FUNCTIONS OF LEUKEMIA VIRUS R REGIONS

我们已经获得了初步的数据， 某些小鼠白血病基因组的R组分的核苷酸 病毒（MuLV），有助于转录活性的 病毒 MuLV的R区位于细胞的下游， 转录起始位点，与那些 猩猩白血病病毒，猿猴肉瘤病毒， 白血病病毒 我们的初步数据表明， 的R序列是重要的活动的元素。 还有， R区元件至少部分地增加RNA聚合酶II 加载到病毒LTR模板上，如在核连续测定中检测到的。 我们建议在这里进行一系列详细的研究，以调查 MuLV元件的功能。 特别是，我们假设， MuLV R区元件以类似于 HIV-1 TAR元件。 具体来说，我们假设一种细胞因子 存在功能上等同于HIV-1达特并识别 MuLV R元件在RNA水平上刺激转录 起始和/或RNA聚合酶持续合成能力。 我们建议使用 诱变方法，以准确地鉴定哪些核苷酸内的 MuLV R元件对活性至关重要。 一系列的实验将 以测试MuLV序列是否作为DNA或RNA发挥功能 部分。 我们还将确定它们是否严格影响 转录起始或它们是否影响RNA的持续合成能力 聚合酶分子装载到病毒转录模板上。其他 将对病毒进行检测，以确定它们是否含有类似的元素 以及MuLV功能的序列上下文要求 元素是。 我们还将测试MuLV序列是否至少可以 部分取代HIV-1 TAR元件。 蛋白质-核酸 结合试验将被用来寻找细胞因子， MuLV R区元件。

We have obtained preliminary data that an element exists within the 5' 32 nucleotides of the R components of the genomes of certain murine leukemia viruses (MuLVs) that contributes to the transcriptional activity of the virus. The R regions of the MuLVs, which are situated downstream of the initiation site of the transcription, bear striking similarity to those of the gibbon ape leukemia virus, simian sarcoma virus, and feline leukemia viruses. Our preliminary data indicate that secondary structure of the R sequences is important for the activity of the element. Also, the R region element acts at least in part to increase RNA polymerase II loading onto viral LTR templates, as detected in nuclear run-on assays. We propose here to perform a detailed series of studies to investigate how the MuLV element functions. In particular, we hypothesize that the MuLV R region element functions in a manner analogous to that of the HIV-1 TAR element. Specifically, we hypothesize that a cellular factor exists that is functionally equivalent to HIV-1 Tat and recognizes the MuLV R element at the level of RNA to stimulate transcriptional initiation and/or RNA polymerase processivity. We propose to use a mutagenesis approach to identify precisely which nucleotides within the MuLV R element are critical for activity. A series of experiments will be performed to test whether the MuLV sequences function as a DNA or RNA moiety. We will also determine whether they strictly affect transcriptional initiation or whether they affect processivity of RNA polymerase molecules loaded onto viral transcriptional templates. other viruses will be examined to see whether they contain a similar element and what the sequence context requirements for the function of the MuLV element are. We will also test whether the MuLV sequence can at least partially substitute for the HIV-1 TAR element. Protein-nucleic acid binding assays will be used to look for cellular factors that recognize the MuLV R region element.