Transcriptional regulation of the carbohydrate metabolism of the facultatively heterotrophic crenarchaeote Thermoproteus tenax

拟议的项目重点是编码兼性异养菌的中央碳水化合物代谢酶的基因的转录调控。这些研究应深入了解控制分解代谢的EmbdenMeyerhof-Parna(EMP)途径、Entner-Doudoroff(ED)途径、戊糖磷酸(PP)途径和氧化三羧酸循环(TCA)的遗传控制机制，并根据生长条件确定通过EMP途径和TCA循环的可逆途径的碳通量方向。我们的主要目标是识别调节转录因子，这些转录因子主要影响参与中枢碳水化合物代谢的基因对碳源的反应的转录启动，并表征它们的调节作用。作为我们研究的模型靶点，我们选择了可逆EMP途径的已有特征基因，这些基因在自养和异养生长条件下表现出差异的mRNA表达。为了分析对转录启动的调控作用，将对已识别的因子的DNA结合位点进行定位，并确定它们与目标位点的特异性相互作用。通过将研究扩展到正在进行的T.tenax基因组计划确定的另一条途径的差异表达基因，将研究它们在中心碳代谢的全球控制中的作用。

The proposed project focuses on the transcriptional regulation of genes encoding the enzymes of the central carbohydrate metabolism of the facultative heterotroph crenarchaeote Thermoproteus tenax. The studies should provide insight into the genetic control mechanisms, which govern the selection of the EmbdenMeyerhof-Parnas (EMP) pathway, the Entner-Doudoroff (ED) pathway, the pentose phosphate (PP) pathway and the oxidative tricarboxylic acid cycle (TCA) for catabolism and determine the direction of the carbon flux through the reversible routes of EMP pathway and TCA cycle in dependence of growth conditions. Our principal aim is to identify regulatory transcription factors, which primarily affect the transcription initiation of genes involved in the central carbohydrate metabolism in response to a carbon source, and to characterize their regulatory effects. As model targets of our investigations, we chose the already characterized genes of the reversible EMP pathway, which show differential mRNA expression under autotrophical and heterotrophical growth conditions. For analyzing the regulatory effects on the transcription initiation, the DNA-binding sites of identified factors will be localized and their specific interaction with their target sites will be determined. Their role in the global control of the central carbon metabolism will be investigated by extending the studies to differentially expressed genes of the other pathway, identified by the ongoing T. tenax genome project.