一种新的链霉菌表达载体启动子

eryA基因直接控制着红霉素母环6-脱氧-红霉内酯B的合成,在红霉素生物合成过程中具有重要作用。本文克隆了eryA基因的启动子PeryA,以绿色荧光蛋白基因为报告基因,构建了大肠埃希菌-糖多孢红霉菌穿梭型质粒。PEG介导原生质体转化法将穿梭型质粒分别转入糖多孢红霉菌A226与变铅青链霉菌JT46,荧光显微镜检测发现,此启动子在两菌株中都具有功能。随后,以变铅青链霉菌JT46为宿主,对PeryA启动子区域进行了深入研究,结果发现该启动子的-35区并不是必需的,仅有-10区、长度为41bp的该启动子在链霉菌中仍具有功能。定点突变证明-10区对于该启动子是必不可少的。因此,41bp的该启动子片段可作为链霉菌的有效启动子,这是迄今为止所发现的最短的启动子之一,可用于构建新的链霉菌表达载体。     

人类白细胞抗原-DRB1基因启动子区序列多态性与肺结核的相关性分析

目的探讨中国北方地区人群人类白细胞抗原（HLA）-DRB1基因启动子区序列多态性与肺结核的相关性。方法北方汉族肺结核患者97例为肺结核组，北方汉族健康人62例为对照组，采用PCR-SSP法对2组的HLA-DRB1基因启动子区进行PCR扩增，启动子区扩增产物直接测序。结果肺结核组和对照组的HLA-DRB1基因启动子区序列完全一致；对照组启动子区序列与数据库检索的序列比较有3个突变点：-26位的T被C替代，-49位的C被G替代，-78位的C被G替代。结论中国北方地区人群HLA-DRB1基因启动子区序列具有多态性，但此多态性与肺结核的发病没有相关性。     

放射线对肝癌细胞中端粒酶启动子活性的影响

目的:研究放射线对不同的肝癌细胞株中人端粒酶逆转录酶(hTERT)启动子活性的影响。方法:报告质粒phTERTp-Luc经脂质体METAFECTENE介导瞬时转染4种不同的肝癌细胞株后,给予2 Gyγ射线照射,观察照射组与非照射组中荧光素酶的表达。结果:瞬时转染4种不同的肝癌细胞株后,检测到照射可经hTERT启动子而诱导荧光素酶的表达增强,即hTERT启动子在2 Gy照射组中比在非照射组中具有更高的活性。结论:2Gyγ射线可以诱导肝癌细胞中hTERT启动子活性增强,有望用于增强肝癌细胞中hTERT启动子介导的靶向基因治疗,并为进一步深入研究奠定了基础。     

食管癌中DNA修复基因MGMT启动子区CpG岛过甲基化研究

目的：探索O~0-甲基鸟嘌呤-DNA甲基转移酶(O~6-methylguanine-DNA methyltransferase,MGMT)基因启动子区过甲基化状态与食管癌的关系。方法：采用甲基化特异性聚合酶链反应(methylation-specific PCR,MSP)分析食管癌、癌旁和正常食管黏膜细胞中MGMT基因启动子区过甲基化状态。用免疫组织化学SP法检测上述组织中MGMT蛋白表达情况。结果：76例食管癌组织中有26例(34.2%)MGMT基因启动子过甲基化,相应的癌旁组织中有8例发生甲基化,而正常食管黏膜细胞中均无甲基化。所有甲基化的癌组织中均无MGMT蛋白表达,而所有非甲基化的癌组织、相应癌旁组织和8例正常组织中均有MGMT蛋白表达。结论：MGMT基因启动子区过甲基化而使其蛋白表达缺失,可能是食管癌发生的重要因素。     

survivin基因启动子的克隆及其在人喉癌Hep-2细胞中的特异性表达

目的:构建survivin启动子调控的真核表达载体pSurp-EGFP,利用增强型绿色荧光蛋白(EGFP)检测该启动子在Hep-2细胞中的特异表达活性。方法:PCR扩增survivin启动子,置换pShuttle载体中的CMV启动子,构建质粒pSurp;分别双酶切pShuttle、pSurp和pEGFP-C1载体,构建分别携带survivin启动子和巨细胞病毒(CMV)启动子的真核表达载体pCMV-EGFP和pSurp-EGFP;脂质体法转染Hep-2细胞及血管内皮细胞ECV304,荧光显微镜下观察EGFP的表达。结果:成功扩增survivin基因启动子,构建了survivin基因启动子调控的真核表达载体pSurp-EGFP,用其转染两种细胞后,荧光显微镜下见Hep-2细胞发出较强的绿色荧光,而ECV304细胞没有表达。结论:成功克隆survivin启动子,其在Hep-2细胞具有较强的肿瘤特异性启动活性,为进一步开发肿瘤的特异性基因治疗奠定了实验基础。     

Susceptibility for schizophrenia is not influenced by a functional insertion/deletion variant in the promoter of the serotonin transporter gene

A possible dysregulation of serotonergic neurotransmission has been implicated in the aetiology of schizophrenic psychoses. In the present study we analysed allelic and genotypic variations of a recently described functional polymorphic region in the promoter of the human serotonin transporter gene (5-HTTLPR) and a variable tandem repeat (VNTR) in intron 2 of the 5-HTT gene. We investigated 413 unrelated individuals, 180 schizophrenic patients and 233 blood donors as controls. With regard to the 5-HTTLPR, both the schizophrenic and the control group did not significantly differ between genotype frequencies (χ², p = 0.920) and allele frequencies (χ², p = 0.836). The odds ratio for subjects with schizophrenia who were homozygous for the short allele was 1.04 (95% CI 0.59–1.84). No evidence of allelic association to specific schizophrenia subtypes was found. The 5-HTT associated VNTR also showed no significant differences between either the allelic or the genotypic distributions. Haplotype analysis revealed a significant overall linkage disequilibrium at a level of p = 0.00004. Our findings indicate that both polymorphisms are unlikely to play a substantial role in the genetic predisposition to schizophrenic disorders. Received: 14 April 1997 / Accepted: 16 October 1997     

谷胱甘肽-S-转移酶P1启动子调控的胞嘧啶脱氨酶和尿嘧啶磷酸核糖转移酶融合基因对卵巢癌顺铂耐药细胞的体外杀伤作用

目的　观察谷胱甘肽 S 转移酶P1(GSTP1)启动子调控的胞嘧啶脱氨酶和尿嘧啶磷酸核糖转移酶融合基因 (CD UPP ,即自杀基因 )表达的腺病毒载体 ,对卵巢癌顺铂耐药细胞的体外杀伤作用。方法　采用细菌内同源重组法构建腺病毒载体 ,设立卵巢癌顺铂敏感细胞株A2 780和以其诱导的耐药细胞株A2 780 /DDP ,在体外用重组腺病毒转染两组细胞并联合应用前药 5 氟胞嘧啶 (5 FC) ,观察两组卵巢癌细胞对 5 FC的敏感性。将CD UPP阳性和CK UPP阴性的A2 780 /DDP细胞按不同比例混合后给予 5 FC ,观察 5 FC对混合细胞的杀伤作用。结果　当重组腺病毒滴度为 10 0感染复数(MOI)、5 FC浓度为 2 5 0 μg/ml时 ,对顺铂耐药的A2 780 /DDP细胞的存活率为 (3 6± 1 0 ) % ,对顺铂敏感的A2 780细胞的存活率为 (76 5± 2 8) % ,两者比较 ,差异有显著性 (P <0 0 5 )。此外 ,2 0 ? UPP阳性A2 780 /DDP细胞 ,即可引起 80 3%的混合细胞死亡 ,CD UPP / 5 FC系统表现出明显的旁观者效应。结论　由腺病毒介导的含有GSTP1调控的CD UPP/ 5 FC系统 ,对卵巢癌顺铂耐药细胞具有特异性杀伤作用 ,为临床上克服卵巢癌化疗耐药 ,提供了一条安全、高效的治疗途径。     

Functional characterization of genetic polymorphisms identified in the human cytochrome P450 4F12 (CYP4F12) promoter region

The human cytochrome CYP4F12 has been shown to be active toward inflammatory mediators and exogenous compounds such as antihistaminic drugs. In the present study, we report the first investigation of polymorphisms in the human CYP4F12 gene. A screening for sequence variations in the 5'-flanking region was performed by a Polymerase Chain Reaction-Single Strand Conformational Polymorphism (PCR-SSCP) strategy, using DNA samples from 53 unrelated French individuals of Caucasian origin. Several polymorphisms were identified, comprising a large deletion located in intron 1 (CYP4F12*v1), two isolated substitutions -402G>A (CYP4F12*v3) and -188 T>C (CYP4F12*v4) and nine combined mutations, -474T>C, -279A>C, -224A>G, -173G>A, -145C>G, -140T>C, -126T>C, -56T>C, and -21T>G (CYP4F12*v2). Considering the nature and location of the polymorphisms characterizing the CYP4F12*v1 and *v2, the functional relevance of those two allelic variants was further examined by transfecting different cell lines with constructs of the related region of the CYP4F12/luciferase reporter gene. Both alleles lead to a significant decrease of CYP4F12 gene expression in HepG2 cell line and, therefore, are likely to determine interindividual differences in CYP4F12 gene expression.