镇江地区H pylori的cagA基因及其3′可变区结构的变化  

Study of the 3' terminal variable region of the cagA gene in Helicobacter pylori isolated from patients living in Zhenjiang

作　　者：吴莺[1] 张尤历[1] 范钰[1] 魏金文[1] 何亚龙[1] 沈琰[1] 陈劲频[1] 印亦萍[1] 王文兵[2] 

机构地区：[1]江苏大学附属医院消化科,江苏省镇江市212001 [2]江苏大学生命科学院,江苏省镇江市212000

出　　处：《世界华人消化杂志》2007年第29期3147-3151,共5页World Chinese Journal of Digestology

基　　金：江苏省科学技术厅社会发展基金;No.BS2006041

摘　　要：目的:评估镇江地区H pylori临床株的cagA基因阳性率、了解菌株CagA蛋白的可能分型、其羧端可变区EPIYA的数目以及与临床结果之间有无关联.方法:培养分离来自临床胃十二指肠疾病患者的H pvlori,提取基因组DNA,通过PCR方法检测H pylori cagA基因的状况.随机选择不同病种的cagA基因阳性(cagA^+)的PCR产物.通过转化质粒,进行cagA^+PCR产物测序,通过ExPASY-Tranlation软件获得cagA基因相应的CagA蛋白的氨基酸序列.国际标准株NCTC11637的cagA基因以及CagA蛋白序列通过搜索NCBI(www.ncbi.nlm.nih.gov)数据库获得.结果:60株H pylori临床株中,56例为cagA^+,阳性率达93.3%.20例测序的结果表明,CagA蛋白结构可分为2种类型,19株东亚型和1株西方型.所有19株东亚型均为Yamaoka分型的A型,所有20例菌株的EPIYA的数目均为3个,与临床结果无关联.结论:cagA基因阳性率在不同病种之间无差异.镇江地区H pylori临床株的CagA蛋白的一级结构,与日本、韩国菌株一样,主要为东亚型,其CagA蛋白羧端可变区EPIYA数目均为3个,与临床结果无关联.AIM： To evaluate the expression of cagA gene of Helicobacter pylori strains isolated from Chinese patients living in Zhenjiang, Jiangsu Province, their CagA protein type, and the relationship between the number of EPIYA located in CagA protein C terminus and the clinical outcome. METHODS： After H pylori isolated from patients with gastrointestinal diseases were cultured, the genomic DNA was extracted and PCR was performed to examine the expression of the variable region of the cagA gene. The DNA fragments from 20 isolated strains with cagA^＋ were sequenced. RESULTS： CagA gene expression was found in 56 of 60 patients. According to the amino acid sequences of CagA protein variable region, the isolates fell into two groups： the East-Asia type that contained 19 isolated strains belonging to Yamaoka＇s A type, and one strain that belonged to the Western type. All 20 isolated strains possessed three EPIYA motifs, and had no relationship between the amount of EPIYA and clinical outcome. CONCLUSION： It is no distinguish that the expression of CagA gene between different diseases. CagA proteins of H pylori isolated from patients living in Zhenjiang all belong to the East-Asia type, the same as strains isolated from Korea and Japan. There are three EPIYA motifs in the CagA C-terminal variable region of all H pylori strains, and there is no relationship between the amount and clinical outcome.

关 键 词：幽门螺杆菌 CAGA基因 CAGA蛋白 EPIYA 临床结果 

分 类 号：R378[医药卫生—病原生物学]