ROLE OF VIRAL IRES-RIBOSOME INTERACTIONS IN TRANLATION

真核细胞的生存依赖于对蛋白质合成起始的严格调控。 越来越多的证据表明，这一规定涉及到 核糖体的小(40s)亚单位。为了探索其分子基础和功能作用 这些40s亚基的构象变化，我们将考察翻译启动的各个方面 由病毒基因表达控制的调控。许多病毒，如丙型肝炎，都含有内部 在它们的信使RNA中绕过常规启动的核糖体进入位点(IRESS)。这些 IRESS不需要翻译启动因素的全部补充才能发挥作用。这将使 病毒绕过在病毒感染时抑制翻译的细胞途径。了解 病毒IRESS使用的分子机制将极大地帮助开发抗病毒策略 与毁灭性的人类病毒疾病作斗争。板球麻痹病毒包含和IRES(CRPV IRES) 这不需要任何启动因素，甚至避免了对启动子tRNA的需要。 有趣的是，CRPV IRES在所有类别的真核核糖体上都有功能，包括人类 核糖体。因此，阐明其潜在的作用机制将揭示其一般特征 真核核糖体对翻译起始很重要。 该提案的具体目标如下。1)定位40s亚基的构象变化 在翻译起始过程中由丙型肝炎病毒IRES诱导，以及2)MAP构象变化 在由蟋蟀麻痹病毒IRES在翻译起始过程中诱导的40s亚基中。

The viability of eukaryotic cells relies upon the tight regulation of the initiation of protein synthesis. There is mounting evidence that this regulation involves important conformational changes within the small (40S) subunit of the ribosome. In order to probe the molecular basis and functional roles of these conformational changes in the 40S subunit, we will examine aspects of translation initiation regulation controlled by viral gene expression. Many viruses such as hepatitis C contain internal ribosome entry sites (IRESs) in their messenger RNAs that circumvent conventional initiation. These IRESs do not require the full complement of translation initiation factors to function. This enables viruses to bypass cellular pathways that inhibit translation upon viral infection. Understanding the molecular mechanisms used by viral IRESs will greatly aid in the development of antiviral strategies to combat devastating human viral diseases. The Cricket Paralysis Virus contains and IRES (CrPV IRES) that requires none of the initiation factors, and even circumvents the need for initiator tRNA. Interestingly, the CrPV IRES functions on all classes of eukaryotic ribosome, including human ribosomes. Elucidating its underlying mechanism of action will therefore reveal general features of eukaryotic ribosomes important for translation initiation. The specific aims of the proposal are the following. 1) Map conformational changes in the 40S subunit induced by the hepatitis C Virus IRES during translation initiation, and 2) map conformational changes in the 40S subunit induced by the Cricket Paralysis Virus IRES during translation initiation.