新疆克里米亚-刚果出血热病毒株S基因分子生物学特性研究

Molecular analysis on the S gene of three Crimean-Congo hemorrhagic fever virus strains in China

目的对新疆地区2005年分离自亚洲璃眼蜱的3株克里米亚-刚果出血热(CCHF)病毒株进行S基因序列测定并分析比较该病毒的分子生物学遗传特性。方法应用逆转录聚合酶链反应扩增出病毒基因组S片段,纯化后直接测定其核苷酸序列,用DNASTAR软件对测定的核苷酸序列和推导的氨基酸序列进行比较分析。结果3株病毒s基因都由1673个核苷酸组成,开放阅读框均为1449个核苷酸,编码482个氨基酸,3株病毒间核苷酸及氨基酸同源性序列为99．5％,与其他已发表的9株CCHF病毒株的核苷酸序列同源性在92．7％-99．8％之间。这3株病毒与已分离的7001和79121株同属1个基因组,序列相差2％-3％之间。与尼日利亚的原型株IBAR10200的差异性为13％,远大于与中国原型株66019之间的6．8％的差异。结论中国株为相对独立的一个类群,新疆自治区境内不同地区分离的CCHF病毒S基因分子结构差异相对较小。

Objective To compare the molecular characteristics of 3 Crimean-Congo hemorrhagic fever viruses（CCHFV） isolated in Xinjiang province. Methods YL05035, YT05099 and LT05146 were isolated in 2005 from Hyalomma ticks and viral RNA was extracted from suckling mouse brains infected with these three strains respectively. The polymerase chain reaction（PCR） products of S segments from the 3 strains of CCHFV were directly sequenced. Results The full-length S RNA from the 3 strains of CCHFV all comprised 1673 nucleotides with ORF of them including 1449 nucleotides and encoding a protein which comprised 482 amino acids in a viral complementary sense. The sequences indicated that the three strains of CCHFV isolated from ticks in Xinjiang province were highly homologenic, Data from the phylogenetic analysis showed that the obtained sequences were identical. The homology between 3 strains of CCHFV was 99.5 % . Their homologies compared with that of the other strains isolated from other region of Xinjiang were also high at nucleotide levels（92,7 % -99.8 % ）. The three strains which were clustered together with 7001 strain and 79121 strain （isolated from patient and rat in Xinjiang respectively） was only different by 2%-3%. The genetic difference from the prototype CCHFV Nigerian strain IBAR10200 was 13%. In comparison,the Nigerian CCHFV tick isolate was more divergent when compared with the reference China strains 66019 and with the three variants mentioned above. Conclusion The CCHFV isolated from China comprised a group of genetically high conserved strains.