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ABSTRACT: The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a well-known carcinogen, however, the biological mechanism of carcinogenesis by TCDD has not been established.
Recently, protein arginine methyltransferases (PRMTs) have been identified as secondary transcription co-activators and are
proposed to be co-activators of aryl hydrocarbon receptors binding to xenobiotic response elements. Both PRMT1 and PRMT4 were
also reported to be involved with carcinogenesis. The aim of this study was to identify cancer-related genes that are regulated
by TCDD exposure and the effect of arginine methylation on TCDD toxicity by transfecting human hepatocarcinoma cells with
PRMT1 and PRMT4 siRNA. By microarray analysis, 1,461 genes were up-regulated and 1,591 genes were down-regulated by TCDD exposure.
Among the 16 up-regulated genes which had functions related to cancer or metastasis, 13 genes were confirmed by quantitative
real time RT-PCR: ABCG2, NRP1, SOX5, BIRC3, CD109, CYP1A1, ERBB2, MTA1, FURIN, F3, PIK3R3, NPTN and NTN4. Co-inhibition of
PRMT1 and PRMT4 resulted in decreased expression of eight of these genes, MTA1, ERBB2, SOX5, CD109, FURIN, NRP1, PIK3R3 and
ABCG2, all of which have been reportedly involved in breast, ovary, prostate and lung cancers, and metastasis.
KeywordsTCDD-Protein arginine methylation-PRMT1-PRMT4-Cancer-Metastasis
Molecular and Cellular Toxicology 04/2012; 6(2):111-118. · 0.88 Impact Factor
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Md Lutfor Rahman,
Wenzhu Jiang,
Sang Ho Chu,
Yongli Qiao,
Tae-Ho Ham,
Mi-Ok Woo, Joohyun Lee,
M. Sakina Khanam,
Joong-Hyoun Chin,
Ji-Ung Jeung,
D. S. Brar,
K. K. Jena,
Hee-Jong Koh
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ABSTRACT: Brown planthopper (BPH) is one of the most destructive insect pests of rice. Wild species of rice are a valuable source of
resistance genes for developing resistant cultivars. A molecular marker-based genetic analysis of BPH resistance was conducted
using an F2 population derived from a cross between an introgression line, ‘IR71033-121-15’, from Oryza minuta (Accession number 101141) and a susceptible Korean japonica variety, ‘Junambyeo’. Resistance to BPH (biotype 1) was evaluated using 190 F3 families. Two major quantitative trait loci (QTLs) and two significant digenic epistatic interactions between marker intervals
were identified for BPH resistance. One QTL was mapped to 193.4-kb region located on the short arm of chromosome 4, and the
other QTL was mapped to a 194.0-kb region on the long arm of chromosome 12. The two QTLs additively increased the resistance
to BPH. Markers co-segregating with the two resistance QTLs were developed at each locus. Comparing the physical map positions
of the two QTLs with previously reported BPH resistance genes, we conclude that these major QTLs are new BPH resistance loci
and have designated them as Bph20(t) on chromosome 4 and Bph21(t) on chromosome 12. This is the first report of BPH resistance genes from the wild species O. minuta. These two new genes and markers reported here will be useful to rice breeding programs interested in new sources of BPH
resistance.
Theoretical and Applied Genetics 04/2012; 119(7):1237-1246. · 3.30 Impact Factor
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ABSTRACT: Two sets of rice materials, 166 RILs derived from a cross between Milyang 23 (Korean indica-type rice) and Tong 88-7 (japonica Rice), and BC1F1 hybrids derived from crosses be-tween the RILs and the female parent, Milyang 23, were pro-duced to identify QTLs for heterosis of yield and yield-related traits. The QTLs were detected from three different phenotype data sets including the RILs, BC1F1 hybrids, and mid-parental heterosis data set acquired from the definition of mid-parental heterosis. A total of 57 QTLs were identified for nine traits. Of eight QTLs detected for yield heterosis, five overlapped with other heterosis QTLs for yield-related traits such as spike-let number per plant, days to heading, and spikelet fertility. Four QTLs for yield heterosis, gy1.1, py6, gy10, and py11, were newly identified in this study. We identified a total of 17 EpQTLs for yield heterosis that explain 21.4 ~ 59.0 % of total phenotypic variation, indicating that epistatic inter-actions may play an important role in heterosis.
Genes and Genomics 01/2012; -(--DOI: 10.1007/s13258-011-0209-8):-.
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Wenzhu Jiang,
Yong-Mei Jin, Joohyun Lee,
Kang-Ie Lee,
Rihua Piao,
Longzhi Han,
Jin-Chul Shin,
Rong-De Jin,
Tiehua Cao,
Hong-Yu Pan,
Xinglin Du,
Hee-Jong Koh
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ABSTRACT: Low temperature is one of the major environmental stresses in rice cultivation in high-altitude and high-latitude regions. In this study, we cultivated a set of recombinant inbred lines (RIL) derived from Dasanbyeo (indica) / TR22183 (japonica) crosses in Yanji (high-latitude area), Kunming (high-altitude area), Chuncheon (cold water irrigation) and Suwon (normal) to evaluate the main effects of quantitative trait loci (QTL) and epistatic QTL (E-QTL) with regard to their interactions with environments for cold-related traits. Six QTLs for spikelet fertility (SF) were identified in three cold treatment locations. Among them, four QTLs on chromosomes 2, 7, 8, and 10 were validated by several near isogenic lines (NILs) under cold treatment in Chuncheon. A total of 57 QTLs and 76 E-QTLs for nine cold-related traits were identified as distributing on all 12 chromosomes; among them, 19 QTLs and E-QTLs showed significant interactions of QTLs and environments (QEIs). The total phenotypic variation explained by each trait ranged from 13.2 to 29.1% in QTLs, 10.6 to 29.0% in EQTLs, 2.2 to 8.8% in QEIs and 1.0% to 7.7% in E-QTL × environment interactions (E-QEIs). These results demonstrate that epistatic effects and QEIs are important properties of QTL parameters for cold tolerance at the reproductive stage. In order to develop cold tolerant varieties adaptable to wide-ranges of cold stress, a strategy facilitating marker-assisted selection (MAS) is being adopted to accumulate QTLs identified from different environments.
Molecules and Cells 11/2011; 32(6):579-87. · 2.18 Impact Factor
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ABSTRACT: ABSTRACT:
Although a great deal of rice proteomic research has been conducted, there are relatively few studies specifically addressing the rice grain proteome. The existing rice grain proteomic researches have focused on the identification of differentially expressed proteins or monitoring protein expression patterns during grain filling stages.
Proteins were extracted from rice grains 10, 20, and 30 days after flowering, as well as from fully mature grains. By merging all of the identified proteins in this study, we identified 4,172 non-redundant proteins with a wide range of molecular weights (from 5.2 kDa to 611 kDa) and pI values (from pH 2.9 to pH 12.6). A Genome Ontology category enrichment analysis for the 4,172 proteins revealed that 52 categories were enriched, including the carbohydrate metabolic process, transport, localization, lipid metabolic process, and secondary metabolic process. The relative abundances of the 1,784 reproducibly identified proteins were compared to detect 484 differentially expressed proteins during rice grain development. Clustering analysis and Genome Ontology category enrichment analysis revealed that proteins involved in the metabolic process were enriched through all stages of development, suggesting that proteome changes occurred even in the desiccation phase. Interestingly, enrichments of proteins involved in protein folding were detected in the desiccation phase and in fully mature grain.
This is the first report conducting comprehensive identification of rice grain proteins. With a label free shotgun proteomic approach, we identified large number of rice grain proteins and compared the expression patterns of reproducibly identified proteins during rice grain development. Clustering analysis, Genome Ontology category enrichment analysis, and the analysis of composite expression profiles revealed dynamic changes of metabolisms during rice grain development. Interestingly, we detected that proteins involved in glycolysis, TCA-cycle, lipid metabolism, and proteolysis accumulated at higher levels in fully mature grain compared to grain developing stages, suggesting that the accumulation of these proteins during the desiccation stage may be associated with the preparation of proteins required in germination.
Proteome Science 09/2011; 9(1):61. · 2.33 Impact Factor
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ABSTRACT: Rice sucrose synthase 3 (RSUS3) is expressed predominantly in rice seed endosperm and is thought to play an important role in starch filling during the milky stage of rice seed ripening. Because the genetic diversity of this locus is not known yet, the full sequence of RSUS3 from 43 rice varieties was amplified to examine the distribution of DNA polymorphisms. A total of 254 sequence variants, including SNPs and insertion/deletions, were successfully identified in the 7733 bp sequence that comprises the promoter, exons and introns, and 3' downstream nontranscribed region (NTR). Eleven haplotypes were distinguished among the 43 rice varieties based on nucleotide variation in the 3 defined regions (5' NTR, transcript, and 3' NTR). The promoter region showed evidence of a base change on a cis-element that might influence the functional role of the motif in seed-specific expression. The genetic diversity of the RSUS3 gene sequences in the rice germplasm used in this study appears to be the result of nonrandom processes. Analysis of polymorphism sites indicated that at least 11 recombinations have occurred, primarily in the transcribed region. This finding provides insight into the development of a cladistic approach for establishing future genetic association studies of the RSUS3 locus.
The Journal of heredity 09/2011; 102(6):735-46. · 2.05 Impact Factor
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ABSTRACT: Tillering is an important trait of cereal crops that optimizes plant architecture for maximum yield. Teosinte Branched 1 (TB1) is a negative regulator of lateral branching and an inducer of female inflorescence formation in Zea mays (maize). Recent studies indicate that TB1 homologs in Oryza sativa (rice), Sorghum bicolor and Arabidopsis thaliana act downstream of the auxin and MORE AUXILIARY GROWTH (MAX) pathways. However, the molecular mechanism by which rice produces tillers remains unknown. In this study, transgenic rice plants were produced that overexpress the maize TB1 (mTB1) or rice TB1 (OsTB1) genes and silence the OsTB1 gene through RNAi-mediated knockdown. Because lateral branching in rice is affected by the environmental conditions, the phenotypes of transgenic plants were observed in both the greenhouse and the paddy field. Compared to wild-type plants, the number of tillers and panicles was reduced and increased in overexpressed and RNAi-mediated knockdown OsTB1 rice plants, respectively, under both environmental conditions. However, the effect was small for plants grown in paddy fields. These results demonstrate that both mTB1 and OsTB1 moderately regulate the tiller development in rice.
Plant Cell Reports 09/2011; 31(1):57-65. · 2.27 Impact Factor
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Wenzhu Jiang, Joohyun Lee,
Yong-Mei Jin,
Yongli Qiao,
Rihua Piao,
Sun Mi Jang,
Mi-Ok Woo,
Soon-Wook Kwon,
Xianhu Liu,
Hong-Yu Pan,
Xinglin Du,
Hee-Jong Koh
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ABSTRACT: Seed germination capability of rice is one of the important traits in the production and storage of seeds. Quantitative trait loci (QTL) associated with seed germination capability in various storage periods was identified using two sets of recombinant inbred lines (RILs) which derived from crosses between Milyang 23 and Tong 88-7 (MT-RILs) and between Dasanbyeo and TR22183 (DT-RILs). A total of five and three main additive effects (QTLs) associated with seed germination capability were identified in MT-RILs and DT-RILs, respectively. Among them, six QTLs were identified repeatedly in various seed storage periods designated as qMT-SGC5.1, qMT-SGC7.2, and qMT-SGC9.1 on chromosomes 5, 7, and 9 in MT-RILs, and qDT-SGC2.1, qDT-SGC3.1, and qDT-SGC9.1 on chromosomes 2, 3, and 9 in DT-RILs, respectively. The QTL on chromosome 9 was identified in both RIL populations under all three storage periods, explaining up to 40% of the phenotypic variation. Eight and eighteen pairs additive × additive epistatic effect (epistatic QTL) were identified in MT-RILs and DT-RILs, respectively. In addition, several near isogenic lines (NILs) were developed to confirm six repeatable QTL effects using controlled deterioration test (CDT). The identified QTLs will be further studied to elucidate the mechanisms controlling seed germination capability, which have important implications for long-term seed storage.
Molecules and Cells 03/2011; 31(4):385-92. · 2.18 Impact Factor
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ABSTRACT: To survey protein expression patterns in the reduced culm number (RCN) rice, a comparative shotgun proteomic analysis was conducted. For large-scale protein identification, multidimensional protein identification technology (MudPIT) coupled with pre-fractionation of plant shoot proteins led to the identification of 3004 non-redundant rice proteins. By statistically comparing relative amounts of 1353 reproducibly identified proteins between the RCN rice and the wild-type rice, 44 differentially expressed proteins were detected, where 42 proteins were increased and 2 proteins were decreased in the RCN rice. These proteins appear to have roles in glycolysis, trichloroacetic acid cycle, secondary metabolism, nutrient recycling, and nucleotide metabolism and repair. Consequently, we hypothesized that the RCN rice might fail to maintain sugar nutrient homeostasis. This was confirmed with the observation that the sucrose concentration was increased significantly in the RCN rice compared with the wild-type rice. Also, the RCN rice showed a hypersensitive response to exogenous sucrose treatment.
Proteomics 02/2011; 11(3):455-68. · 4.43 Impact Factor
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ABSTRACT: Architecture of the rice inflorescence, which is determined mainly by the morphology, number and length of primary and secondary inflorescence branches, is an important agronomical trait. In the current study, we characterized a novel dense and erect panicle (EP) mutant, dep3, derived from the Oryza sativa ssp. japonica cultivar Hwacheong treated with N-methyl-N-nitrosourea. The panicle of the dep3 mutant remained erect from flowering to full maturation, whereas the panicle of the wild type plant began to droop after flowering. The dep3 mutation also regulated other panicle characteristics, including panicle length, grain shape and grain number per panicle. Anatomical observations revealed that the dep3 mutant had more small vascular bundles and a thicker culm than wild type plants, explaining the EP phenotype. Genetic analysis indicated that the phenotype with the dense and EP was controlled by a single recessive gene, termed dep3. The DEP3 gene was identified as the candidate via a map-based cloning approach and was predicted to encode a patatin-like phospholipase A2 (PLA2) superfamily domain-containing protein. The mutant allele gene carried a 408 bp genomic deletion within LOC_Os06g46350, which included the last 47 bp coding region of the third exon and the first 361 bp of the 3'-untranslated region. Taken together, our results indicated that the patatin-like PLA2 might play a significant role in the formation of vascular bundles, and that the dep3 mutant may provide another EP resource for rice breeding programs.
Theoretical and Applied Genetics 02/2011; 122(7):1439-49. · 3.30 Impact Factor
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ABSTRACT: Zinc is an essential micronutrient for several physiological and biochemical processes. To investigate its transport in rice, we characterized OsZIP8, a rice ZIP (Zrt, Irt-like Protein) gene that is strongly up-regulated in shoots and roots under Zn deficiency. OsZIP8 could complement the growth defect of Zn-uptake yeast mutant. The OsZIP8-GFP fusion proteins were localized to the plasma membrane, suggesting that OsZIP8 is a plasma membrane zinc transporter in rice. Activation and overexpression of this gene disturbed the zinc distribution in rice plants, resulting in lower levels in shoots and mature seeds, but an increase in the roots. Field-grown transgenic plants were shorter than the WT. Under treatment with excess zinc, transgenics contained less zinc in their shoots but accumulated more in the roots. Altogether, these results demonstrate that OsZIP8 is a zinc transporter that functions in Zn uptake and distribution. Furthermore, zinc homeostasis is important to the proper growth and development of rice.
Molecules and Cells 05/2010; 29(6):551-8. · 2.18 Impact Factor
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ABSTRACT: Zinc is essential for normal plant growth and development. To understand its transport in rice, we characterized OsZIP5, which is inducible under Zn deficiency. OsZIP5 complemented the growth defect of a yeast Zn-uptake mutant, indicating that OsZIP5 is a Zn transporter. The OsZIP5-GFP fusion protein was localized to the plasma membrane. Transgenic plants overexpressing the gene grew less well. Overexpression of the gene decreased the Zn concentration in shoots, but caused it to rise in the roots. Knockout plants showed no visible phenotypic changes under either normal or deficient conditions. However, they were tolerant to excess Zn and contained less Zn. In contrast, overexpressing transgenics were sensitive to excess Zn. These results indicate that OsZIP5 plays a role in Zn distribution within rice.
Plant Molecular Biology 04/2010; 73(4-5):507-17. · 4.15 Impact Factor
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ABSTRACT: Cadmium (Cd) is a widespread soil pollutant; thus, the underlying molecular controls of plant Cd tolerance are of substantial interest. A screen for wheat (Triticum aestivum) genes that confer Cd tolerance to a Cd hypersensitive yeast strain identified Heat shock transcription factor A4a (HsfA4a). Ta HsfA4a is most similar to the class A4 Hsfs from monocots. The most closely related rice (Oryza sativa) homolog, Os HsfA4a, conferred Cd tolerance in yeast, as did Ta HsfA4a, but the second most closely related rice homolog, Os HsfA4d, did not. Cd tolerance was enhanced in rice plants expressing Ta HsfA4a and decreased in rice plants with knocked-down expression of Os HsfA4a. An analysis of the functional domain using chimeric proteins constructed from Ta HsfA4a and Os HsfA4d revealed that the DNA binding domain (DBD) of HsfA4a is critical for Cd tolerance, and within the DBD, Ala-31 and Leu-42 are important for Cd tolerance. Moreover, Ta HsfA4a-mediated Cd resistance in yeast requires metallothionein (MT). In the roots of wheat and rice, Cd stress caused increases in HsfA4a expression, together the MT genes. Our findings thus suggest that HsfA4a of wheat and rice confers Cd tolerance by upregulating MT gene expression in planta.
The Plant Cell 12/2009; 21(12):4031-43. · 8.99 Impact Factor
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Yongli Qiao,
Wenzhu Jiang, JooHyun Lee,
BongSoo Park,
Min-Seon Choi,
Rihua Piao,
Mi-Ok Woo,
Jae-Hwan Roh,
Longzhi Han,
Nam-Chon Paek,
Hak Soo Seo,
Hee-Jong Koh
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ABSTRACT: To expand our understanding of cell death in plant defense responses, we isolated a novel rice (Oryza sativa) spotted leaf mutant (spl28) that displays a lesion mimic phenotype in the absence of pathogen attack through treatment of Hwacheongbyeo (an elite Korean japonica cultivar) with N-methyl-N-nitrosourea (MNU). Early stage development of the spl28 mutant was normal. However, after flowering, spl28 mutants exhibited a significant decrease in chlorophyll content, soluble protein content, and photosystem II efficiency, and high concentrations of reactive oxygen species (ROS), phytoalexin, callose, and autofluorescent phenolic compounds that localized in or around the lesions. The spl28 mutant also exhibited significantly enhanced resistance to rice blast and bacterial blight. Using a map-based cloning approach, we determined that SPL28 encodes a clathrin-associated adaptor protein complex 1, medium subunit micro 1 (AP1M1), which is involved in the post-Golgi trafficking pathway. A green fluorescent protein (GFP) fusion protein of SPL28 (SPL28::GFP) localized to the Golgi apparatus, and expression of SPL28 complemented the membrane trafficking defect of apm1-1 Delta yeast mutants. SPL28 was ubiquitously expressed and contained a highly conserved adaptor complex medium subunit (ACMS) family domain. SPL28 appears to be involved in the regulation of vesicular trafficking, and SPL28 dysfunction causes the formation of hypersensitive response (HR)-like lesions, leading to the initiation of leaf senescence.
New Phytologist 10/2009; 185(1):258-74. · 6.64 Impact Factor
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ABSTRACT: Relatively little is known about how metals such as iron are effluxed from cells, a necessary step for transport from the root to the shoot. Ferroportin (FPN) is the sole iron efflux transporter identified to date in animals, and there are two closely related orthologs in Arabidopsis thaliana, IRON REGULATED1 (IREG1/FPN1) and IREG2/FPN2. FPN1 localizes to the plasma membrane and is expressed in the stele, suggesting a role in vascular loading; FPN2 localizes to the vacuole and is expressed in the two outermost layers of the root in response to iron deficiency, suggesting a role in buffering metal influx. Consistent with these roles, fpn2 has a diminished iron deficiency response, whereas fpn1 fpn2 has an elevated iron deficiency response. Ferroportins also play a role in cobalt homeostasis; a survey of Arabidopsis accessions for ionomic phenotypes showed that truncation of FPN2 results in elevated shoot cobalt levels and leads to increased sensitivity to the metal. Conversely, loss of FPN1 abolishes shoot cobalt accumulation, even in the cobalt accumulating mutant frd3. Consequently, in the fpn1 fpn2 double mutant, cobalt cannot move to the shoot via FPN1 and is not sequestered in the root vacuoles via FPN2; instead, cobalt likely accumulates in the root cytoplasm causing fpn1 fpn2 to be even more sensitive to cobalt than fpn2 mutants.
The Plant Cell 10/2009; 21(10):3326-38. · 8.99 Impact Factor
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Rihua Piao,
Wenzhu Jiang,
Tae-Ho Ham,
Min-Seon Choi,
Yongli Qiao,
Sang-Ho Chu,
Jung-Hyun Park,
Mi-Ok Woo,
Zhengxun Jin,
Gynheung An, Joohyun Lee,
Hee-Jong Koh
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ABSTRACT: Panicle architecture in rice can have a strong influence on yield. Using N-methyl-N-nitrosourea mutagenesis, we isolated an erect panicle mutant, Hep, from Hwasunchalbyeo, a glutinous japonica rice cultivar. Genetic analysis revealed that the erect panicle phenotype was controlled by a single recessive mutation designated erect panicle 3 (ep3). Genetic mapping revealed that the ep3 mutation was located on the short arm of chromosome 2 in a 0.1 cM region delimited by the STS markers STS5803-5 and STS5803-7. The ep3 locus corresponded to 46.8 kb region and contained six candidate genes. Comparison of the DNA sequences of the candidate genes from wild-type and erect panicle plants revealed a single base-pair change in the second exon of LOC_Os02g15950, which is predicted to result in a nonsense mutation. LOC_Os02g15950 encodes a putative F-box protein containing 515 amino acids and is expressed throughout the plant during all growth stages. A line carrying a T-DNA insertion in LOC_ Os02g15950 was obtained and shown to have the same phenotype as the ep3 mutant, thus confirming the identification of LOC_Os02g15950 as the ERECT PANICLE 3 (EP3) gene. The ep3 mutation causes a significant increase in the number of small vascular bundles as well as the thickness of parenchyma in the peduncle, which results in the erect panicle phenotype.
Theoretical and Applied Genetics 09/2009; 119(8):1497-506. · 3.30 Impact Factor
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ABSTRACT: Most human metabolomics studies have shown that spectral outputs of (1)H nuclear magnetic resonance fingerprinting are strongly influenced by inter- and intra-individual variations; however, few studies have been performed to evaluate the inter- and intra-individual variations in urinary endogenous metabolites.
We recruited 30 male college students to evaluate the factors affecting intra- and inter-individual variations in urinary endogenous metabolites. Statistical analysis for variations in urinary metabolites was performed after eliminating outliers found in principal component analysis (PCA) plots.
Inter-individual variations were relatively low for 2-oxoglutarate, succinate, citrate, dimethylglycine, and taurine, but high for trimethylaminoxide (TMAO), hippurate, and lactate. Intra-individual variations for 2-oxoglutarate, citrate, dimethylglycine, and taurine were relatively low, but high for TMAO and hippurate. The factors affecting inter-individual variation of lactate were age, body mass index, beverages, and alcohol, whereas the factors affecting intra-individual variation of lactate were age and fish. Kim Chi intake affected the inter-individual variation of succinate, citrate, TMAO, and hippurate; however, it did not affect the intra-individual variation of endogenous metabolites.
Our results showed that inter- and intra-individual variations in urinary endogenous metabolites were very large, and significant factors affecting inter- and intra-individual variation were diverse, even after eliminating outliers in PCA analysis.
Clinical Chemistry and Laboratory Medicine 02/2009; 47(2):188-94. · 2.15 Impact Factor
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ABSTRACT: Protein arginine methylation is one of the post-translational modifications which yield monomethyl and dimethyl (asymmetric or symmetric) arginines in proteins. In the present study, we investigated the status of protein arginine methylation during human diploid fibroblast senescence. When the expression of protein arginine methyltransferases (PRMTs), namely PRMT1, PRMT4, PRMT5 and PRMT6 was examined, a significant reduction was found in replicatively senescent cells as well as their catalytic activities against histone mixtures compared with the young cells. Furthermore, when the endogenous level of arginine-dimethylated proteins was determined, asymmetric modification (the product of type I PRMTs including PRMT1, PRMT4 and PRMT6) was markedly down-regulated. In contrast, both up- and down-regulations of symmetrically arginine-methylated proteins (the product of type II PRMTs including PRMT5) during replicative senescence were found. Furthermore, when young fibroblasts were induced to premature senescence by sub-cytotoxic H2O2 treatment, results similar to replicative senescence were obtained. Finally, we found that SV40-mediated immortalized WI-38 and HeLa cell lines maintained a higher level of asymmetrically modified proteins as well as type I PRMTs than young fibroblasts. These results suggest that the maintenance of asymmetric modification in the expressed target proteins of type I PRMTs might be critical for cellular proliferation.
Journal of Biochemistry 08/2008; 144(4):523-9. · 2.37 Impact Factor
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ABSTRACT: Cadmium causes the generation of reactive oxygen species, which in turn causes cell damage. We isolated a novel gene from a wheat root cDNA library, which conferred Cd(II)-specific tolerance when expressed in yeast (Saccharomyces cerevisiae). The gene, which we called TaTM20, for Triticum aestivum transmembrane 20, encodes a putative hydrophobic polypeptide of 889 amino acids, containing 20 transmembrane domains arranged as a 5-fold internal repeating unit of 4 transmembrane domains each. Expression of TaTM20 in yeast cells stimulated Cd(II) efflux resulting in a decrease in the content of yeast intracellular cadmium. TaTM20-induced Cd(II) tolerance was maintained in yeast even under conditions of reduced GSH. These results demonstrate that TaTM20 enhances Cd(II) tolerance in yeast through the stimulation of Cd(II) efflux from the cell, partially independent of GSH. Treatment of wheat seedlings with Cd(II) induced their expression of TaTM20, decreasing subsequent root Cd(II) accumulation and suggesting a possible role for TaTM20 in Cd(II) tolerance in wheat.
Journal of Biological Chemistry 07/2008; 283(23):15893-902. · 4.77 Impact Factor
