胃癌及癌前病变患者幽门螺杆菌的sabA基因多态性的研究

Helicobacter pylori sabA gene polymorphism in patients with gastric cancer and precancerous lesions

目的对癌症和癌前病变患者幽门螺杆菌进行sabA基因遗传信息多态性的研究。方法采用特异引物聚合酶链反应(PCR)及测序和比较基因组方法分析42株国内癌症及癌前病变患者幽门螺杆菌的sabA基因CT双核苷酸重复序列调节区多态性。结果 sabA基因调节区的阳性检测率为85%,功能性sabA基因占所有测序菌株的55%。对随机挑选的18株检测阳性菌株进行测序分析,结果显示在碱基水平及氨基酸水平存在显著的遗传多态性。对sabA基因调节区的氨基酸序列聚类分析中发现,本研究菌株与国际已经完成测序的7株幽门螺杆菌可以明显的分为两个组,即中国组与西方组。结论 sabA基因CT双核苷酸重复序列调节区在中国菌株中普遍存在,且在翻译水平有很显著的多态性。聚类分析发现含有功能性sabA基因的幽门螺杆菌菌株多态性存在明显的地域性分布差异。

Objective To identify the sialic acid binding adhesin（sabA） gene polymorphism of Helicobacter pylori stains from patients with gastric cancer or precancerous lesions.Methods The sabA gene CT repeats regulatory domain polymorphism of 42 pylori strains sampled from 24 patients with gastric cancer and 18 with precancerous lesions（intestinal metaplasia） were analyzed by PCR-SSP,sequencing and comparative genomes.Results Positive detection rate were 85%,and 83.3% for gastric cancer（20/24） and 88.9% for precancerous lesions（16/18）.Among the positive stains,55% was identified with functional sabA in all sequenced strains.Sequencing on randomly picked 18 sabA regulatory domain positive strains indicated that gene polymorphism was observed in both base and amino acid levels.Clustering analysis demonstrated that these sequenced sabA regulatory domain,along with the internationally published 7 sequenced Helicobacter pylori,could be divided into two categories,a Chinese group and a Western group.Conclusion sabA gene CT repeats regulatory domain is generally presented in Chinese strains,with significant polymorphism at translational level.Clustering analysis indicates apparent geographical regional distribution of strains is seen for functional sabA gene.