摘要
目的研究威海地区幽门螺杆菌(Helicobacter pylori,Hp)临床分离株cagA基因的3′端多态性。方法采用PCR法扩增Hp临床分离株的cagA基因3′端并测序,用DNAStar 5.0软件对其进行编码氨基酸序列的比对分析。结果 63株Hp临床分离株均cagA阳性(cagA+),其中93.7%(59/63)为东亚型(EPIYYA-ABD),6.3%(4/63)为西方型(EPIYYA-ABC)。3.4%(2/59)的东亚型菌株EPIYA-B突变为ESIYA-B,4株西方型型均突变为EPIYT-B。胃癌患者分离株中88.9%(16/18)为东亚型,11.1%(2/18)为西方型;非胃癌分离株中95.6%(43/45)为东亚型,4.4%(2/45)为西方型。2株分离自胃癌患者的西方型Hp EPIYA-A后的第一个氨基酸残基由赖氨酸(K)突变为谷氨酸(E)。结论威海地区Hp cagA基因以东亚型为主,但东、西方亚型Hp的致病性无显著差别,两型都存在cagA基因3′端编码氨基酸序列的改变。
Objective To characterize the variants of the 3′region of cytotoxin-associated gene A（cagA）in Helicobacter pylori strains isolated from Weihai. Methods The 3′region of the cagAgene was amplified with PCR,and then the products were sequenced and the amino acid sequences were analyzed with DNAStar 5.0software. Results Sixtythree H.pylori strains were cagA-positive（cagA＋）.cagAprotein in 93.7%（59/63）of these strains was the East Asian type,and its tyrosine phosphorylation motif（TPM）was EPIYA-ABD.cagAprotein in the remaining strains（6.3%,4/63）was the Western type,and its TPM was EPIYA-ABC.cagAprotein in 3.4%（2/59）of the strains was the East Asian type but its motif had changed to ESIYA-B,whereas Western-type cagAprotein in all 4strains（100%）had a motif of EPIYT-B.Of the stains isolated from patients with gastric cancer in this study,88.9%（16/18）had East Asian-type cagAprotein while the remaining 11.1%（2/18）had Western-type cagAprotein.Of the strains isolated from patients without gastric cancer,95.6%（43/45）had East Asian-type cagAprotein while 4.4%（2/45）had Western-type cagAprotein.Two strains with Western-type cagAprotein were obtained from gastric cancer patients in this study,and both displayed a mutation,from K（lysine）to E（glutamate）,on the first residue following the EPIYA site in the EPIYA-A motif. Conclusion cagAprotein in H.pylori strains isolated from patients in Weihai was mostly the East Asian type,but the pathogenicity of H.pylori does not differ significantly between in strains with the East Asian-type cagAprotein and Western-type East Asian-type cagAprotein.There are mutations in the amino acid sequences in the 3′region of both types of cagAprotein.
出处
《中国病原生物学杂志》
CSCD
北大核心
2014年第9期783-787,共5页
Journal of Pathogen Biology
基金
国家自然科学基金项目(No.81072429)
教育部"新世纪优秀人才支持计划"项目(No.NCET-11-1026)
