease, we called CaMNUC32, is inhibited by Zn2+ and by acid pH, it is mainly localized in the nucleus and it cleaves single- and double-stranded DNA, with a higher activity against single-stranded DNA. Two-dimensional electrophoresis combined with mass spectrometry suggests that CaMNUC32 is a member of the type I S1/P1 nuclease family. This type of nucleases are usually Zn2+-dependent but our results support previous indications that S1-type nucleases have a wide variety of enzyme activities, including Ca2+/Mg2+-dependent. CONCLUSIONS We have identified and characterized CaMNUC32, a 32 kDa Ca2+/Mg2+-dependent nuclease of the S1/P1 family induced by the topoisomerase I inhibitor camptothecin in maize cultured cells.
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Affiliation(s)
- Núria Sánchez-Pons
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics CRAG (CSIC-IRTA-UAB-UB), Campus UAB, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain
| | - Carlos M Vicient
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics CRAG (CSIC-IRTA-UAB-UB), Campus UAB, Bellaterra (Cerdanyola del Vallès), 08193 Barcelona, Spain
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59
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Guo K, Bu Y, Takano T, Liu S, Zhang X. Arabidopsis cysteine proteinase inhibitor AtCYSb interacts with a Ca(2+)-dependent nuclease, AtCaN2. FEBS Lett 2013; 587:3417-21. [PMID: 24076026 DOI: 10.1016/j.febslet.2013.09.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/31/2013] [Accepted: 09/10/2013] [Indexed: 10/26/2022]
Abstract
Plant cysteine proteinase inhibitors (cystatins) play important roles in plant defense mechanisms. Some proteins that interact with cystatins may defend against abiotic stresses. Here, we showed that AtCaN2, a Ca(2+)-dependent nuclease in Arabidopsis, is transcribed in senescent leaves and stems and interacts with an Arabidopsis cystatin (AtCYSb) in a yeast two-hybrid screen. The interaction between AtCYSb and AtCaN2 was confirmed by in vitro pull-down assay and bimolecular fluorescence complementation. Agarose gel electrophoresis showed that the nuclease activity of AtCaN2 against λDNA was inhibited by AtCYSb, which suggests that AtCYSb regulates nucleic acid degradation in cells.
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Affiliation(s)
- Kunyuan Guo
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field (SAVER), Ministry of Education, Alkali Soil Natural Environmental Science Center (ASNESC), Northeast Forestry University, Harbin 150040, China
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60
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Matallana-Ramirez LP, Rauf M, Farage-Barhom S, Dortay H, Xue GP, Dröge-Laser W, Lers A, Balazadeh S, Mueller-Roeber B. NAC transcription factor ORE1 and senescence-induced BIFUNCTIONAL NUCLEASE1 (BFN1) constitute a regulatory cascade in Arabidopsis. MOLECULAR PLANT 2013; 6:1438-52. [PMID: 23340744 DOI: 10.1093/mp/sst012] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Senescence is a highly regulated process that involves the action of a large number of transcription factors. The NAC transcription factor ORE1 (ANAC092) has recently been shown to play a critical role in positively controlling senescence in Arabidopsis thaliana; however, no direct target gene through which it exerts its molecular function has been identified previously. Here, we report that BIFUNCTIONAL NUCLEASE1 (BFN1), a well-known senescence-enhanced gene, is directly regulated by ORE1. We detected elevated expression of BFN1 already 2 h after induction of ORE1 in estradiol-inducible ORE1 overexpression lines and 6 h after transfection of Arabidopsis mesophyll cell protoplasts with a 35S:ORE1 construct. ORE1 and BFN1 expression patterns largely overlap, as shown by promoter-reporter gene (GUS) fusions, while BFN1 expression in senescent leaves and the abscission zones of maturing flower organs was virtually absent in ore1 mutant background. In vitro binding site assays revealed a bipartite ORE1 binding site, similar to that of ORS1, a paralog of ORE1. A bipartite ORE1 binding site was identified in the BFN1 promoter; mutating the cis-element within the context of the full-length BFN1 promoter drastically reduced ORE1-mediated transactivation capacity in transiently transfected Arabidopsis mesophyll cell protoplasts. Furthermore, chromatin immunoprecipitation (ChIP) demonstrates in vivo binding of ORE1 to the BFN1 promoter. We also demonstrate binding of ORE1 in vivo to the promoters of two other senescence-associated genes, namely SAG29/SWEET15 and SINA1, supporting the central role of ORE1 during senescence.
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Affiliation(s)
- Lilian P Matallana-Ramirez
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Straβe 24-25, 14476 Potsdam-Golm, Germany
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61
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Lesniewicz K, Karlowski WM, Pienkowska JR, Krzywkowski P, Poreba E. The plant s1-like nuclease family has evolved a highly diverse range of catalytic capabilities. PLANT & CELL PHYSIOLOGY 2013; 54:1064-78. [PMID: 23620482 DOI: 10.1093/pcp/pct061] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plant S1-like nucleases, often referred to as nuclease I enzymes, are the main class of enzymes involved in nucleic acid degradation during plant programmed cell death. The catalytically active site of these enzymes shows a significant similarity to the well-described P1 nuclease from Penicillium citrinum. Previously published studies reported that plant S1-like nucleases possess catalytic activities similar to their fungal orthologs, i.e. they hydrolyze single-stranded DNA and RNA, and less efficiently double-stranded DNA, in the presence of zinc ions. Here we describe a comprehensive study of the nucleolytic activities of all Arabidopsis S1-like paralogs. Our results revealed that different members of this family are characterized by a surprisingly large variety of catalytic properties. We found that, in addition to Zn(2+)-dependent enzymes, this family also comprises nucleases activated by Ca(2+) and Mn(2+), which implies that the apparently well-known S1 nuclease active site in plant nucleases is able to cooperate with different activatory ions. Moreover, particular members of this class differ in their optimum pH value and substrate specificity. These results shed new light on the widely accepted classification of plant nucleases which is based on the assumption that the catalytic requirements of plant nucleases reflect their phylogenetic origin. Our results imply the need to redefine the understanding of the term 'nuclease I'. Analysis of the phylogenetic relationships between S1-like enzymes shows that plant representatives of this family evolve toward an increase in catalytic diversity. The importance of this process for the biological functions of plant S1-type enzymes is discussed.
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Affiliation(s)
- Krzysztof Lesniewicz
- Department of Molecular and Cellular Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, 89 Umultowska St., 61-614 Poznan, Poland.
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Chou TL, Ko TP, Ko CY, Lin TY, Guo RT, Yu TF, Chan HC, Shaw JF, Wang AHJ. Mechanistic insights to catalysis by a zinc-dependent bi-functional nuclease from Arabidopsis thaliana. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2013. [DOI: 10.1016/j.bcab.2013.03.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Golisz A, Sikorski PJ, Kruszka K, Kufel J. Arabidopsis thaliana LSM proteins function in mRNA splicing and degradation. Nucleic Acids Res 2013; 41:6232-49. [PMID: 23620288 PMCID: PMC3695525 DOI: 10.1093/nar/gkt296] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Sm-like (Lsm) proteins have been identified in all organisms and are related to RNA metabolism. Here, we report that Arabidopsis nuclear AtLSM8 protein, as well as AtLSM5, which localizes to both the cytoplasm and nucleus, function in pre-mRNA splicing, while AtLSM5 and the exclusively cytoplasmic AtLSM1 contribute to 5'-3' mRNA decay. In lsm8 and sad1/lsm5 mutants, U6 small nuclear RNA (snRNA) was reduced and unspliced mRNA precursors accumulated, whereas mRNA stability was mainly affected in plants lacking AtLSM1 and AtLSM5. Some of the mRNAs affected in lsm1a lsm1b and sad1/lsm5 plants were also substrates of the cytoplasmic 5'-3' exonuclease AtXRN4 and of the decapping enzyme AtDCP2. Surprisingly, a subset of substrates was also stabilized in the mutant lacking AtLSM8, which supports the notion that plant mRNAs are actively degraded in the nucleus. Localization of LSM components, purification of LSM-interacting proteins as well as functional analyses strongly suggest that at least two LSM complexes with conserved activities in RNA metabolism, AtLSM1-7 and AtLSM2-8, exist also in plants.
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Affiliation(s)
- Anna Golisz
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
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64
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Fedoreyeva LI, Vanyushin BF. Mechanisms of catalytic action and chemical modifications of endonucleases WEN1 and WEN2 from wheat seedlings. BIOCHEMISTRY (MOSCOW) 2013; 78:41-52. [PMID: 23379558 DOI: 10.1134/s0006297913010057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hydrolysis of DNA catalyzed by wheat endonucleases WEN1 and WEN2 is pronouncedly processive. A correlation has been revealed between appearance of new products of DNA hydrolysis with different length and conformational changes in the enzymes. The first conformational conversion of the endonucleases is associated with appearance of large fragments of DNA hydrolysis with length longer than 500 bp, and the second conversion is associated with formation of oligonucleotides with length of 120-140 bp, and the third conversion is associated with formation of short oligonucleotides and mononucleotides. Formation of the DNA-enzyme complex is accompanied by appearance of fluorescence at λ = 410-440 nm. The intensity, positions, and numbers of maximums of the fluorescence spectra of DNA-WEN1 and DNA-WEN2 complexes are different and depend on the methylation status of the DNA and on the presence of Mg2+. The endonucleases hydrolyze DNA by two mechanisms: one is metal-independent, and the other depends on one or two Mg2+ ions. One Mg2+ ion is located inside the catalytic center of WEN1, whereas the WEN2 center contains two Mg2+ ions. The first (site-specific) stage of DNA hydrolysis does not depend on Mg2+. Mg2+ ions evoke changes in the site specificity of the endonuclease action (WEN1) and abolish their ability to recognize the methylation status of DNA. Products of DNA hydrolysis by endonucleases WEN1 and WEN2 in the presence of Mg2+ are similar in length (120-140 bp). The endonucleases have at least two centers (domains) - catalytic and substrate-binding. Two histidine and apparently two lysine plus two dicarboxylic amino acid residues are present inside the catalytic center of WEN1. The catalytic center of WEN2 contains at least one histidine residue and apparently two residues of aspartic or glutamic acid, which are involved in coordination of the metal ions. The catalytic centers of WEN1 and WEN2 seem to be formed, respectively, by HD/E(D/EK)KH and HD/ED/E amino acid residues. The site-specificity of the endonuclease action is due to the DNA-binding domain. This domain contains dicarboxylic amino acid residues, which seem to be responsible for sensitivity of the enzymes to the methylation status of DNA. The hydroxyl groups of tyrosine residues in the enzymes also seem to contribute to recognizing methylated bases in DNA.
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Affiliation(s)
- L I Fedoreyeva
- All-Russian Research Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, Moscow, 127550, Russia
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65
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Koval' T, Lipovová P, Podzimek T, Matoušek J, Dušková J, Skálová T, Stěpánková A, Hašek J, Dohnálek J. Plant multifunctional nuclease TBN1 with unexpected phospholipase activity: structural study and reaction-mechanism analysis. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:213-26. [PMID: 23385457 DOI: 10.1107/s0907444912043697] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 10/22/2012] [Indexed: 11/11/2022]
Abstract
Type I plant nucleases play an important role in apoptotic processes and cell senescence. Recently, they have also been indicated to be potent anticancer agents in in vivo studies. The first structure of tomato nuclease I (TBN1) has been determined, its oligomerization and activity profiles have been analyzed and its unexpected activity towards phospholipids has been discovered, and conclusions are drawn regarding its catalytic mechanism. The structure-solution process required X-ray diffraction data from two crystal forms. The first form was used for phase determination; the second form was used for model building and refinement. TBN1 is mainly α-helical and is stabilized by four disulfide bridges. Three observed oligosaccharides are crucial for its stability and solubility. The active site is localized at the bottom of the positively charged groove and contains a zinc cluster that is essential for enzymatic activity. An equilibrium between monomers, dimers and higher oligomers of TBN1 was observed in solution. Principles of the reaction mechanism of the phosphodiesterase activity are suggested, with central roles for the zinc cluster, the nucleobase-binding pocket (Phe-site) and Asp70, Arg73 and Asn167. Based on the distribution of surface residues, possible binding sites for dsDNA and other nucleic acids with secondary structure were identified. The phospholipase activity of TBN1, which is reported for the first time for a nuclease, significantly broadens the substrate promiscuity of the enzyme, and the resulting release of diacylglycerol, which is an important second messenger, can be related to the role of TBN1 in apoptosis.
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Affiliation(s)
- Tomáš Koval'
- Institute of Macromolecular Chemistry, AS CR, v.v.i., Heyrovskeho nam. 2, 162 06 Praha 6, Czech Republic.
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Schreeg LA, Mack MC, Turner BL. Nutrient-specific solubility patterns of leaf litter across 41 lowland tropical woody species. Ecology 2013; 94:94-105. [DOI: 10.1890/11-1958.1] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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67
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Leśniewicz K, Poręba E, Smolarkiewicz M, Wolff N, Stanisławski S, Wojtaszek P. Plant plasma membrane-bound staphylococcal-like DNases as a novel class of eukaryotic nucleases. BMC PLANT BIOLOGY 2012; 12:195. [PMID: 23102437 PMCID: PMC3505149 DOI: 10.1186/1471-2229-12-195] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 10/22/2012] [Indexed: 05/22/2023]
Abstract
BACKGROUND The activity of degradative nucleases responsible for genomic DNA digestion has been observed in all kingdoms of life. It is believed that the main function of DNA degradation occurring during plant programmed cell death is redistribution of nucleic acid derived products such as nitrogen, phosphorus and nucleotide bases. Plant degradative nucleases that have been studied so far belong mainly to the S1-type family and were identified in cellular compartments containing nucleic acids or in the organelles where they are stored before final application. However, the explanation of how degraded DNA components are exported from the dying cells for further reutilization remains open. RESULTS Bioinformatic and experimental data presented in this paper indicate that two Arabidopsis staphylococcal-like nucleases, named CAN1 and CAN2, are anchored to the cell membrane via N-terminal myristoylation and palmitoylation modifications. Both proteins possess a unique hybrid structure in their catalytic domain consisting of staphylococcal nuclease-like and tRNA synthetase anticodon binding-like motifs. They are neutral, Ca2+-dependent nucleaces showing a different specificity toward the ssDNA, dsDNA and RNA substrates. A study of microarray experiments and endogenous nuclease activity revealed that expression of CAN1 gene correlates with different forms of programmed cell death, while the CAN2 gene is constitutively expressed. CONCLUSIONS In this paper we present evidence showing that two plant staphylococcal-like nucleases belong to a new, as yet unidentified class of eukaryotic nucleases, characterized by unique plasma membrane localization. The identification of this class of nucleases indicates that plant cells possess additional, so far uncharacterized, mechanisms responsible for DNA and RNA degradation. The potential functions of these nucleases in relation to their unique intracellular location are discussed.
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Affiliation(s)
- Krzysztof Leśniewicz
- Department of Molecular and Cellular Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, 89 Umultowska St, Poznan 61-614, Poland
| | - Elżbieta Poręba
- Department of Molecular Virology, Institute of Experimental Biology, Adam Mickiewicz University, Poznań, 89 Umultowska St, Poznan, 61-614, Poland
| | - Michalina Smolarkiewicz
- Department of Molecular and Cellular Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, 89 Umultowska St, Poznan 61-614, Poland
| | - Natalia Wolff
- Department of Molecular and Cellular Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, 89 Umultowska St, Poznan 61-614, Poland
| | - Sławoj Stanisławski
- Department of Molecular and Cellular Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, 89 Umultowska St, Poznan 61-614, Poland
| | - Przemysław Wojtaszek
- Department of Molecular and Cellular Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznań, 89 Umultowska St, Poznan 61-614, Poland
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68
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Fedoreyeva LI, Vanyushin BF. Processing character of the action of wheat endonucleases WEN1 and WEN2. Kinetic parameters. BIOCHEMISTRY (MOSCOW) 2012; 77:485-91. [PMID: 22813589 DOI: 10.1134/s0006297912050082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The wheat seedling endonucleases WEN1 and WEN2 dependent on Mg(2+), Ca(2+), and S-adenosyl-L-methionine (SAM) and sensitive to the substrate DNA methylation status have an expressed processing action. The enzymes hydrolyze DNA at a few subsequent stages: first, they split λ phage DNA specifically at CNG-sites (WEN1) with liberation of large fragments; second, they hydrolyze these fragments to 120-140 bp oligonucleotides that finally are hydrolyzed to very short fragments and mononucleotides. Initial stages of DNA hydrolysis may proceed in the absence of Mg(2+), but subsequent hydrolysis stages are very strongly stimulated by Mg(2+). It cannot be ruled out that modulation of enzymatic activity with Mg(2+) and probably with DNA fragments formed is associated with reorganization of the structure of eukaryotic (wheat) endonucleases with respective changes in their catalytic properties and site specificity of action. Michaelis constant value for WEN1 endonuclease on hydrolysis of methylated λ phage DNA containing Cm(5)CWGG and Gm(6)ATC sites is four-fold lower compared with that observed on hydrolysis of unmethylated λ phage DNA. This may indicate that affinity of WEN1 enzyme to methylated DNA is higher than that to unmethylated DNA. In the presence of SAM, the Michaelis constant for WEN2 on the DNA hydrolysis stage characterized by formation of 120-140 bp fragments is decreased, but for WEN1 it is increased by 1.5-2.0-fold. This means that SAM inhibits WEN1 but stimulates WEN2. Thus, wheat endonucleases WEN1 and WEN2 differ significantly in affinities to substrate DNAs with different methylation status, in velocities of DNA hydrolysis, and time of production of DNA fragments of similar length. It seems that the investigated plant endonucleases can hydrolyze DNA in the nucleus as well to both large and very short fragments including mononucleotides, that is, in particular, essential for utilization of cell nucleic acid material during apoptosis.
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Affiliation(s)
- L I Fedoreyeva
- All Russia Research Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, ul. Timiryazevskaya 42, 127550 Moscow, Russia
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69
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Chen HM, Pang Y, Zeng J, Ding Q, Yin SY, Liu C, Lu MZ, Cui KM, He XQ. The Ca2+ -dependent DNases are involved in secondary xylem development in Eucommia ulmoides. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2012; 54:456-70. [PMID: 22694768 DOI: 10.1111/j.1744-7909.2012.01134.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Secondary xylem development has long been recognized as a typical case of programmed cell death (PCD) in plants. During PCD, the degradation of genomic DNA is catalyzed by endonucleases. However, to date, no endonuclease has been shown to participate in secondary xylem development. Two novel Ca(2+) -dependent DNase genes, EuCaN1 and EuCaN2, were identified from the differentiating secondary xylem of the tree Eucommia ulmoides Oliv., their functions were studied by DNase activity assay, in situ hybridization, protein immunolocalization and virus-induced gene silencing experiments. Full-length cDNAs of EuCaN1 and EuCaN2 contained an open reading frame of 987 bp, encoding two proteins of 328 amino acids with SNase-like functional domains. The genomic DNA sequence for EuCaN1 had no introns, while EuCaN2 had 8 introns. EuCaN1 and EuCaN2 digested ssDNA and dsDNA with Ca(2+) -dependence at neutral pH. Their expression was confined to differentiating secondary xylem cells and the proteins were localized in the nucleus. Their activity dynamics was closely correlated with secondary xylem development. Secondary xylem cell differentiation is influenced by RNAi of endonuclease genes. The results provide evidence that the Ca(2+) -dependent DNases are involved in secondary xylem development.
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Affiliation(s)
- Hui-Min Chen
- State Key Laboratory of Protein and Plant Gene Research, College of Life Sciences, Peking University, Beijing, China
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70
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Ko CY, Lai YL, Liu WY, Lin CH, Chen YT, Chen LFO, Lin TY, Shaw JF. Arabidopsis ENDO2: its catalytic role and requirement of N-glycosylation for function. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:5169-5179. [PMID: 22506810 DOI: 10.1021/jf300945c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The Arabidopsis thaliana At1g68290 gene encoding an endonuclease was isolated and designated ENDO2, which was cloned into a binary vector to overexpress ENDO2 with a C-terminal 6 × His-tag in A. thaliana. Our Arabidopsis transgenic lines harboring 35SP::ENDO2 produced stable active enzyme with high yield. The protein was affinity purified from transgenic plants, and its identity was confirmed by liquid chromatography-mass spectrometry and automatic Edman degradation. ENDO2 enzyme digests RNA, ssDNA, and dsDNA, with a substrate preference for ssDNA and RNA. The activity toward ssDNA (361.7 U/mg) is greater than its dsDNase activity (14.1 U/mg) at neutral pH. ENDO2 effectively cleaves mismatch regions in heteroduplex DNA containing single base pair mismatches or insertion/deletion bases and can be applied to high-throughput detection of single base mutation. Our data also validated that the removal of sugar groups from ENDO2 strongly affects its enzymatic stability and activity.
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Affiliation(s)
- Chia-Yun Ko
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University , Hsinchu, 30013, Taiwan
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71
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Guo K, Liu S, Takano T, Zhang X. Molecular cloning, expression, and characterization of a Ca2+-dependent nuclease of Arabidopsis thaliana. Protein Expr Purif 2012; 83:70-4. [DOI: 10.1016/j.pep.2012.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 03/06/2012] [Accepted: 03/08/2012] [Indexed: 11/25/2022]
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72
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Bollhöner B, Prestele J, Tuominen H. Xylem cell death: emerging understanding of regulation and function. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1081-94. [PMID: 22213814 DOI: 10.1093/jxb/err438] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Evolutionary, as well as genetic, evidence suggests that vascular development evolved originally as a cell death programme that allowed enhanced movement of water in the extinct protracheophytes, and that secondary wall formation in the water-conducting cells evolved afterwards, providing mechanical support for effective long-distance transport of water. The extant vascular plants possess a common regulatory network to coordinate the different phases of xylem maturation, including secondary wall formation, cell death, and finally autolysis of the cell contents, by the action of recently identified NAC domain transcription factors. Consequently, xylem cell death is an inseparable part of the xylem maturation programme, making it difficult to uncouple cell death mechanistically from secondary wall formation, and thus identify the key factors specifically involved in regulation of cell death. Current knowledge suggests that the necessary components for xylem cell death are produced early during xylem differentiation, and cell death is prevented through the action of inhibitors and storage of hydrolytic enzymes in inactive forms in compartments such as the vacuole. Bursting of the central vacuole triggers autolytic hydrolysis of the cell contents, which ultimately leads to cell death. This cascade of events varies between the different xylem cell types. The water-transporting tracheary elements rely on a rapid cell death programme, with hydrolysis of cell contents taking place for the most part, if not entirely, after vacuolar bursting, while the xylem fibres disintegrate cellular contents at a slower pace, well before cell death. This review includes a detailed description of cell morphology, function of plant growth regulators, such as ethylene and thermospermine, and the action of hydrolytic nucleases and proteases during cell death of the different xylem cell types.
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Affiliation(s)
- Benjamin Bollhöner
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE-90187 Umeå, Sweden
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73
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Farage-Barhom S, Burd S, Sonego L, Mett A, Belausov E, Gidoni D, Lers A. Localization of the Arabidopsis senescence- and cell death-associated BFN1 nuclease: from the ER to fragmented nuclei. MOLECULAR PLANT 2011; 4:1062-73. [PMID: 21665915 DOI: 10.1093/mp/ssr045] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plant senescence- or PCD-associated nucleases share significant homology with nucleases from different organisms. However, knowledge of their function is limited. Intracellular localization of the Arabidopsis senescence- and PCD-associated nuclease BFN1 was investigated. Analysis of BFN1-GFP localization in transiently transformed tobacco protoplasts revealed initial localization in filamentous structures spread throughout the cytoplasm, which then clustered around the nuclei as the protoplasts senesced. These filamentous structures were identified as being of ER origin. In BFN1-GFP-transgenic Arabidopsis plants, similar localization of BFN1-GFP was observed in young leaves, that is, in filamentous structures that reorganized around the nuclei only in senescing cells. In late senescence, BFN1-GFP was localized with fragmented nuclei in membrane-wrapped vesicles. BFN1's postulated function as a nucleic acid-degrading enzyme in senescence and PCD is supported by its localization pattern. Our results suggest the existence of a dedicated compartment mediating nucleic acid degradation in senescence and PCD processes.
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Affiliation(s)
- Sarit Farage-Barhom
- Department of Postharvest Science of Fresh Produce, Volcani Center, Agricultural Research Organization, Bet Dagan, 50250, Israel
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74
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Gu HT, Wang DH, Li X, He CX, Xu ZH, Bai SN. Characterization of an ethylene-inducible, calcium-dependent nuclease that is differentially expressed in cucumber flower development. THE NEW PHYTOLOGIST 2011; 192:590-600. [PMID: 21801181 DOI: 10.1111/j.1469-8137.2011.03825.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
• Production of unisexual flowers is an important mechanism that promotes cross-pollination in angiosperms. We previously identified primordial anther-specific DNA damage and organ-specific ethylene perception responsible for the arrest of stamen development in female flowers, but little is known about how the two processes are linked. • To identify potential links between the two processes, we performed suppression subtractive hybridization (SSH) on cucumber (Cucumis sativus L.) stamens of male and female flowers at stage 6, with stamens at stage 5 of bisexual flowers as a control. • Among the differentially expressed genes, we identified an expressed sequence tag (EST) encoding a cucumber homolog to an Arabidopsis calcium-dependent nuclease (CAN), designated CsCaN. Full-length CsCaN cDNA and the respective genomic DNA sequence were cloned and characterized. The CsCaN protein exhibited calcium-dependent nuclease activity. CsCaN showed ubiquitous expression; however, increased gene expression was detected in the stamens of stage 6 female flowers compared with male flowers. As expected, CsCaN expression was ethylene inducible. It was of great interest that CsCaN was post-translationally modified. • This study demonstrated that CsCaN is a novel cucumber nuclease gene, whose DNase activity is regulated at multiple levels, and which could be involved in the primordial anther-specific DNA damage of developing female cucumber flowers.
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Affiliation(s)
- Hai-Tao Gu
- PKU-Yale Joint Research Center of Agricultural and Plant Molecular Biology, National Key Laboratory of Protein Engineering and Plant Gene Engineering, College of Life Sciences, Peking University, Beijing, China
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75
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Amplification-free detection of grapevine viruses using an oligonucleotide microarray. J Virol Methods 2011; 178:1-15. [PMID: 21820011 DOI: 10.1016/j.jviromet.2011.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 07/14/2011] [Accepted: 07/20/2011] [Indexed: 11/21/2022]
Abstract
A single-colour microarray hybridization system was designed and evaluated for the detection of viruses infecting grapevine. Total RNA (≥0.5μg) from infected plants was converted to cDNA and labelled with Cy3 using two different strategies. While amine-modified and labelled cDNA was adequate for the detection of nepoviruses, the 3DNA technique, a post-hybridization detection method that uses intensely fluorescent dendrimer reagents, was required for the detection of closteroviruses in infected plants. Threshold detection levels were based on the ratio between viral specific and 18S rRNA positive control signal intensities. Oligonucleotides between 27 and 75 nucleotides in length were evaluated and compared. Viruses detected include eight nepoviruses, two vitiviruses, and one each of closterovirus, foveavirus, ampelovirus, maculavirus and sadwavirus. Results of this work demonstrate the potential of microarray technique to detect viral pathogens without sequence bias amplification of template RNA.
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76
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Jámbrik K, Máthé C, Vasas G, Beyer D, Molnár E, Borbély G, M-Hamvas M. Microcystin-LR induces chromatin alterations and modulates neutral single-strand-preferring nuclease activity in Phragmites australis. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:678-686. [PMID: 21145617 DOI: 10.1016/j.jplph.2010.10.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 10/01/2010] [Accepted: 10/01/2010] [Indexed: 05/30/2023]
Abstract
Microcystin-LR (MCY-LR), a toxin produced mainly by freshwater cyanobacteria, is a potent inhibitor of type 1 and 2A protein phosphatases. As such, it induces biochemical, cellular and tissue alterations in vascular plants, including cell death. The aim of this study was the analysis of MCY-LR induced changes in the activity of single-strand preferring nuclease (SSP nuclease) isoenzymes that are possibly involved in programmed cell death (PCD) of Phragmites australis (common reed, an aquatic macrophyte) cells. We analyzed both single-stranded DNA (ssDNase) and double-stranded DNA (dsDNase) cleaving activities. Activity gels revealed a number of seven isoenzymes named bands A-G in control reed shoots and roots. Their activity was organ- and age-dependent. We stained nuclei of root tip meristematic cells and found total and marginal chromatin condensations at relatively short-term (2-10 days) cyanotoxin exposure. At 10-20 days of cyanotoxin treatment, the number of cells with condensed chromatin decreased, which coincided with the occurrence of necrotic cell death. In parallel, overall ssDNase activity increased in the short term (five days) and gradually decreased at 10-20 days of MCY-LR treatment. In this context, the most important changes occurred for isoenzyme G of 28-32kDa in roots and isoenzyme F of 35-38kDa in shoots. dsDNase activity of isoenzyme E was decreased by MCY-LR in shoots, but increased in roots at 10 days of exposure. We conclude that the early induction of chromatin condensation and increase of SSP nuclease activities is related to PCD that will lead to necrosis with the cease of all cellular activities, including a decrease in nuclease activity.
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Affiliation(s)
- Katalin Jámbrik
- Department of Botany, University of Debrecen, Faculty of Science and Technology, P.O. Box 14, H-4010 Debrecen, Hungary
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77
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Karuppanapandian T, Wang HW, Prabakaran N, Jeyalakshmi K, Kwon M, Manoharan K, Kim W. 2,4-dichlorophenoxyacetic acid-induced leaf senescence in mung bean (Vigna radiata L. Wilczek) and senescence inhibition by co-treatment with silver nanoparticles. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2011; 49:168-177. [PMID: 21144762 DOI: 10.1016/j.plaphy.2010.11.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 10/14/2010] [Accepted: 11/14/2010] [Indexed: 05/30/2023]
Abstract
Leaf senescence induced by 2,4-dichlorophenoxyacetic acid (2,4-D) and senescence inhibition caused by supplementation with silver (Ag(+)) ions in the form of silver nitrate (AgNO(3)) or silver nanoparticles (AgNPs) were investigated in 8-day-old mung bean (Vigna radiata L. Wilczek) seedlings. Inhibition of root and shoot elongation were observed in mung bean seedlings treated with 500μM 2,4-D. Concomitantly, the activity of 1-aminocyclopropane-1-carboxylic acid synthase was significantly induced in leaf tissue. Leaf senescence induced by 2,4-D was closely associated with lipid peroxidation as well as increased levels of cytotoxic hydrogen peroxide (H(2)O(2)) and superoxide radicals (O(2)(·-)). Despite decreased catalase activity, the activities of peroxidase, superoxide dismutase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase were increased during 2,4-D-induced leaf senescence. Further, the levels of reduced ascorbate, oxidized ascorbate, and reduced glutathione were markedly decreased, whereas the level of oxidized glutathione increased. 2,4-D-induced leaf senescence in mung bean was accompanied by an increase in positive terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, nuclear DNA fragmentation, and the activity of a 15-kDa Ca(2+)-dependent DNase. Supplementation with 100μM AgNO(3) or AgNPs inhibited 2,4-D-induced leaf senescence. The present results suggest that increased oxidative stress (O(2)(·-) and H(2)O(2)) led to senescence in mung bean leaves. Furthermore, significantly induced antioxidative enzymes are not sufficient to protect mung bean cells from 2,4-D-induced harmful ROS.
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Affiliation(s)
- Thirupathi Karuppanapandian
- Department of Plant Sciences, Centre for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai 625021, India
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78
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Podzimek T, Matoušek J, Lipovová P, Poučková P, Spiwok V, Santrůček J. Biochemical properties of three plant nucleases with anticancer potential. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2011; 180:343-51. [PMID: 21421379 DOI: 10.1016/j.plantsci.2010.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 09/15/2010] [Accepted: 10/08/2010] [Indexed: 05/30/2023]
Abstract
Biochemical and structural properties of three recombinant (R), highly homologous, plant bifunctional nucleases from tomato (R-TBN1), hop (R-HBN1) and Arabis brassica (R-ABN1) were determined. These nucleases cleave single- and double-stranded substrates, as well as both RNA and DNA with nearly the same efficiency. In addition, they are able to cleave several artificial substrates and highly stable viroid RNA. They also possess 3'-nucleotidase activity; therefore, they can be classified as nuclease I family members. Interestingly, poly(G) is resistant to cleavage and moreover it inhibits dsDNase, ssDNase and RNase activity of the studied nucleases. All three nucleases exhibit zinc-dependence and a strong stimulatory effect of Zn²+ for dsDNA cleavage. 3-D models, predicted on the basis of experimental structure of P1 nuclease, show nine amino acid residues responsible for interactions with zinc atoms, located in the same positions as in P1 nuclease. It was also shown that R-TBN1, R-HBN1, and R-ABN1 are all N-glycosylated. Oligosaccharidic chains constitute about 16% of their MW. In addition, an anticancer potential of the R-ABN1 is compared in this work with previously tested R-TBN1, and R-HBN1. R-ABN1 injected intravenously showed 70% inhibitory effect on growth of human prostate carcinoma in athymic mice.
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Affiliation(s)
- Tomáš Podzimek
- Institute of Chemical Technology Prague, Technická 3, 166 28 Prague, Czech Republic; Biology Centre, ASCR v.v.i., Institute of Plant Molecular Biology, Branišovská 32, 37005 České Budějovice, Czech Republic.
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79
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RNS2, a conserved member of the RNase T2 family, is necessary for ribosomal RNA decay in plants. Proc Natl Acad Sci U S A 2011; 108:1093-8. [PMID: 21199950 DOI: 10.1073/pnas.1009809108] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
RNase T2 enzymes are conserved in most eukaryotic genomes, and expression patterns and phylogenetic analyses suggest that they may carry out an important housekeeping role. However, the nature of this role has been elusive. Here we show that RNS2, an intracellular RNase T2 from Arabidopsis thaliana, is essential for normal ribosomal RNA recycling. This enzyme is the main endoribonuclease activity in plant cells and localizes to the endoplasmic reticulum (ER), ER-derived structures, and vacuoles. Mutants lacking RNS2 activity accumulate RNA intracellularly, and rRNA in these mutants has a longer half-life. Normal rRNA turnover seems essential to maintain cell homeostasis because rns2 mutants display constitutive autophagy. We propose that RNS2 is part of a process that degrades rRNA to recycle its components. This process appears to be conserved in all eukaryotes.
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80
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Koval' T, Lipovová P, Podzimek T, Matoušek J, Dušková J, Skálová T, Stěpánková A, Hašek J, Dohnálek J. Crystallization of recombinant bifunctional nuclease TBN1 from tomato. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:124-8. [PMID: 21206042 PMCID: PMC3079990 DOI: 10.1107/s1744309110048177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 11/18/2010] [Indexed: 11/10/2022]
Abstract
The endonuclease TBN1 from Solanum lycopersicum (tomato) was expressed in Nicotiana benthamiana leaves and purified with suitable quality and in suitable quantities for crystallization experiments. Two crystal forms (orthorhombic and rhombohedral) were obtained and X-ray diffraction experiments were performed. The presence of natively bound Zn2+ ions was confirmed by X-ray fluorescence and by an absorption-edge scan. X-ray diffraction data were collected from the orthorhombic (resolution of 5.2 Å) and rhombohedral (best resolution of 3.2 Å) crystal forms. SAD, MAD and MR methods were applied for solution of the phase problem, with partial success. TBN1 contains three Zn2+ ions in a similar spatial arrangement to that observed in nuclease P1 from Penicillium citrinum.
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Affiliation(s)
- Tomáš Koval'
- Institute of Physics AS CR, v.v.i., Na Slovance 2, 182 21 Praha 8, Czech Republic.
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81
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Carbonell-Bejerano P, Urbez C, Carbonell J, Granell A, Perez-Amador MA. A fertilization-independent developmental program triggers partial fruit development and senescence processes in pistils of Arabidopsis. PLANT PHYSIOLOGY 2010; 154:163-72. [PMID: 20625003 PMCID: PMC2938164 DOI: 10.1104/pp.110.160044] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 07/09/2010] [Indexed: 05/18/2023]
Abstract
The pistil is the specialized plant organ that enables appropriate pollination and ovule fertilization, after which it undergoes growth and differentiation to become a fruit. However, in most species, if ovules are not fertilized around anthesis the pistil irreversibly loses its growth capacity. We used physiological, molecular, and transcriptomic tools to characterize the post-anthesis development of the unfertilized Arabidopsis (Arabidopsis thaliana) pistil. Surprisingly, developmental processes that have been previously described in developing Arabidopsis fruits, such as the collapse of the adaxial epidermis, differentiation of a sclerenchyma layer in the adaxial subepidermis and the dehiscence zone, and valve dehiscence, were also observed in the unfertilized pistil. We determined that senescence is first established in the transmitting tract, stigma, and ovules immediately after anthesis, and that the timing of senescence in the stigma and ovules correlates with the loss of fruit-set responsiveness of the pistil to pollen and the hormone gibberellin (GA), respectively. Moreover, we showed that mutants with altered ovule development have impaired fruit-set response to the GA gibberellic acid, which further indicates that the presence of viable ovules is required for fruit-set responsiveness to GAs in the unfertilized pistil. Our data suggest that a fertilization-independent developmental program controls many of the processes during post-anthesis development, both in unfertilized pistils and seeded fruits, and point to a key role of the ovule in the capacity of pistils to undergo fruit set in response to GA.
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Affiliation(s)
| | | | | | | | - Miguel A. Perez-Amador
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Ciudad Politécnica de la Innovación, Ingeniero Fausto Elio s/n, 46022 Valencia, Spain
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Xiao YL, Redman JC, Monaghan EL, Zhuang J, Underwood BA, Moskal WA, Wang W, Wu HC, Town CD. High throughput generation of promoter reporter (GFP) transgenic lines of low expressing genes in Arabidopsis and analysis of their expression patterns. PLANT METHODS 2010; 6:18. [PMID: 20687964 PMCID: PMC2927586 DOI: 10.1186/1746-4811-6-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 08/06/2010] [Indexed: 05/20/2023]
Abstract
BACKGROUND Although the complete genome sequence and annotation of Arabidopsis were released at the end of year 2000, it is still a great challenge to understand the function of each gene in the Arabidopsis genome. One way to understand the function of genes on a genome-wide scale is expression profiling by microarrays. However, the expression level of many genes in Arabidopsis genome cannot be detected by microarray experiments. In addition, there are many more novel genes that have been discovered by experiments or predicted by new gene prediction programs. Another way to understand the function of individual genes is to investigate their in vivo expression patterns by reporter constructs in transgenic plants which can provide basic information on the patterns of gene expression. RESULTS A high throughput pipeline was developed to generate promoter-reporter (GFP) transgenic lines for Arabidopsis genes expressed at very low levels and to examine their expression patterns in vivo. The promoter region from a total of 627 non- or low-expressed genes in Arabidopsis based on Arabidopsis annotation release 5 were amplified and cloned into a Gateway vector. A total of 353 promoter-reporter (GFP) constructs were successfully transferred into Agrobacterium (GV3101) by triparental mating and subsequently used for Arabidopsis transformation. Kanamycin-resistant transgenic lines were obtained from 266 constructs and among them positive GFP expression was detected from 150 constructs. Of these 150 constructs, multiple transgenic lines exhibiting consistent expression patterns were obtained for 112 constructs. A total 81 different regions of expression were discovered during our screening of positive transgenic plants and assigned Plant Ontology (PO) codes. CONCLUSIONS Many of the genes tested for which expression data were lacking previously are indeed expressed in Arabidopsis during the developmental stages screened. More importantly, our study provides plant researchers with another resource of gene expression information in Arabidopsis. The results of this study are captured in a MySQL database and can be searched at http://www.jcvi.org/arabidopsis/qpcr/index.shtml. Transgenic seeds and constructs are also available for the research community.
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Affiliation(s)
- Yong-Li Xiao
- J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD 20850, USA
| | - Julia C Redman
- J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD 20850, USA
| | - Erin L Monaghan
- J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD 20850, USA
| | - Jun Zhuang
- J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD 20850, USA
| | - Beverly A Underwood
- J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD 20850, USA
| | - William A Moskal
- J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD 20850, USA
| | - Wei Wang
- J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD 20850, USA
| | - Hank C Wu
- J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD 20850, USA
| | - Christopher D Town
- J. Craig Venter Institute, 9704 Medical Center Drive, Rockville, MD 20850, USA
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83
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Chai L, Ge X, Xu Q, Deng X. CgSL2, an S-like RNase gene in 'Zigui shatian' pummelo (Citrus grandis Osbeck), is involved in ovary senescence. Mol Biol Rep 2010; 38:1-8. [PMID: 20306304 DOI: 10.1007/s11033-010-0070-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 03/05/2010] [Indexed: 11/29/2022]
Abstract
'Zigui shatian' pummelo (Citrus grandis Osbeck) is one nature mutant from 'Shatian' pummelo, which showed self-compatibility, because self-pollen tubes were not arrested in the style, moreover abnormal post-zygotic development in ovary caused seed abortion in the cultivar. Herein we constructed a cDNA library from flowers of 'Zigui shatian' pummelo and identified one RNase gene fragment. The full length of cDNA sequence of this gene, with an open reading frame of 834 bp, was isolated by 5'-RACE method. The gene, named as CgSL2, contained five conserved regions and two histidine residues essential for RNase activity. Phylogenetic analysis indicated that CgSL2 was mostly similar to AhSL28, an S-like RNase from Antirrhinum. Southern hybridization verified CgSL2 existed in the genome as multiple copies. qRT-PCR and RT-PCR analysis showed that the expression of CgSL2 was not tissue-specific. The expression of CgSL2 was down-regulated during senescence of stem, petal, style and stamen, whereas up-regulated during ovary senescence. Further in situ hybridization of CgSL2 in the ovary during the balloon stage to anthesis stage also showed that it dramatically increased in mature flower, consistent with qRT-PCR and RT-PCR results. These findings suggested that CgSL2 might play an important role during ovary senescence.
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Affiliation(s)
- Lijun Chai
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.
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84
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You MK, Shin HY, Kim YJ, Ok SH, Cho SK, Jeung JU, Yoo SD, Kim JK, Shin JS. Novel bifunctional nucleases, OmBBD and AtBBD1, are involved in abscisic acid-mediated callose deposition in Arabidopsis. PLANT PHYSIOLOGY 2010; 152:1015-29. [PMID: 20018603 PMCID: PMC2815893 DOI: 10.1104/pp.109.147645] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 12/08/2009] [Indexed: 05/23/2023]
Abstract
Screening of the expressed sequence tag library of the wild rice species Oryza minuta revealed an unknown gene that was rapidly and strongly induced in response to attack by a rice fungal pathogen (Magnaporthe oryzae) and an insect (Nilaparvata lugens) and by wounding, abscisic acid (ABA), and methyl jasmonate treatments. Its recombinant protein was identified as a bifunctional nuclease with both RNase and DNase activities in vitro. This gene was designated OmBBD (for O. minuta bifunctional nuclease in basal defense response). Overexpression of OmBBD in an Arabidopsis (Arabidopsis thaliana) model system caused the constitutive expression of the PDF1.2, ABA1, and AtSAC1 genes, which are involved in priming ABA-mediated callose deposition. This activation of defense responses led to an increased resistance against Botrytis cinerea. atbbd1, the knockout mutant of the Arabidopsis ortholog AtBBD1, was susceptible to attack by B. cinerea and had deficient callose deposition. Overexpression of either OmBBD or AtBBD1 in atbbd1 plants complemented the susceptible phenotype of atbbd1 against B. cinerea as well as the deficiency of callose deposition. We suggest that OmBBD and AtBBD1 have a novel regulatory role in ABA-mediated callose deposition.
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85
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Fiorilli V, Catoni M, Miozzi L, Novero M, Accotto GP, Lanfranco L. Global and cell-type gene expression profiles in tomato plants colonized by an arbuscular mycorrhizal fungus. THE NEW PHYTOLOGIST 2009; 184:975-87. [PMID: 19765230 DOI: 10.1111/j.1469-8137.2009.03031.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
*Arbuscular mycorrhizal symbiosis develops in roots; extensive cellular reorganizations and specific metabolic changes occur, which are mirrored by local and systemic changes in the transcript profiles. *A TOM2 microarray (c. 12 000 probes) has been used to obtain an overview of the transcriptional changes that are triggered in Solanum lycopersicum roots and shoots, as a result of colonization by the arbuscular mycorrhizal fungus Glomus mosseae. The cell-type expression profile of a subset of genes was monitored, using laser microdissection, to identify possible plant determinants of arbuscule development,. *Microarrays revealed 362 up-regulated and 293 down-regulated genes in roots. Significant gene modulation was also observed in shoots: 85 up- and 337 down-regulated genes. The most responsive genes in both organs were ascribed to primary and secondary metabolism, defence and response to stimuli, cell organization and protein modification, and transcriptional regulation. Six genes, preferentially expressed in arbusculated cells, were identified. *A comparative analysis only showed a limited overlap with transcript profiles identified in mycorrhizal roots of Medicago truncatula, probably as a consequence of the largely nonoverlapping probe sets on the microarray tools used. The results suggest that auxin and abscisic acid metabolism are involved in arbuscule formation and/or functioning.
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Affiliation(s)
- Valentina Fiorilli
- Dipartimento di Biologia Vegetale, Università degli Studi di Torino, Torino, Italy
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86
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Wagstaff C, Yang TJW, Stead AD, Buchanan-Wollaston V, Roberts JA. A molecular and structural characterization of senescing Arabidopsis siliques and comparison of transcriptional profiles with senescing petals and leaves. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 57:690-705. [PMID: 18980641 DOI: 10.1111/j.1365-313x.2008.03722.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Senescence of plant organs is a genetically controlled process that regulates cell death to facilitate nutrient recovery and recycling, and frequently precedes, or is concomitant with, ripening of reproductive structures. In Arabidopsis thaliana, the seeds are contained within a silique, which is itself a photosynthetic organ in the early stages of development and undergoes a programme of senescence prior to dehiscence. A transcriptional analysis of the silique wall was undertaken to identify changes in gene expression during senescence and to correlate these events with ultrastructural changes. The study revealed that the most highly up-regulated genes in senescing silique wall tissues encoded seed storage proteins, and the significance of this finding is discussed. Global transcription profiles of senescing siliques were compared with those from senescing Arabidopsis leaf or petal tissues using microarray datasets and metabolic pathway analysis software (MapMan). In all three tissues, members of NAC and WRKY transcription factor families were up-regulated, but components of the shikimate and cell-wall biosynthetic pathways were down-regulated during senescence. Expression of genes encoding ethylene biosynthesis and action showed more similarity between senescing siliques and petals than between senescing siliques and leaves. Genes involved in autophagy were highly expressed in the late stages of death of all plant tissues studied, but not always during the preceding remobilization phase of senescence. Analyses showed that, during senescence, silique wall tissues exhibited more transcriptional features in common with petals than with leaves. The shared and distinct regulatory events associated with senescence in the three organs are evaluated and discussed.
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Affiliation(s)
- Carol Wagstaff
- School of Food Biosciences, University of Reading, Whiteknights, PO Box 226, Reading RG6 6AP, UK.
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87
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Chapin LJ, Jones ML. Ethylene regulates phosphorus remobilization and expression of a phosphate transporter (PhPT1) during petunia corolla senescence. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:2179-90. [PMID: 19380421 PMCID: PMC2682506 DOI: 10.1093/jxb/erp092] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 03/04/2009] [Accepted: 03/04/2009] [Indexed: 05/20/2023]
Abstract
The programmed degradation of macromolecules during petal senescence allows the plant to remobilize nutrients from dying to developing tissues. Ethylene is involved in regulating the timing of nucleic acid degradation in petunia, but it is not clear if ethylene has a role in the remobilization of phosphorus during petal senescence. To investigate ethylene's role in nutrient remobilization, the P content of petals (collectively called the corolla) during early development and senescence was compared in ethylene-sensitive wild type Petunia x hybrida 'Mitchell Diploid' (MD) and transgenic petunias with reduced sensitivity to ethylene (35S::etr1-1). When compared to the total P content of corollas on the day of flower opening (the early non-senescing stage), P in MD corollas had decreased 74% by the late stage of senescence (advanced wilting). By contrast, P levels were only reduced by an average of 32% during etr1-1 corolla (lines 44568 and Z00-35-10) senescence. A high-affinity phosphate transporter, PhPT1 (PhPht1;1), was cloned from senescing petunia corollas by RT-PCR. PhPT1 expression was up-regulated during MD corolla senescence and a much smaller increase was detected during the senescence of etr1-1 petunia corollas. PhPT1 mRNA levels showed a rapid increase in detached corollas (treated at 1 d after flower opening) following treatment with low levels of ethylene (0.1 microl l(-1)). Transcripts accumulated in the presence of the protein synthesis inhibitor, cycloheximide, indicating that PhPT1 is a primary ethylene response gene. PhPT1 is a putative phosphate transporter that may function in Pi translocation during senescence.
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88
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Fedoreyeva LI, Sobolev DE, Vanyushin BF. Wheat coleoptile endonuclease Wen2 is dependent on S-adenosyl-L-methionine and sensitive to DNA methylation status. BIOCHEMISTRY (MOSCOW) 2008; 73:1000-6. [DOI: 10.1134/s0006297908090071] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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89
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Jiang AL, Cheng Y, Li J, Zhang W. A zinc-dependent nuclear endonuclease is responsible for DNA laddering during salt-induced programmed cell death in root tip cells of rice. JOURNAL OF PLANT PHYSIOLOGY 2008; 165:1134-41. [PMID: 18295371 DOI: 10.1016/j.jplph.2007.12.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 12/21/2007] [Accepted: 12/21/2007] [Indexed: 05/10/2023]
Abstract
DNA laddering is one of the biochemical processes characteristic of programmed cell death (PCD) both in animals and plants. However, the mechanism of DNA laddering varies in different species, even in different tissues of one organism. In the present study, we used root tip cells of rice, which have been induced by NaCl stress to undergo PCD, to analyze the endonuclease activities of cytoplasmic and nuclear extracts. Two endonucleases, a cytoplasmic of 20kDa (OsCyt20) and a nuclear of 37kDa (OsNuc37), were identified as PCD related. Our results indicated that OsCyt20 is a Ca(2+)/Mg(2+)-dependent nuclease, which is most active at neutral pH, and that OsNuc37 is Zn(2+)-dependent, with a pH optimum of 4.5-6. Both nucleases were induced at the early stage of PCD (2h salt treatment) and exhibited the highest activity approximately 4h after exposure to NaCl, paralleling with the occurrence of DNA laddering. In vitro assays of endonuclease activities further revealed that OsNuc37, a glycoprotein localized in the nucleus, is the executor for DNA laddering. The different effects of both endonucleases on DNA degradation during salt-induced PCD are discussed.
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Affiliation(s)
- Ai-Liang Jiang
- Department of Biochemistry & Molecular Biology, College of Life Science, Nanjing Agricultural University, Nanjing, PR China
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90
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Farage-Barhom S, Burd S, Sonego L, Perl-Treves R, Lers A. Expression analysis of the BFN1 nuclease gene promoter during senescence, abscission, and programmed cell death-related processes. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:3247-58. [PMID: 18603613 PMCID: PMC2529240 DOI: 10.1093/jxb/ern176] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 05/19/2008] [Accepted: 06/03/2008] [Indexed: 05/18/2023]
Abstract
Little is known about the biological role of nucleases induced during plant senescence and programmed cell death (PCD). Arabidopsis BFN1 has been identified as a senescence-associated type I nuclease, whose protein sequence shares high homology with some other senescence- or PCD-associated plant nucleases. To learn about BFN1 regulation, its expression pattern was analysed. A 2.3 kb portion of the 5' promoter sequence of BFN1 was cloned and its ability to activate the GUS reporter gene was examined. Transgenic Arabidopsis and tomato plants harbouring this chimeric construct were analysed for GUS expression. In both, the BFN1 promoter was able specifically to direct GUS expression in senescent leaves, differentiating xylem and the abscission zone of flowers. Thus, at least part of the regulation of BFN1 is mediated at the transcriptional level, and the regulatory elements are recognized in the two different plants. In tomato, specific expression was observed in the leaf and the fruit abscission zones. The BFN1 promoter was also active in other tissues, including developing anthers and seeds, and in floral organs after fertilization. PCD has been implicated in all of these processes, suggesting that in addition to senescence, BFN1 is involved in PCD associated with different development processes in Arabidopsis.
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Affiliation(s)
- Sarit Farage-Barhom
- Department of Postharvest Science of Fresh Produce, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel
- Faculty of Life Science, Bar Ilan University, Ramat Gan, Israel
| | - Shaul Burd
- Department of Postharvest Science of Fresh Produce, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel
| | - Lilian Sonego
- Department of Postharvest Science of Fresh Produce, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel
| | | | - Amnon Lers
- Department of Postharvest Science of Fresh Produce, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel
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91
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Denoux C, Galletti R, Mammarella N, Gopalan S, Werck D, De Lorenzo G, Ferrari S, Ausubel FM, Dewdney J. Activation of defense response pathways by OGs and Flg22 elicitors in Arabidopsis seedlings. MOLECULAR PLANT 2008; 1:423-45. [PMID: 19825551 PMCID: PMC2954645 DOI: 10.1093/mp/ssn019] [Citation(s) in RCA: 319] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We carried out transcriptional profiling analysis in 10-d-old Arabidopsis thaliana seedlings treated with oligogalacturonides (OGs), oligosaccharides derived from the plant cell wall, or the bacterial flagellin peptide Flg22, general elicitors of the basal defense response in plants. Although detected by different receptors, both OGs and Flg22 trigger a fast and transient response that is both similar and comprehensive, and characterized by activation of early stages of multiple defense signaling pathways, particularly JA-associated processes. However, the response to Flg22 is stronger in both the number of genes differentially expressed and the amplitude of change. The magnitude of induction of individual genes is in both cases dose-dependent, but, even at very high concentrations, OGs do not induce a response that is as comprehensive as that seen with Flg22. While high doses of either microbe-associated molecular pattern (MAMP) elicit a late response that includes activation of senescence processes, SA-dependent secretory pathway genes and PR1 expression are substantially induced only by Flg22. These results suggest a lower threshold for activation of early responses than for sustained or SA-mediated late defenses. Expression patterns of amino-cyclopropane-carboxylate synthase genes also implicate ethylene biosynthesis in regulation of the late innate immune response.
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Affiliation(s)
- Carine Denoux
- Department of Genetics, Harvard Medical School, and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 USA
- Institut de Biologie Moléculaire des Plantes, CNRS, Université Louis Pasteur, Strasbourg, France
| | - Roberta Galletti
- Dipartimento di Biologia Vegetale, Università di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Nicole Mammarella
- Department of Genetics, Harvard Medical School, and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 USA
| | - Suresh Gopalan
- Department of Genetics, Harvard Medical School, and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 USA
| | - Danièle Werck
- Institut de Biologie Moléculaire des Plantes, CNRS, Université Louis Pasteur, Strasbourg, France
| | - Giulia De Lorenzo
- Dipartimento di Biologia Vegetale, Università di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Simone Ferrari
- Dipartimento di Biologia Vegetale, Università di Roma “La Sapienza”, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Frederick M. Ausubel
- Department of Genetics, Harvard Medical School, and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 USA
| | - Julia Dewdney
- Department of Genetics, Harvard Medical School, and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 USA
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92
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Triques K, Piednoir E, Dalmais M, Schmidt J, Le Signor C, Sharkey M, Caboche M, Sturbois B, Bendahmane A. Mutation detection using ENDO1: application to disease diagnostics in humans and TILLING and Eco-TILLING in plants. BMC Mol Biol 2008; 9:42. [PMID: 18433472 PMCID: PMC2386800 DOI: 10.1186/1471-2199-9-42] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Accepted: 04/23/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Most enzymatic mutation detection methods are based on the cleavage of heteroduplex DNA by a mismatch-specific endonuclease at mismatch sites and the analysis of the digestion product on a DNA sequencer. Important limitations of these methods are the availability of a mismatch-specific endonuclease, their sensitivity in detecting one allele in pool of DNA, the cost of the analysis and the ease by which the technique could be implemented in a standard molecular biology laboratory. RESULTS The co-agroinfiltration of ENDO1 and p19 constructs into N. benthamiana leaves allowed high level of transient expression of a mismatch-specific and sensitive endonuclease, ENDO1 from Arabidopsis thaliana. We demonstrate the broad range of uses of the produced enzyme in detection of mutations. In human, we report the diagnosis of the G1691A mutation in Leiden factor-V gene associated with venous thrombosis and the fingerprinting of HIV-1 quasispecies in patients subjected to antiretroviral treatments. In plants, we report the use of ENDO1 system for detection of mutant alleles of Retinoblastoma-related gene by TILLING in Pisum sativum and discovery of natural sequence variations by Eco-TILLING in Arabidopsis thaliana. CONCLUSION We introduce a cost-effective tool based on a simplified purification protocol of a mismatch-specific and sensitive endonuclease, ENDO1. Especially, we report the successful applications of ENDO1 in mutation diagnostics in humans, fingerprinting of complex population of viruses, and in TILLING and Eco-TILLING in plants.
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Affiliation(s)
- Karine Triques
- Unité Mixte de Recherche en Génomique Végétale, 2 rue Gaston Crémieux, CP5708, 91 057 Evry Cedex, France
| | - Elodie Piednoir
- Unité Mixte de Recherche en Génomique Végétale, 2 rue Gaston Crémieux, CP5708, 91 057 Evry Cedex, France
| | - Marion Dalmais
- Unité Mixte de Recherche en Génomique Végétale, 2 rue Gaston Crémieux, CP5708, 91 057 Evry Cedex, France
| | - Julien Schmidt
- Unité Mixte de Recherche en Génomique Végétale, 2 rue Gaston Crémieux, CP5708, 91 057 Evry Cedex, France
| | - Christine Le Signor
- Unité Mixte de Recherche en Génétique et Ecophysiologie des Légumineuses, Domaine d'Epoisses, 21110 Bretenières, France
| | - Mark Sharkey
- University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Michel Caboche
- Unité Mixte de Recherche en Génomique Végétale, 2 rue Gaston Crémieux, CP5708, 91 057 Evry Cedex, France
| | - Bénédicte Sturbois
- Unité Mixte de Recherche en Génomique Végétale, 2 rue Gaston Crémieux, CP5708, 91 057 Evry Cedex, France
| | - Abdelhafid Bendahmane
- Unité Mixte de Recherche en Génomique Végétale, 2 rue Gaston Crémieux, CP5708, 91 057 Evry Cedex, France
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93
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Kim CY, Bove J, Assmann SM. Overexpression of wound-responsive RNA-binding proteins induces leaf senescence and hypersensitive-like cell death. THE NEW PHYTOLOGIST 2008; 180:57-70. [PMID: 18705666 DOI: 10.1111/j.1469-8137.2008.02557.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Leaf senescence is a form of programmed cell death, and involves regulated expression of a specific set of senescence-associated genes (SAGs). In Arabidopsis, three UBA2 genes, UBA2a, UBA2b, and UBA2c, encode heterogeneous nuclear ribonucleoprotein (hnRNP)-type RNA-binding proteins. Previously, it has been demonstrated that expression of UBA2 genes is induced by mechanical wounding in a splice variant-dependent manner. Constitutive overexpression of the UBA2 genes proved lethal. Accordingly, a conditional gain-of-function system was used here to assess phenotypes related to UBA2 overexpression. Overexpression of each of the three UBA2 genes leads to a leaf yellowing/cell death-like phenotype in Arabidopsis plants. Expression levels of a number of SAGs, such as SAG13, SAG14, SAG15, SAG101, WRKY6, WRKY53, WRKY70, ACS2, ACS6, CML38 and SIRK, were elevated upon induction of UBA2 overexpression, as were transcripts of multiple wounding- and defense-related genes, including EDS1, CK1, JR1, WR3 and MPK3. Elevated ethylene biosynthesis and hypersensitive-like patterns of cell death and callose deposition, shown by Trypan blue and aniline blue staining, respectively, were also observed following induced overexpression of UBA2a, UBA2b, and UBA2c. These results indicate that induction of UBA2 gene expression stimulates leaf yellowing and cell death phenotypes through senescence and defense response pathways.
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Affiliation(s)
- Cha Young Kim
- Biology Department, Penn State University, 208 Mueller Laboratory, University Park, PA 16802, USA
- Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660-701, Korea
| | - Jérôme Bove
- Biology Department, Penn State University, 208 Mueller Laboratory, University Park, PA 16802, USA
| | - Sarah M Assmann
- Biology Department, Penn State University, 208 Mueller Laboratory, University Park, PA 16802, USA
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94
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Gadjev I, Stone JM, Gechev TS. Programmed cell death in plants: new insights into redox regulation and the role of hydrogen peroxide. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 270:87-144. [PMID: 19081535 DOI: 10.1016/s1937-6448(08)01403-2] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Programmed cell death (PCD), the highly regulated dismantling of cells, is essential for plant growth and survival. PCD plays key roles in embryo development, formation and maturation of many cell types and tissues, and plant reaction/adaptation to environmental conditions. Reactive oxygen species (ROS) are not only toxic by products of aerobic metabolism with strictly controlled cellular levels, but they also function as signaling agents regulating many biological processes and producing pleiotropic effects. Over the last decade, ROS have become recognized as important modulators of plant PCD. Molecular genetic approaches using plant mutants and transcriptome studies related to ROS-mediated PCD have revealed a wide array of plant-specific cell death regulators and have contributed to unraveling the elaborate redox signaling network. This review summarizes the biological processes, in which plant PCD participates and discusses the signaling functions of ROS with emphasis on hydrogen peroxide.
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Affiliation(s)
- Ilya Gadjev
- Department of Plant Physiology and Plant Molecular Biology, University of Plovdiv, Plovdiv 4000, Bulgaria
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95
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Triques K, Sturbois B, Gallais S, Dalmais M, Chauvin S, Clepet C, Aubourg S, Rameau C, Caboche M, Bendahmane A. Characterization of Arabidopsis thaliana mismatch specific endonucleases: application to mutation discovery by TILLING in pea. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 51:1116-25. [PMID: 17651368 DOI: 10.1111/j.1365-313x.2007.03201.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Scanning DNA sequences for mutations and polymorphisms has become one of the most challenging, often expensive and time-consuming obstacles in many molecular genetic applications, including reverse genetic and clinical diagnostic applications. Enzymatic mutation detection methods are based on the cleavage of heteroduplex DNA at the mismatch sites. These methods are often limited by the availability of a mismatch-specific endonuclease, their sensitivity in detecting one allele in a pool of DNA and their costs. Here, we present detailed biochemical analysis of five Arabidopsis putative mismatch-specific endonucleases. One of them, ENDO1, is presented as the first endonuclease that recognizes and cleaves all types of mismatches with high efficiency. We report on a very simple protocol for the expression and purification of ENDO1. The ENDO1 system could be exploited in a wide range of mutation diagnostic tools. In particular, we report the use of ENDO1 for discovery of point mutations in the gibberellin 3beta-hydrolase gene of Pisum sativum. Twenty-one independent mutants were isolated, five of these were characterized and two new mutations affecting internodes length were identified. To further evaluate the quality of the mutant population we screened for mutations in four other genes and identified 5-21 new alleles per target. Based on the frequency of the obtained alleles we concluded that the pea population described here would be suitable for use in a large reverse-genetics project.
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Affiliation(s)
- Karine Triques
- URGV, Unité de Recherche en Génomique Végétale, UMR INRA CNRS. 2, Rue Gaston Crémieux, 91057 Evry Cedex, France
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96
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Matousek J, Kozlová P, Orctová L, Schmitz A, Pesina K, Bannach O, Diermann N, Steger G, Riesner D. Accumulation of viroid-specific small RNAs and increase in nucleolytic activities linked to viroid-caused pathogenesis. Biol Chem 2007; 388:1-13. [PMID: 17214544 DOI: 10.1515/bc.2007.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Strong viroid-caused pathogenesis was achieved in tomato cv. Rutgers by biolistic transfer of severe or lethal potato spindle tuber viroid (PSTVd) strains, while other tomato genotypes (e.g., Moneymaker) were tolerant. With reciprocal hybrids between sensitive and tolerant genotypes, we show that plant depression dominates over tolerance. Biolistic transfer of the most pathogenic PSTVd strain AS1 to Nicotiana benthamiana, which is considered to be a symptomless PSTVd host, led to a strong pathogenesis reaction and stunting, suggesting the presence of specific viroid pathogenesis-promoting target(s) in this plant species. Total levels of small siRNA-like PSTVd-specific RNAs were enhanced in strongly symptomatic tomato and N. benthamiana plants after biolistic infection with AS1 in comparison to the mild QFA strain. This indicates association of elevated levels of viroid-specific small RNA with production of strong symptoms. In symptom-bearing tomato leaves in comparison to controls, an RNase of approximately 18 kDa was induced and the activity of a nuclease of 34 kDa was elevated by a factor of seven in the vascular system. Sequence analysis of the nuclease cDNA designated TBN1 showed high homology with plant apoptotic endonucleases. The vascular-specific pathogenesis action is supported by light microscopic observations demonstrating a certain lack of xylem tissue and an arrest of the establishment of new vascular bundles in collapsed plants.
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MESH Headings
- Amino Acid Sequence
- Base Sequence
- Biolistics/methods
- Blotting, Northern
- Cloning, Molecular
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- Endonucleases/genetics
- Endonucleases/metabolism
- Genotype
- Solanum lycopersicum/genetics
- Solanum lycopersicum/metabolism
- Solanum lycopersicum/virology
- Molecular Sequence Data
- Nucleic Acid Conformation
- Plant Diseases/genetics
- Plant Diseases/virology
- Plant Leaves/genetics
- Plant Leaves/metabolism
- Plant Leaves/virology
- Plant Proteins/genetics
- Plant Proteins/metabolism
- Plant Viruses/genetics
- Plant Viruses/pathogenicity
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- RNA, Viral/chemistry
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Solanum tuberosum/genetics
- Solanum tuberosum/metabolism
- Solanum tuberosum/virology
- Viroids/genetics
- Viroids/pathogenicity
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Affiliation(s)
- Jaroslav Matousek
- Department of Molecular Genetics, Biological Centre of the Czech Academy of Sciences, Institute of Plant Molecular Biology, Branisovská 31, CZ-37005 Ceské Budĕjovice, Czech Republic
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97
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Mitsuda N, Seki M, Shinozaki K, Ohme-Takagi M. The NAC transcription factors NST1 and NST2 of Arabidopsis regulate secondary wall thickenings and are required for anther dehiscence. THE PLANT CELL 2005. [PMID: 16214898 DOI: 10.1105/tpc.105.036004.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In plants, secondary wall thickenings play important roles in various biological processes, although the factors regulating these processes remain to be characterized. We show that expression of chimeric repressors derived from NAC SECONDARY WALL THICKENING PROMOTING FACTOR1 (NST1) and NST2 in Arabidopsis thaliana resulted in an anther dehiscence defect due to loss of secondary wall thickening in anther endothecium. Plants with double, but not single, T-DNA-tagged lines for NST1 and NST2 had the same anther-indehiscent phenotype as transgenic plants that expressed the individual chimeric repressors, indicating that NST1 and NST2 are redundant in regulating secondary wall thickening in anther walls. The activity of the NST2 promoter was particularly strong in anther tissue, while that of the NST1 promoter was detected in various tissues in which lignified secondary walls develop. Ectopic expression of NST1 or NST2 induced ectopic thickening of secondary walls in various aboveground tissues. Epidermal cells with ectopic thickening of secondary walls had structural features similar to those of tracheary elements. However, among genes involved in the differentiation of tracheary elements, only those related to secondary wall synthesis were clearly upregulated. None of the genes involved in programmed cell death were similarly affected. Our results suggest NAC transcription factors as possible regulators of secondary wall thickening in various tissues.
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Affiliation(s)
- Nobutaka Mitsuda
- Gene Function Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8562, Japan
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98
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Mitsuda N, Seki M, Shinozaki K, Ohme-Takagi M. The NAC transcription factors NST1 and NST2 of Arabidopsis regulate secondary wall thickenings and are required for anther dehiscence. THE PLANT CELL 2005; 17:2993-3006. [PMID: 16214898 PMCID: PMC1276025 DOI: 10.1105/tpc.105.036004] [Citation(s) in RCA: 460] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2005] [Revised: 09/05/2005] [Accepted: 09/26/2005] [Indexed: 05/04/2023]
Abstract
In plants, secondary wall thickenings play important roles in various biological processes, although the factors regulating these processes remain to be characterized. We show that expression of chimeric repressors derived from NAC SECONDARY WALL THICKENING PROMOTING FACTOR1 (NST1) and NST2 in Arabidopsis thaliana resulted in an anther dehiscence defect due to loss of secondary wall thickening in anther endothecium. Plants with double, but not single, T-DNA-tagged lines for NST1 and NST2 had the same anther-indehiscent phenotype as transgenic plants that expressed the individual chimeric repressors, indicating that NST1 and NST2 are redundant in regulating secondary wall thickening in anther walls. The activity of the NST2 promoter was particularly strong in anther tissue, while that of the NST1 promoter was detected in various tissues in which lignified secondary walls develop. Ectopic expression of NST1 or NST2 induced ectopic thickening of secondary walls in various aboveground tissues. Epidermal cells with ectopic thickening of secondary walls had structural features similar to those of tracheary elements. However, among genes involved in the differentiation of tracheary elements, only those related to secondary wall synthesis were clearly upregulated. None of the genes involved in programmed cell death were similarly affected. Our results suggest NAC transcription factors as possible regulators of secondary wall thickening in various tissues.
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Affiliation(s)
- Nobutaka Mitsuda
- Gene Function Research Center, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8562, Japan
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99
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Larsen K. Molecular cloning and characterization of a cDNA encoding endonuclease from potato (Solanum tuberosum). JOURNAL OF PLANT PHYSIOLOGY 2005; 162:1263-9. [PMID: 16323278 DOI: 10.1016/j.jplph.2005.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A cDNA, StEN1, encoding a potato (Solanum tuberosum) endonuclease was cloned and sequenced. The nucleotide sequence of this clone contains an open reading frame of 906 nucleotides encoding a protein of 302 amino acids, and with a calculated molecular mass of 34.4kDa and a Pi of 5.6. The deduced StEN1 protein contains a putative signal sequence of 25 amino acid residues. The StEN1 encoded protein shows substantial homology to both plant and fungal endonucleases isolated and cloned from other sources. The highest identity (73%) was observed with AgCEL I from celery, Apium graveolens, ZEN1 from Zinnia elegans (69%) and DSA6 from daylily, Hemerocallis (68%). RT-PCR expression analysis demonstrated that the potato StEN1 gene is constitutively expressed in potato, although minor differences in expression level in different tissues were observed.
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Affiliation(s)
- Knud Larsen
- Department of Animal Breeding and Genetics, Danish Institute of Agricultural Sciences, Denmark.
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100
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Yeung AT, Hattangadi D, Blakesley L, Nicolas E. Enzymatic mutation detection technologies. Biotechniques 2005; 38:749-58. [PMID: 15948293 DOI: 10.2144/05385rv01] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Mutation is as necessary for life as fidelity is in DNA replication. The study of mutations reveals the normal functions of genes, messages, proteins, the causes of many diseases, and the variability of responses among individuals. Indeed, recent mutations that have not yet become polymorphisms are often deleterious and pertinent to the disease history of afflicted individuals. This review discusses the principles behind a variety of methods for the detection of mutations and factors that should be considered in future methods design. One enzymatic approach in particular using orthologs of the CEL I nuclease that show high specificity for all mismatches, appears to be easy and robust. Further developments of this and other methods will allow mutation detection to become an integral component of individualized medicine.
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