Transcriptional Regulation in Giardia lamblia

描述：(申请人提供)：蓝氏贾第鞭毛虫是最多的 普遍存在的原生寄生虫，也是全世界腹泻疾病的主要原因。 寄生的生活方式和与真核生物的极早期分歧 Tree允许Giardia开发独立的解决方案来解决共同 真核细胞问题。这种生物多样性有助于 它们致病的能力。贾第虫生物学的显著特征是它的两个 细胞核及其异常紧凑和可塑性的基因组。我们的长期目标是 了解基因组结构对基因表达的影响。一个 基本的出发点是转录调控的研究。虽然 在高等真核生物中已经描绘出转录的‘规则’，广泛 在低等真核生物和古生物中的研究清楚地表明了在 基因表达的机制。贾第鞭毛虫转录的研究 因此，重要的是作为了解蛋白质表达的先决条件 参与了发病机制，也加深了我们对进化的理解 转录机器。我们将测试关于RNA的两个假设 蓝氏贾第鞭毛虫中的聚合酶II转录：(I)贾第虫将包含一个 简单化、简单化的核心启动子。两个核心推动因素，塔塔 Box和启动器元素(INR)，尽管基于其 相似的序列图谱，它们将能够独立地启动 抄写。一个TATA结合蛋白的同源物将被呈现给 来自塔塔盒子和Mnr的转录。(Ii)放松的顺序 转录起始的制约因素和四倍体的存在 分布在两个核之间的基因组表明基因的作用增强 染色质和核水平的调节。为了从实验上测试这些 假设我们将产生四个具体的目标：(1)表征 在我们的模型启动子-α-2微管蛋白中，核心启动子元件所起的作用。 (2)隐蔽启动子元件的特征。(3)功能 TATA结合蛋白(TBP)同源物的鉴定。(4)考试 在染色质和核水平上的转录调控。这些研究 将建立对蓝氏贾第鞭毛虫和产蛋虫转录的理解 基因表达调控作用的研究基础 疾病。

DESCRIPTION: (provided by the applicant): Giardia lamblia is one of the most prevalent parasitic protists and a major cause of diarrheal disease worldwide. A parasitic lifestyle and an extremely early divergence from the eukaryotic tree have permitted Giardia to develop independent solutions to common eukaryotic cellular problems. This biological diversity is instrumental in their ability to cause disease. Notable features of Giardia biology are its two nuclei and its unusually compact and plastic genome. Our long-term goal is to understand the consequences that genomic structure exerts on gene expression. A fundamental starting point is the study of transcriptional regulation. Although 'rules' of transcription have been delineated in higher eukaryotes, extensive work in lower eukaryotes and archaea have clearly indicated many differences in the mechanics of gene expression. Investigation of transcription in Giardia is therefore important both as a prerequisite to understand expression of proteins involved in pathogenesis and also to further our understanding of the evolution of transcriptional machinery. We will test two hypotheses regarding RNA Polymerase II transcription in Giardia lamblia: (I) Giardia will contain a simplified and degenerate core promoter. Two core promoter elements, the TATA box and initiator element (Inr), will be present, although based on their similar sequence profiles, they will be independently able to initiate transcription. A homologue of TATA binding protein will be present to direct transcription from both the TATA box and mnr. (II) The relaxed sequence constraints for transcription initiation and the presence of a tetraploid genome distributed between two nuclei suggests an enhanced role for gene regulation at the chromatin and nuclear level. To experimentally test these hypotheses we will ronduct four specific aims: (1) Characterization of the roles served by core promoter elements in our model promoter - alpha-2 tubulin. (2) Characterization of cryptic promoter elements. (3) Functional rharacterization of a homologue of TATA binding protein (TBP). (4) Examination of transcriptional regulation at the chromatin and nuclear level. These studies will build an understanding of transcription in Giardia lamblia and lay foundations for study of the role of the regulation of gene expression in disease.