23 results on '"Kang, Hunseung"'
Search Results
2. Molecular cloning, characterization, and stress-responsive expression of genes encoding glycine-rich RNA-binding proteins in Camelina sativa L.
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Kwak, Kyung Jin, Kang, Hunseung, Han, Kyung-Hwan, and Ahn, Sung-Ju
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MOLECULAR cloning , *GENE expression in plants , *BIOMASS energy , *CAMELINA , *ENERGY crops , *CARRIER proteins , *MOLECULAR chaperones , *GENETIC code - Abstract
Abstract: Camelina sativa L. is an oil-seed crop that has potential for biofuel applications. Although the importance of C. sativa as a biofuel crop has increased in recent years, reports demonstrating the stress responsiveness of C. sativa and characterizing the genes involved in stress response of C. sativa have never been published. Here, we isolated and characterized three genes encoding glycine-rich RNA-binding proteins (GRPs) from camelina: CsGRP2a, CsGRP2b, and CsGRP2c. The three CsGRP2 proteins were very similar in amino acid sequence and contained a well-conserved RNA-recognition motif at the N-terminal region and glycine-rich domain at the C-terminal region. To understand the functional roles of CsGRP2s under stress conditions, we investigated the expression patterns of CsGRP2s under various environmental stress conditions. The expressions of the three CsGRP2s were highly up-regulated under cold stress. The expression of CsGRP2a was up-regulated under salt or dehydration stress, whereas the transcript levels of CsGRP2b and CsGRP2c were decreased under salt or dehydration stress conditions. The three CsGRP2s had the ability to complement cold-sensitive Escherichia coli mutants at low temperatures and harbored transcription anti-termination and nucleic acid-melting activities, indicating that the CsGRP2s possess RNA chaperone activity. The CsGRP2a protein was localized to both the nucleus and the cytoplasm. Expression of CsGRP2a in cold-sensitive Arabidopsis grp7 mutant plants resulted in decreased electrolyte leakage at freezing temperatures. Collectively, these results suggest that the stress-responsive CsGRP2s play a role as an RNA chaperone during the stress adaptation process in camelina. [Copyright &y& Elsevier]
- Published
- 2013
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3. Plant RNA chaperones in stress response
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Kang, Hunseung, Park, Su Jung, and Kwak, Kyung Jin
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PLANT RNA , *RNA metabolism , *MOLECULAR chaperones , *GENE regulatory networks , *REGULATION of plant metabolism , *ORGANISMS , *PLANT biotechnology - Abstract
Post-transcriptional regulation of RNA metabolism is a key regulatory process in diverse cellular processes, including the stress response of plants, during which a variety of RNA-binding proteins (RBPs) function as central regulators in cells. RNA chaperones are RBPs found in all living organisms and function by providing assistance to the correct folding of RNA molecules during RNA metabolism. Although our understanding of the role of RNA chaperones in plants is far less advanced than in bacteria, viruses, and animals, recent progress in functional characterization and determination of RNA chaperone activity of several RBPs has shed new light on the emerging roles of RNA chaperones during the stress response of plants. [Copyright &y& Elsevier]
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- 2013
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4. Expression and functional analyses of microRNA417 in Arabidopsis thaliana under stress conditions
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Jung, Hyun Ju and Kang, Hunseung
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ARABIDOPSIS thaliana , *NUCLEOTIDES , *MORPHOGENESIS , *DEHYDRATION - Abstract
Abstract: MicroRNAs (miRNAs) are 20–25 nucleotides-long RNA transcripts that are capable of suppressing target gene expression by either mRNA cleavage or translational repression. Although many recent reports propose that miRNAs play diverse roles in growth, development, morphogenesis, and stress responses of plants, the biological roles of many miRNAs remain to be verified. Here, we investigated stress-responsive expression patterns and functional roles of miRNA417 in seed germination and seedling growth of Arabidopsis thaliana under various abiotic stress conditions. miRNA417 was expressed constantly throughout the entire growth stages and ubiquitously in all organs including stems, roots, leaves, and flowers. The expression of miRNA417 was regulated by salt stress, dehydration stress, or abscisic acid treatment. To examine the biological roles of miRNA417 in stress responses, the transgenic Arabidopsis plants that constitutively overexpress miRNA417 under the control of cauliflower mosaic virus 35S promoter were generated, and their phenotypes were analyzed under stress conditions. Results showed that seed germination of the transgenic plants was retarded compared with the wild-type plants in the presence of high salt or abscisic acid. These results imply that miRNA417 plays a role as a negative regulator of seed germination in Arabidopsis plants under salt stress conditions. [Copyright &y& Elsevier]
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- 2007
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5. Prokaryotic and eukaryotic translational machineries respond differently to the frameshifting RNA signal from plant or animal virus
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Sung, Deukyong and Kang, Hunseung
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RNA , *RIBOSOMES - Abstract
Many mutational and structural analyses of the RNA signals propose a hypothesis that programmed frameshifting occurs by a specific interaction between ribosome and frameshifting signals comprised of a shifty site and a downstream RNA structure, in which the exact nature of the interaction has not yet been proven. To address this question, we analyzed the frameshifting sequence elements from animal or plant virus in yeast and Escherichia coli. Frameshifting efficiencies varied in yeast, but not in E. coli, depending on the specific conformation of mouse mammary tumor virus (MMTV) RNA pseudoknot. Similar changes in frameshifting efficiencies were observed in yeast, but not in E. coli, for the mutations in frameshifting sequence elements from cereal yellow dwarf virus serotype RPV (CYDV-RPV). The differential response of MMTV or CYDV-RPV frameshifting signal to prokaryotic and eukaryotic translational machineries implies that ribosome pausing alone is insufficient to mediate frameshifting, and additional events including specific interaction between ribosome and RNA structural element are required for efficient frameshifting. These results supports the hypothesis that frameshifting occurs by a specific interaction between ribosome and frameshifting signal. [Copyright &y& Elsevier]
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- 2003
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6. Overexpression of phytochelatin synthase AtPCS2 enhances salt tolerance in Arabidopsis thaliana.
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Kim, Yeon-Ok, Kang, Hunseung, and Ahn, Sung-Ju
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ARABIDOPSIS thaliana , *METAL-binding peptides , *OSMOREGULATION , *WILD plants , *SALT - Abstract
Phytochelatin synthase (PCS) is an enzyme that synthesizes phytochelatins, which are metal-binding peptides. Despite the important role of PCS in heavy metal detoxification or tolerance, the functional role of PCS with respect to other abiotic stresses remains largely unknown. In this study, we determined the function of Arabidopsis thaliana phytochelatin synthase 2 (AtPCS2) in the salt stress response. Expression of AtPCS2 was significantly increased in response to 100 and 200 mM NaCl treatment. AtPCS2-overexpressing transgenic Arabidopsis and tobacco plants displayed increased seed germination rates and seedling growth under high salt stress. In addition, transgenic Arabidopsis subjected to salt stress exhibited enhanced proline accumulation and reduced Na+/K+ ratios compared to wild type plants. Furthermore, decreased levels of hydrogen peroxide (H 2 O 2) and lipid peroxidation were observed in transgenic Arabidopsis compared to wild type specimens. Salt stress greatly reduced transcript levels of CuSOD2, FeSOD2, CAT2 , and GR2 in wild type but not transgenic Arabidopsis. Notably, levels of CAT3 in transgenic Arabidopsis were markedly increased upon salt stress, suggesting that low accumulation of H 2 O 2 in transgenic Arabidopsis is partially achieved through induction of CAT. Collectively, these results suggest that AtPCS2 plays a positive role in seed germination and seedling growth under salt stress through a series of indirect effects that are likely involved in H 2 O 2 scavenging, regulation of osmotic adjustment and ion homeostasis. [ABSTRACT FROM AUTHOR]
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- 2019
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7. Abiotic stress: Interplay between ROS, hormones and MAPKs.
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Raja, Vaseem, Majeed, Umer, Kang, Hunseung, Andrabi, Khursheed Iqbal, and John, Riffat
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PLANT hormones , *ABIOTIC stress , *MITOGEN-activated protein kinases , *OXYGEN in the body , *ELECTRON transport , *PLANT cell microbodies , *BIOACCUMULATION in plants , *PLANTS - Abstract
Reactive oxygen species (ROS) are endogenously produced by several plant organelles and compartments, particularly those with high electron transport rates, such as chloroplasts, mitochondria and peroxisomes as metabolic by-products that act as cellular messengers and redox regulators of several plant biological processes. Excessive accumulation of ROS causes oxidative stress leading to protein denaturation, lipids peroxidation, and nucleotides degradation, which results in cellular damage and ultimately cell death. Functional approaches have provided evidence of the convergence of signaling pathways regulating plant responses to developmental cues and abiotic and biotic stress factors. They have highlighted the role of phytohormones and redox signaling, and identified key regulatory elements – molecular hubs – where multiple signaling cascades converge. The integration of multiple signals through these hubs allows the plant to fine-tune its response to particular conditions. In this regard, growing evidence shows that the generation of ROS is one of the most common plant responses to different stresses, representing a point at which various signaling pathways come together to modulate the plant response to environmental cues. Redox regulation of integral pathway proteins provides a rapid and simple mechanism for the regulation of plant development and defence pathways. MAPK pathways are common and versatile signaling components that lie downstream of second messengers and hormones, and play central roles in plant responses to various stresses. In this review, the complex nature of plant stress signaling network is discussed. An emphasis on different signaling players with a specific attention to ROS as the primary source of the signaling battery in plants is presented. The interaction between ROS and other signaling components, e.g., redox homeostasis, MAPKs, and plant hormones has also been assessed. [ABSTRACT FROM AUTHOR]
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- 2017
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8. Structural features important for the RNA chaperone activity of zinc finger-containing glycine-rich RNA-binding proteins from wheat (Triticum avestivum) and rice (Oryza sativa).
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Xu, Tao, Han, Ji Hoon, and Kang, Hunseung
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MOLECULAR chaperones , *ZINC-finger proteins , *GLYCINE , *CARRIER proteins , *WHEAT , *RICE - Abstract
Highlights: [•] The structural feature relevant to the RNA chaperone activity of RZs was determined. [•] Wheat TaRZ2 but not wheat TaRZ3 and rice OsRZ1 harbor RNA chaperone activity. [•] The arrangement of RRM and glycine-rich region is crucial for RNA chaperone activity. [•] The size of disordered glycine-rich region is important for RNA chaperone activity. [Copyright &y& Elsevier]
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- 2013
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9. An ABA-regulated putative RNA-binding protein affects seed germination of Arabidopsis under ABA or abiotic stress conditions
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Jung, Hyun Ju, Kim, Min Kyung, and Kang, Hunseung
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RNA-protein interactions , *CARRIER proteins , *GERMINATION , *ARABIDOPSIS , *ABSCISIC acid , *EFFECT of stress on plants , *RNA metabolism , *GENE expression in plants - Abstract
Abstract: Diverse RNA-binding proteins (RBPs) have increasingly been determined to perform crucial roles in posttranscriptional regulation of RNA metabolism during plant response to abscisic acid (ABA) or abiotic stresses, but the functional roles of a variety of ABA-responsive RBPs in ABA and stress response remain poorly understood. Here, we characterized an ABA-regulated putative RBP (At3g54770) in Arabidopsis thaliana, designated ARP1, for its role in response to ABA or abiotic stresses. The expression of ARP1 was markedly downregulated by ABA, and ARP1 is localized to the nucleus. Interestingly, both overexpression and knockout of ARP1 resulted in delayed seed germination under ABA, high salt, or dehydration stress conditions. The identical phenotypes of ARP1-overexpressing plants and the arp1 null mutant indicate that a tight regulation of ARP1 transcript is required for normal function. Transcript levels of several germination-responsive genes were modulated by ARP1 under ABA. Taken together, the results of the present study demonstrate that ARP1 affects ABA-regulated seed germination of Arabidopsis, and indicate that the regulation of posttranscriptional RNA metabolism is critical in plant response to ABA or abiotic stresses. [Copyright &y& Elsevier]
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- 2013
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10. Molecular cloning of a cDNA encoding a high mobility group protein in Cucumis sativus and its expression by abiotic stress treatments
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Young Jang, Ji, Jin Kwak, Kyung, and Kang, Hunseung
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DNA , *CUCUMBERS , *MOLECULAR cloning , *PROTEINS - Abstract
Summary: A cDNA encoding a high mobility group B (HMGB) protein was isolated from Cucumis sativus and characterized with respect to its sequence, expression and responses to various abiotic stress treatments. The predicted polypeptide of 146 amino acid residues contains characteristic features of HMGB family proteins including the N-terminal basic region, one HMG-box and a stretch of acidic amino acid residues at the C-terminus. In vitro nucleic acid-binding assay revealed that the HMGB protein bound to both single-stranded DNA and double-stranded DNA. DNA gel blot analysis indicated that the HMGB gene is a single copy gene in cucumber genome. RNA gel blot analysis showed that the cucumber HMGB was more abundantly expressed in the roots than in shoots and leaves. Various abiotic stresses, including cold, drought and high salinity, down regulated markedly the expression of the HMGB in cucumber. The present report identifies a novel gene encoding HMGB protein in cucumber that shows a significant response to abiotic stress treatments. [Copyright &y& Elsevier]
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- 2007
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11. Molecular cloning and characterization of a cDNA encoding a kinase in Cucumis sativus and its expression by abiotic stress treatments
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Jang, Ji Young, Kwak, Kyung Jin, and Kang, Hunseung
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CLONING , *DNA , *GENE expression , *GENETIC regulation - Abstract
As a part of an integrated study of stress-related gene expression, a cDNA clone coding for a protein kinase in the root of Cucumis sativus was isolated and characterized with respect to its sequence and the expression patterns upon various abiotic stress treatments. The predicted polypeptide of 352 amino acid residues contains characteristic features of both the serine/threonine and tyrosine kinase families. In vitro kinase assay confirmed that the isolated protein kinase has autophosphorylation activity. Southern blot analysis showed that the kinase gene is a single-copy gene. Northern blot analysis showed that the kinase gene was more abundantly expressed in the roots and shoots than in the leaves. A quantitative real-time reverse-transcription-polymerase chain reaction analysis revealed that, among the abiotic stresses tested, drought treatment markedly decreased the transcript level of the kinase, whereas the expression of the kinase gene significantly increased by cold treatment. High salinity did not influence its expression. The present report identifies a dual specificity protein kinase in cucumber that shows different responses to abiotic stress treatments. [Copyright &y& Elsevier]
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- 2004
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12. ECT12, an YTH-domain protein, is a potential mRNA m6A reader that affects abiotic stress responses by modulating mRNA stability in Arabidopsis.
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Amara, Umme, Hu, Jianzhong, Park, Su Jung, and Kang, Hunseung
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ABIOTIC stress , *RNA metabolism , *ARABIDOPSIS proteins , *ARABIDOPSIS , *MESSENGER RNA , *PLANT proteins - Abstract
N6-methyladenosine (m6A), the most abundant modification found in eukaryotic mRNAs, is interpreted by m6A "readers," thus playing a crucial role in regulating RNA metabolism. The YT521-B homology-domain (YTHD) proteins, also known as EVOLUTIONARILY CONSERVED C-TERMINAL REGION (ECT), are recognized as m6A reader proteins in plants and animals. Among the 13 potential YTHD family proteins in Arabidopsis thaliana , the functions of only a few members are known. In this study, we determined the function of ECT12 (YTH11) as a potential m6A reader that plays a crucial role in response to abiotic stresses. The loss-of-function ect12 mutants showed no noticeable developmental defects under normal conditions but displayed hypersensitivity to salt or dehydration stress. The salt- or dehydration-hypersensitive phenotypes were correlated with altered levels of several m6A-modified stress-responsive transcripts. Notably, the increased or decreased transcript levels were associated with each transcript's reduced or enhanced decay, respectively. Electrophoretic mobility shift and RNA-immunoprecipitation assays showed that ECT12 binds to m6A-modified RNAs both in vitro and in planta , suggesting its role as an m6A reader. Collectively, these results indicate that the potential m6A reader ECT12 regulates the stability of m6A-modified RNA transcripts, thereby facilitating the response of Arabidopsis to abiotic stresses. • ECT12 plays a positive role in Arabidopsis seedling growth under abiotic stress conditions. • ECT12 is a potential m6A reader in Arabidopsis. • ECT12 modulates the stability of m6A-modified transcripts. • A potential m6A reader ECT12 facilitates the response of Arabidopsis to abiotic stresses. ECT12 is a potential mRNA m6A reader that regulates the stability of m6A-modified RNA transcripts, thereby facilitating the response of Arabidopsis to abiotic stresses. [ABSTRACT FROM AUTHOR]
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- 2024
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13. A chloroplast-targeted cabbage DEAD-box RNA helicase BrRH22 confers abiotic stress tolerance to transgenic Arabidopsis plants by affecting translation of chloroplast transcripts.
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Nawaz, Ghazala, Lee, Kwanuk, Park, Su Jung, Kim, Yeon-Ok, and Kang, Hunseung
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CABBAGE , *CHLOROPLASTS , *RNA helicase , *ABIOTIC stress , *GENETIC transcription in plants , *PHYSIOLOGY - Abstract
Although the roles of many DEAD-box RNA helicases (RHs) have been determined in the nucleus as well as in cytoplasm during stress responses, the importance of chloroplast-targeted DEAD-box RHs in stress response remains largely unknown. In this study, we determined the function of BrRH22, a chloroplast-targeted DEAD-box RH in cabbage ( Brassica rapa ), in abiotic stress responses. The expression of BrRH22 was markedly increased by drought, heat, salt, or cold stress and by ABA treatment, but was largely decreased by UV stress. Expression of BrRH22 in Arabidopsis enhanced germination and plantlet growth under high salinity or drought stress. BrRH22-expressing plants displayed a higher cotyledon greening and better plantlet growth upon ABA treatment due to decreases in the levels of ABI3, ABI4, and ABI5 . Further, BrRH22 affected translation of several chloroplast transcripts under stress. Notably, BrRH22 had RNA chaperone function. These results altogether suggest that chloroplast-transported BrRH22 contributes positively to the response of transgenic Arabidopsis to abiotic stress by affecting translation of chloroplast genes via its RNA chaperone activity. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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14. An RRM-containing mei2-like MCT1 plays a negative role in the seed germination and seedling growth of Arabidopsis thaliana in the presence of ABA.
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Gu, Lili, Jung, Hyun Ju, Kwak, Kyung Jin, Dinh, Sy Nguyen, Kim, Yeon-Ok, and Kang, Hunseung
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MONOCARBOXYLATE transporters , *RNA-binding proteins , *ARABIDOPSIS thaliana , *DNA synthesis , *GENETIC overexpression - Abstract
Despite an increasing understanding of the essential role of the Mei2 gene encoding an RNA-binding protein (RBP) in premeiotic DNA synthesis and meiosis in yeasts and animals, the functional roles of the mei2 -like genes in plant growth and development are largely unknown. Contrary to other mei2-like RBPs that contain three RNA-recognition motifs (RRMs), the mei2 C-terminal RRM only (MCT) is unique in that it harbors only the last C-terminal RRM. Although MCTs have been implicated to play important roles in plants, their functional roles in stress responses as well as plant growth and development are still unknown. Here, we investigated the expression and functional role of MCT1 (At1g37140) in plant response to abscisic acid (ABA). Confocal analysis of MCT1-GFP-expressing plants revealed that MCT1 is localized to the nucleus. The transcript level of MCT1 was markedly increased upon ABA treatment. Analysis of MCT1-overexpressing transgenic Arabidopsis plants and artificial miRNA-mediated mct1 knockdown mutants demonstrated that MCT1 inhibited seed germination and cotyledon greening of Arabidopsis plants under ABA. The transcript levels of ABA signaling-related genes, such as ABI3 , ABI4 , and ABI5 , were markedly increased in the MCT1-overexpressing transgenic plant. Collectively, these results suggest that ABA-upregulated MCT1 plays a negative role in Arabidopsis seed germination and seedling growth under ABA by modulating the expression of ABA signaling-related genes. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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15. Abiotic stresses affect differently the intron splicing and expression of chloroplast genes in coffee plants (Coffea arabica) and rice (Oryza sativa).
- Author
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Nguyen Dinh, Sy, Sai, Than Zaw Tun, Nawaz, Ghazala, Lee, Kwanuk, and Kang, Hunseung
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GENE expression in plants , *CHLOROPLASTS , *ABIOTIC stress , *INTRONS , *KNOTS & splices - Abstract
Despite the increasing understanding of the regulation of chloroplast gene expression in plants, the importance of intron splicing and processing of chloroplast RNA transcripts under stress conditions is largely unknown. Here, to understand how abiotic stresses affect the intron splicing and expression patterns of chloroplast genes in dicots and monocots, we carried out a comprehensive analysis of the intron splicing and expression patterns of chloroplast genes in the coffee plant ( Coffea arabica ) as a dicot and rice ( Oryza sativa ) as a monocot under abiotic stresses, including drought, cold, or combined drought and heat stresses. The photosynthetic activity of both coffee plants and rice seedlings was significantly reduced under all stress conditions tested. Analysis of the transcript levels of chloroplast genes revealed that the splicing of tRNAs and mRNAs in coffee plants and rice seedlings were significantly affected by abiotic stresses. Notably, abiotic stresses affected differently the splicing of chloroplast tRNAs and mRNAs in coffee plants and rice seedlings. The transcript levels of most chloroplast genes were markedly downregulated in both coffee plants and rice seedlings upon stress treatment. Taken together, these results suggest that coffee and rice plants respond to abiotic stresses via regulating the intron splicing and expression of different sets of chloroplast genes. [ABSTRACT FROM AUTHOR]
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- 2016
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16. Stress-responsive expression patterns and functional characterization of cold shock domain proteins in cabbage (Brassica rapa) under abiotic stress conditions.
- Author
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Choi, Min Ji, Park, Ye Rin, Park, Su Jung, and Kang, Hunseung
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EFFECT of stress on plants , *GENE expression in plants , *COLD shock proteins , *CABBAGE , *ABIOTIC stress , *GERMINATION , *ARABIDOPSIS thaliana , *MOLECULAR chaperones , *PHYSIOLOGY - Abstract
Although the functional roles of cold shock domain proteins (CSDPs) have been demonstrated during the growth, development, and stress adaptation of Arabidopsis ( Arabidopsis thaliana ), rice ( Oryza sativa ), and wheat ( Triticum aestivum ), the functions of CSDPs in other plants species, including cabbage ( Brassica rapa ), are largely unknown. To gain insight into the roles of CSDPs in cabbage under stress conditions, the genes encoding CSDPs in cabbage were isolated, and the functional roles of CSDPs in response to environmental stresses were analyzed. Real-time RT-PCR analysis revealed that the levels of BrCSDP transcripts increased during cold, salt, or drought stress, as well as upon ABA treatment. Among the five BrCSDP genes found in the cabbage genome, one CSDP (BRU12051), named BrCSDP3, was unique in that it is localized to the chloroplast as well as to the nucleus. Ectopic expression of BrCSDP3 in Arabidopsis resulted in accelerated seed germination and better seedling growth compared to the wild-type plants under high salt or dehydration stress conditions, and in response to ABA treatment. BrCSDP3 did not affect the splicing of intron-containing genes and processing of rRNAs in the chloroplast. BrCSDP3 had the ability to complement RNA chaperone-deficient Escherichia coli mutant cells under low temperatures as well as DNA- and RNA-melting abilities, suggesting that it possesses RNA chaperone activity. Taken together, these results suggest that BrCSDP3, harboring RNA chaperone activity, plays a role as a positive regulator in seed germination and seedling growth under stress conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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17. A chloroplast-localized S1 domain-containing protein SRRP1 plays a role in Arabidopsis seedling growth in the presence of ABA.
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Gu, Lili, Jung, Hyun Ju, Kim, Bo Mi, Xu, Tao, Lee, Kwanuk, Kim, Yeon-Ok, and Kang, Hunseung
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CHLOROPLASTS , *CYTOPLASM , *SEED development , *PLANT genes , *ARABIDOPSIS thaliana , *PLANT growth - Abstract
Although the roles of S1 domain-containing proteins have been characterized in diverse cellular processes in the cytoplasm, the functional roles of a majority of S1 domain-containing proteins targeted to the chloroplast are largely unknown. Here, we characterized the function of a nuclear-encoded chloroplast-targeted protein harboring two S1 domains, designated SRRP1 (for S1 RNA-binding ribosomal protein 1), in Arabidopsis thaliana . Subcellular localization analysis of SRRP1-GFP fusion proteins revealed that SRRP1 is localized to the chloroplast. The T-DNA tagged loss-of-function srrp1 mutants displayed poorer seedling growth and less cotyledon greening than the wild-type plants on MS medium supplemented with abscisic acid (ABA), suggesting that SRRP1 plays a role in seedling growth in the presence of ABA. Splicing of the trnL intron and processing of 5S rRNA in chloroplasts were altered in the mutant plants. Importantly, SRRP1 complemented the growth-defective phenotypes of an RNA chaperone-deficient Escherichia coli mutant at low temperatures and had nucleic acid-melting ability, indicating that SRRP1 possesses RNA chaperone activity. Taken together, these results suggest that SRRP1, the chloroplast-localized S1 domain-containing protein, harboring RNA chaperone activity affects the splicing and processing of chloroplast transcripts and plays a role in Arabidopsis seedling growth in the presence of ABA. [ABSTRACT FROM AUTHOR]
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- 2015
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18. A chloroplast-localized DEAD-box RNA helicaseAtRH3 is essential for intron splicing and plays an important role in the growth and stress response in Arabidopsis thaliana.
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Gu, Lili, Xu, Tao, Lee, Kwanuk, Lee, Kwang Ho, and Kang, Hunseung
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CHLOROPLASTS , *RNA helicase , *GENETIC engineering , *PLANT growth , *EFFECT of stress on plants , *ARABIDOPSIS thaliana - Abstract
Although many DEAD-box RNA helicases (RHs) are targeted to chloroplasts, the functional roles of the majority of RHs are still unknown. Recently, the chloroplast-localized Arabidopsis thaliana AtRH3 has been demonstrated to play important roles in intron splicing, ribosome biogenesis, and seedling growth. To further understand the functional role of AtRH3 in intron splicing and growth and the stress response in Arabidopsis, the newly-generated artificial microRNA-mediated knockdown plants as well as the previously characterized T-DNA tagged rh3-4 mutant were analyzed under normal and stress conditions. The rh3 mutants displayed retarded growth and pale-green phenotypes, and the growth of mutant plants was inhibited severely under salt or cold stress but marginally under dehydration stress conditions. Splicing of several intron-containing chloroplast genes was defective in the mutant plants. Importantly, splicing of ndhA and ndhB genes was severely inhibited in the mutant plants compared with the wild-type plants under salt or cold stress but not under dehydration stress conditions. Moreover, AtRH3 complemented the growth-defect phenotype of the RNA chaperone-deficient Escherichia coli mutant and had the ability to disrupt RNA and DNA base pairs, indicating that AtRH3 possesses RNA chaperone activity. Taken together, these results demonstrate that AtRH3 plays a prominent role in the growth and stress response of Arabidopsis, and suggest that proper splicing of introns governed by RNA chaperone activity of AtRH3 is crucial for chloroplast function and the growth and stress response of plants. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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19. Expression of Arabidopsis glycine-rich RNA-binding protein AtGRP2 or AtGRP7 improves grain yield of rice (Oryza sativa) under drought stress conditions.
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Yang, Deok Hee, Kwak, Kyung Jin, Kim, Min Kyung, Park, Su Jung, Yang, Kwang-Yeol, and Kang, Hunseung
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GENE expression in plants , *ARABIDOPSIS , *PLANT proteins , *GRAIN yields , *DROUGHT tolerance , *EFFECT of stress on plants , *RNA metabolism ,RICE genetics - Abstract
Abstract: Although posttranscriptional regulation of RNA metabolism is increasingly recognized as a key regulatory process in plant response to environmental stresses, reports demonstrating the importance of RNA metabolism control in crop improvement under adverse environmental stresses are severely limited. To investigate the potential use of RNA-binding proteins (RBPs) in developing stress-tolerant transgenic crops, we generated transgenic rice plants (Oryza sativa) that express Arabidopsis thaliana glycine-rich RBP (AtGRP) 2 or 7, which have been determined to harbor RNA chaperone activity and confer stress tolerance in Arabidopsis, and analyzed the response of the transgenic rice plants to abiotic stresses. AtGRP2- or AtGRP7-expressing transgenic rice plants displayed similar phenotypes comparable with the wild-type plants under high salt or cold stress conditions. By contrast, AtGRP2- or AtGRP7-expressing transgenic rice plants showed much higher recovery rates and grain yields compared with the wild-type plants under drought stress conditions. The higher grain yield of the transgenic rice plants was due to the increases in filled grain numbers per panicle. Collectively, the present results show the importance of posttranscriptional regulation of RNA metabolism in plant response to environmental stress and suggest that GRPs can be utilized to improve the yield potential of crops under stress conditions. [Copyright &y& Elsevier]
- Published
- 2014
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20. Functional characterization of a plastid-specific ribosomal protein PSRP2 in Arabidopsis thaliana under abiotic stress conditions.
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Xu, Tao, Lee, Kwanuk, Gu, Lili, Kim, Jeong-Il, and Kang, Hunseung
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ARABIDOPSIS thaliana , *EFFECT of stress on plants , *RIBOSOMAL proteins , *PLASTIDS , *PLANT growth , *GERMINATION - Abstract
Abstract: Plastids possess a small set of proteins unique to plastid ribosome, named plastid-specific ribosomal proteins (PSRPs). Among the six PSRPs found in Arabidopsis thaliana, PSRP2 is unique in that it harbors two RNA-recognition motifs found in diverse RNA-binding proteins. A recent report demonstrated that PSRP2 is not essential for ribosome function and plant growth under standard greenhouse conditions. Here, we investigated the functional role of PSRP2 during Arabidopsis seed germination and seedling growth under different light environments and various stress conditions, including high salinity, dehydration, and low temperature. The transgenic Arabidopsis plants overexpressing PSRP2 showed delayed germination compared with that of the wild-type plants under salt, dehydration, or low temperature stress conditions. The T-DNA insertion psrp2 mutant displayed better seedling growth but PSRP2-overexpressing transgenic plants showed poorer seedling growth than that of the wild-type plants under salt stress conditions. No noticeable differences in seedling growth were observed between the genotypes when grown under different light environments including dark, red, far-red, and blue light. Interestingly, the PSRP2 protein possessed RNA chaperone activity. Taken together, these results suggest that PSRP2 harboring RNA chaperone activity plays a role as a negative regulator in seed germination under all three abiotic stress conditions tested and in seedling growth of Arabidopsis under salt stress but not under cold or dehydration stress conditions. [Copyright &y& Elsevier]
- Published
- 2013
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21. Different roles of glycine-rich RNA-binding protein7 in plant defense against Pectobacterium carotovorum, Botrytis cinerea, and tobacco mosaic viruses
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Lee, Hwa Jung, Kim, Jin Seo, Yoo, Seung Jin, Kang, Eun Young, Han, Song Hee, Yang, Kwang-Yeol, Kim, Young Cheol, McSpadden Gardener, Brian, and Kang, Hunseung
- Subjects
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GLYCINE , *RNA , *CARRIER proteins , *PLANT defenses , *BOTRYTIS cinerea , *ERWINIA , *TOBACCO mosaic virus - Abstract
Abstract: Glycine-rich RNA-binding protein7 (AtGRP7) has previously been demonstrated to confer plant defense against Pseudomonas syringae DC3000. Here, we show that AtGRP7 can play different roles in plant defense against diverse pathogens. AtGRP7 enhances resistance against a necrotrophic bacterium Pectobacterium carotovorum SCC1 or a biotrophic virus tobacco mosaic virus. By contrast, AtGRP7 plays a negative role in defense against a necrotrophic fungus Botrytis cinerea. These results provide evidence that AtGRP7 is a potent regulator in plant defense response to diverse pathogens, and suggest that the regulation of RNA metabolism by RNA-binding proteins is important for plant innate immunity. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
22. Comparative analysis of Arabidopsis zinc finger-containing glycine-rich RNA-binding proteins during cold adaptation
- Author
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Kim, Won Yong, Kim, Joo Yeol, Jung, Hyun Ju, Oh, Seung Han, Han, Yeon Soo, and Kang, Hunseung
- Subjects
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COMPARATIVE studies , *ARABIDOPSIS , *ZINC-finger proteins , *GLYCINE , *CARRIER proteins , *EFFECT of cold on plants , *BIOLOGICAL adaptation , *PLANT genetics - Abstract
Abstract: Among the three zinc finger-containing glycine-rich RNA-binding proteins, named AtRZ-1a, AtRZ-1b, and AtRZ-1c, in the Arabidopsis thaliana genome, AtRZ-1a has previously been shown to enhance cold and freezing tolerance in Arabidopsis. Here, we determined and compared the functional roles of AtRZ-1b and AtRZ-1c in Arabidopsis and Escherichia coli under cold stress conditions. AtRZ-1b, but not AtRZ-1c, successfully complemented the cold sensitivity of E. coli BX04 mutant cells lacking four cold shock proteins. Domain deletion and site-directed mutagenesis showed that the zinc finger motif of AtRZ-1b is important for its complementation ability, and that the truncated N- and C-terminal domains of AtRZ-1b and AtRZ-1c harbor the complementation ability. Despite an increase in transcript levels of AtRZ-1b and AtRZ-1c under cold stress, overexpression or loss-of-function mutations did not affect seed germination or seedling growth of Arabidopsis under cold stress conditions. AtRZ-1b and AtRZ-1c proteins, being localized to the nucleus, have been shown to bind non-specifically to RNA sequences in vitro, in comparison to AtRZ-1a that is localized to both the nucleus and the cytoplasm and binds preferentially to G- or U-rich RNA sequences. Taken together, these results demonstrate that the three AtRZ-1 family members showing different cellular localization and characteristic nucleic acid-binding property have a potential to contribute differently to the enhancement of cold tolerance in Arabidopsis and E. coli. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
23. The C-terminal zinc finger domain of Arabidopsis cold shock domain proteins is important for RNA chaperone activity during cold adaptation
- Author
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Park, Su Jung, Kwak, Kyung Jin, Jung, Hyun Ju, Lee, Hwa Jung, and Kang, Hunseung
- Subjects
- *
ZINC-finger proteins , *ARABIDOPSIS thaliana , *PLANT proteins , *MOLECULAR chaperones , *RNA , *COLD adaptation , *PLANT adaptation , *GENETIC transcription regulation - Abstract
Abstract: Among the four cold shock domain proteins (CSDPs) identified in Arabidopsis thaliana, it has recently been shown that CSDP1 harboring seven CCHC-type zinc fingers, but not CSDP2 harboring two CCHC-type zinc fingers, function as a RNA chaperone during cold adaptation. However, the structural features relevant to this differing RNA chaperone activity between CSDP1 and CSDP2 remain largely unknown. To determine which structural features are necessary for the RNA chaperone activity of the CSDPs, the importance of the N-terminal cold shock domain (CSD) and the C-terminal zinc finger glycine-rich domains of CSDP1 and CSDP2 were assessed. The results of sequence motif-swapping and deletion experiments showed that, although the CSD itself harbored RNA chaperone activity, the number and length of the zinc finger glycine-rich domains of CSDPs were crucial to the full activity of the RNA chaperones. The C-terminal domain itself of CSDP1, harboring seven CCHC-type zinc fingers, also has RNA chaperone activity. The RNA chaperone activity and nuclei acid-binding property of the native and chimeric proteins were closely correlated with each other. Collectively, these results indicate that a specific modular arrangement of the CSD and the zinc finger domain determines both the RNA chaperone activity and nucleic acid-binding property of CSDPs; this, in turn, contributes to enhanced cold tolerance in plants as well as in bacteria. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
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