云南省现场恶性疟原虫3个抗药性基因点突变特征

目的 研究云南省现场恶性疟原虫3个与抗疟药抗性有关的dhfr、pfmdr1和pfcrt的点突变特征，为抗药性恶性疟原虫的分子生物学研究提供背景资料。方法 应用特异性套式多聚酶链反应(PCR)和限制性酶切片段长度分析(RFLP)方法，检测恶性疟现症病人干滤纸血样的恶性疟原虫3个抗药性基因点突变情况。结果 恶性疟原虫dhfr基因内16，51，108和164位氨基酸有不同程度的突变，突变型比例高，以Asn—108和Ile—51为甚，频度分别为94．3％和81．3％。野生型(3D7型)Ser—108出现较低频率8．6％，而AIa—16出现频率较高68．6％；plcrt基因的76位点由K突变为T，突变型(含混合)占96．7％；野生型仅占3．4％；pfmdr1基因86位点由Asn突变为Tyr，突变型占34．％：野生型点48．7％；混合型占16．7％。未发现1246位点突变的存在。结论 云南现场恶性疟原虫与抗疟药抗性有关的3个pfdhfr、pfmdr1和pfcrt基因有较广泛的点突变特征。

Characteristic of point mutation of three Plasmodium falciparum resistant genes in Yunnan Province

Objective To study the characters of point mutations in Plasmodium falciparum digestive vacuole transmembrane protein gene(pfcrt),the multidrug resistance gene (pfmdr1) and the dihydrofolate reductase thymidylate synthase gene(pfdhfr) of Plasmodium falciparum has been studied so good that provided the background data of molecular biology for drug resistance malaria parasite. Methods Mainly using nested PCR and Restrict Enzyme Fragment Length Polymorphism(REFLP) examined point mutations of the three drug resistance genes in Plasmodium falciparum from dry filter papers with acute falciparum malaria patients in Yunnan. Results There were the different point mutations in position 16,51,108,164 in within pfdhfr gene.Mutant type,especially Asn-108 and Ile-51,was very high,and its frequency was 94.3% and 81.3% respectively.The lower frequency of the wildtyp(3D7) Ser-108 was 8.6% while higher AIa-16 was 68.6%.Position 76 in pfcrt gene is mutant to T from K,that is,mutant type (including mixed) accounted for 96.7% while the wild type was only 3.4%.Position 86 in pfmdr1 gene is mutant to Tyr from Asn,that is,mutant type (including mixed) accounted for 34.6% while the wild type was 48.7%.and mixed type was 16.7%.Mutant type at position 1246 in pfmdr1 gene was not found. Conclusion Plasmodium falciparum from Yunnan fields commonly exists point mutations in pfcrt,pfmdr1 and pfdhfr gene.