Transcriptional Regulation in Giardia lamblia

贾第鞭毛虫的转录调控

• 批准号: 6621972
• 负责人: HEIDI G ELMENDORF
• 金额: $ 27.16万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-01-01 至 2006-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6621972
• 关键词: DNA directed RNA polymerase; DNA footprinting; Giardia; binding proteins; biochemical evolution; chromatin; enzyme activity; fluorescent in situ hybridization; gel mobility shift assay; gene expression; genetic promoter element; genetic regulation; genetic transcription; messenger RNA; nuclear runoff assay; nucleic acid sequence; structural genes; transcription factor; tubulin

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.

描述：（由申请人提供）：贾第鞭毛虫是最常见的贾第鞭毛虫之一。 普遍存在的寄生原生生物，是全世界腹泻病的主要原因。 寄生生活方式和与真核生物的极早分化 树允许贾第鞭毛虫开发独立的解决方案来解决常见问题 真核细胞问题。这种生物多样性有助于 他们引起疾病的能力。贾第鞭毛虫生物学的显着特征是它的两个 细胞核及其异常紧凑和可塑的基因组。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 根本出发点是转录调控的研究。虽然 转录的“规则”已在高等真核生物中被描绘出来，广泛 低等真核生物和古细菌的工作清楚地表明了许多差异 基因表达的机制。贾第鞭毛虫转录的研究是 因此作为理解蛋白质表达的先决条件很重要 参与发病机制并进一步加深我们对进化的理解 转录机器。我们将测试关于 RNA 的两个假设 贾第鞭毛虫中的聚合酶 II 转录： (I) 贾第鞭毛虫将包含 简化和简并的核心启动子。两个核心启动子元件，TATA 盒子和引发剂元素（Inr）将出现，尽管基于它们 相似的序列概况，他们将能够独立启动 转录。 TATA 结合蛋白的同源物将存在以指导 来自 TATA 盒和 mnr 的转录。 （二）宽松序列 转录起始和四倍体存在的限制 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控。为了通过实验测试这些 假设我们将实现四个具体目标：（1）表征 我们的模型启动子 - α-2 微管蛋白中的核心启动子元件所发挥的作用。 (2)神秘启动子元件的表征。 (3) 功能性 TATA 结合蛋白 (TBP) 同源物的表征。 （四）考试 染色质和核水平的转录调控。这些研究 将建立对贾第鞭毛虫转录的理解并奠定基础 为研究基因表达调控的作用奠定了基础 疾病。