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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
Bovine foam virus (BFV) is a member of the genus Retroviridae. Its genome contains two ORFs (ORF-1 and ORF-2) between env and 3’LTR, encoding its regulatory protein such as the transactivator Tas, in addition to the three structural genes gag, pol and env. In this study, we used the BFV3026 Chinese strain [12] isolated and identified by our laboratory as the material to clone the Orf-1 gene and constructed the pBFVORF-1 expression plasmid, which was cotransfected with pBFVORF-1 by LTR deletion plasmid with luc gene. Transient Expression Analysis Results Tas response element (TRE) on BFVLTR was localized at -983 / -668 (TREI), -470/140 (TREI), and RU5 region. Among them, TREI and TREII are positive regulatory regions, and RU5 is a negative regulatory region, further demonstrating that RU5 has a function of inhibiting the expression of its downstream genes on the heterologous promoter (BIVLTR). These results suggest that the mechanism of action of BFVTas is different from that of lentivirus (Tat) and tumorigenic virus (Tax)