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Kim YH, Her AY, Rha SW, Choi BG, Mashaly A, Park Y, Jang WY, Kim W, Choi JY, Park EJ, Na JO, Choi CU, Kim EJ, Park CG, Seo HS. 119Angiotensin converting enzyme inhibitor versus angiotensin receptor blockers on the top of calcium channel blocker in development of new-onset diabetes mellitus in hypertensive Korean patients. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy564.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Rha SW, Choi BG, Choi SY, Byun JK, Hong JY, Park JY, Park SH, Choi CU, Park CG, Seo HS. P282Application of machine learning for predicting new-onset diabetes mellitus during 5-year follow-up in non-diabetic patients with cardiovascular risk. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy564.p282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kim YH, Her AY, Rha SW, Choi BG, Mashaly A, Park Y, Jang WY, Kim W, Choi JY, Park EJ, Na JO, Choi CU, Kim EJ, Park CG, Seo HS. P3209Calcium channel blocker monotherapy versus combination with renin-angiotensin system blockers in the development of new-onset diabetes mellitus in hypertensive Korean patients. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p3209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Park EJ, Eo JS, Jang WY, Na JO, Choi CU, Kim EJ, Rha SW, Park CG, Seo HS, Kim JW. P1689Association of brain amygdalar activity with plaque burden and vulnerability in coronary artery. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy565.p1689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Park EJ, Kim WH, Choi JY, Jang WY, Na JO, Choi JI, Kim JW, Kim EJ, Rha SW, Park CG, Seo HS, Choi CU. P2690The bleeding and cardiovascular risk according to NSAIDs selectivity in patients receiving antithrombotics and concomitant NSAIDs after myocardial infarction: a nationwide cohort study. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy565.p2690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Rha SW, Byun JK, Choi BG, Choi SY, Hong JY, Park JY, Park SH, Choi CU, Park CG, Seo HS. P3623Impact of blood urea nitrogen/creatinine ratio in coronary artery disease patients underwent successful percutaneous coronary intervention with drug eluting stents: 5-year follow-up results. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy563.p3623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Rha SW, Mashaly A, Choi BG, Choi SY, Byun JK, Hong JY, Park JY, Park SH, Choi CU, Park CG, Seo HS. P1636Impact of uric acid on 5-year clinical outcomes after below-the-knee endovascular intervention. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy565.p1636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Choi BS, Kim YJ, Markkandan K, Koo YJ, Song JT, Seo HS. GW2 Functions as an E3 Ubiquitin Ligase for Rice Expansin-Like 1. Int J Mol Sci 2018; 19:E1904. [PMID: 29958473 PMCID: PMC6073362 DOI: 10.3390/ijms19071904] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 06/18/2018] [Accepted: 06/25/2018] [Indexed: 01/30/2023] Open
Abstract
Seed size is one of the most important traits determining the yield of cereal crops. Many studies have been performed to uncover the mechanism of seed development. However, much remains to be understood, especially at the molecular level, although several genes involved in seed size have been identified. Here, we show that rice Grain Width 2 (GW2), a RING-type E3 ubiquitin ligase, can control seed development by catalyzing the ubiquitination of expansin-like 1 (EXPLA1), a cell wall-loosening protein that increases cell growth. Microscopic examination revealed that a GW2 mutant had a chalky endosperm due to the presence of loosely packed, spherical starch granules, although the grain shape was normal. Yeast two-hybrid and in vitro pull-down assays showed a strong interaction between GW2 and EXPLA1. In vitro ubiquitination analysis demonstrated that EXPLA1 was ubiquitinated by GW2 at lysine 279 (K279). GW2 and EXPLA1 colocalized to the nucleus when expressed simultaneously. These results suggest that GW2 negatively regulates seed size by targeting EXPLA1 for degradation through its E3 ubiquitin ligase activity.
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Kim JY, Seo HS. In vitro Nitrate Reductase Activity Assay from Arabidopsis Crude Extracts. Bio Protoc 2018; 8:e2785. [PMID: 34286008 PMCID: PMC8275288 DOI: 10.21769/bioprotoc.2785] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/13/2018] [Accepted: 03/19/2018] [Indexed: 11/02/2022] Open
Abstract
Nitrate reductase (NR) reduces the major plant nitrogen source, NO3-, into NO2-. NR activity can be measured by its final product, nitrite through its absorbance under optimized condition. Here, we present a detailed protocol for measuring relative enzyme activity of NR from Arabidopsis crude extracts. This protocol offers simple procedure and data analysis to compare NR activity of multiple samples.
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Sundaramoorthy J, Park GT, Mukaiyama K, Tsukamoto C, Chang JH, Lee JD, Kim JH, Seo HS, Song JT. Molecular elucidation of a new allelic variation at the Sg-5 gene associated with the absence of group A saponins in wild soybean. PLoS One 2018; 13:e0192150. [PMID: 29381775 PMCID: PMC5790262 DOI: 10.1371/journal.pone.0192150] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 01/17/2018] [Indexed: 11/18/2022] Open
Abstract
In soybean, triterpenoid saponin is one of the major secondary metabolites and is further classified into group A and DDMP saponins. Although they have known health benefits for humans and animals, acetylation of group A saponins causes bitterness and gives an astringent taste to soy products. Therefore, several studies are being conducted to eliminate acetylated group A saponins. Previous studies have isolated and characterized the Sg-5 (Glyma.15g243300) gene, which encodes the cytochrome P450 72A69 enzyme and is responsible for soyasapogenol A biosynthesis. In this study, we elucidated the molecular identity of a novel mutant of Glycine soja, 'CWS5095'. Phenotypic analysis using TLC and LC-PDA/MS/MS showed that the mutant 'CWS5095' did not produce any group A saponins. Segregation analysis showed that the absence of group A saponins is controlled by a single recessive allele. The locus was mapped on chromosome 15 (4.3 Mb) between Affx-89193969 and Affx-89134397 where the previously identified Glyma.15g243300 gene is positioned. Sequence analysis of the coding region for the Glyma.15g243300 gene revealed the presence of four SNPs in 'CWS5095' compared to the control lines. One of these four SNPs (G1127A) leads to the amino acid change Arg376Lys in the EXXR motif, which is invariably conserved among the CYP450 superfamily proteins. Co-segregation analysis showed that the missense mutation (Arg376Lys) was tightly linked with the absence of group A saponins in 'CWS5095'. Even though Arg and Lys have similar chemical features, the 3D modelled protein structure indicates that the replacement of Arg with Lys may cause a loss-of-function of the Sg-5 protein by inhibiting the stable binding of a heme cofactor to the CYP72A69 apoenzyme.
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Kim JY, Song JT, Seo HS. COP1 regulates plant growth and development in response to light at the post-translational level. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:4737-4748. [PMID: 28992300 DOI: 10.1093/jxb/erx312] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Photoreceptors perceive different wavelengths of light and transduce light signals downstream via a range of proteins. COP1, an E3 ubiquitin ligase, regulates light signaling by mediating the ubiquitination and subsequent proteasomal degradation of photoreceptors such as phytochromes and cryptochromes, as well as various development-related proteins including other light-responsive proteins. COP1 is itself regulated by direct interactions with several signaling molecules that modulate its activity. The control of photomorphogenesis by COP1 is also regulated by its localization to the cytoplasm in response to light. COP1 thus acts as a tightly regulated switch that determines whether development is skotomorphogenic or photomorphogenic. In this review, we discuss the effects of COP1 on the abundance and activity of various development-related proteins, including photoreceptors, and summarize the regulatory mechanisms that influence COP1 activity and stability in plants.
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Kim JY, Song JT, Seo HS. Post-translational modifications of Arabidopsis E3 SUMO ligase AtSIZ1 are controlled by environmental conditions. FEBS Open Bio 2017; 7:1622-1634. [PMID: 28979848 PMCID: PMC5623694 DOI: 10.1002/2211-5463.12309] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 08/27/2017] [Accepted: 08/29/2017] [Indexed: 01/04/2023] Open
Abstract
Sumoylation regulates numerous cellular functions in plants as well as in other eukaryotic systems. However, the regulatory mechanisms controlling E3 small ubiquitin‐related modifier (SUMO) ligase are not well understood. Here, post‐translational modification of the Arabidopsis E3 SUMO ligase AtSIZ1 was shown to be specifically controlled by abiotic stresses. AtSIZ1 ubiquitination was induced by exposure to heat stress in transgenic plants overexpressing the E3 ubiquitin ligase COP1. In addition, AtSIZ1 ubiquitination was strongly enhanced in transgenic plants overexpressing SUMO isopeptidase ESD4 under heat stress. By contrast, drought stress induced sumoylation rather than ubiquitination of AtSIZ1 and sumoylated forms of AtSIZ1 accumulated in esd4 and cop1–4 mutants. Moreover, siz1 mutants were found to be tolerant to heat and drought stresses. Taken together, these results indicate that ubiquitination and sumoylation of AtSIZ1 in response to abiotic stresses depend on the activities of COP1 and ESD4 and that the activity and stability of AtSIZ1 can be specifically controlled by different abiotic stresses.
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Kwak JS, Son GH, Song JT, Seo HS. Post-translational modifications of FLOWERING LOCUS C modulate its activity. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:383-389. [PMID: 28204510 DOI: 10.1093/jxb/erw431] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Flowering Locus C (FLC) is a key floral repressor that precisely controls flowering time. The role of FLC has been extensively studied at the transcriptional level using molecular biological and epigenetic approaches. However, how FLC functions and how its stability is controlled at the post-translational level are only beginning to be understood. Recent studies show that various post-translational modifications (PTMs) control the stability and activity of FLC. In this review, we focus on three types of PTMs that regulate FLC function: phosphorylation, ubiquitination, and sumoylation. This report should serve as a model to guide post-translational studies of other important floral regulators.
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Kim SI, Kwak JS, Song JT, Seo HS. The E3 SUMO ligase AtSIZ1 functions in seed germination in Arabidopsis. PHYSIOLOGIA PLANTARUM 2016; 158:256-271. [PMID: 27130140 DOI: 10.1111/ppl.12462] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 02/16/2016] [Accepted: 03/22/2016] [Indexed: 05/20/2023]
Abstract
Seed germination is an important stage in the lifecycle of a plant because it determines subsequent vegetative growth and reproduction. Here, we show that the E3 SUMO ligase AtSIZ1 regulates seed dormancy and germination. The germination rates of the siz1 mutants were less than 50%, even after a short period of ripening. However, their germination rates increased to wild-type levels after cold stratification or long periods of ripening. In addition, exogenous gibberellin (GA) application improved the germination rates of the siz1 mutants to the wild-type level. In transgenic plants, suppression of AtSIZ1 caused rapid post-translational decay of SLEEPY1 (SLY1), a positive regulator of GA signaling, during germination, and inducible AtSIZ1 overexpression led to increased SLY1 levels. In addition, overexpressing wild-type SLY1 in transgenic sly1 mutants increased their germination ratios to wild-type levels, whereas the germination ratio of transgenic sly1 mutants overexpressing mSLY1 was similar to that of sly1. The germination ratios of siz1 mutant seeds in immature developing siliques were much lower than those of the wild-type. Moreover, SLY1 and DELAY OF GERMINATION 1 (DOG1) transcript levels were reduced in the siz1 mutants, whereas the transcript levels of DELLA and ABSCISIC ACID INSENSITIVE 3 (ABI3) were higher than those of the wild-type. Taken together, these results indicate that the reduced germination of the siz1 mutants results from impaired GA signaling due to low SLY1 levels and activity, as well as hyperdormancy due to high levels of expression of dormancy-related genes including DOG1.
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Chung SM, Hyun MH, Lee E, Seo HS. Novel effects of sarcopenic osteoarthritis on metabolic syndrome, insulin resistance, osteoporosis, and bone fracture: the national survey. Osteoporos Int 2016; 27:2447-57. [PMID: 27177746 DOI: 10.1007/s00198-016-3548-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 02/19/2016] [Indexed: 12/14/2022]
Abstract
UNLABELLED This study compared the effects sarcopenic osteoarthritis on metabolic syndrome, insulin resistance, osteoporosis, and bone fracture. By using national survey data, we suggest that the relationship between sarcopenia and metabolic syndrome or insulin resistance is potentiated by the severity of osteoarthritis and is independent of body weight. INTRODUCTION Sarcopenia and osteoarthritis are known risk factors for metabolic syndrome. However, their combined effects on metabolic syndrome, insulin resistance and osteoporosis remain uncertain. METHODS We used data from the fifth Korean National Health and Nutrition Examination Survey using a total of 3158 adults (age >50 years). Sarcopenia was defined as a skeletal muscle index score (appendicular skeletal muscle mass/body weight) within the fifth percentile of sex-matched younger reference participants. Radiographic knee osteoarthritis was defined as a Kellgren-Lawrence (K-L) grade of 2 or greater. Metabolic syndrome was diagnosed using the National Cholesterol Education Program criteria. Insulin resistance was evaluated using the homeostasis model assessment-estimated insulin resistance index (HOMA-IR). Osteoporosis was defined using the World Health Organization T-score criteria. RESULTS In multivariable logistic regression analysis, the sarcopenic osteoarthritis group had a higher odds ratio (OR) for metabolic syndrome (OR = 11.00, 95 % confidential interval (CI) = 2.12-56.99, p = 0.013) than the non-sarcopenic osteoarthritis (OR = 1.02, 95 % CI = 0.65-1.62, p = 0.972) and sarcopenic non-osteoarthritis groups (OR = 7.15, 95 % CI = 1.57-32.53, p = 0.027). Similarly, sarcopenic osteoarthritis had a greater OR of highest HOMA-IR quartiles (OR = 8.19, 95 % CI = 2.03-33.05, p = 0.003) than the other groups. Overall, the association between the K-L grade and body mass index was significant; however, this significance was lower in individuals with sarcopenia and was lost in those with sarcopenic osteoarthritis. Additionally, osteoporosis and bone fracture were not associated to sarcopenic osteoarthritis (p > 0.05). CONCLUSIONS These results suggest that the relationship between sarcopenia and metabolic syndrome or insulin resistance is potentiated by the severity of osteoarthritis and is independent of body weight.
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Sundaramoorthy J, Park GT, Chang JH, Lee JD, Kim JH, Seo HS, Chung G, Song JT. Identification and Molecular Analysis of Four New Alleles at the W1 Locus Associated with Flower Color in Soybean. PLoS One 2016; 11:e0159865. [PMID: 27442124 PMCID: PMC4956318 DOI: 10.1371/journal.pone.0159865] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 07/09/2016] [Indexed: 11/18/2022] Open
Abstract
In soybean, flavonoid 3'5'-hydroxylase (F3'5'H) and dihydroflavonol-4-reductase (DFR) play a crucial role in the production of anthocyanin pigments. Loss-of-function of the W1 locus, which encodes the former, or W3 and W4, which encode the latter, always produces white flowers. In this study, we searched for new genetic components responsible for the production of white flowers in soybean and isolated four white-flowered mutant lines, i.e., two Glycine soja accessions (CW12700 and CW13381) and two EMS-induced mutants of Glycine max (PE1837 and PE636). F3'5'H expression in CW12700, PE1837, and PE636 was normal, whereas that in CW13381 was aberrant and missing the third exon. Sequence analysis of F3'5'H of CW13381 revealed the presence of an indel (~90-bp AT-repeat) in the second intron. In addition, the F3'5'H of CW12700, PE1837, and PE636 harbored unique single-nucleotide substitutions. The single nucleotide polymorphisms resulted in substitutions of amino acid residues located in or near the SRS4 domain of F3'5'H, which is essential for substrate recognition. 3D structure modeling of F3'5'H indicated that the substitutions could interfere with an interaction between the substrate and heme group and compromise the conformation of the active site of F3'5'H. Recombination analysis revealed a tight correlation between all of the mutant alleles at the W1 locus and white flower color. On the basis of the characterization of the new mutant alleles, we discussed the biological implications of F3'5'H and DFR in the determination of flower colors in soybean.
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Kim SI, Song JT, Jeong JY, Seo HS. Niclosamide inhibits leaf blight caused by Xanthomonas oryzae in rice. Sci Rep 2016; 6:21209. [PMID: 26879887 PMCID: PMC4754756 DOI: 10.1038/srep21209] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 01/19/2016] [Indexed: 01/24/2023] Open
Abstract
Rice leaf blight, which is caused by the bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo), results in huge losses in grain yield. Here, we show that Xoo-induced rice leaf blight is effectively controlled by niclosamide, an oral antihelminthic drug and molluscicide, which also functions as an anti-tumor agent. Niclosamide directly inhibited the growth of the three Xoo strains PXO99, 10208 and K3a. Niclosamide moved long distances from the site of local application to distant rice tissues. Niclosamide also increased the levels of salicylate and induced the expression of defense-related genes such as OsPR1 and OsWRKY45, which suppressed Xoo-induced leaf wilting. Niclosamide had no detrimental effects on vegetative/reproductive growth and yield. These combined results indicate that niclosamide can be used to block bacterial leaf blight in rice with no negative side effects.
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Park GT, Sundaramoorthy J, Lee JD, Kim JH, Seo HS, Song JT. Elucidation of Molecular Identity of the W3 Locus and Its Implication in Determination of Flower Colors in Soybean. PLoS One 2015; 10:e0142643. [PMID: 26555888 PMCID: PMC4640537 DOI: 10.1371/journal.pone.0142643] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 10/23/2015] [Indexed: 12/03/2022] Open
Abstract
The wide range of flower colors in soybean is controlled by six independent loci (W1, W2, W3, W4, Wm, and Wp). Among these loci, mutations in the W3 locus under the w4 allelic background (i.e., w3w4) produce near-white flowers, while the W3w4 genotype produces purple throat flowers. Although a gene encoding dihydroflavonol 4-reductase, DFR1, has been known to be closely associated with the W3 locus, its molecular identity has not yet been characterized. In the present study, we aimed to determine whether DFR1 is responsible for allelic variations in the W3 locus. On the basis of the sequence of a DFR probe, Glyma.14G072700 was identified as a candidate gene for DFR1, and nucleotide sequences of Glyma.14G072700 from cultivars with previously validated genotypes for the W3 locus were determined. As a result, a number of nucleotide polymorphisms, mainly single-base substitutions, between both coding and 5'-upstream region sequences of the W3 and w3 alleles were identified. Among them, an indel of 311-bp in the 5'-upstream region was noteworthy, since the Glyma.14G072700 in all the w3 alleles examined contained the indel, whereas that in all the W3 alleles did not; the former was barely expressed, but the latter was well expressed. These results suggest that Glyma.14G072700 is likely to correspond to DFR1 for the W3 locus and that its expression patterns may lead to allelic color phenotypes of W3 and w3 alleles under the w4 allelic background.
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Kim DY, Han YJ, Kim SI, Song JT, Seo HS. Arabidopsis CMT3 activity is positively regulated by AtSIZ1-mediated sumoylation. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 239:209-15. [PMID: 26398805 DOI: 10.1016/j.plantsci.2015.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/04/2015] [Accepted: 08/04/2015] [Indexed: 05/09/2023]
Abstract
The activities of mammalian DNA and histone methyltransferases are regulated by post-translational modifications such as phosphorylation and sumoylation; however, it is unclear how the activities of these enzymes are regulated at the post-translational level in plants. Here, we demonstrate that the DNA methylation activity of Arabidopsis CHROMOMETHYLASE 3 (CMT3) is positively regulated by the E3 SUMO ligase AtSIZ1. The methylation level of the Arabidopsis genome, including transposons, was significantly lower in the siz1-2 mutant than in wild-type plants. CMT3 was sumoylated by the E3 ligase activity of AtSIZ1 through a direct interaction, and the DNA methyltransferase activity of CMT3 was enhanced by this modification. In addition, the methylation levels of a large number of genes, including the nitrate reductase gene NIA2, were lower in siz1-2 and cmt3 plants than in wild-type plants. Furthermore, the CHG methylation activity of CMT3 was specific for NIA2and not NIA1 (the other nitrate reductase gene in Arabidopsis), indicating that CMT3 selectively regulates the CHG methylation levels of target genes. Taken together, our results indicate that the sumoylation of CMT3 is critical for its role in the control of gene expression and that AtSIZ1 positively controls the epigenetic repression of CMT3-mediated gene expression.
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Sundaramoorthy J, Park GT, Lee JD, Kim JH, Seo HS, Song JT. Genetic and molecular regulation of flower pigmentation in soybean. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/s13765-015-0077-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kim YJ, Kim SI, Kesavan M, Kwak JS, Song JT, Seo HS. Ascorbate Peroxidase OsAPx1 is Involved in Seed Development in Rice. ACTA ACUST UNITED AC 2015. [DOI: 10.9787/pbb.2015.3.1.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kim JY, Kwon YJ, Kim SI, Kim DY, Song JT, Seo HS. Ammonium Inhibits Chromomethylase 3-Mediated Methylation of the Arabidopsis Nitrate Reductase Gene NIA2. FRONTIERS IN PLANT SCIENCE 2015; 6:1161. [PMID: 26834755 PMCID: PMC4720742 DOI: 10.3389/fpls.2015.01161] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 12/07/2015] [Indexed: 05/10/2023]
Abstract
Gene methylation is an important mechanism regulating gene expression and genome stability. Our previous work showed that methylation of the nitrate reductase (NR) gene NIA2 was dependent on chromomethylase 3 (CMT3). Here, we show that CMT3-mediated NIA2 methylation is regulated by ammonium in Arabidopsis thaliana. CHG sequences (where H can be A, T, or C) were methylated in NIA2 but not in NIA1, and ammonium [(NH4)2SO4] treatment completely blocked CHG methylation in NIA2. By contrast, ammonium had no effect on CMT3 methylation, indicating that ammonium negatively regulates CMT3-mediated NIA2 methylation without affecting CMT3 methylation. Ammonium upregulated NIA2 mRNA expression, which was consistent with the repression of NIA2 methylation by ammonium. Ammonium treatment also reduced the overall genome methylation level of wild-type Arabidopsis. Moreover, CMT3 bound to specific promoter and intragenic regions of NIA2. These combined results indicate that ammonium inhibits CMT3-mediated methylation of NIA2 and that of other target genes, and CMT3 selectively binds to target DNA sequences for methylation.
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Seo HS, Kim YJ. Effect of electrode positions on the mixing characteristics of an electroosmotic micromixer. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2014; 14:6167-6171. [PMID: 25936080 DOI: 10.1166/jnn.2014.8802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this study, an electrokinetic microchannel with a ring-type mixing chamber is introduced for fast mixing. The modeled micromixer that is used for the study of the electroosmotic effect takes two fluids from different inlets and combines them in a ring-type mixing chamber and, then, they are mixed by the electric fields at the electrodes. In order to compare the mixing performance in the modeled micromixer, we numerically investigated the flow characteristics with different positions of the electrodes in the mixing chamber using the commercial code, COMSOL. In addition, we discussed the concentration distributions of the dissolved substances in the flow fields and compared the mixing efficiency in the modeled micromixer with different electrode positions and operating conditions, such as the frequencies and electric potentials at the electrodes.
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Son GH, Park BS, Song JT, Seo HS. FLC-mediated flowering repression is positively regulated by sumoylation. JOURNAL OF EXPERIMENTAL BOTANY 2014. [PMID: 24218331 DOI: 10.1093/jxb/ert383ert383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Flowering locus C (FLC), a floral repressor, is a critical factor for the transition from the vegetative to the reproductive phase. Here, the mechanisms regulating the activity and stability of the FLC protein were investigated. Bimolecular fluorescence complementation and in vitro pull-down analyses showed that FLC interacts with the E3 small ubiquitin-like modifier (SUMO) ligase AtSIZ1, suggesting that AtSIZ1 is an E3 SUMO ligase for FLC. In vitro sumoylation assays showed that FLC is modified by SUMO in the presence of SUMO-activating enzyme E1 and conjugating enzyme E2, but its sumoylation is inhibited by AtSIZ1. In transgenic plants, inducible AtSIZ1 overexpression led to an increase in the concentration of FLC and delayed the post-translational decay of FLC, indicating that AtSIZ1 stabilizes FLC through direct binding. Also, the flowering time in mutant FLC (K154R, a mutation of the sumoylation site)-overexpressing plants was comparable with that in the wild type, whereas flowering was considerably delayed in FLC-overexpressing plants, supporting the notion that sumoylation is an important mechanism for FLC function. The data indicate that the sumoylation of FLC is critical for its role in the control of flowering time and that AtSIZ1 positively regulates FLC-mediated floral suppression.
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Son GH, Park BS, Song JT, Seo HS. FLC-mediated flowering repression is positively regulated by sumoylation. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:339-51. [PMID: 24218331 PMCID: PMC3883301 DOI: 10.1093/jxb/ert383] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Flowering locus C (FLC), a floral repressor, is a critical factor for the transition from the vegetative to the reproductive phase. Here, the mechanisms regulating the activity and stability of the FLC protein were investigated. Bimolecular fluorescence complementation and in vitro pull-down analyses showed that FLC interacts with the E3 small ubiquitin-like modifier (SUMO) ligase AtSIZ1, suggesting that AtSIZ1 is an E3 SUMO ligase for FLC. In vitro sumoylation assays showed that FLC is modified by SUMO in the presence of SUMO-activating enzyme E1 and conjugating enzyme E2, but its sumoylation is inhibited by AtSIZ1. In transgenic plants, inducible AtSIZ1 overexpression led to an increase in the concentration of FLC and delayed the post-translational decay of FLC, indicating that AtSIZ1 stabilizes FLC through direct binding. Also, the flowering time in mutant FLC (K154R, a mutation of the sumoylation site)-overexpressing plants was comparable with that in the wild type, whereas flowering was considerably delayed in FLC-overexpressing plants, supporting the notion that sumoylation is an important mechanism for FLC function. The data indicate that the sumoylation of FLC is critical for its role in the control of flowering time and that AtSIZ1 positively regulates FLC-mediated floral suppression.
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