Isolation of cDNA of an auxin-regulated gene encoding a G protein beta subunit-like protein from tobacco BY-2 cells.

The addition of 2,4-dichlorophenoxyacetic acid to tobacco BY-2 cells that had been cultured in modified Linsmaier and Skoog medium deprived of auxin for 3 days induced cell division, whereas without 2,4-dichlorophenoxy-acetic acid application, no such induction of cell division was seen. When differential cDNA screening for auxin was done at 4 hr after the addition of 2,4-dichlorophenoxyacetic acid, the cDNA of an auxin-responsive gene designated arcA was isolated. The predicted gene product of arcA is a polypeptide with a M(r) of 35,825. arcA, thus, is a plant hormone-regulated gene that encodes a protein structurally related to the beta subunit of a guanine nucleotide-binding regulatory protein, which is composed of seven repetitive segments of Trp-Asp 40-aa repeats. The possibility that arcA gene products induce cell division is discussed.     

亚洲带绦虫成虫谷胱甘肽S-转移酶基因的克隆及生物信息学分析

目的分析亚洲带绦虫成虫谷胱甘肽S-转移酶（GST,glutathione S-transferase）基因结构并预测其编码蛋白的结构和功能。方法利用生物信息网站如美国国家生物技术信息中心（NCBI,http：//www.ncbi.nl m.nih.gov/）和瑞士生物信息学研究所的蛋白分析专家系统（ExPASY,http：//ca.expasy.org/）中生物信息学分析工具,并结合其它分析软件,从获得亚洲带绦虫成虫全长cDNA质粒文库的表达序列标签（EST,expression sequence tag）中识别GST基因,分析该基因的结构并预测其编码的蛋白质的结构和功能特征。结果该基因与猪带绦虫GST的一致性为94%,相似性为97%;全长810bp,编码区为28-687bp,编码219个氨基酸,无各种亚细胞定位序列,具有多个潜在的磷酸化位点,蛋白的理化性质稳定;预测三个主要的抗原表位89aa-94aa,27aa-32aa,119aa-124aa位于空间结构上相距较远的分子表面,前面两个表位属于绦虫共有的线性抗原表位。结论从亚洲带绦虫成虫cDNA文库中筛选出GST基因,预测为胞浆型蛋白,可能具有较好的免疫诊断抗原应用前景。     

Human isotype antibody responses to an Onchocerca volvulus glutathione S-transferase

Human isotype specific antibody responses to a recombinant π-class glutathione S-transferase (Ov24) from Onchocerca volvulus were assesed by ELISA, using a large and well-characterized bank sera (n=238) from an hyper-endemic area of moderate intensity from Sierra Leone. IgG1, IgG4 and IgA responses, but neither IgG2 nor IgE response, to Ov24 were detected in infected subjects. The relationships between Ov24 antibody levels and skin microfilarial density, number of nodules, age, sex, eosinophil counts and clinical sign of reactive and chronic pathology were analysed using Pearson's correlation coefficient. Significant correlations between both IgA and IgG3 antibody levels and age were found (P<0.01). Although no firm conclusions could be drawn from this study sample regarding the relationships between antibody levels and parasite load or clinical status, a negative correlation (P=0.06) between Ov24 IgG3 antibody levels and microfilarodermia was found.     

Drosophila glutathione S-transferase 1-1 shares a region of sequence homology with the maize glutathione S-transferase III.

We have characterized a Drosophila glutathione S-transferase (RX:glutathione R-transferase, EC 2.5.1.18) cDNA encoding a protein of 209 amino acids. The cDNA was expressed in Escherichia coli harboring the expression plasmid construct pGTDml-KK. The active enzyme, designated as Drosophila glutathione S-transferase 1-1, had a specific activity toward 1-chloro-2,4-dinitrobenzene comparable to that for the mammalian glutathione S-transferases but did not have as broad a substrate specificity pattern. There is a region of 44 amino acids in this enzyme that shares 66% identity with an analogous region of maize glutathione S-transferase III. Drosophila glutathione S-transferase 1-1 had no obvious homology to any mammalian or parasitic glutathione S-transferases. The gene was found to be a member of a multigene family.     

Intradermal immunization of rats with plasmid DNA encoding Schistosoma mansoni 28 kDa glutathione S-transferase

Direct administration of plasmid DNA encoding an antigen represents an attractive approach to vaccination against infectious diseases, particularly in developing countries where easy-to-handle and cost-effective vaccines are needed. We have investigated the potential of DNA immunization to induce a specific antibody response against Schistosoma mansoni , using plasmid-DNA encoding the protective antigen, S. mansoni 28 kDa glutathione S-transferase (Sm28GST). Since S. mansoni parasite penetrates into its host through the skin, this tissue was chosen for plasmid DNA delivery. Following plasmid DNA administration into the skin of rats, the parasite antigen was detected in skin cells by immunohistochemistry. Three administrations of 200 μg plasmid at 14 day intervals led to the induction of a long-lasting specific IgG antibody response in the sera of immunized rats, with a predominance of IgG2a and IgG2b subclasses. Sera of immunized animals were able to mediate antibody-dependent cellular cytotoxicity in vitro , leading to the specific killing of parasite larvae. A parasite challenge performed on plasmid DNA-immunized animals induced a strong and rapid boosting effect on the specific IgG antibody response. These results demonstrate the potential of genetic immunization via the skin with plasmid DNA encoding Sm28GST for inducing immune responses with protective patterns against an S. mansoni infection .     

Cytidine methylation of regulatory sequences near the pi-class glutathione S-transferase gene accompanies human prostatic carcinogenesis.

Hypermethylation of regulatory sequences at the locus of the pi-class glutathione S-transferase gene GSTP1 was detected in 20 of 20 human prostatic carcinoma tissue specimens studied but not in normal tissues or prostatic tissues exhibiting benign hyperplasia. In addition, a striking decrease in GSTP1 expression was found to accompany human prostatic carcinogenesis. Immunohistochemical staining with anti-GSTP1 antibodies failed to detect the enzyme in 88 of 91 prostatic carcinomas analyzed. In vitro, GSTP1 expression was limited to human prostatic cancer cell lines containing GSTP1 alleles with hypomethylated promoter sequences; a human prostatic cancer cell line containing only hypermethylated GSTP1 promoter sequences did not express GSTP1 mRNA or polypeptides. Methylation of cytidine nucleotides in GSTP1 regulatory sequences constitutes the most common genomic alteration yet described for human prostate cancer.     

老年人胃癌与谷胱甘肽转硫酶P1基因多态性关系的研究

目的 探讨幽门螺杆菌(Hp)感染及谷胱甘肽转硫酶P1(GSTP1)基因多态性与胃癌的关系.方法 选择老年胃癌患者(胃癌组)98例和胃镜检查正常者(对照组)149例,以快速尿素酶试验、13C-尿素呼气试验或活检标本吉姆萨染色(Giemsa)检测Hp感染;通过聚合酶链式反应-限制性片段长度多态性(PCR-RFLP)分析方法检测GSTP1基因型.结果 Hp感染率胃癌组(54.1%)与对照组(40.9%)比较,差异有统计学意义(x2=4.11,P＜0.05);具有GSTP1突变纯和基因型并有Hp感染阳性的人群胃癌发病风险显著增加OR值5.44(1.26～26.79)(x2=7.13,P＜0.01).结论 老年患者Hp感染和GSTP1基因型多态性与胃癌的发病风险有关.

Abstract：

Objective To study the relationships of Helicobacter pylori (Hp) infection and genetic polymorphisms of glutathione s-transferase P1 (GSTP1) with gastric cancer (GC). Methods The 98 patients with GC and 149 controls with normal finding at endoscopy were enrolled for this study. The rapid urease test (RUT), 13C- urea breath test (13C-UBT) and Giemsa staining of biopsy samples were used to check Hp infection. PCR-based restriction fragment length polymorphisms (PCR-RFLP) was used to detect GSTP1 genotype. Results The rate of Hp infection was higher in GC group than in control group (54.1% vs. 40.9%, x2 =4.11, P＜0. 05). The risk of GC would significantly increase in the GSTP1 homozygous mutant gene (MM) group with Hp infection (OR=5.44, 95%CI 1. 26-26. 79, x2=7.13, P＜0.05). Conclusions Hp infection and GSTP1 genetic polymorphisms are associated with gastric cancer risk in the elderly.     

Genetic polymorphism of epoxide hydrolase and glutathione S-transferase in COPD.

Genetic susceptibility to the development of chronic obstructive pulmonary disease (COPD) might depend on variation in the activities of enzymes that detoxify cigarette smoke products, such as microsomal epoxide hydrolase (mEPHX) and glutathione S-transferase (GST). It was investigated whether polymorphisms in these genes had any association with susceptibility to COPD and COPD severity. The genotypes of 184 patients with COPD and 212 control subjects were determined by polymerase chain reaction followed by restriction fragment length polymorphism analysis of the mEPHX, GSTM1, GSTT1 and GSTP1 genes. All subjects were smokers or exsmokers. The proportion of GSTM1-null genotypes was significantly higher in patients with COPD than in control subjects (61.4 versus 42.5%). No differences were observed in the frequency of polymorphic genotypes for mEPHX, GSTT1 and GSTP1. During combined analysis of genetic polymorphisms for mEPHX, GSTM1 and GSTP1, it was found that there are strong indicators for susceptibility to COPD (genotype combination with at least one mutant mEPHX exon-3 allele (histidine 113), GSTM1 null and homozygous for the GSTPI isoleucine 105 allele). The frequencies of homozygous mutant alleles of mEPHX exon 3 and the GSTMI-null genotype were significantly higher in patients with severe COPD (forced expiratory volume in one second of <35% of the predicted value). It is proposed that the combination of genetic variants including at least one mutant microsomal epoxide hydrolase exon-3 allele and glutathione S-transferase M1-null and homozygous isoleucine 105 glutathione S-transferase P1 genotypes are significant indicators of susceptibility to chronic obstructive pulmonary disease in the Taiwanese population. In addition, the homozygous variant of microsomal epoxide hydrolase exon 3 and the glutathione S-transferase M1-null genotype are independent risk factors for developing severe chronic obstructive pulmonary disease.     

Microsomal glutathione S-transferase gene polymorphisms and colorectal cancer risk in a Han Chinese population

BACKGROUND AND AIMS: Glutathione S-transferases (GSTs) are phase II detoxification enzymes. Human GSTs have been classified into cytosolic, mitochondrial, and microsomal families. Several studies reported the association of colorectal cancer (CRC) risk with the genetic polymorphisms of cytosolic GSTs. The microsomal GSTs are structurally distinct but functionally similar to cytosolic GSTs; their association with CRC has not been reported. In this report, we summarized the result of a case-control study aimed at investigating the association of MGST1 gene locus polymorphisms with CRC risk among Han Chinese. PATIENT/METHODS: Three hundred and seventy-two healthy controls and 238 sporadic CRC patients participated in this study. DNA resequencing was conducted for the 3.4 kb genomic DNA region containing the promoter, exons, exon-intron junctions, and the 5' and 3' untranslated regions. RESULTS: We detected 13 single nucleotide polymorphisms (SNPs) including four novel SNPs not reported in database/literature. The gene shows a much higher nucleotide diversity than most human genes. The linkage and recombination analysis revealed 24 common haplotypes (13% > or = freq > or = 1%) and identified extensive intragenic recombination throughout the MGST1 locus (R = 81.8). Significant CRC association (P < or = 0.005) was not detected for each individual SNP. However, SNPs 102G>A and 16416G>A reached a marginal level of statistical significance with P values of 0.016 and 0.078, respectively. A combined genotype analysis detected a statistically significant CRC association for individuals carrying 102G>A/16416G>A (GG/GG) genotype (adjusted OR, 1.682; 95% confidence interval (CI), 1.177-2.404; P = 0.004). Consistent with the results of genotype analysis, the GG haplotype (102G>A/16416G>A) with two risk alleles was associated with a significantly higher CRC risk comparing with the haplotypes with one or no risk allele (adjusted OR 1.744; 95% CI 1.309-2.322; P = 0.0001). CONCLUSION: The results suggest that MGST1 polymorphisms may contribute to CRC risk among Han Chinese.     

Erythrocyte glutathione S-transferase deficiency and hemolytic anemia

A patient with unexplained erythrocyte glutathione-S-transferase (GST) deficiency has been detected among 513 unrelated persons with hemolytic anemia. An otherwise healthy adult male, the deficient individual had a mild hemolytic anemia with splenomegaly, indirect hyperbilirubinemia, and cholelithiasis. Because he was adopted and childless, the hereditary nature of the defect could not be established. The residual enzyme activity was only about 15% of mean normal. Depletion of glutathione (GSH) from the cells by 1-chloro-2,4-dinitrobenzene (CDNB), a substrate for GST, was somewhat decreased in the red cells from the patient, suggesting that a functional defect existed. The kinetic properties of the residual enzyme and the ratio of activity to antigenicity were normal. Modest decreases in leukocyte and platelet GST activities were documented. Although a cause-and-effect relationship between the GST deficiency and hemolysis may exist, this cannot be proven in the absence of affected family members.     

Plasma glutathione S-transferase measurements after paracetamol overdose: evidence for early hepatocellular damage.

Plasma glutathione S-transferase (GST) measurements have been used to study early changes in hepatocellular integrity after paracetamol overdose and treatment with N-acetylcysteine (NAC). Patients admitted within seven hours and successfully treated had raised or equivocal GST on admission and each showed a transient peak in GST approximately 12 hours after the overdose. Similar, though smaller changes in GST, were seen in untreated patients whose paracetamol level fell below the treatment line. The plasma GST concentrations in successfully treated patients were small compared with values found in patients who subsequently developed severe liver damage. The changes in GST concentration observed in patients who developed severe liver damage indicated that distinct early and late phases of paracetamol-induced hepatotoxicity occurred. Although the mechanism by which paracetamol exerts its early toxic effect is unclear, our data suggest that prompt treatment with NAC can successfully prevent both clinical and subclinical hepatotoxicity in this early period.     

The therapeutic response to D-penicillamine in rheumatoid arthritis: influence of glutathione S-transferase polymorphisms.

OBJECTIVES: To investigate whether the therapeutic response of rheumatoid arthritis (RA) patients to D-penicillamine is associated with polymorphisms in genes of the glutathione S-transferase (GST) supergene family. METHODS: Disease activity in 81 patients with RA treated with D-penicillamine monotherapy was assessed using the Stoke Index, a validated index of disease activity, prior to treatment and at 6 months. GST typing was performed using a polymerase chain reaction-based approach and a logistic regression model was used to investigate any possible association between the therapeutic response to D-penicillamine and the GST genotype. RESULTS: A poor therapeutic response was associated with the GSTM1 null genotype [odds ratio (OR) 3.94], and in particular with the GSTM1*0/GSTM3*A haplotype (OR 7.63). CONCLUSIONS: Our results suggest that GST polymorphisms may influence the response to D-penicillamine in RA, and that patients in possession of the GSTM1*0/GSTM3*A haplotype are significantly less likely to show a beneficial response to the drug.     

猪囊尾蚴谷胱甘肽S-转移酶的表达研究

目的应用免疫组化、双向电泳（2-DE）结合蛋白质印迹（Western-blotting）技术分析猪囊尾蚴谷胱甘肽S-转移酶（GST）的表达。方法用猪带绦虫卵1 mL（8万个/mL）灌胃20d龄健康乳猪6头,于感染后40d、80d和120 d分别宰杀2头猪并取含囊尾蚴的肌肉及肝脏（120 d除外）制作4μm厚石蜡切片,采用Envision二步法,观察不同时期寄生在肌肉及肝脏的猪囊尾蚴GST的表达;同时制备感染后40d取自肌肉的猪囊尾蚴蛋白进行2-DE分析,将凝胶蛋白斑点转移至聚偏氟乙烯膜（PVDF膜）,用本课题组自制的大鼠抗猪带绦虫GST血清作为一抗、健康大鼠血清作为阴性对照进行western-blotting分析。结果不同时期寄生在肌肉及肝脏的猪囊尾蚴均表达GST,随感染时间增加,寄生在肌肉的猪囊尾蚴GST的表达变化不大（P〉0.05）,寄生在肝脏的猪囊尾蚴GST的表达升高（P〈0.05）;双向电泳凝胶共检测到207±9个蛋白质斑点,相对分子质量（Mr）为14 400-94 000,等电点（pI）为3.0-10.0。Western-blotting分析显示,实验组特异性抗原抗体阳性杂交斑点为1个,阴性对照未见阳性杂交斑点。将Western-blotting检测的抗原抗体阳性杂交斑点与原双向电泳凝胶斑点进行比对,找到对应蛋白斑点,经ImageMaster 2D Platinum 5.0软件分析后初步确定该蛋白斑点的pI/Mr为6.6/25 548,与猪带绦虫GST的理论推导值接近。结论感染时间及感染部位组织学特征不同,猪囊尾蚴GST的表达略有差异。     

Regulation of glutathione S-transferase Ya subunit gene expression: identification of a unique xenobiotic-responsive element controlling inducible expression by planar aromatic compounds.

We have identified a region in the 5' flanking sequence of the glutathione S-transferase (RX:glutathione R-transferase, EC 2.5.1.18) Ya subunit gene that contains a unique xenobiotic-responsive element (XRE). The regulatory region spans nucleotides -722 to -682 of the 5' flanking sequence and is responsible for part of the basal level as well as inducible expression of the Ya subunit gene by planar aromatic compounds such as beta-naphthoflavone (beta-NF) and 3-methyl-cholanthrene. The DNA sequence of this region (beta-NF-responsive element) is distinct from the DNA sequence of the XRE found in the cytochrome P-450 IA1 gene. In addition to the region containing the beta-NF-responsive element, two other regulatory regions of the Ya subunit gene have been identified. One region spans nucleotides -867 to -857 and has a DNA sequence with identity to the hepatocyte nuclear factor 1 recognition motif found in several liver-specific genes. The second region spans nucleotides -908 to -899 and contains a DNA sequence with identity to the XRE found in the cytochrome P-450 IA1 gene. The XRE sequence also contributes to part of the responsiveness of the Ya subunit gene to planar aromatic compounds. Our data suggest that regulation of gene expression by planar aromatic compounds can be mediated by a DNA sequence that is distinct from the XRE sequence.     

Overexpression of the gene encoding the multidrug resistance-associated protein results in increased ATP-dependent glutathione S-conjugate transport.

The multidrug resistance-associated protein (MRP) is a 180- to 195-kDa glycoprotein associated with multidrug resistance of human tumor cells. MRP is mainly located in the plasma membrane and it confers resistance by exporting natural product drugs out of the cell. Here we demonstrate that overexpression of the MRP gene in human cancer cells increases the ATP-dependent glutathione S-conjugate carrier activity in plasma membrane vesicles isolated from these cells. The glutathione S-conjugate export carrier is known to mediate excretion of bivalent anionic conjugates from mammalian cells and is thought to play a role in the elimination of conjugated xenobiotics. Our results suggest that MRP can cause multidrug resistance by promoting the export of drug modification products from cells and they shed light on the reported link between drug resistance and cellular glutathione and glutathione S-transferase levels.