一株输血传播病毒新变种的克隆和序列分析  

Cloning and sequence analysis of a novel TT virus variant

作　　者：刘志华[1] 骆抗先[1] 何海棠[1] 

机构地区：[1]第一军医大学南方医院感染内科,广东广州510515

出　　处：《第一军医大学学报》2002年第8期690-692,共3页Journal of First Military Medical University

基　　金：军队九五医药卫生科研基金(98z073)

摘　　要：目的从1例不明原因转氨酶升高的病人血清中克隆输血传播病毒(TTV)DNA,并进行序列分析。方法用巢式PCR扩增TTVDNA长片段,连接至pGEM-T载体上,挑选一个克隆(56-B)进行测序。将56-B与GenBank中五株TTV进行氨基酸和核苷酸序列的同源性分析,并用最大似然法进行分子进化分析。结果56-B株与TA278等五株TTV序列的核苷酸同源性分别为42.4%、48.2%、47.9%、49.8%、61.7%,氨基酸序列的同源性更低,但其5'和3'两端非编码区的序列仍然很保守。结论56-B株与其他TTV株之间的同源性很低,有很高的基因异质性,是TT 的一个新变种,代表TTV的一个新的基因型。Objective To clone the DNA of a TT virus (TTV) variant isolated from a patient with elevated alanine transaminase (ALT) of unknown etiology, and conduct sequence analysis. Methods The long fragment of TTV DNA was amplified by nested PCR and then cloned into pGEM-T vector. A clone named 56-B containing 3.2 kb TTV DNA was selected for sequence analysis besides homology analysis with other 5 TTV variants retrieved from GenBank, and phylogenetic analysis was carried out by maximum likelihood method. Results The nucleotide identities of 56-B with the other 5 TTV strains TA278, JA10, US35, SANBAN and TUS01 were 42.4%, 48.2%, 47.9%, 49.8% and 61.7% respectively, and the corresponding amino acid identities were even lower. Phylogenetic analysis showed that 56-B was far from other TTV strains in genetic distance that ranged from 0.344 to 0.458. However, the sequences in the 5'- and 3'-end were still much conservative. Conclusion The isolated 56-B showed high heterogeneity in genetic background and was therefore quite distinct from other TTV strains as a novel TTV variant that represents a new TTV genotype.

关 键 词：输血传播病毒 基因异质性 巢式PCR 

分 类 号：Q78[生物学—分子生物学]