Loss of AtPDR8, a Plasma Membrane ABC Transporter of Arabidopsis thaliana, Causes Hypersensitive Cell Death Upon Pathogen Infection

Plants contain a large number of ATP-binding cassette (ABC) transporters belonging to different subclasses. AtPDR8 is the only member of the pleiotropic drug resistance (PDR) ABC transporter subclass in Arabidopsis that is constitutively highly expressed. In transgenic Arabidopsis plants harboring the AtPDR8 promoter fused to β-glucuronidase (GUS), reporter expression was shown to be strong in the stomata and hydathode. In the stomata, transcripts of AtPDR8 were particularly frequent in the cells surrounding air spaces. Subcellular fractionation and immunochemical analysis showed that AtPDR8 was localized in the plasma membrane. When a knockout mutant of AtPDR8 (atpdr8) was infected with bacterial and oomycete pathogens, the plants exhibited chlorotic lesions and a hypersensitive response (HR)-like cell death. Cell death was detected in the atpdr8 mutants within 10h of infection with the virulent bacterial pathogen, Pseudomonas syringae. As a result, the growth of P. syringae in the leaves of the atpdr8 mutant was reduced to 1% of that in the wild type. The defense response genes, PR-1, PR-2, PR-5, VPEγ, AtrbohD and AtrbohF were highly expressed when the mutant plants were grown under non-sterile conditions. The expression of the AtPDR8 gene was enhanced by infection of virulent and avirulent bacterial pathogens. Our results indicate that AtPDR8 is a key factor controlling the extent of cell death in the defense response and suggest that AtPDR8 transports some substance(s) which is closely related to the response of plants to pathogen

Functional interaction of hepatitis C virus NS5B with nucleolin GAR domain

金沢大学がん研究所Hepatitis C Virus (HCV) non-structural proteins are major components of replication complex that is modulated by several host factors. We previously reported that nucleolin, a representative nucleolar marker, interacts with the NS5B through two separated sequences, amino acids (aa) 208-214 and 500-506, and that W208 in the former stretch is essential for both nucleolin-binding and HCV replication. Here we evaluated the role of the latter stretch aa 500-506 of WRHRARS in nucleolin-binding and HCV replication scanned by alanine-substituted clustered mutant (cm) or point mutant (pm). One tryptophan and three arginine residues in the sequence were found to be essential both for nucleolin-binding in vivo and HCV replication detected with a HCV subgenomic replicon transfected into Huh7 cells. NS5B-binding of nucleolin was further delineated by truncation and clustered mutants of nucleolin. Arginine-glycine-glycine (RGG) repeat in the Glycine arginine rich (GAR) domain were defined to be indispensable for NS5B-binding immunologically detected in in vivo and in vitro although short internal-truncations of RGG repeat are tolerable for NS5B-binding. These results indicate that nucleolin is a critical host factor for HCV replication through the direct interaction between W208 and several residues at the sequence, aa 500-505, of NS5B, and the long-turn motif including RGG repeat at nucleolin C-terminal. © 2007 The Japanese Biochemical Society

Histone H3.3 sub-variant H3mm7 is required for normal skeletal muscle regeneration

Regulation of gene expression requires selective incorporation of histone H3 variant H3.3 into chromatin. Histone H3.3 has several subsidiary variants but their functions are unclear. Here we characterize the function of histone H3.3 sub-variant, H3mm7, which is expressed in skeletal muscle satellite cells. H3mm7 knockout mice demonstrate an essential role of H3mm7 in skeletal muscle regeneration. Chromatin analysis reveals that H3mm7 facilitates transcription by forming an open chromatin structure around promoter regions including those of myogenic genes. The crystal structure of the nucleosome containing H3mm7 reveals that, unlike the S57 residue of other H3 proteins, the H3mm7-specific A57 residue cannot form a hydrogen bond with the R40 residue of the cognate H4 molecule. Consequently, the H3mm7 nucleosome is unstable in vitro and exhibited higher mobility in vivo compared with the H3.3 nucleosome. We conclude that the unstable H3mm7 nucleosome may be required for proper skeletal muscle differentiation

Advanced Clinical Usefulness of Ultrasonography for Diseases in Oral and Maxillofacial Regions

Various kinds of diseases may be found in the oral and maxillofacial regions and various modalities may be applied for their diagnosis, including intra-oral radiography, panoramic radiography, ultrasonography, computed tomography, magnetic resonance imaging, and nuclear medicine methods such as positron emission tomography. Of these modalities, ultrasound imaging is easy to use for the detection of noninvasive and soft tissue-related diseases. Doppler ultrasound images taken in the B-mode can provide vascular information associated with the morphology of soft tissues. Thus, ultrasound imaging plays an important role in confirming the diagnosis of many kinds of diseases in such oral and maxillofacial regions as the tongue, lymph nodes, salivary glands, and masticatory muscles. In the present article, we introduce three new applications of ultrasonography: guided fine-needle aspiration, measurement of tongue cancer thickness, and diagnosis of metastasis to cervical lymph nodes

Relations of occupational stress to occupational class in Japanese civil servants : analysis by two occupational stress models

The aim of the present study was to identify relations between occupational stress and occupational class in Japanese civil servants, using two occupational stress models – the Effort-Reward Imbalance (ERI) Model and the Job Demand-Control (JDC) Model. The subjects were employees of three local public organizations. We distributed self-administered questionnaires and assessed occupational stress by ERI and JDC. We used seven occupational categories based on the Standard Occupational Classification for Japan. The data of 6,423 male and 1,606 female subjects were analyzed by logistic regression analysis to obtain odds ratios (OR) for relations between occupational stress and occupational class. In JDC, male clerical workers, transport/communication workers and protective service workers showed a significantly higher OR of being in the high occupational stress group, compared to managers. In ERI, male professionals/technicians, transport/communication workers, clerical workers and protective service workers showed a significantly higher prevalence OR, compared to managers, the two models giving different results. In ERI, female production workers/laborers and clerical workers had a significantly lower prevalence OR, compared to managers. The results of this study showed that occupational stress differed by occupational class and the two occupational stress models gave different results for occupational classes with high occupational stress

Relationship of β2-Microglobulin to Arterial Stiffness in Japanese Subjects(日本人対象者における血中β2ミクログロブリンと動脈硬度との関係)

著者最終原稿版日本人男性614例と女性158例とを対象とした研究を行った.上腕足首脈波速度を測定して動脈硬度を評価した.β2ミクログロブリン(β2m)血中濃度を4群に分類すると,濃度が高い群ほど脈波速度が大であった(p<0.037).交絡因子調整後のβ2m最高値群,4群に分けたCRP値最高値群, 両者合併群が3群に分類した脈波速度最高値群を合併するOdds比は,それぞれ2.53(95%CI(信頼区間)1.31-4.89),2.27(1.18-4.34),5.60(2.38-13.2)であった.以上から血中βm濃度高値は動脈硬度と関連すると思われ

Relationship of Helicobacter pylori Infection to Arterial Stiffness in Japanese Subjects(日本人におけるピロリ菌感染と動脈硬度との関係)

著者最終原稿版日本人男性3,412名と女性854名を対象とし,抗ヘリコバクター・ピロリ菌抗体とCRPとを測定し,動脈硬度は上腕-足首動脈脈波速度によって評価した.男性対象者についての多変量ロジスティク回帰解析によると脈波速度高値と有意の関連があったのは,ピロリ菌血清反応陽性のodds比は1.27t(信頼区間(CI)1.05-1.52),ピロリ菌血清反応陽性とCRP高値との組合せのodds比は1.50(CI:1.14-1.98)であった.49歳以下の男性対象者についての解析ではそれぞれのodds比は1.40(1.04-1.88),1.81(1.16-2.80)であった.しかし,50歳以上の男性及び女性対象者についての解析ではいずれも有意の関連はなかっ

Original Article Relations of Occupational Stress to Occupational Class in Japanese Civil Servants—Analysis by Two Occupational Stress Models

Abstract: The aim of the present study was to identify relations between occupational stress and occupational class in Japanese civil servants, using two occupational stress models—the Effort-Reward Imbalance (ERI) Model and the Job Demand-Control (JDC) Model. The subjects were employees of three local public organizations. We distributed self-administered questionnaires and assessed occupational stress by ERI and JDC. We used seven occupational categories based on the Standard Occupational Classification for Japan. The data of 6,423 male and 1,606 female subjects were analyzed by logistic regression analysis to obtain odds ratios (OR) for relations between occupational stress and occupational class. In JDC, male clerical workers, transport/communication workers and protective service workers showed a significantly higher OR of being in the high occupational stress group, compared to managers. In ERI, male professionals/technicians, transport/ communication workers, clerical workers and protective service workers showed a significantly higher prevalence OR, compared to managers, the two models giving different results. In ERI, female production workers/laborers and clerical workers had a significantly lower prevalence OR, compared to managers. The results of this study showed that occupational stress differed by occupational class and the two occupational stress models gave different results for occupational classes with high occupational stress

Loss of AtPDR8, a plasma membrane ABC transporter of Arabidopsis thaliana, causes hypersensitive cell death upon pathogen infection

Plants contain a large number of ATP-binding cassette (ABC) transporters belonging to different subclasses. AtPDR8 is the only member of the pleiotropic drug resistance (PDR) ABC transporter subclass in Arabidopsis that is constitutively highly expressed. In transgenic Arabidopsis plants harboring the AtPDR8 promoter fused to β-glucuronidase (GUS), reporter expression was shown to be strong in the stomata and hydathode. In the stomata, transcripts of AtPDR8 were particularly frequent in the cells surrounding air spaces. Subcellular fractionation and immunochemical analysis showed that AtPDR8 was localized in the plasma membrane. When a knockout mutant of AtPDR8 (atpdr8) was infected with bacterial and oomycete pathogens, the plants exhibited chlorotic lesions and a hypersensitive response (HR)-like cell death. Cell death was detected in the atpdr8 mutants within 10h of infection with the virulent bacterial pathogen, Pseudomonas syringae. As a result, the growth of P. syringae in the leaves of the atpdr8 mutant was reduced to 1% of that in the wild type. The defense response genes, PR-1, PR-2, PR-5, VPEγ, AtrbohD and AtrbohF were highly expressed when the mutant plants were grown under non-sterile conditions. The expression of the AtPDR8 gene was enhanced by infection of virulent and avirulent bacterial pathogens. Our results indicate that AtPDR8 is a key factor controlling the extent of cell death in the defense response and suggest that AtPDR8 transports some substance(s) which is closely related to the response of plants to pathogen