26
|
Higo H, Tahir M, Takashima K, Miura A, Watanabe K, Tagiri A, Ugaki M, Ishikawa R, Eiguchi M, Kurata N, Sasaki T, Richards E, Takano M, Kishimoto N, Kakutani T, Habu Y. DDM1 (decrease in DNA methylation) genes in rice (Oryza sativa). Mol Genet Genomics 2012; 287:785-92. [PMID: 22915302 DOI: 10.1007/s00438-012-0717-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Accepted: 08/03/2012] [Indexed: 11/28/2022]
Abstract
Regulation of cytosine methylation in the plant genome is of pivotal in determining the epigenetic states of chromosome regions. Relative tolerance of plant to deficiency in cytosine methylation provides unparalleled opportunities to study the mechanism for regulation of cytosine methylation. The Decrease in DNA Methylation 1 (DDM1) of Arabidopsis thaliana is one of the best characterized plant epigenetic regulators that are necessary for maintenance of cytosine methylation in genomic DNA. Although cytosine methylation could affect various aspects of plant growth and development including those related to agricultural importance, orthologs of DDM1 in plants other than Arabidopsis has not been studied in detail. In this study, we identified two rice genes with similarity to Arabidopsis DDM1 and designated them OsDDM1a and OsDDM1b. Both of the rice DDM1 homologs are transcribed during development and their amino acid sequences are 93 % identical to each other. Transgenic rice lines expressing the OsDDM1a cDNA in the antisense orientation exhibited genomic DNA hypomethylation. In those lines, repeated sequences were more severely affected than a single copy sequence as is the case in Arabidopsis ddm1 mutants. Transcripts derived from endogenous transposon-related loci were up-regulated in the antisense OsDDM1 lines, opening a possibility to identify and utilize potentially active transposons for rice functional genomics.
Collapse
|
27
|
Yuki M, Takase K, Ishida T, Sekine S, Miura A. 3629 POSTER Amount of Cyclophosphamide Excreted in the Urine of Patients During the 48h After Chemotherapy and Secondary Enviromental Contamination of Home Settings Due to the Drug. Eur J Cancer 2011. [DOI: 10.1016/s0959-8049(11)71226-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
28
|
Akira S, Ichikawa M, Iwasaki N, Ouchi N, Mine K, Miura A, Kurose K, Takeshita T. Gasless laparoscopically assisted myomectomy using a wound retraction system. Asian J Endosc Surg 2011; 4:133-7. [PMID: 22776277 DOI: 10.1111/j.1758-5910.2011.00086.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION The purpose of this study was to elucidate the feasibility of gasless laparoscopically assisted myomectomy (LAM) using a wound retraction system. This method treats symptomatic uterine myomas by combining laparoscopy with a mini-laparotomy to enucleate myoma nodules and to close the uterine myometrium. METHODS This study includes 275 patients who underwent gasless LAM. For patients with fewer than three myoma nodules, the location of the largest nodule was classified as anterior, fundal, or posterior. The operative outcomes, intraoperative and postoperative courses, and complications were examined. RESULTS All operations were performed satisfactorily, and no conversions to laparotomy were required. None of the patients developed serious complications. The mean blood loss and operating time were 190.3 mL and 152.2 minutes, respectively. The mean myoma size was 8.9 cm, and the mean number of myomas per patient was 2.8. The average postoperative hospital stay was 5.7 days. There were no significant differences in resected myoma size, blood loss, and surgical duration with respect to the location of the largest nodule. CONCLUSION Gasless LAM with a wound retractor is feasible and allows surgeons to perform myomectomy safely and cost-effectively, without requiring advanced laparoscopic surgical skills and while maintaining minimum invasiveness.
Collapse
|
29
|
Tai K, Park JH, Hayashi D, Miura A. Autotransplantation of premolars in a patient with multiple congenitally missing teeth. JOURNAL OF CLINICAL ORTHODONTICS : JCO 2011; 45:399-407. [PMID: 21965322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
|
30
|
Kumabe Y, Miura A, Yamashita T, Oshima T, Misumi Y, Ueda M, Obayashi K, Horibata Y, Jono H, Ando Y, Uchino M. A homozygote case of familial amyloid polyneuropathy amyloidgenic transthyretin Val30Met in a non-endemic area. Amyloid 2011; 18 Suppl 1:169-70. [PMID: 21838475 DOI: 10.3109/13506129.2011.574354063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
31
|
Honda M, Miura A, Izumi Y, Kato T, Ryotokuji T, Monma K, Fujiwara J, Egashira H, Nemoto T. Doxorubicin, cisplatin, and fluorouracil combination therapy for metastatic esophageal squamous cell carcinoma. Dis Esophagus 2010; 23:641-5. [PMID: 20545978 DOI: 10.1111/j.1442-2050.2010.01070.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The chemotherapy regimen currently used for treating esophageal and gastric carcinoma has been either epirubicin, cisplatin, and fluorouracil (5-FU) or docetaxel, cisplatin, and 5-FU. Here, we report the efficacy and toxicity of doxorubicin, cisplatin, and 5-FU for only esophageal squamous cell carcinoma (ESCC). Between January 2000 and October 2008, a total of 41 ESCC patients with a distant metastasis were enrolled. The most common sites of metastasis were liver (26, 63.4%), lung (9, 22.0%), and bone (8, 19.5%). Doxorubicin was administered on day 1 at 30 mg/m(2) , cisplatin on days 1-5 at 14 mg/m(2)/day, and 5-FU on days 1-5 at 700 mg/m(2)/day. The median number of cycles was 2.0 (range 1-8). The dose intensities of doxorubicin, cisplatin, and 5-FU were 92.9, 92.4, and 92.5%, respectively. The overall response rate was 43.9%; one showed complete response, 17 showed partial response, 13 showed a stable disease, and 10 showed progressive disease (PD). The median survival time was 306 days (95% CI = 74-935) and the 1-year survival rate was 37.6%. Grade 3 neutropenia was seen in seven patients and grade 4 in one patient. Grade 3 fatigue, anorexia, mucositis, and diarrhea were observed in three, two, two, and one patient, respectively. This regimen is effective as a first-line therapy for ESCC with distant metastasis.
Collapse
|
32
|
Sajan MP, Bandyopadhyay G, Miura A, Standaert ML, Nimal S, Longnus SL, Van Obberghen E, Hainault I, Foufelle F, Kahn R, Braun U, Leitges M, Farese RV. AICAR and metformin, but not exercise, increase muscle glucose transport through AMPK-, ERK-, and PDK1-dependent activation of atypical PKC. Am J Physiol Endocrinol Metab 2010; 298:E179-92. [PMID: 19887597 PMCID: PMC2822478 DOI: 10.1152/ajpendo.00392.2009] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Activators of 5'-AMP-activated protein kinase (AMPK) 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR), metformin, and exercise activate atypical protein kinase C (aPKC) and ERK and stimulate glucose transport in muscle by uncertain mechanisms. Here, in cultured L6 myotubes: AICAR- and metformin-induced activation of AMPK was required for activation of aPKC and ERK; aPKC activation involved and required phosphoinositide-dependent kinase 1 (PDK1) phosphorylation of Thr410-PKC-zeta; aPKC Thr410 phosphorylation and activation also required MEK1-dependent ERK; and glucose transport effects of AICAR and metformin were inhibited by expression of dominant-negative AMPK, kinase-inactive PDK1, MEK1 inhibitors, kinase-inactive PKC-zeta, and RNA interference (RNAi)-mediated knockdown of PKC-zeta. In mice, muscle-specific aPKC (PKC-lambda) depletion by conditional gene targeting impaired AICAR-stimulated glucose disposal and stimulatory effects of both AICAR and metformin on 2-deoxyglucose/glucose uptake in muscle in vivo and AICAR stimulation of 2-[(3)H]deoxyglucose uptake in isolated extensor digitorum longus muscle; however, AMPK activation was unimpaired. In marked contrast to AICAR and metformin, treadmill exercise-induced stimulation of 2-deoxyglucose/glucose uptake was not inhibited in aPKC-knockout mice. Finally, in intact rodents, AICAR and metformin activated aPKC in muscle, but not in liver, despite activating AMPK in both tissues. The findings demonstrate that in muscle AICAR and metformin activate aPKC via sequential activation of AMPK, ERK, and PDK1 and the AMPK/ERK/PDK1/aPKC pathway is required for metformin- and AICAR-stimulated increases in glucose transport. On the other hand, although aPKC is activated by treadmill exercise, this activation is not required for exercise-induced increases in glucose transport, and therefore may be a redundant mechanism.
Collapse
|
33
|
Yoneyama K, Nakayama H, Doi D, Miura A, Mita S, Kurose K, Kamoi S, Takeshita T. P1125 Evaluation of prognostic factors in endometrial cancer. Int J Gynaecol Obstet 2009. [DOI: 10.1016/s0020-7292(09)62609-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
34
|
Tsukahara S, Kobayashi A, Kawabe A, Mathieu O, Miura A, Kakutani T. Bursts of retrotransposition reproduced in Arabidopsis. Nature 2009; 461:423-6. [PMID: 19734880 DOI: 10.1038/nature08351] [Citation(s) in RCA: 249] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 07/27/2009] [Indexed: 11/09/2022]
Abstract
Retrotransposons, which proliferate by reverse transcription of RNA intermediates, comprise a major portion of plant genomes. Plants often change the genome size and organization during evolution by rapid proliferation and deletion of long terminal repeat (LTR) retrotransposons. Precise transposon sequences throughout the Arabidopsis thaliana genome and the trans-acting mutations affecting epigenetic states make it an ideal model organism with which to study transposon dynamics. Here we report the mobilization of various families of endogenous A. thaliana LTR retrotransposons identified through genetic and genomic approaches with high-resolution genomic tiling arrays and mutants in the chromatin-remodelling gene DDM1 (DECREASE IN DNA METHYLATION 1). Using multiple lines of self-pollinated ddm1 mutant, we detected an increase in copy number, and verified this for various retrotransposons in a gypsy family (ATGP3) and copia families (ATCOPIA13, ATCOPIA21, ATCOPIA93), and also for a DNA transposon of a Mutator family, VANDAL21. A burst of retrotransposition occurred stochastically and independently for each element, suggesting an additional autocatalytic process. Furthermore, comparison of the identified LTR retrotransposons in related Arabidopsis species revealed that a lineage-specific burst of retrotransposition of these elements did indeed occur in natural Arabidopsis populations. The recent burst of retrotransposition in natural population is targeted to centromeric repeats, which is presumably less harmful than insertion into genes. The ddm1-induced retrotransposon proliferations and genome rearrangements mimic the transposon-mediated genome dynamics during evolution and provide experimental systems with which to investigate the controlling molecular factors directly.
Collapse
|
35
|
Sajan MP, Standaert ML, Rivas J, Miura A, Kanoh Y, Soto J, Taniguchi CM, Kahn CR, Farese RV. Role of atypical protein kinase C in activation of sterol regulatory element binding protein-1c and nuclear factor kappa B (NFkappaB) in liver of rodents used as a model of diabetes, and relationships to hyperlipidaemia and insulin resistance. Diabetologia 2009; 52:1197-207. [PMID: 19357831 PMCID: PMC4766834 DOI: 10.1007/s00125-009-1336-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 02/25/2009] [Indexed: 02/06/2023]
Abstract
AIMS/HYPOTHESIS Previous findings in rodents used as a model of diabetes suggest that insulin activation of atypical protein kinase C (aPKC) is impaired in muscle, but, unexpectedly, conserved in liver, despite impaired hepatic protein kinase B (PKB/Akt) activation. Moreover, aPKC at least partly regulates two major transactivators: (1) hepatic sterol receptor binding protein-1c (SREBP-1c), which controls lipid synthesis; and (2) nuclear factor kappa B (NFkappaB), which promotes inflammation and systemic insulin resistance. METHODS In Goto-Kakizaki rats used as a model of type 2 diabetes, we examined: (1) whether differences in hepatic aPKC and PKB activation reflect differences in activation of IRS-1- and IRS-2-dependent phosphatidylinositol 3-kinase (PI3K); (2) whether hepatic SREBP-1c and NFkappaB are excessively activated by aPKC; and (3) metabolic consequences of excessive activation of hepatic aPKC, SREBP-1c and NFkappaB. RESULTS In liver, as well as in muscle, IRS-2/PI3K activation by insulin was intact, whereas IRS-1/PI3K activation by insulin was impaired. Moreover, hepatic IRS-2 is known to control hepatic aPKC during insulin activation. Against this background, selective inhibition of hepatic aPKC by adenoviral-mediated expression of mRNA encoding kinase-inactive aPKC or short hairpin RNA targeting Irs2 mRNA and partially depleting hepatic IRS-2 diminished hepatic SREBP-1c production and NFkappaB activities, concomitantly improving serum lipids and insulin signalling in muscle and liver. Similar improvements in SREBP-1c, NFkappaB and insulin signalling were seen in ob/ob mice following inhibition of hepatic aPKC. CONCLUSIONS/INTERPRETATION In diabetic rodent liver, diminished PKB activation may largely reflect impaired IRS-1/PI3K activation, while conserved aPKC activation reflects retained IRS-2/PI3K activity. Hepatic aPKC may also contribute importantly to excessive SREPB-1c and NFkappaB activities. Excessive hepatic aPKC-dependent activation of SREBP-1c and NFkappaB may contribute importantly to hyperlipidaemia and systemic insulin resistance.
Collapse
|
36
|
Miura A, Nakamura M, Inagaki S, Kobayashi A, Saze H, Kakutani T. An Arabidopsis jmjC domain protein protects transcribed genes from DNA methylation at CHG sites. EMBO J 2009; 28:1078-86. [PMID: 19262562 PMCID: PMC2653724 DOI: 10.1038/emboj.2009.59] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 02/05/2009] [Indexed: 12/17/2022] Open
Abstract
Differential cytosine methylation of genes and transposons is important for maintaining integrity of plant genomes. In Arabidopsis, transposons are heavily methylated at both CG and non-CG sites, whereas the non-CG methylation is rarely found in active genes. Our previous genetic analysis suggested that a jmjC domain-containing protein IBM1 (increase in BONSAI methylation 1) prevents ectopic deposition of non-CG methylation, and this process is necessary for normal Arabidopsis development. Here, we directly determined the genomic targets of IBM1 through high-resolution genome-wide analysis of DNA methylation. The ibm1 mutation induced extensive hyper-methylation in thousands of genes. Transposons were unaffected. Notably, long transcribed genes were most severely affected. Methylation of genes is limited to CG sites in wild type, but CHG sites were also methylated in the ibm1 mutant. The ibm1-induced hyper-methylation did not depend on previously characterized components of the RNAi-based DNA methylation machinery. Our results suggest novel transcription-coupled mechanisms to direct genic methylation not only at CG but also at CHG sites. IBM1 prevents the CHG methylation in genes, but not in transposons.
Collapse
|
37
|
Saze H, Shiraishi A, Miura A, Kakutani T. Control of genic DNA methylation by a jmjC domain-containing protein in Arabidopsis thaliana. Science 2008; 319:462-5. [PMID: 18218897 DOI: 10.1126/science.1150987] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Differential cytosine methylation of repeats and genes is important for coordination of genome stability and proper gene expression. Through genetic screen of mutants showing ectopic cytosine methylation in a genic region, we identified a jmjC-domain gene, IBM1 (increase in bonsai methylation 1), in Arabidopsis thaliana. In addition to the ectopic cytosine methylation, the ibm1 mutations induced a variety of developmental phenotypes, which depend on methylation of histone H3 at lysine 9. Paradoxically, the developmental phenotypes of the ibm1 were enhanced by the mutation in the chromatin-remodeling gene DDM1 (decrease in DNA methylation 1), which is necessary for keeping methylation and silencing of repeated heterochromatin loci. Our results demonstrate the importance of chromatin remodeling and histone modifications in the differential epigenetic control of repeats and genes.
Collapse
|
38
|
Hashimoto S, Ubano M, Miura Y, Miura A, Yamaguchi S, Shimizu M, Takemiya T, Iwata M. High altitude headache in highland inhabitants: Investigation in China–Japan Women Mt. Qomolangma Medical Expedition. Auton Neurosci 2007. [DOI: 10.1016/j.autneu.2007.06.255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
39
|
Wada H, Ishizuka T, Itaya S, Yamada K, Kajita K, Kimura M, Miura A, Shibata T, Kanoh Y, Ishizawa M, Yasuda K. Inhibitory effect of glyburide on thrombin-induced platelet aggregation and phosphoinositide metabolism in normal human platelets. Platelets 2007; 10:45-51. [PMID: 16801070 DOI: 10.1080/09537109976347] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
We previously reported the effects of diet, sulphonylureas or insulin on thrombin-induced platelet aggregation, phosphoinositide metabolism and protein phosphorylation in non-insulin-dependent diabetes mellitus (NIDDM) patients. To clarify the mechanism of glyburide and insulin on platelet function, here we studied the in vitro effects of glyburide and insulin on thrombin-induced metabolic changes using normal human platelets. Platelet aggregation stimulated with <0.5 U/ml thrombin, 0.75-3 microM adenosine diphosphate (ADP) or 1 microg/ml collagen was significantly lower in glyburide-treated platelets, but not in insulin-treated platelets, than in untreated ones (control). Thrombin-induced incorporation of 32P radioactivity into phosphatidic acid (PA) in glyburide-treated platelets was lower than that in control but not in insulin-treated platelets. Phosphorylated proteins of platelets induced by thrombin and 12- O -tetradecanoylphorbol 13-acetate (TPA) in glyburide-treated platelets were suppressed, but not in insulin-treated platelets, compared with control. These results suggest that glyburide induces suppression of thrombin-induced activation of phospholipase C, which mediates hydrolysis of PIP and PIP(2) and production of PA, and subsequently inhibits platelet aggregation.
Collapse
|
40
|
Hamada K, Yoshinaga I, Hitomi T, Miura A, Shiratani E, Takaki K. Surface discharge of heavy metals from low farmland. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2007; 56:99-104. [PMID: 17711004 DOI: 10.2166/wst.2007.440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Runoff heavy metals from farmland were examined using the field data for the summer of 2005. The observation farmland is located on lowland where the irrigation water was contaminated with the drained water from the upstream farmlands. The area of the farmland is 11.2 ha, of which 6.0 ha and 4.5 ha have been used for rice paddy fields and soybean cultivation, respectively. During the observation, heavy metal concentrations at the downstream end were usually found to be higher than those in the irrigation water. That is, the heavy metal concentrations increased due to the passage of the water through the farmland. This increase in the heavy metal concentrations is not equal to the discharge of the heavy metal because the evaporation on the surface of the paddy field and the absorption by plants makes the surface water volume small. The discharged load from the farmland generally indicates the gross surface load from the farmland. When the effects of circulation irrigation on the heavy metal concentrations are estimated, the discharged load from the farmland should be calculated as the net surface load. When the runoff heavy metals from the circulation irrigation farmland are estimated, it is important to consider the inflowing heavy metals with irrigation water. All the heavy metal types observed in this study were discharged from the farmland. The net surface loads of Cr, Fe, Cd, and Pb were 371 microg m(-2) day(-1), 14.9 mg m(-2) day(-1), 0.26 microg m(-2) day(-1), and 3.3 microm( -2) day(-1), respectively.
Collapse
|
41
|
Kinoshita Y, Saze H, Kinoshita T, Miura A, Soppe WJJ, Koornneef M, Kakutani T. Control of FWA gene silencing in Arabidopsis thaliana by SINE-related direct repeats. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 49:38-45. [PMID: 17144899 DOI: 10.1111/j.1365-313x.2006.02936.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A unique feature of late-flowering fwa epigenetic mutations is that the phenotype is caused by ectopic expression of the homeobox gene FWA. During normal development the FWA gene is expressed specifically in the endosperm in an imprinted manner. Ectopic FWA expression and disruption of imprinting can be induced in mutants of a CG methyltransferase MET1 (methyltransferase 1) or a chromatin-remodeling gene DDM1 (decrease in DNA methylation 1), suggesting that the proper FWA expression depends on cytosine methylation. However, critical methylated residues controlling FWA silencing are not pinpointed. Nor is it understood how the FWA gene is initially methylated and silenced in wild-type plants. Here we mapped sequences critical for FWA silencing by application of RdDM (RNA-directed DNA methylation) to a ddm1-induced stable fwa epiallele. Transcription of double-stranded RNA corresponding to the tandem direct repeats around the FWA transcription start site induced de novo DNA methylation, transcriptional suppression and phenotypic reversion. The induced changes were heritable even without the transgene, which correlates with inheritance of CG methylation in the direct repeats. The newly silenced FWA allele was transcribed in an endosperm-specific and imprinted manner, as is the case for the wild-type FWA gene. The results indicate that methylation of the direct repeats, which presumably originated from a short interspersed nuclear element (SINE), is sufficient to induce proper epigenetic control of the FWA gene.
Collapse
|
42
|
Ito H, Miura A, Takashima K, Kakutani T. Ecotype-specific and chromosome-specific expansion of variant centromeric satellites in Arabidopsis thaliana. Mol Genet Genomics 2006; 277:23-30. [PMID: 17033808 DOI: 10.1007/s00438-006-0172-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Accepted: 09/16/2006] [Indexed: 10/24/2022]
Abstract
Despite the conserved roles and conserved protein machineries of centromeres, their nucleotide sequences can be highly diverse even among related species. The diversity reflects rapid evolution, but the underlying mechanism is largely unknown. One approach to monitor rapid evolution is examination of intra-specific variation. Here we report variant centromeric satellites of Arabidopsis thaliana found through survey of 103 natural accessions (ecotypes). Among them, a cluster of variant centromeric satellites was detected in one ecotype, Cape Verde Islands (Cvi). Recombinant inbred mapping revealed that the variant satellites are distributed in centromeric region of the chromosome 5 (CEN5) of this ecotype. This apparently recent variant accumulation is associated with large deletion of a pericentromeric region and the expansion of satellite region. The variant satellite was bound to HTR12 (centromeric variant histone H3), although expansion of the satellite was not associated with comparable increase in the HTR12 binding. The results suggest that variant satellites with centromere function can rapidly accumulate in one centromere, supporting the model that the satellite repeats in the array are homogenized by occasional unequal crossing-over, which has a potential to generate an expansion of local sequence variants within a centromere cluster.
Collapse
|
43
|
Luna V, Casauban L, Sajan MP, Gomez-Daspet J, Powe JL, Miura A, Rivas J, Standaert ML, Farese RV. Metformin improves atypical protein kinase C activation by insulin and phosphatidylinositol-3,4,5-(PO4)3 in muscle of diabetic subjects. Diabetologia 2006; 49:375-82. [PMID: 16395615 DOI: 10.1007/s00125-005-0112-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Accepted: 08/22/2005] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS Metformin is widely used for treating type 2 diabetes mellitus, but its actions are poorly understood. In addition to diminishing hepatic glucose output, metformin, in muscle, activates 5'-AMP-activated protein kinase (AMPK), which alone increases glucose uptake and glycolysis, diminishes lipid synthesis, and increases oxidation of fatty acids. Moreover, such lipid effects may improve insulin sensitivity and insulin-stimulated glucose uptake. Nevertheless, the effects of metformin on insulin-sensitive signalling factors in human muscle have only been partly characterised to date. Interestingly, other substances that activate AMPK, e.g., aminoimidazole-4-carboxamide-1-beta-D: -riboside (AICAR), simultaneously activate atypical protein kinase C (aPKC), which appears to be required for the glucose transport effects of AICAR and insulin. METHODS Since aPKC activation is defective in type 2 diabetes, we evaluated effects of metformin therapy on aPKC activity in muscles of diabetic subjects during hyperinsulinaemic-euglycaemic clamp studies. RESULTS After metformin therapy for 1 month, basal aPKC activity increased in muscle, with little or no change in insulin-stimulated aPKC activity. Metformin therapy for 8 to 12 months improved insulin-stimulated, as well as basal aPKC activity in muscle. In contrast, IRS-1-dependent phosphatidylinositol (PI) 3-kinase activity and Ser473 phosphorylation of protein kinase B were not altered by metformin therapy, whereas the responsiveness of muscle aPKC to PI-3,4,5-(PO(4))(3), the lipid product of PI 3-kinase, was improved. CONCLUSIONS/INTERPRETATION These findings suggest that the activation of AMPK by metformin is accompanied by increases in aPKC activity and responsiveness in skeletal muscle, which may contribute to the therapeutic effects of metformin.
Collapse
|
44
|
Ohyauchi M, Imatani A, Yonechi M, Asano N, Miura A, Iijima K, Koike T, Sekine H, Ohara S, Shimosegawa T. The polymorphism interleukin 8 -251 A/T influences the susceptibility of Helicobacter pylori related gastric diseases in the Japanese population. Gut 2005; 54:330-5. [PMID: 15710978 PMCID: PMC1774396 DOI: 10.1136/gut.2003.033050] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Helicobacter pylori infection is associated with variable clinical outcomes, including gastroduodenal diseases, and genetic factors may be relevant in this process. AIMS We investigated the effects of an interleukin 8 (IL-8) gene polymorphism on the risk of gastroduodenal diseases, the degree of H pylori induced gastritis, and IL-8 gene transcription. SUBJECTS The study was performed in 244 healthy control subjects and 690 H pylori positive patients with non-cardia gastric cancer, gastric ulcer, duodenal ulcer, or gastritis. METHODS We identified the IL-8 -251 A/T polymorphism by direct sequence analysis, and measured the gastritis score and serum pepsinogen (PG). The transcriptional promoter activity of the IL-8 gene was assessed by luciferase assay. RESULTS IL-8 -251A was associated with a higher risk of gastric cancer and gastric ulcer. Patients carrying IL-8 -251A showed an increased risk of gastric cancer (odds ratios (OR) 2.01 (95% confidence interval (CI) 1.38-2.92)) and gastric ulcer (OR 2.07 (95% CI 1.37-3.12)). Compared with patients younger than 49 years, atrophy and metaplasia scores in the antrum were significantly higher and the PG I/II ratio significantly lower in -251A carriers than in T/T carriers. In the in vitro assay, IL-8 -251A showed enhanced promoter activity in response to IL-1beta or tumour necrosis factor alpha. CONCLUSIONS The IL-8 -251A allele may be associated with progression of gastric atrophy in patients with H pylori infection, and may increase the risk of gastric cancer and gastric ulcer in Japanese people.
Collapse
|
45
|
Ohyama T, Ko IK, Miura A, Iwata H, Taki W. ProNectin F-grafted-ethylene vinyl alcohol copolymer (EVAL) as a liquid type material for treating cerebral aneurysm—An in vivo and in vitro study. Biomaterials 2004; 25:3845-52. [PMID: 15020160 DOI: 10.1016/j.biomaterials.2003.10.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2003] [Accepted: 10/07/2003] [Indexed: 11/28/2022]
Abstract
The authors aimed to develop a liquid material for embolization of aneurysms. In vitro and in vivo performances of the new embolic material were examined by cell culture and using an aneurysm model made in common carotid arteries (CCAs) of adult rats. Engineered protein ProNectin F (PnF), which contains 13 sites of an arginine-glycine-aspartic acid (RGD), was grafted onto ethylene vinyl alcohol copolymer (EVAL-g-PnF). The liquid material, EVAL-g-PnF dissolved in DMSO, was infused into an aneurysm model. The blood segments were harvested 2, 5, and 14 days and examined histologically. A number of bovine coronary artery endothelial cells became able to attach to and form cobblestone-like islands on the EVAL by incorporating PnF. The aneurysm model infused with the EVAL-g-PnF solution revealed that the aneurysm lumen was filled with proliferated fibroblasts and macrophages. On the other hand, the aneurysm model treated with unmodified EVAL showed that the cavity was almost filled with EVAL mass and that fibroblasts and macrophages filled a narrow space between the EVAL mass and the cavity wall. The results indicate that EVAL-g-PnF could be more suitable for reorganizing the cavity of an aneurysm than native EVAL.
Collapse
|
46
|
Sajan MP, Standaert ML, Miura A, Bandyopadhyay G, Vollenweider P, Franklin DM, Lea-Currie R, Farese RV. Impaired activation of protein kinase C-zeta by insulin and phosphatidylinositol-3,4,5-(PO4)3 in cultured preadipocyte-derived adipocytes and myotubes of obese subjects. J Clin Endocrinol Metab 2004; 89:3994-8. [PMID: 15292339 DOI: 10.1210/jc.2004-0106] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Insulin resistance in obesity is partly due to diminished glucose transport in myocytes and adipocytes, but underlying mechanisms are uncertain. Insulin-stimulated glucose transport requires activation of phosphatidylinositol (PI) 3-kinase (3K), operating downstream of insulin receptor substrate-1. PI3K stimulates glucose transport through increases in PI-3,4,5-(PO(4))(3) (PIP(3)), which activates atypical protein kinase C (aPKC) and protein kinase B (PKB/Akt). However, previous studies suggest that activation of aPKC, but not PKB, is impaired in intact muscles and cultured myocytes of obese subjects. Presently, we examined insulin activation of glucose transport and signaling factors in cultured adipocytes derived from preadipocytes harvested during elective liposuction in lean and obese women. Relative to adipocytes of lean women, insulin-stimulated [(3)H]2-deoxyglucose uptake and activation of insulin receptor substrate-1/PI3K and aPKCs, but not PKB, were diminished in adipocytes of obese women. Additionally, the direct activation of aPKCs by PIP(3) in vitro was diminished in aPKCs isolated from adipocytes of obese women. Similar impairment in aPKC activation by PIP(3) was observed in cultured myocytes of obese glucose-intolerant subjects. These findings suggest the presence of defects in PI3K and aPKC activation that persist in cultured cells and limit insulin-stimulated glucose transport in adipocytes and myocytes of obese subjects.
Collapse
|
47
|
Kinoshita T, Miura A, Choi Y, Kinoshita Y, Cao X, Jacobsen SE, Fischer RL, Kakutani T. One-Way Control of FWA Imprinting in Arabidopsis Endosperm by DNA Methylation. Science 2004; 303:521-3. [PMID: 14631047 DOI: 10.1126/science.1089835] [Citation(s) in RCA: 437] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Arabidopsis FWA gene was initially identified from late-flowering epigenetic mutants that show ectopic FWA expression associated with heritable hypomethylation of repeats around transcription starting sites. Here, we show that wild-type FWA displays imprinted (maternal origin-specific) expression in endosperm. The FWA imprint depends on the maintenance DNA methyltransferase MET1, as is the case in mammals. Unlike mammals, however, the FWA imprint is not established by allele-specific de novo methylation. It is established by maternal gametophyte-specific gene activation, which depends on a DNA glycosylase gene, DEMETER. Because endosperm does not contribute to the next generation, the activated FWA gene need not be silenced again. Double fertilization enables plants to use such "one-way" control of imprinting and DNA methylation in endosperm.
Collapse
|
48
|
Kakutani T, Kato M, Kinoshita T, Miura A. Control of development and transposon movement by DNA methylation in Arabidopsis thaliana. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2004; 69:139-43. [PMID: 16117643 DOI: 10.1101/sqb.2004.69.139] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
|
49
|
Mineshita S, Wang LM, Miura A, Umezu S, Honda Y, Satoh T. The influence of plasma fibrinogen and serum ferrum on blood viscosity in Adamantiades-Behçet's disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 528:405-12. [PMID: 12918734 DOI: 10.1007/0-306-48382-3_83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
50
|
Miura A, Kato M, Watanabe K, Kawabe A, Kotani H, Kakutani T. Genomic localization of endogenous mobile CACTA family transposons in natural variants of Arabidopsis thaliana. Mol Genet Genomics 2003; 270:524-32. [PMID: 14608503 DOI: 10.1007/s00438-003-0943-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2003] [Accepted: 10/02/2003] [Indexed: 11/27/2022]
Abstract
The differentiation between gene-rich and transposon-rich (gene-poor) regions is a common feature of plant genomes. This may be due to preferential integration of transposons into gene-poor regions or may be due to purifying selection against transposon insertion into gene-rich regions. We examined the distribution of a low-copy-number mobile subfamily of Arabidopsis CACTA transposons in the genomes of 19 natural variants (ecotypes) of A. thaliana, and compared that to the pattern of integrations induced in the laboratory by mutation of the DDM1 (Decrease in DNA Methylation) gene. Sequences similar to mobile CACTA1 copies were distributed among the ecotypes and showed high degrees of polymorphism in genomic localization. Despite the high level of polymorphism, the copy number was low in all the ecotypes examined, and the elements were localized preferentially in pericentromeric and transposon-rich regions. This contrasts with the pattern of transposition induced by the ddm1 mutation, in which the range of integration sites is less biased and the copy number frequently increases. Based on these observations, we discuss the possible contribution of natural selection and chromatin structure to the distribution of transposons.
Collapse
|