Investigating the Potential of Endogenous RNAi in Mediating Adaptation to Environ

描述(由申请人提供) 摘要：RNA干扰(RNAi)在不同的生物体中提供了对病毒和转座子等外源核酸的防御。产生与病毒或转座子序列反义的短干扰RNA(SiRNAs)是RNAi反应的一个标志。线虫内源性反义siRNAs(Endo-siRNAs)的发现与线虫数千个蛋白质编码序列相匹配，并在果蝇和哺乳动物中发现了类似的分子，这给它们的功能提出了一个问题。我们最近对线虫RNAi途径突变中错误调控基因的微阵列分析表明，RNAi成分和内源短RNA优先靶向于其失活有利于抗逆性和寿命延长的基因，如编码翻译因子的基因。我们认为线虫的内源性短RNA池受到自然选择的影响。因此，种群中的siRNAs的组成会随着环境的变化而调整，以实现最大的适应度。本项目的目标是对上述模型进行测试。我们将选择对特定环境条件具有抗性的线虫种群，并测试这些种群是否积累了针对非常特定的基因的反义endsiRNAs，这些基因的失活允许在测试条件下存活。我们已经建立了耐热性和翻译启动因子特异的内切RNA积累之间的相关性。此外，在杀死线虫的药物伊维菌素和左旋咪唑上生存的自然选择将被用于产生抗药性的线虫菌株，这是由于表观遗传的基于Endo-siRNA的特定基因失活造成的。证明存在基于siRNA的表观遗传自然选择将代表着基础科学的根本性突破。表观遗传的RNAi机制不太可能仅限于低等生物，可能涉及恶性肿瘤的免疫逃逸和耐药性，以及在其他情况下，当细胞进化以逃避治疗剂的作用时。 与公共卫生的相关性：该项目的重点是揭示生物体用来适应环境的新机制。如果我们确认线虫体内短RNA分子的组成是为了在特定条件下最大限度地存活，这将为旨在产生具有特定特征的细胞的“自然选择”实验打开大门。例如，可以产生具有增强的抵抗氧化应激能力的神经细胞。

DESCRIPTION (Provided by the applicant) Abstract: RNA interference (RNAi) provides defense against exogenous nucleic acids, such as viruses and transposons, in diverse organisms. The production of short interfering RNAs (siRNAs) antisense to the viral or transposon sequences is a hallmark of the RNAi response. The discovery of the endogenous antisense siRNAs (endo-siRNAs) matching thousands of protein coding sequences in C. elegans and identification of similar molecules in Drosophila and mammals poses a question about their function. Our recent microarray analysis of genes misregulated in the RNAi pathway mutants in C. elegans revealed preferential targeting by the RNAi components and endogenous short RNAs of genes whose inactivation is beneficial for stress resistance and lifespan extension, such as genes encoding translation factors. We propose that pools of endogenous short RNAs in C. elegans are subject to natural selection. Therefore, the composition of siRNAs in populations is adjusted in response to the environmental changes to achieve maximum fitness. The goal of this project is to test the above model. We will select populations of C. elegans resistant to specific environmental conditions and test these populations for the accumulation of endosiRNAs antisense to very specific genes whose inactivation allows survival under the tested condition. We already established a correlation between thermotolerance and accumulation of endo-siRNAs specific to translation initiation factors. In addition, natural selection for survival on the nematocidal drugs ivermectin and levamisole will be used to generate C. elegans strains resistant to drugs due to epigenetic endo-siRNA-based inactivation of specific genes. Proving the existence of a siRNA-based epigenetic natural selection would represent a fundamental breakthrough in basic science. Epigenetic RNAi-based mechanisms are not likely to be limited to lower organisms and may be involved in the immune escape and drug-resistance of malignant tumors and in other cases when cells evolve to escape the action of therapeutic agents. Public Health Relevance: This project is focused on revealing new mechanisms used by organisms for the adaptation to environment. If we confirm that composition of short RNA molecules in the nematode C. elegans is selected to maximize survival under specific conditions, this will open the doors for "natural selection" experiments aimed at generation of cells with specific characteristics. For example, neuronal cells with enhanced ability to resist oxidative stress could be generated.