Characterization of tiRNA-mediated Translational Repression

 描述(申请人提供)：细胞存活途径允许细胞在应激环境中存活，直到短暂的应激过去。这对正常细胞的生存至关重要，但也在肿瘤的生长中发挥作用，并在各种炎症性疾病中过度活跃。我们发现了一种新的依赖于血管生成素(Ang)的应激反应途径，Ang是胰腺核糖核酸酶超家族中14 kDa的成员，它可以促进细胞的存活和增殖。Ang已被发现是前列腺癌和其他癌症以及包括肠易激综合征在内的其他疾病中表达最高的蛋白质之一。在肌萎缩侧索硬化症(ALS)和帕金森氏病患者中，它也发生了突变。这项拟议工作的目的是剖析这一途径的机制和分子细节。这些知识将被证明是我们理解ANG如何促进细胞生存和增殖的关键，并将确定癌症和ALS治疗的可用药靶点。Ang靶向并切割反密码子环中的tRNAs，产生tRNA衍生的应激诱导RNAs(TiRNAs)。5‘，但不是3’，tiRNAs的一个子集能够在无细胞系统中抑制含有mRNAs的无上限IRES的翻译。生物活性的tiRNAs与Y-box结合蛋白1(YB-1)和细胞质核酸结合蛋白(CNBP)相互作用。这项提议中提出的假设解决了Ang/tiRNAs重新编程细胞翻译以促进细胞生长和增殖的分子机制。这一提议将确定新发现的tiRNAs如何能够抑制翻译，然后确定它们针对的是细胞中的哪些mRNAs。我将确定CNBP和YB-1在多大程度上需要翻译抑制。然后，我将确定tiRNAs在应对各种细胞压力时能够促进细胞存活的水平。我还将调查如何 TiRNAs可促进乳腺癌细胞的增殖和转移潜能。我推测，翻译减弱抑制了许多家务管理蛋白的翻译，同时上调了编码具有促生长和细胞保护活性的蛋白质的翻译。这些目标的完成将使人们更好地理解细胞如何能够在不利的环境中生存和增殖。这将导致识别靶点，以抑制这一途径，以防止细胞生长。

 DESCRIPTION (provided by applicant): Cell survival pathways allow cells to survive in stressful environments until transient stresses have passed. This is critical for the survival of normal cells, but also plays a role in the growth of tumors and is hyperactive in various inflammatory diseases. We have discovered a novel stress response pathway that is dependent upon angiogenin (ANG), a 14 kDa member of the pancreatic ribonuclease superfamily, which enhances cell survival and proliferation. ANG has been found to be among the most highly upregulated proteins in prostate and other cancers as well as other diseases including irritable bowel syndrome. It is also mutated in a subset of patients with amyotrophic lateral sclerosis (ALS) and parkinson's disease. The purpose of the proposed work is to dissect the mechanisms and molecular details of this pathway. This knowledge will prove critical in our understanding of how ANG promotes cell survival and proliferation and will identify druggable targets for cancer and ALS treatments. ANG targets and cleaves tRNAs in the anti-codon loop to produce tRNA-derived stress- induced RNAs (tiRNAs). A subset of 5', but not 3', tiRNAs are able to inhibit translation of uncapped>capped>IRES containing mRNAs in cell free systems. Bioactive tiRNAs interact with two proteins, Y-box Binding protein 1 (YB-1) and Cytoplasmic Nucleic acid binding protein (CNBP). The hypotheses presented in this proposal address the molecular mechanisms by which ANG/tiRNAs reprogram cellular translation to promote cell growth and proliferation. This proposal will determine how newly discovered tiRNAs are able to inhibit translation and then determine which mRNAs they target in cells. I will determine the extent to which CNBP and YB-1 are required for translation inhibition. Then, I will determine the level to which tiRNAs are able to promote survival in cells in response to various cell stresses. I will also investigate how tiRNAs promote increased proliferation and metastatic potential in breast cancer cells. I hypothesize that translation attenuation inhibits the translation of many housekeeping mRNAs while upregulating the translation of mRNAs encoding proteins with pro-growth and cytoprotective activities. The completion of these aims will result in a better understanding of how cells are able to survive and proliferate in adverse environments. This will result in the identification of targets to inhibit this pathway to prevent cell growth.