Molecular mechanisms of gene regulation in Chlamydia

简介(申请人提供)：谭明博士是一名内科科学家，对细菌致病机制和传染病有研究兴趣。他是加州大学欧文分校微生物学和分子遗传学系的一名教员，该系在微生物发病机制和基因调控方面有着良好的研究记录。谭博士正在研究细菌病原体衣原体，它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项目，最终导致对衣原体发病机制的新见解，以及针对衣原体感染的新的治疗和预防方法。 谭博士正在研究衣原体在细胞内的存活和复制，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，该方法基于纯化的RNA聚合酶对克隆的衣原体启动子的转录。在这项提案中，将研究几种不同的调节启动子活性的机制。在许多衣原体启动子中已经发现了一个顺式作用的DNA元件，它的存在增加了启动子的活性。谭博士假设，一个假定的激活剂结合到这个DNA元件上，并上调转录，为启动衣原体基因表达提供了一个通用开关。这一假设将通过确定依赖于DNA元件的活性是否可与RNA聚合酶的活性分开来检验。谭博士还证明，通过在体外实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受转录抑制因子的调控。温度升高调节这种抑制因子的活性，并导致热休克基因表达上调的机制，将在这项建议中进行研究。将通过测试候选转录因子的活性来研究其他形式的调控。谭博士重建了另一种衣原体RNA聚合酶的活性，这种聚合酶通过识别不同的启动子结构来转录特定的基因。这种重组的活性将与生物信息学方法相结合，以确定受这种替代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.