Small RNA regulation of gene expression in Entamoeba

溶组织内阿米巴是一种原生动物寄生虫，是人类重要的病原体。由E. 溶组织性疾病包括痢疾和肝脓肿，这种有机体是一种主要的寄生性死亡原因 全球范围。基因表达的调节是使寄生虫适应宿主的关键因素 在组织入侵期间的环境中，并在生命阶段之间转换以将疾病传播到宿主之外。 内阿米巴基因调控的一个机制是一个强大而复杂的内源RNAi途径。完毕 在过去的几年里，我们对这一途径进行了重要的观察，包括阿米巴小分子 RNA有非常不寻常的5‘-息肉末端，并与阿米巴ArgAerte2-2蛋白相联系以介导 转录基因沉默。此外，我们还鉴定了内阿米巴含有三种Argavite蛋白 具有不同的细胞定位和明显的非冗余功能。我们还使用了关于 利用阿米巴RNAi途径在内阿米巴中开发一种新的、强大的基因沉默工具 “触发”基因。Trigger基因沉默是高度稳定和稳定的，由抑制性组蛋白介导 对触发沉默的基因进行修改。我们的目标是专注于阿米巴中的RNAi方面，这些方面 与其他系统相比是独一无二的，或者与寄生虫生物学的重要方面相交。因此，我们将 (I)确定小RNA“触发”介导的基因沉默的分子机制；和(Ii) 鉴定ArgAerte RNA诱导的沉默复合体的组成。这些数据将 提高我们对内阿米巴中RNAi分子机制的理解。我们的工作是在 RNA干扰和阿米巴生物学的基本细胞过程的交叉。出现的数据将 有助于理解阿米巴生物学中的一个基本过程，并扩展关于 RNAi的基本过程。

Entamoeba histolytica, a protozoan parasite, is an important human pathogen. Diseases caused by E. histolytica include dysentery and liver abscesses, and the organism is a leading parasitic cause of death on a global scale. Regulation of gene expression is a key factor that enables the parasite to adapt to the host environment during tissue invasion and to convert between life stages to propagate disease outside the host. One mechanism of gene regulation in Entamoeba is a robust and complex endogenous RNAi pathway. Over the last several years we have made important observations about this pathway including that amebic small RNAs have highly unusual 5'-polyP termini and associate with amebic Argonaute 2-2 protein to mediate transcriptional gene silencing. Additionally, we identified that Entamoeba contains three Argonaute proteins with different cellular localizations and apparently non-redundant functions. We have also used information on the amebic RNAi pathway to develop a novel and robust gene-silencing tool in Entamoeba based on use of a “trigger” gene. Trigger gene silencing is highly robust and stable and is mediated by repressive histone modifications on the trigger-silenced loci. Our goal is to focus on aspects of RNAi in ameba that are either unique compared to other systems or which intersect with important aspects of parasite biology. Thus, we will (i) determine the molecular mechanisms of small RNA “trigger” mediated gene silencing, and (ii) characterize the components of the Argonaute RNA induced silencing complexes. These data will improve our understanding of the molecular mechanisms of RNAi in Entamoeba. Our work is at the intersection of the basic cellular process of RNA-interference and amebic biology. Data that emerge will contribute to both understanding a basic process in amebic biology and to expanding the knowledge about the fundamental process of RNAi.