RNA SPLICING CONTROL IN ROUS SARCOMA VIRUS

描述(摘自摘要)：此应用程序使用Rous肉瘤 以病毒(RSV)为模型，研究RNA加工的调控。主要呼吸道合胞病毒 转录本是由宿主RNA剪接机器剪接的，但这个过程 是受控制的，因为大多数(75%)的RNA保持未拼接以服务 作为给Gag-Poll蛋白的信息和作为后代的基因组RNA 病毒粒子。病毒蛋白不是正常加工所必需的 表明顺式元件存在于RNA中并由宿主派生 反式作用因子决定剪接体与非剪接体的比率 核糖核酸。这项研究描述了这些顺式和反式作用因素。一 控制元件已经确定，剪接的负调节因子 (NRS)，位于GAG，其独特之处在于它不位于 接近任何剪接位点，但同时抑制env和src 3剪接。 站点(Ss)。已经确定了NRS的两个亚区；上游 富含嘌呤的区域，结合称为SR蛋白的基本剪接因子 和未知因子(P55)，以及以下所需的下游序列 U11 SnRNP的结合，一种RNP粒子，它识别新的 稀有内含子类(AT-AC内含子)。U1和U2，丰富的SnRNPs 主要的剪接途径也与NRS RNA相互作用。四个具体目标 都被提出了。第一个使用体内和体外方法来进一步 描述支配NRS的顺式要素和反式作用因素 剪接抑制。第二个目的是检验一个假设，即U11 SNRNP， 当与NRS结合时，与主要途径的相互作用是非生产性的 在可信的3ss中存在剪接因素，不包括与 正宗的5个ss.第三个目的是研究一种抑制src的元素。 拼接，命名为SSS。最终目的是调查 NRS和SSS在剪接抑制中的位置依赖性。这可能是 受剪接部位竞争或相对于5‘帽的位置的影响 结构。

DESCRIPTION (Adapted from Abstract): This application uses the Rous sarcoma virus (RSV) as a model to study regulation of RNA processing. RSV primary transcripts are spliced by the host RNA splicing machinery, but this process is controlled since the majority (75%) of the RNA remain unspliced to serve as the message for the gag-pol proteins and as genomic RNA for progeny virions. Viral proteins are not required for the normal processing indicating that the cis elements are in the RNA and host-derived trans-acting factors are responsible for the ratio of spliced to unspliced RNA. This study characterizes these cis and trans-acting factors. One control element has been identified, the Negative regulator of splicing (NRS), which is located in gag and is distinctive in that it is not located near any of the splice sites, yet suppresses both the env and src 3 splice sites (ss). Two subregions of the NRS have been identified; an upstream purine-rich region that binds essential splicing factors called SR proteins and an unknown factor (p55), and a downstream sequence that is required for binding of U11 snRNP, an RNP particle that recognizes the 5 ss in a new class of rare introns (AT-AC introns). U1 and U2, abundant snRNPs of the major splicing pathway also interact with the NRS RNA. Four specific aims are proposed. The first uses in vivo and in vitro approaches to further characterize the cis elements and trans-acting factors which govern NRS splicing inhibition. The second aim tests a hypothesis that the U11 snRNP, when bound to the NRS interacts nonproductively with the major pathway splicing factors present at the authentic 3 ss, excluding pairing with the authentic 5 ss. The third aim studies an element which suppresses src splicing, named the SSS. The final aim investigates the basis of the position dependence of the NRS and SSS in splicing inhibition. This may be effected by splice site competition or the position relative to the 5' cap structure.