湖北省间日疟原虫分离株环子孢子蛋白部分序列分析

ANALYSISOF PARTIAL SEQUENCE OF CIRCUMSPOROZOITE PROTEIN OF PLASMODIUM VIVAX ISOLATES IN HUBEI PROVINCE

目的 :为了确定湖北省间日疟原虫虫株环子孢子蛋白 ( CSP)的分型和探讨 CSP多态性的生物学特征。方法 :采用常规的克隆和 Sanger链终止法 ,首次对湖北省间日疟原虫的环子孢子蛋白 ( CSP)基因测序。结果 :HB2株 CSP基因的 N- C-端非重复区包括重复区后可变区核苷酸序列与北朝鲜 ( NK)株和中国株 ( CH2 - CH7)相同 ,而中央前后重复区则有较大变异。在 HB2 CSP中央前后重复区 ,有 8种变异型。与其它已发表的间日疟原虫 CSP核苷酸序列相比 ,重复体 GNGAG-GQP/AA和重复后可变区有明显的地理学特征。此外同一份 HB2 CSP基因 PCR产物克隆后获得含两个大小不等插入片段的阳性克隆 ,分别为 0 .75kb和 1.1kb。两者非重复区的核苷酸序列相同 ,在中央前后重复区除了重复数次不同外 ,仅有 3处隐性核苷酸变异和 1处显性核苷酸变异。结论 :CSP基因变异 ,尤其是重复区的变异不仅与 DNA聚合酶的自身作用有关 ,而且还可能牵涉到间日疟原虫潜伏期的改变。

AIM:To identify circumsporozoite protein(CSP) genes of Plasmodium vivax in Hubei endemic areas and explore the biological features of CSP polymorphism.METHODS:Cir- cumsporozoite protein(CSP) gene of P.vivax in Hubei was firstly sequenced by using rou- tine cloning and Sanger Chain Terminal method.RESULTS:The N- and C- terminus se- quences flanking the central tandem repeat,including post- repeat variable region of CSP gene of HB2 isolate were identical to those of North Korean(NK) isolate and Southern Chi- na isolates(CH2 - 7) ,while the central tandem repeat region existed extensive polymor- phism.Compared with the other CSP gene sequences published so far,the repeat form GN- GAGGQP/AA and the post- repeat variable region had obvious geographical characteristics. Incidentally,one CSP gene PCR product of HB2 isolate produced two clones containing0 .75 kb and1 .1 kb DNA fragment,respectively.Their nucleotide sequences were almost the same except for three silient changes and one nonsilient change and the difference in the re- peat number as well.CONCL USION:The variation of CSP gene sequence,especially in the repeat and the post- repeat variable region,possibly involve the changes of latent period of P.vivax.