FUNCTIONAL ORGANIZATION OF BK VIRUS PROMOTER/ENHANCER

人乳头状瘤病毒BK广泛分布于人群中。 像其他乳头病毒一样，它在啮齿类动物中具有致瘤作用。这个 BK的整体基因组结构与Well-Well相似 特征为猴乳头状病毒SV40，具有早期和晚期 以相反方向转录的RNA来自共同的 转录控制区。不同的BK分离株显示 控制区域中的重新排列、删除和插入， 导致病毒的致瘤潜力发生变化。这 控制区是BK基因组中仅有的一部分 与SV40的序列同源性，似乎BK可能相互作用 一组不同的宿主细胞转录因子。 我们提出了一些实验，试图了解 BK控制区工作正常。使用DNase I足迹和其他 DNA结合的分析，我们将绘制出 宿主细胞蛋白的相互作用，然后将决定是否 结合这些位点的蛋白质与 已知与其他病毒和细胞结合的转录因子 启动子/增强子区。使用来自绑定的信息 分析，我们将继续关联序列特异性结合 具有生物功能。我们将开发一种体外转录 依赖于部分或全部被鉴定为 结合到控制区，并将在体内发展 可分别测定早期和晚期启动子的检测方法 功能和转录增强子活性。 我们将对比BK(Dunlop)中序列特异的蛋白质结合 菌株)与其他BK变种中的相同，并特别注意 可能由内部的超可变连接形成的位置 直接序列的区域重复。沿途的实验 这里提出的线条应该彻底地阐明 BK控制区，因此将允许合理解释 关于致瘤性的现在和未来的观察或 BK病毒及其变种的其他致病作用。

The papovavirus BK is widely distributed in the human population. Like other papovaviruses, it is tumorigenic in rodents. The overall genome structure of BK is similar to the well- characterized monkey papovavirus SV40, with early and late RNAs transcribed in opposite directions from a common transcriptional control region. Different BK isolates show rearrangements, deletions, and insertions in the control region, leading to alterations in the virus's tumorigenic potential. This control region is the only part of the BK genome with little sequence homology to SV40, and it seems likely that BK interacts with a different set of host cell transcription factors. We propose a number of experiments to try a understand how the BK control region works. Using DNase I footprinting and other assays of DNA binding, we will map the precise sites of interaction of host cell proteins, and then will determine whether the proteins that bind these sites are the same or different from transcription factors known to bind other viral and cellular promoter/enhancer regions. Using information from the binding assays, we will proceed to correlate sequence-specific binding with biological function. We will develop an in vitro transcription system dependent on some or all of the proteins identified as binding to the control region, and will in addition develop in vivo assays capable of separately measuring early and late promoter function, and transcriptional enhancer activity. We will contrast sequence-specific protein binding in BK (Dunlop strain) with that in other BK variants, with special attention to sites that may be formed by the hyper-variable junctions within the region of direct sequence repeats. Experiments along the lines proposed here should thoroughly illuminate the workings of the BK control region, and thus will allow rational interpretation of present and future observations relating to tumorigenicity or other pathogenic effects of BK virus and its variants.