Molecular mechanisms of gene regulation in Chlamydia

描述（由申请人提供）：Ming Tan博士是一名医生科学家，研究兴趣是细菌发病机制和传染病。他是加州大学欧文分校微生物学和分子遗传学系的教员，该系在微生物发病机制和基因调控方面拥有良好的研究记录。谭博士正在研究细菌病原体衣原体，这是发达国家性传播疾病的主要原因，也是发展中国家可预防失明的主要原因之一。此外，衣原体与动脉粥样硬化性心脏病有关。谭博士的职业目标是保持一个独立的研究计划，最终导致对衣原体发病机制的新见解，以及对衣原体感染的新的治疗和预防方法。 博士Tan正在研究衣原体的细胞内存活和复制，重点是衣原体基因调控的分子机制。他正在使用一种体外方法来研究基因调控，该方法基于克隆的衣原体启动子通过纯化的RNA聚合酶的转录。在这个提议中，几个不同的机制，调节启动子活性将进行调查。在许多衣原体启动子中发现了一个顺式作用DNA元件，它的存在增加了启动子活性。Tan博士推测，一个假定的激活因子与这个DNA元件结合并上调转录，为启动衣原体基因表达提供了一个通用开关。将通过确定依赖于DNA元件的活性是否可与RNA聚合酶的活性分离来检验该假设。Tan博士还证明，通过在体外试验中加入重组衣原体蛋白，可以重建受调控的衣原体转录。例如，热休克启动子已被证明是由转录阻遏物调节。该机制通过增加温度调节这种阻遏物的活性，并导致上调热休克基因的表达，将在本提案中进行检查。其他形式的调控将通过测试候选转录因子的活性来研究。Tan博士重建了另一种衣原体RNA聚合酶的活性，该聚合酶通过识别不同的启动子结构来转录特定基因。这种重建的活性将与生物信息学方法相结合，以确定由这种替代RNA聚合酶调控的基因。

DESCRIPTION (provided by applicant): Dr. Ming Tan is a physician scientist with a research interest in bacterial pathogenesis and infectious diseases. He is a faculty member in the Department of Microbiology and Molecular Genetics at the University of California, Irvine, which has a strong record of research in microbial pathogenesis and gene regulation. Dr. Tan is studying the bacterial pathogen, Chlamydia, which is the leading cause of sexually transmitted disease in the developed world and one of the main causes of preventable blindness in the developing world. In addition, Chlamydia has been associated with atherosclerotic heart disease. Dr. Tan's career goal is to maintain an independent research program that ultimately leads to new insights into chlamydial pathogenesis, and new therapeutic and preventative approaches towards chlamydial infections. Dr. Tan is investigating the intracellular survival and replication of Chlamydia, with a focus on the molecular mechanisms of chlamydial gene regulation. He is using an in vitro approach to study gene regulation, based on the transcription of cloned chlamydial promoters by purified RNA polymerase. In this proposal, several different mechanisms that regulate promoter activity will be investigated. A cis-acting DNA element has been identified in many chlamydial promoters and its presence increases promoter activity. Dr. Tan hypothesizes that a putative activator binds to this DNA element and upregulates transcription, providing a general switch for turning on chlamydial gene expression. This hypothesis will be tested by determining if the activity that is dependent on the DNA element is separable from the activity of RNA polymerase. Dr. Tan has also demonstrated that regulated chlamydial transcription can be reconstituted by adding recombinant chlamydial proteins to his in vitro assay. For example, heat shock promoters have been shown to be regulated by a transcriptional repressor. The mechanism by which increased temperature modulates the activity of this repressor, and leads to upregulation of heat shock gene expression, will be examined in this proposal. Additional forms of regulation will be studied by testing the activity of candidate transcription factors. Dr. Tan has reconstituted the activity of an alternative chlamydial RNA polymerase that transcribes specific genes by recognizing a different promoter structure. This reconstituted activity will be combined with a bioinformatics approach to identify genes that are regulated by this alternative RNA polymerase.