幽门螺杆菌vacA基因PCR-RFLP分型

目的为幽门螺杆菌(Helicobacterpylori,简称Hp)的基因分型提供一种可选择的指标,并通过分型与空泡毒素(vacuolatingcytotoxingeneAproduct,VacA)表达情况分析HpvacA基因的多态性。方法用自行设计的引物对18株Hp的vacA基因进行扩增,用7种限制性内切酶对基因扩增产物进行限制性片段长度多态性(RestrictionFragmentLengthPolymorphism,RFLP)分析;通过细胞测毒法对18株HpVacA活性进行检测。结果18株Hp的vacA扩增产物为2.75kb左右,但长度有差异;只有HeaⅢ可将vacA基因切出整齐的谱型,18株Hp被分为12种谱型。未发现VacA表达相关的谱型。结论HpvacA基因具有一定的多态性,而vacA基因的PCR产物经HeaⅢ酶切的RFLP分型可作为Hp基因分型的较理想选择指标。为Hp分子流行病学调查提供一种有效方法。

Analysis of the vacA gene of Helicobacter pylori by PCR-RFLP

In order to find out a reliable index for the studies on the relationship between the variability of vacA gene of Helicobacter pylori and its expressions, the vacA gene from 18 strains of H.pylori were amplified by using a pair of the self designed primers, and the amplified products were analyzed by RFLP with 7 restriction endonucleases.The expressions of VacA were determined by the use of the BHK cells cultivated with H.pylori extracts.Experimental results showed that the length of the amplified products of vacA gene was about 2.75 kb, but there were some variations in length. Among 7 endonucleases used, only the HaeIII could produce d definite patthern of genotypes, in which 12 patterns could be distinguished after cleavage with HaeIII in these 18 strains of bacteria.No relationship between the PCR RLFP pattern of vacA and its expression was found.It is concluded that certain polymorphisms exist in the vacA gene and this may be used as an effective index for the genotyping of H.pylori.