【摘要】 牛泡沫病毒（ＢＦＶ）是反转录病毒科泡沫病毒属成员之一．其基因组除编码ｇａｇ，ｐｏｌ，ｅｎｖ三个结构基因外，在ｅｎｖ和３＇ＬＴＲ之间有２个ＯＲＦ（ＯＲＦ－１和ＯＲＦ－２），编码自身的反式激活因子Ｔａｓ等调节蛋白．本研究利用我们实验室分离鉴定的ＢＦＶ３０２６中国毒株［１２］为材料，克隆Ｏｒｆ－１基因，构建ｐＢＦＶＯＲＦ－１表达质粒，通过带有ｌｕｃ基因的ＬＴＲ系列缺失质粒与ｐＢＦＶＯＲＦ－１共转染，瞬时表达分析结果将ＢＦＶＬＴＲ上Ｔａｓ应答元件（ＴＲＥ）定位于－９８３／－６６８（ＴＲＥＩ），－４７０／－１４０（ＴＲＥＩ）和ＲＵ５区．其中ＴＲＥＩ、ＴＲＥＩＩ为正调控区域，ＲＵ５为负调控区域，并进一步证明ＲＵ５在异源启动子（ＢＩＶＬＴＲ）上具有抑制其下游基因表达的功能．这些结果表明ＢＦＶＴａｓ作用机理与慢病毒（Ｔａｔ），致瘤病毒（Ｔａｘ）等均不相同更多还原

【Abstract】 Bovine foamy virus(BFV),a member of the Spumaviriane subfamily of retroviruses,contains two open reading frames (ORF 1 and ORF 2) in addition to gag,pol and env genes.The transcriptional transactivator Borf 1(Tas) protein,encoded by ORF 1,augments gene expression directed by the viral long terminal repeat(LTR).A series of LTR mutant promoter constructs have been analyzed in transient expression assays for responsiveness to Tas.The Tas positive responsive elements(TRE) have been mapped to the U3 domain of the LTR,between positions -983 and -668 and between positions -470 and -140 (+1 represents the transcription initiation site).The RU5 region is shown to have a negative effect on LTR directed gene expression.These results indicate that the mechanism of transactivation of foamy viruses is significantly different from that of lentiviruses and oncoviruses.更多还原