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Callender C, Koizumi N, Miles P, Melancon J. Organ Donation in the United States: The Tale of the African-American Journey of Moving From the Bottom to the Top. Transplant Proc 2016; 48:2392-2395. [DOI: 10.1016/j.transproceed.2016.02.094] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/02/2016] [Indexed: 10/20/2022]
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Iwata Y, Hayashi N, Tabara K, Mishiba KI, Koizumi N. Tunicamycin-induced inhibition of protein secretion into culture medium of Arabidopsis T87 suspension cells through mRNA degradation on the endoplasmic reticulum. Biosci Biotechnol Biochem 2016; 80:1168-71. [DOI: 10.1080/09168451.2016.1151340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Abstract
The N-glycosylation inhibitor tunicamycin triggers endoplasmic reticulum stress response and inhibits efficient protein secretion in eukaryotes. Using Arabidopsis suspension cells, we showed that the reduced secretion of mannose-binding lectin 1 (MBL1) protein by tunicamycin is accompanied by a significant decrease in MBL1 mRNA, suggesting that mRNA destabilization is the major cause of the inhibition of protein secretion in plants.
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Koizumi N, Harada Y, Beika M, Minamikawa T, Yamaoka Y, Dai P, Murayama Y, Yanagisawa A, Otsuji E, Tanaka H, Takamatsu T. Highly sensitive fluorescence detection of metastatic lymph nodes of gastric cancer with photo-oxidation of protoporphyrin IX. Eur J Surg Oncol 2016; 42:1236-46. [PMID: 27055944 DOI: 10.1016/j.ejso.2016.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 12/25/2015] [Accepted: 03/04/2016] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND The establishment of a precise and rapid method to detect metastatic lymph nodes (LNs) is essential to perform less invasive surgery with reduced gastrectomy along with reduced lymph node dissection. We herein describe a novel imaging strategy to detect 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX (PpIX) fluorescence in excised LNs specifically with reduced effects of tissue autofluorescence based on photo-oxidation of PpIX. We applied the method in a clinical setting, and evaluated its feasibility. METHODS To reduce the unfavorable effect of autofluorescence, we focused on photo-oxidation of PpIX: Following light irradiation, PpIX changes into another substance, photo-protoporphyrin, via an oxidative process, which has a different spectral peak, at 675 nm, whereas PpIX has its spectral peak at 635 nm. Based on the unique spectral alteration, fluorescence spectral imaging before and after light irradiation and subsequent originally-developed image processing was performed. Following in vitro study, we applied this method to a total of 662 excised LNs obtained from 30 gastric cancer patients administered 5-ALA preoperatively. RESULTS Specific visualization of PpIX was achieved in in vitro study. The method allowed highly sensitive detection of metastatic LNs, with sensitivity of 91.9% and specificity of 90.8% in the in vivo clinical trial. Receiver operating characteristic analysis indicated high diagnostic accuracy, with the area under the curve of 0.926. CONCLUSIONS We established a highly sensitive and specific 5-ALA-induced fluorescence imaging method applicable in clinical settings. The novel method has a potential to become a useful tool for intraoperative rapid diagnosis of LN metastasis.
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Okumura A, Shimada A, Yamasaki S, Horino T, Iwata Y, Koizumi N, Nishihara M, Mishiba KI. CaMV-35S promoter sequence-specific DNA methylation in lettuce. PLANT CELL REPORTS 2016; 35:43-51. [PMID: 26373653 DOI: 10.1007/s00299-015-1865-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 08/08/2015] [Accepted: 09/03/2015] [Indexed: 05/28/2023]
Abstract
KEY MESSAGE We found 35S promoter sequence-specific DNA methylation in lettuce. Additionally, transgenic lettuce plants having a modified 35S promoter lost methylation, suggesting the modified sequence is subjected to the methylation machinery. We previously reported that cauliflower mosaic virus 35S promoter-specific DNA methylation in transgenic gentian (Gentiana triflora × G. scabra) plants occurs irrespective of the copy number and the genomic location of T-DNA, and causes strong gene silencing. To confirm whether 35S-specific methylation can occur in other plant species, transgenic lettuce (Lactuca sativa L.) plants with a single copy of the 35S promoter-driven sGFP gene were produced and analyzed. Among 10 lines of transgenic plants, 3, 4, and 3 lines showed strong, weak, and no expression of sGFP mRNA, respectively. Bisulfite genomic sequencing of the 35S promoter region showed hypermethylation at CpG and CpWpG (where W is A or T) sites in 9 of 10 lines. Gentian-type de novo methylation pattern, consisting of methylated cytosines at CpHpH (where H is A, C, or T) sites, was also observed in the transgenic lettuce lines, suggesting that lettuce and gentian share similar methylation machinery. Four of five transgenic lettuce lines having a single copy of a modified 35S promoter, which was modified in the proposed core target of de novo methylation in gentian, exhibited 35S hypomethylation, indicating that the modified sequence may be the target of the 35S-specific methylation machinery.
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Nagashima Y, Iwata Y, Ashida M, Mishiba KI, Koizumi N. Exogenous Salicylic Acid Activates Two Signaling Arms of the Unfolded Protein Response in Arabidopsis. ACTA ACUST UNITED AC 2014; 55:1772-8. [DOI: 10.1093/pcp/pcu108] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Amijima M, Iwata Y, Koizumi N, Mishiba KI. The polar auxin transport inhibitor TIBA inhibits endoreduplication in dark grown spinach hypocotyls. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 225:45-51. [PMID: 25017158 DOI: 10.1016/j.plantsci.2014.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 04/25/2014] [Accepted: 05/18/2014] [Indexed: 06/03/2023]
Abstract
We addressed the question of whether an additional round of endoreduplication in dark-grown hypocotyls is a common feature in dicotyledonous plants having endopolyploid tissues. Ploidy distributions of hypocotyl tissues derived from in vitro-grown spinach (Spinacia oleracea L. cv. Atlas) seedlings grown under different light conditions were analyzed by flow cytometry. An additional round of endoreduplication (represented by 32C cells) was found in the dark-grown hypocotyl tissues. This response was inhibited by light, the intensity of which is a crucial factor for the inhibition of endoreduplication. The higher ploidy cells in cortical tissues of the dark-grown hypocotyls had larger cell sizes, suggesting that the additional round of endoreduplication contributes to hypocotyl elongation. More importantly, a polar auxin transport inhibitor, 2,3,5-triiodobenzoic acid (TIBA), strongly inhibits endoreduplication, not only in spinach but also in Arabidopsis. Because other polar auxin transport inhibitors or an auxin antagonist show no or mild effects, TIBA may have a specific feature that inhibits endoreduplication.
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Lee EJ, Iai H, Sano H, Koizumi N. Sugar Responsible and Tissue Specific Expression of a Gene Encoding AtCIPK14, anArabidopsisCBL-Interacting Protein Kinase. Biosci Biotechnol Biochem 2014; 69:242-5. [PMID: 15665497 DOI: 10.1271/bbb.69.242] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Expression of AtCIPK14 (an Arabidopsis CBL-interacting protein kinase 14) was induced by metabolic sugars. Two A/T-rich sequences similar to elements involved in sugar-inducible expression of other genes were found within the -183 bp 5' region of the AtCIPK14 promoter that was responsible for the sugar induction. Histochemical analysis using a reporter gene indicated vascular-specific expression of AtCIPK14.
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Koizumi N, Nagashima Y. [Conservation and divergence of cytoplasmic splicing in the organisms]. SEIKAGAKU. THE JOURNAL OF JAPANESE BIOCHEMICAL SOCIETY 2013; 85:1095-1099. [PMID: 24505943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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Miyagawa Y, Ogawa J, Iwata Y, Koizumi N, Mishiba KI. An attempt to detect siRNA-mediated genomic DNA modification by artificially induced mismatch siRNA in Arabidopsis. PLoS One 2013; 8:e81326. [PMID: 24278423 PMCID: PMC3837478 DOI: 10.1371/journal.pone.0081326] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 10/18/2013] [Indexed: 12/21/2022] Open
Abstract
Although tremendous progress has been made in recent years in identifying molecular mechanisms of small interfering RNA (siRNA) functions in higher plants, the possibility of direct interaction between genomic DNA and siRNA remains an enigma. Such an interaction was proposed in the ‘RNA cache’ hypothesis, in which a mutant allele is restored based on template-directed gene conversion. To test this hypothesis, we generated transgenic Arabidopsis thaliana plants conditionally expressing a hairpin dsRNA construct of a mutated acetolactate synthase (mALS) gene coding sequence, which confers chlorsulfuron resistance, in the presence of dexamethasone (DEX). In the transgenic plants, suppression of the endogenous ALS mRNA expression as well as 21-nt mALS siRNA expression was detected after DEX treatment. After screening >100,000 progeny of the mALS siRNA-induced plants, no chlorsulfuron-resistant progeny were obtained. Further experiments using transgenic calli also showed that DEX-induced expression of mALS siRNA did not affect the number of chlorsulfuron-resistant calli. No trace of cytosine methylation of the genomic ALS region corresponding to the dsRNA region was observed in the DEX-treated calli. These results do not necessarily disprove the ‘RNA cache’ hypothesis, but indicate that an RNAi machinery for ALS mRNA suppression does not alter the ALS locus, either genetically or epigenetically.
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Iwata Y, Koizumi N. Plant transducers of the endoplasmic reticulum unfolded protein response. TRENDS IN PLANT SCIENCE 2012; 17:720-7. [PMID: 22796463 DOI: 10.1016/j.tplants.2012.06.014] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 06/21/2012] [Accepted: 06/27/2012] [Indexed: 05/20/2023]
Abstract
The unfolded protein response (UPR) activates a set of genes to overcome accumulation of unfolded proteins in the endoplasmic reticulum (ER), a condition termed ER stress, and constitutes an essential part of ER protein quality control that ensures efficient maturation of secretory and membrane proteins in eukaryotes. Recent studies on Arabidopsis and rice identified the signaling pathway in which the ER membrane-localized ribonuclease IRE1 (inositol-requiring enzyme 1) catalyzes unconventional cytoplasmic splicing of mRNA, thereby producing the active transcription factor Arabidopsis bZIP60 (basic leucine zipper 60) and its ortholog in rice. Here we review recent findings identifying the molecular components of the plant UPR, including IRE1/bZIP60 and the membrane-bound transcription factors bZIP17 and bZIP28, and implicating its importance in several physiological phenomena such as pathogen response.
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Abstract
The unfolded protein response (UPR) activates a set of genes to overcome accumulation of unfolded proteins in the endoplasmic reticulum (ER), a condition termed ER stress, and constitutes an essential part of ER protein quality control that ensures efficient maturation of secretory and membrane proteins in eukaryotes. Recent studies on Arabidopsis and rice identified the signaling pathway in which the ER membrane-localized ribonuclease IRE1 (inositol-requiring enzyme 1) catalyzes unconventional cytoplasmic splicing of mRNA, thereby producing the active transcription factor Arabidopsis bZIP60 (basic leucine zipper 60) and its ortholog in rice. Here we review recent findings identifying the molecular components of the plant UPR, including IRE1/bZIP60 and the membrane-bound transcription factors bZIP17 and bZIP28, and implicating its importance in several physiological phenomena such as pathogen response.
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Gamage CD, Koizumi N, Perera AKC, Muto M, Nwafor-Okoli C, Ranasinghe S, Kularatne SAM, Rajapakse RPVJ, Kanda K, Lee RB, Obayashi Y, Ohnishi M, Tamashiro H. Carrier Status of Leptospirosis Among Cattle in Sri Lanka: A Zoonotic Threat to Public Health. Transbound Emerg Dis 2012; 61:91-6. [DOI: 10.1111/tbed.12014] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Indexed: 11/29/2022]
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Watanabe Y, Shigematsu H, Obitsu Y, Koizumi N, Saiki N, Iwahashi T. Growth rates of abdominal aortic aneurysms in Japanese patients observed in one institute. INT ANGIOL 2012; 31:181-186. [PMID: 22466985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
AIM The aim of this paper was to investigate the growth rate of abdominal aortic aneurysms (AAA) in Japanese patients. METHODS We retrospectively studied patients conservatively followed with infrarenal AAA in terms of AAA diameter measured using computed tomography (CT) in our hospital between 1999 and 2009. The AAA surgery criterion in our institute was a diameter ≥ 5.0 cm or a growth rate ≥5 mm/year. We estimated operation-free ratios by initial AAA diameter and changes in AAA growth rates. Patients with an initial AAA diameter < 5.0 cm were divided into 2 groups. Patients with AAA that met the criteria for surgery were classified into the expansion group, and those remaining into the non-expansion group. Their AAA growth rates were compared. RESULTS The group consisted of 124 patients (average age, 73.7±8.6 years (range 54-92)) who had at least 2 recorded AAA measurements. The average follow-up period was 3.0±2.2 years (range 0.3-10.2). There were no cases of rupture during follow-up. Twenty-six patients (21.0%) underwent surgery (open replacement [N.=20]; endovascular abdominal aneurysm repair [N.=6]). The growth rate determined from the initially measured diameter was significantly faster in AAAs measuring 5.0-5.4 cm than in AAAs measuring 4.5-4.9 cm (P=0.01). More than 90% of patients with an initial AAA diameter <5.0 cm were observed conservatively for 2 years or more. However, more than half of the patients with an initial AAA diameter ≥4.0 cm needed surgery within 5 years. The growth rates of AAAs for each size during growth were significantly faster when the AAA diameter was 4.5-4.9 cm than when it was 4.0-4.4 cm (P=0.006), and when the AAA diameter was 5.0-5.4 cm than when it was 4.5-4.9 cm (P = 0.009). The expansion and non-expansion groups consisted of 38 (34.2%) and 73 (75.8%) patients, respectively. The AAA growth rate in the expansion group was significantly faster than that in the non-expansion group (3.4±2.2 mm/year vs. 1.4±1.3 mm/year, P=0.0001). CONCLUSION It may be considered that the appropriate indication for AAA repair is defined by a diameter of 5.0 cm for Japanese patients. Patients with AAA that is growing continuously by ≥3 mm/year and who have low operative risk may undergo surgery even if their AAA is <5.0 cm.
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Rikimaru K, Sasaki O, Koizumi N, Komatsu M, Suzuki K, Takahashi H. Mapping of Quantitative Trait Loci Affecting Growth Traits in a Japanese Native Chicken Cross. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2011. [DOI: 10.5713/ajas.2011.11004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Nagashima Y, Mishiba KI, Suzuki E, Shimada Y, Iwata Y, Koizumi N. Arabidopsis IRE1 catalyses unconventional splicing of bZIP60 mRNA to produce the active transcription factor. Sci Rep 2011; 1:29. [PMID: 22355548 PMCID: PMC3216516 DOI: 10.1038/srep00029] [Citation(s) in RCA: 245] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 06/08/2011] [Indexed: 11/09/2022] Open
Abstract
IRE1 plays an essential role in the endoplasmic reticulum (ER) stress response in yeast and mammals. We found that a double mutant of Arabidopsis IRE1A and IRE1B (ire1a/ire1b) is more sensitive to the ER stress inducer tunicamycin than the wild-type. Transcriptome analysis revealed that genes whose induction was reduced in ire1a/ire1b largely overlapped those in the bzip60 mutant. We observed that the active form of bZIP60 protein detected in the wild-type was missing in ire1a/ire1b. We further demonstrated that bZIP60 mRNA is spliced by ER stress, removing 23 ribonucleotides and therefore causing a frameshift that replaces the C-terminal region of bZIP60 including the transmembrane domain (TMD) with a shorter region without a TMD. This splicing was detected in ire1a and ire1b single mutants, but not in the ire1a/ire1b double mutant. We conclude that IRE1A and IRE1B catalyse unconventional splicing of bZIP60 mRNA to produce the active transcription factor.
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Obitsu Y, Koizumi N, Kawaguchi S, Shigematsu H. Endovascular Treatment of Late Anastomotic Aneurysm Following Bypass Surgery for Atypical Aortic Coarctation due to Takayasu Arteritis. Eur J Vasc Endovasc Surg 2010. [DOI: 10.1016/j.ejvs.2010.04.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Iwahashi T, Obitsu Y, Koizumi N, Shiraishi Y, Shigematsu H. Clinical comparison of two different types of bifurcated graft for postoperative baPWV and ABI. INT ANGIOL 2009; 28:232-237. [PMID: 19506543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
AIM A newly-designed bifurcated graft with the distal end larger than the conventional type has been developed. The purpose of this study was to evaluate the early results of graft replacement using this new graft, and to compare whether the new graft is more advantageous than the conventional graft in terms of peripheral blood flow and arterial stiffness. METHODS Records of 36 patients who underwent bifurcated graft replacement for infrarenal abdominal aortic aneurysm (AAA), from May 2003 to September 2006 were reviewed after excluding peripheral arterial disease (ABI > 0.9). Subjects were divided into two groups: group C (N.=20), with implantation of the conventional type and group N (N.=16), with implantation of the new type. We investigated changes in brachial-ankle pulse wave velocity (baPWV) and ankle-brachial pressure index (ABI), measurements being performed preoperatively and postoperatively. RESULTS baPWV in the postoperative group as a whole was significantly higher than in the preoperative group (P<0.05), while ABI in the postoperative group was lower than in the preoperative group (P<0.05). In group C, baPWV increased (P<0.05) and ABI decreased (P<0.05) after bifurcated graft replacement, whereas in group N, there were no significant differences in changes of baPWV and ABI. CONCLUSIONS This study shows that the new graft reduces the development of arterial stiffness postoperatively compared with the conventional type. These results may predict the new type graft decrease in the risk of morbidity and mortality caused by atherosclerotic disease.
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Iwata Y, Fedoroff NV, Koizumi N. The Arabidopsis membrane-bound transcription factor AtbZIP60 is a novel plant-specific endoplasmic reticulum stress transducer. PLANT SIGNALING & BEHAVIOR 2009; 4:514-516. [PMID: 19816135 PMCID: PMC2688297 DOI: 10.4161/psb.4.6.8585] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Accepted: 03/19/2009] [Indexed: 05/23/2023]
Abstract
Accumulation of unfolded proteins in the endoplasmic reticulum (ER) of eukaryotic cells triggers a protective response, termed the ER stress response or the unfolded protein response, to maintain cellular homeostasis. Recently we characterized the Arabidopsis (Arabidopsis thaliana) membrane-bound basic leucine zipper (bZIP) transcription factor AtbZIP60 involved in the ER stress response. We reported that AtbZIP60 is activated by regulated intramembrane proteolysis (RIP), a mechanism by which a membrane-bound transcription factor is released by proteolytic cleavage. We presented evidence that the AtbZIP60 protein resides in the ER membrane under unstressed conditions and is activated by proteolytic cleavage in response to ER stress to translocate into the nucleus where it acts as a transcription factor. Further analysis, however, showed that this cleavage is independent of the function of Arabidopsis homologs of S1P and S2P proteases, which mediate the proteolytic cleavage of the mammalian transcription factor ATF6. Thus AtbZIP60 is an ER stress transducer activated by a novel RIP mechanism that may be unique to plants.
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Koizumi N, Hemmi T, Matsui K, Nakajima H, Okuno K, Kuno K, Nomoto K. Critical issues for the manufacture of the ITER TF coil winding pack. FUSION ENGINEERING AND DESIGN 2009. [DOI: 10.1016/j.fusengdes.2008.12.105] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Koizumi N, Warisawa S, Nagoshi M, Hashizume H, Mitsuishi M. Construction Methodology for a Remote Ultrasound Diagnostic System. IEEE T ROBOT 2009. [DOI: 10.1109/tro.2009.2019785] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Iwata Y, Fedoroff NV, Koizumi N. Arabidopsis bZIP60 is a proteolysis-activated transcription factor involved in the endoplasmic reticulum stress response. THE PLANT CELL 2008; 4:514-6. [PMID: 19017746 PMCID: PMC2613661 DOI: 10.1105/tpc.108.061002] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2008] [Revised: 10/18/2008] [Accepted: 10/31/2008] [Indexed: 05/18/2023]
Abstract
Proteins synthesized in the endoplasmic reticulum (ER) of eukaryotic cells must be folded correctly before translocation out of the ER. Disruption of protein folding results in the induction of genes for ER-resident chaperones, for example, BiP. This phenomenon is known as the ER stress response. We report here that bZIP60, an Arabidopsis thaliana basic leucine zipper (bZIP) transcription factor with a transmembrane domain, is involved in the ER stress response. When compared with wild-type Arabidopsis plants, homozygous bzip60 mutant plants show a markedly weaker induction of many ER stress-responsive genes. The bZIP60 protein resides in the ER membrane under unstressed condition and is cleaved in response to ER stress caused by either tunicamycin or DTT. The N-terminal fragment containing the bZIP domain is then translocated into the nucleus. Cleavage of bZIP60 is independent of the function of Arabidopsis homologs of mammalian S1P and S2P proteases, which mediate the proteolytic cleavage of the mammalian transcription factor ATF6. In Arabidopsis, expression of the bZIP60 gene and cleavage of the bZIP60 protein are observed in anthers in the absence of stress treatment, suggesting that the ER stress response functions in the normal development of active secretory cells.
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Tateda C, Ozaki R, Onodera Y, Takahashi Y, Yamaguchi K, Berberich T, Koizumi N, Kusano T. NtbZIP60, an endoplasmic reticulum-localized transcription factor, plays a role in the defense response against bacterial pathogens in Nicotiana tabacum. JOURNAL OF PLANT RESEARCH 2008; 121:603-11. [PMID: 18758894 DOI: 10.1007/s10265-008-0185-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Accepted: 07/23/2008] [Indexed: 05/23/2023]
Abstract
A spermine-based signal transduction pathway plays a defensive role against incompatible pathogens. We identified a novel spermine-responsive cDNA from Nicotiana tabacum that encodes a basic region/leucine zipper protein with a putative transmembrane domain. Identity to Arabidopsis thaliana AtbZIP60 was sufficiently high to name the novel cDNA NtbZIP60. Expression analysis revealed that NtbZIP60 is a component of the spermine-signal pathway, and is also involved in the unfolded protein response (UPR), as demonstrated for AtbZIP60. The gene product, NtbZIP60, localizes to the endoplasmic reticulum (ER) in plant cells; once the putative transmembrane domain is eliminated from the intact protein, it targets the nucleus. The putative processed form of NtbZIP60 transactivates target genes through binding to plant-specific UPR cis-elements. Expression of NbbZIP60, an NtbZIP60 ortholog in Nicotiana benthamiana, was significantly up-regulated at 6 h and later time points upon infection with the non-host pathogen Pseudomonas cichorii, while it was unaffected by infection with the compatible pathogen Pseudomonas syringae pv. tabaci. Furthermore, NbbZIP60-silenced N. benthamiana plants allowed higher multiplication of P. cichorii compared to the control plants. Taken together, the results suggest that this ER-localized transcription factor is involved in the spermine-signal transduction pathway and plays an important role in plant innate immunity.
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Inatomi T, Nakamura T, Koizumi N, Sotozono C, Kinoshita S. Current progress and challenges in ocular surface reconstruction using cultivated epithelial sheet transplantation. THE MEDICAL JOURNAL OF MALAYSIA 2008; 63 Suppl A:42. [PMID: 19024975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The cultivated epithelial transplantation is a new surgical modality for treating a variety of severe ocular surface disorders. This type of tissue-engineered epithelial sheet provides a rapid epithelial coverage on the corneal surface that reduces inflammation and postoperative complications. Although cultivated corneal epithelial transplantation is an effective surgical strategy, autologous transplantation is limited to unilateral cases. Autologous cultivated oral mucosal epithelial transplantation (COMET) enables surgeons to reconstruct the ocular surface using autologous, non-ocular surface cells, and has opened a new pathway for treating severe, bilateral ocular surface disorders.
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Idesaki A, Koizumi N, Sugimoto M, Morishita N, Ohshima T, Okuno K, Balachandran U(B, Amm K, Evans D, Gregory E, Lee P, Osofsky M, Pamidi S, Park C, Wu J, Sumption M. GAS EVOLUTION FROM INSULATING MATERIALS FOR SUPERCONDUCTING COIL OF ITER BY GAMMA RAY IRRADIATION AT LIQUID NITROGEN TEMPERATURE. ACTA ACUST UNITED AC 2008. [DOI: 10.1063/1.2900341] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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