首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Nornicotine accumulation in tobacco is of concern because nornicotine is a precursor of N-nitrosonornicotine (NNN), a tobacco constituent recognized as a carcinogen by the health community. Nornicotine is derived from nicotine through a demethylation process catalyzed by nicotine demethylase enzymes. Three genes (CYP82E4, CYP82E5v2, and CYP82E10) have currently been identified that encode for these enzymes. Ethyl methane sulfonate has been used to introduce mutations into each of these genes to prevent production of functional gene products. These mutants represent a valuable tool for reducing nornicotine and NNN levels in cured tobacco leaves and their derived products. Methods are currently needed to rapidly and efficiently develop new cultivars possessing these mutant alleles. The objective of this study was to develop efficient, user-friendly DNA markers to identify these mutations based on single nucleotide polymorphisms (SNPs). Four dCAPS (derived cleaved amplified polymorphic sequence) markers were designed for a truncation mutation in CYP82E4, and a single marker was developed for a similar mutation in CYP82E5v2. Two CAPS (cleaved amplified polymorphic sequence) markers were designed for a missense mutation in CYP82E10. Because of the co-dominant nature of the CAPS and dCAPS markers, heterozygous and homozygous plants can be easily differentiated. Genotypes determined by the CAPS and dCAPS marker methods were validated by DNA sequencing and phenotypic analysis of plants carrying various mutant combinations. These markers can be used in marker-assisted selection programs to quickly introgress the desired mutations into commercial varieties in order to reduce nornicotine and NNN levels in tobacco leaves.  相似文献   

2.
Cytochrome P450 (CYP) 1A2 gene is involved in the metabolic activation of several carcinogens and altered metabolization of some clinically used drugs. We aimed to investigate the distributions of genetic polymorphisms-3860 (G/A)(CYP1A2*1C) and-2467 (T/del)(CYP1A2*1D) in the 5′-flanking region and-739 (T/G)(CYP1A2*1E) and-163(C/A)(CYP1A2*1F) in the first intron of the CYP1A2 gene in 110 unrelated healthy Turkish volunteers by PCR-RFLP technique. The frequencies of each polymorphism in Turkish population were found as 0.04, 0.92, 0.01, 0.27 for CYP1A2*1C, CYP1A2*1D, CYP1A2*1E, CYP1A2*1F, respectively. Compared with other populations, CYP1A2*1Dhas been found to be significantly increased in Turkish population. On the other hand, in general, the frequencies of the other polymorphisms were concordant with those in the Egyptian and Caucasian populations, and were different from those in the Japanese, Chinese and Ethiopian populations. Our results suggest that due to increased frequency of CYP1A2*1D in Turkish population, unctional significance of CYP1A2*1D should be evaluated. It might be screened to determine the relationship between CYP1A2*1D and CYP1A2 related drug metabolisms in associated groups. This article was submitted by the authors in English.  相似文献   

3.
The effects of cell wall mutation on the oxygenation of linoleic acid (M.W. 280) by recombinant Escherichia coli expressing the CYP102A2 gene encoding self-sufficient P450 monooxygenase of Bacillus subtilis was investigated. After the CYP102A2 gene was heterologously expressed in E. coli W3110 and its isogenic lipopolysaccharide (LPS) structural mutant strains, their whole-cell biotransformation activities were compared. The mutants used in this study had previously been designated as MLK53, MLK1067, and MLK986. These strains carry one or two defined mutations in the secondary acyl fatty acids of the LPS lipid A constituent. The CYP102A2 gene was overexpressed in both wild type E. coli W3110 and its mutant strains, with the specific activity ranging from 1.7 to 2.1 U/mg protein. Interestingly, the whole-cell biotransformation activity of those recombinant biocatalysts differed significantly. Indeed, MLK986 possessing the tetraacylated LPS showed a higher oxygenation activity of linoleic acid than those in wild type or other mutant strains having hexa- or penta-acylated LPSs. These results suggest that the biotransformation efficiency of E. coli-based biocatalysts, especially for medium- to large-sized lipophilic organic substrates, can be enhanced via engineering their LPS, which is known to function as a formidable barrier for hydrophobic molecules.  相似文献   

4.
Many studies have examined the association between the CYP2E1 Rsa Ι/Pst Ι (rs3813867) polymorphism gene polymorphisms and lung cancer risk in various populations, but their results have been inconsistent. The PubMed and CNKI database was searched for case–control studies published up to October 2013. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. In this meta‐analysis, we assessed 23 published studies involving comprising 4727 lung cancer cases and 6220 controls of the association between CYP2E1 Rsa Ι/Pst Ι polymorphism and lung cancer risk. For the homozygote c2/c2 and c2 allele carriers (c1/c2 + c2/c2), the pooled ORs for all studies were 0.73(95% CI = 0.62–0.84; P = 0.005 for heterogeneity) and 0.84 (95% CI = 0.77–0.92; P = 0.001 for heterogeneity) when compared with the homozygous wild‐type genotype (c1/c1). In the stratified analysis by ethnicity, the same significantly risks were found among Asians and mixed population for both the c2 allele carriers and homozygote c2/c2. However, no significant associations were found in Caucasian population all genetic models. This updated meta‐analysis suggests that CYP2E1 Rsa Ι/Pst Ι c2 allele is a decreased risk factor for the developing lung cancer among Asians and mixed population.  相似文献   

5.

Introduction  

Cytochrome P-450 2E1 (CYP2E1) is an important member of the CYP superfamily, which is involved in the metabolism and activation of many low molecular weight toxic compounds. We tried to investigate the possible association of CYP2E1 tag single nucleotide polymorphisms (SNPs) with susceptibility to systemic lupus erythematosus (SLE) in a Chinese Han population.  相似文献   

6.
The CYP2E1 gene polymorphism has been studied in Yakut women with ovarian cancer and without cancer. The two groups have been found to substantially differ in the frequency of the CYP2E1* 1D allele (with a 96-bp insertion in the promoter region of the gene): it is more frequent in healthy women (16.3 versus 7.4%, P = 0.007).  相似文献   

7.
Bentazon and sulfonylurea are two different classes of herbicides that have been widely used to kill broad-leaf weeds in rice fields. A cytochrome P450 gene, CYP81A6, encoding a monooxygenase has been previously identified to confer resistance to these two classes of herbicides in wild-type rice. In this study, we introduced the rice CYP81A6 gene into Arabidopsis and tobacco plants to test the possibility of engineering tolerance to these two types of herbicides in other susceptible plants. Arabidopsis and tobacco plants expressing CYP81A6 showed tolerance to both bentazon and bensulfuron-methyl (BSM), a widely applied sulfonylurea herbicide. The optimal concentrations of bentazon and BSM for the selection of CYP81A6 transgenic plants were also determined. In addition, we also demonstrated that CYP81A6 can be used as a selection marker to effectively screen for positive transgenic Arabidopsis plants. The selection efficiency of CYP81A6 was comparable to that of the bar gene in Arabidopsis. These results suggest that CYP81A6 can not only be used to produce transgenic plants tolerant to both bentazon and sulfonylureas, but that it can also be used as a novel plant-derived selection marker in plant transformation.  相似文献   

8.
9.
Abstract

Chronic exposure to n-hexane may result in peripheral neuropathy. 2,5-Hexanedione (2,5-HD) has been identified as a toxic metabolite of n-hexane. The CYP2E1, CYP1A1 and GST genes are involved in the formation of 2,5-hexanedione from n-hexane as well as the elimination of 2,5-HD-formed electrophile, and these genes are highly polymorphic in the general population. A nested case-control study in an industrial cohort was conducted to evaluate the associations between polymorphisms in these metabolic genes and n-hexane-induced peripheral nerve damage. The study subjects included 22 cases, who worked in a printing factory with symptoms of peripheral nerve damage, and 163 controls, who came from the same factory of cases. DNA was extracted from blood samples and genotyping was conducted for CYP2E1 Pst, CYP2E1 Dra, CYP2E1 Ins96, CYP1A1 Msp, GSTT1 null, GSTM1 null and GSTP1 105V. Unconditional logistic regression was applied to estimate the odds ratio and 95% confidence intervals. There were no significant differences between the two groups regarding age, sex, smoking and alcohol status. A significant association between Dra polymorphism and peripheral nerve damage was found. The frequency of CYP2E1 Dra homozygous mutation in the case group (18.2%) was higher than that in the control group (3.7%, p=0.015). Individuals with homozygote genotype (CC) of CYP2E1 Dra had a significantly higher risk of peripheral nerve damage compared with those with DD genotype (adjusted OR?=?5.58, 95% CI?=?1.32–23.65) after n-hexane exposure duration, sex, age, smoking and alcohol status were adjusted. No significant association was found that CYP2E1 Pst, CYP2E1 Ins96, CYP1A1 Msp, GSTT1, GSTM1, GSTP gene polymorphisms associated with the susceptibility of peripheral nerve damage. These findings suggested that CYP2E1 gene might increase the susceptibility to n-hexane-induced peripheral damage.  相似文献   

10.
Gene–environment interactions have been extensively studied in lung cancer. It is likely that several genetic polymorphisms cooperate in increasing the individual risk. Therefore, the study of gene–gene interactions might be important to identify high-susceptibility subgroups. GSEC is an initiative aimed at collecting available data sets on metabolic polymorphisms and the risks of cancer at several sites and performing pooled analyses of the original data. Authors of published papers have provided original data sets. The present paper refers to gene–gene interactions in lung cancer and considers three polymorphisms in three metabolic genes: CYP1A1, GSTM1 and GSTT1. The present analyses compare the gene–gene interactions of the CYP1A1*2A, GSTM1 and GSTT1 polymorphisms from studies on lung cancer conducted in Europe and the USA between 1991 and 2000. Only Caucasians have been included. The data set includes 1466 cases and 1488 controls. The only clear-cut association was found with CYP1A1*2A. This association remained unchanged after stratification by polymorphisms in other genes (with an odds ratio [OR] of approximately 2.5), except when interaction with GSTM1 was considered. When the OR for CYP1A1*2A was stratified according to the GSTM1 genotype, the OR was increased only among the subjects who had the null (homozygous deletion) GSTM1 genotype (OR=2.8, 95% CI=0.9–8.4). The odds ratio for the interactive term (CYP1A1*2A by GSTM1) in logistic regression was 2.7 (95% CI=0.5–15.3). An association between lung cancer and the homozygous CYP1A1*2A genotype is confirmed. An apparent and biologically plausible interaction is suggested between this genotype and GSTM1.  相似文献   

11.
TMSG-1 was a tumor metastasis-related gene identified using mRNA differential display, whose expression level was lower in cancer cell lines with higher metastatic potential and in tumor tissue with metastasis. TMSG-1 was transfected to prostate cancer cell line (PC-3M-1E8) with high metastatic potential to observe the effects of increased expression of TMSG-1 on V-ATPase activity, intracellular pH and cell apoptosis. Subcellular localization of the encoded protein of TMSG-1 was determined by using GFP. Results showed that there were no differences of V-ATPase activity among parental PC-3M-1E8 cell line, pcDNA3 transfectant and anti-TMSG-1 transfectant, whereas the V-ATPase activity was significantly higher in TMSG-1 transfectant than that in parental PC-3M-1E8 cell line, pcDNA3 transfectant and Anti-TMSG-1 transfectant (p<0.001). Intracellular pH (pHi) was detected by using the pH-dependent fluorescence probe BECEF. Results showed the pHi was significantly increased in TMSG-1 transfectant. Cell apoptosis assay demonstrated cell apoptosis was significantly higher in -1 transfectant (p<0.01) and BCL2 expression was down regulated. Subcellular localization of TMSG-1 protein showed TMSG-1 was a transmembrane protein, which predicted TMSG-1 protein was located in cytoplasm system, such as endoplasmic reticulum and mitochondrial. These results indicated TMSG-1 up regulation in prostate cancer cell line could promote V-ATPase activity, increase pHi and cell apoptosis, and inhibit the expression of BCL2.  相似文献   

12.
Interleukin-13 (IL-13) is a TH2 cytokine with direct and indirect immunoregulatory functions on cancer cells. The cytokine has been reported to have some polymorphic variations at the gene level associated with some immune related diseases including asthma and allergy. In the present study, association of three IL13 gene polymorphisms at positions −1512 A/C and −1055 C/T in the promoter and +2044 G/A in exon-4 was investigated in Iranian women with breast cancer and healthy controls. Genotyping of IL13 gene polymorphisms were performed by PCR–RFLP methods. Serum level of IL-13 was assessed by ELISA. Haplotypes were constructed from genotypic data using Arlequin 3.1 software package. Haplotype analysis revealed higher frequency of a three-locus haplotype, ACA (−1512A/−1055C/+2044A), in normal women than breast cancer patients (P < 0.025). Haplotype CCA, from the other hand, was observed with more frequency among patients than controls (P < 0.03). No statistically significant differences were found in the frequency of genotypes and alleles between patients and control group. No association was observed between investigated genotypes and other prognostic factors including tumor type, lymph node involvement and tumor size. IL-13 serum level was undetectable in both patients and control subjects. Despite observing no association between breast cancer and the single SNPs, results of this investigation suggest that the presence of CCA haplotype of IL13 gene may be associated with susceptibility of Iranian women to breast cancer.  相似文献   

13.
The Enhancer of Zeste (E(z)) Polycomb group (PcG) proteins, which are encoded by a small gene family in Arabidopsis thaliana, have been shown to participate to the control of flowering and seed development. For the time being, little is known about the function of these proteins in other plants. In tomato E(z) proteins are encoded by at least two genes namely SlEZ1 and SlEZ2 while a third gene, SlEZ3, is likely to encode a truncated non-functional protein. The analysis of the corresponding mRNA demonstrates that these two genes are differentially regulated during plant and fruit development. We also show that SlEZ1 and SlEZ2 are targeted to the nuclei. These results together with protein sequence analysis makes it likely that both proteins are functional E(z) proteins. The characterisation of SlEZ1 RNAi lines suggests that although there might be some functional redundancy between SlEZ1 and SlEZ2 in most plant organs, the former protein is likely to play specific function in flower development.  相似文献   

14.
Chronic obstructive pulmonary disease (COPD) is a multifactorial respiratory disorder. Members of the cytochrome P450 family catalyze oxidative metabolism of exogenous chemicals and activate their substrates into reactive intermediates that may initiate lung injury. The frequencies of CYP1B1 and CYP2F1 polymorphic markers were determined in healthy people from Bashkortostan and tested for association with COPD. Using PCR-RFLP, the polymorphic markers Leu432Val (CYP1B1) and c.14-15insC (CYP2F1) were studied in healthy Russians (N = 191), Tatars (N = 198), and Bashkirs (N = 78) and in Russian (N = 169) and Tatar (N = 137) COPD patients. The CYP2F1 genotype frequency distribution proved to differ between the three ethnic groups (χ 2 = 21.29, d.f. = 4, P = 0.0001), Tatars having a higher frequency of the c.14-15insC/c.14-15insC genotype (6.38%). The highest frequency (39.74%) of the heterozygous genotype was observed in Bashkirs. The frequency of the insertion-free CYP2F1 variant in Tatars with extremely severe COPD and onset after 55 years of age was significantly higher (87.5%) than in patients of the same age group with moderate or severe COPD (87.50% vs. 75.53%, χ 2 = 3.964, d.f. = 1, P = 0.046; OR = 2.268). The allele and genotype frequency distributions of the CYP1B1 Leu432Val polymorphism were similar in the Russian, Tatar, and Bashkir ethnic groups. Leu432Val of CYP1B1 was not associated with COPD.  相似文献   

15.
Polymorphic cytochrome P4502E1 (CYP2E1) plays an important role in the metabolic activation of many carcinogens. We have previously shown that the c1/c1 genotype recognized byRsa I in the 5′-regulatory region of theCYP2E1 may be a susceptibility factor for developing esophageal cancer and lung cancer in Chinese. The present study was to investigate the relationship between theRsa I genotype and the expression of CYP2E1 in human livers. A total of 50 liver specimens were genotyped forCYP2E1 and assayed for CYP2E1 protein contents and functional activity by using specific antibody in immunoblot and a probe substrate,p-nitrophenol. A considerable interindividual variation in CYP2E1 protein (20-fold) and functional activity (56-fold) was observed among these liver samples. However, when they were categorized according to genotype, the mean content of CYP2E1 protein was significantly higher among individuals with the c1/c1 genotype than that among those having c1/c2 or c2/c2 genotype [124.0±83.9 pmol/mg (n = 28) versus 65.5 ±38.9 pmol/mg (n = 22),P<0.01]. The mean activity of CYP2E1 towardsp-nitrophenol for the c1/c1 genotype was also higher than that for the variant genotypes (198.4±27.8 pmol/min/mg versus 101.2 ±18.1 pmol-1 · min-1 · mg-1,P<0.01). Also, the protein levels and functional activity showed a significant correlation (r = 0.68,P<0.01). These results demonstrate an association between theRsa I genotype and the phenotype of CYP2E1 in our samples, and the data are compatible with the assumption thatCYP2E1 c1/c1 genotype is a susceptibility factor for certain cancers in Chinese.  相似文献   

16.
CYP714基因在植物赤霉素合成与代谢过程中发挥着重要作用。该研究从甘薯基因组中鉴定出2个CYP714基因,对基因的结构和编码蛋白质的理化性质等进行了生物信息学分析,并利用荧光定量PCR(qRT-PCR)技术分析基因在不同组织和非生物胁迫条件下的表达特征,为解析甘薯CYP714基因的生物学功能提供帮助。结果表明:(1)2个基因为分别编码518个和521个氨基酸的碱性亲水蛋白,被亚细胞定位于细胞质中;(2)2个蛋白质均含有CYP714蛋白亚家族的3个特征结构域,与毛白杨的PtCYP714E2、PtCYP714E4和PtCYP714E5蛋白聚为一类,分别定名为IbCYP714E1和IbCYP714E2;(3)荧光定量PCR分析显示,IbCYP714E1和IbCYP714E2基因的表达部位存在一定差异,IbCYP714E1在柴根、初生根和叶片中表达量较高,而IbCYP714E2基因只在柴根和花上表达量较高,在盐和干旱胁迫下,IbCYP714E1基因表达量均增加,而IbCYP714E2基因只在盐胁迫条件下表达量增加。IbCYP714E1和IbCYP714E2基因可能参与赤霉素的降解和对非生物胁迫的应答。  相似文献   

17.
Polymorphic cytochrome P4502E1 (CYP2E1) plays an important role in the metabolic activation of many carcinogens. We have previously shown that the c1/c1 genotype recognized by Rsa I in the 5'-regulatory region of the CYP2E1 may be a susceptibility factor for developing eso-phageal cancer and lung cancer in Chinese. The present study was to investigate the relationship between the Rsa I genotype and the expression of CYP2E1 in human livers. A total of 50 liver specimens were genotyped for CYP2E1 and assayed for CYP2E1 protein contents and functional activity by using specific antibody in immunoblot and a probe substrate, p-nitrophenol. A considerable interindividual variation in CYP2E1 protein (20-fold) and functional activity (56-fold) was observed among these liver samples. However, when they were categorized according to genotype, the mean content of CYP2E1 protein was significantly higher among individuals with the c1/c1 genotype than that among those having c1/c2 or c2/c2 genotype [124.0 ±83.9 pmol/  相似文献   

18.
Mutations in the BRCA1 and BRCA2 genes profoundly increase the risk of developing breast and/or ovarian cancer among women. To explore the contribution of BRCA1 and BRCA2 mutations in the development of hereditary breast cancer among Indian women, we carried out mutation analysis of the BRCA1 and BRCA2 genes in 61 breast or ovarian cancer patients from south India with a positive family history of breast and/or ovarian cancer. Mutation analysis was carried out using conformation-sensitive gel electrophoresis (CSGE) followed by sequencing. Mutations were identified in 17 patients (28.0%); 15 (24.6%) had BRCA1 mutations and two (3.28%) had BRCA2 mutations. While no specific association between BRCA1 or BRCA2 mutations with cancer type was seen, mutations were more often seen in families with ovarian cancer. While 40% (4/10) and 30.8% (4/12) of families with ovarian or breast and ovarian cancer had mutations, only 23.1% (9/39) of families with breast cancer carried mutations in the BRCA1 and BRCA2 genes. In addition, while BRCA1 mutations were found in all age groups, BRCA2 mutations were found only in the age group of ≤40 years. Of the BRCA1 mutations, there were three novel mutations (295delCA; 4213T→A; 5267T→G) and three mutations that have been reported earlier. Interestingly, 185delAG, a BRCA1 mutation which occurs at a very high frequency in Ashkenazi Jews, was found at a frequency of 16.4% (10/61). There was one novel mutation (4866insT) and one reported mutation in BRCA2. Thus, our study emphasizes the importance of mutation screening in familial breast and/or ovarian cancers, and the potential implications of these findings in genetic counselling and preventive therapy.  相似文献   

19.
Polymorphisms in genes that encode P450 cytochrome enzymes may increase carcinogen activation or decrease their inactivation and consequently, promote the development of cancer. The aims of this study were to identify the MspI-CYP1A1, PstI-CYP2E1 and DraI-CYP2E1 polymorphisms in patients with head and neck cancer and to compare with individuals without cancer; to evaluate the association of these polymorphisms with risk factors and clinical histopathological parameters. In the study group, 313 patients were evaluated for CYP1A1, 217 for CYP2E1 (PstI) and 211 for CYP2E1 (DraI) and in the control group 417, 334 and 374 individuals, respectively. Molecular analysis was performed by PCR–RFLP technique, and chi-square and multiple logistic regression tests were used for statistical analysis. The result of analysis regarding individuals evaluated for CYP1A1 (MspI) showed that age (OR: 8.15; 95% CI 5.57–11.92) and smoking (OR: 5.37; 95% CI 3.52–8.21) were predictors for the disease; for the CYP2E1 (PstI and DraI), there were associations with age (PstI-OR: 9.10; 95% CI 5.86–14.14/DraI-OR: 8.07; 95% CI 5.12–12.72), smoking (PstI-OR: 4.10; 95% CI 2.44–6.89/DraI-OR: 5.73; 95% CI 3.34–9.82), alcohol (PstI-OR: 1.93; 95% CI 1.18–3.16/DraI-OR: 1.69; 95% CI 1.02–2.81), respectively, with disease development. CYP2E1 (PstI) was less frequent in patient group (OR: 0.48; 95% CI 0.23–0.98). Regarding clinical histopathological parameters, CYP1A1 polymorphism was less frequent in the larynx primary anatomic site (OR = 0.45; 95% CI = 0.28–0.73; P = 0.014). In conclusion, we confirm that age, smoking and alcohol consumption are risk factors for this disease and the polymorphisms investigated have no association with the development of head and neck cancer.  相似文献   

20.
In 32 unrelated patients with primary congenital glaucoma (PCG), a search for mutations in the myocilin (MYOC), cytochrome P450B1 (CYP1B1), and WDR36 genes was performed. The Q368X mutation in myocilin gene, typical of the patients with adult-onset primary open-angle glaucoma (POAG), was not detected in the PCG patients. Screening of the CYP1B1 introns 2 and 3 for the presence of mutations in PCG patients revealed only six DNA polymorphisms, including IVS1-12ntT>C (g.3793 T>C), A119S (g.4160 G>T; GCC>TCC), G188G (g.4369 C>A; GGC>GGA), L432V (g.8131 C>G; CTG>GTG), D449D (g.8184 C>T; GAC>GAT), and N453S (g.8195 A>G; AAC>AGC) (nucleotide numbering is given in accordance with the GenBank sequence U56438). In the groups of PCG patients and donors without eye diseases, the frequencies of these variants were not statistically significantly different, pointing to the neutrality of these polymorphisms. Furthermore, the CYP1B1 polymorphism L432V, considered to be associated with POAG in some world populations, was not associated with this disease in the patients from St. Petersburg. DNA collections obtained from the POAG and PCG patients and from the control group were tested for the carriage of the worldwide distributed mutations of the WRD36 gene, D658G, R529Q, A449T, and N355S. D658G variant was found with equally low frequencies in the groups of POAG and PCG patients, as well as in the control group. Mutations A449T and R529Q were found only once each, while mutation N355S was not detected in any of the groups examined. Our results indicate that the WDR36 variants make no substantial contribution to the development of POAG and PCG in the patients from St. Petersburg and represent normal DNA polymorphism. It is likely that in most of the PCG patients from the population examined the disease is not associated with the CYP1B1 gene defects.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号