Prokaryotic Gene Regulation By Light and Oxygen

描述（由申请人提供）：已知氧张力的变化 影响所有细胞类型的基因表达。在细菌系统中，氧气影响 参与有氧与无氧能量的各种基因的表达 生成，如硝酸还原酶和细胞色素氧化酶。的存在 氧活性物质，也影响参与防御的基因的表达 抗氧化损伤各种额外的代谢过程，如 碳固定、氮固定和无氧光合作用也是 根据氧气的存在或缺乏来调节。在酵母和藻类中 在细胞中，已知氧影响氧化防御基因以及参与糖酵解的酶的转录。在哺乳动物细胞中， 已知基因是氧调节的，例如那些编码生长因子的基因 如促红细胞生成素和血管内皮生长因子， 调节剂，用于从预先存在的血管合成新的毛细血管芽。 除了生理作用外，这些生长因子还参与疾病 例如在肿瘤生长期间刺激毛细血管形成的过程。 这项提议的核心是阐明氧气如何 影响细菌的基因表达。作为一个模型系统，我们研究氧气 在荚膜红细菌中调控基因表达， 线粒体谱系该物种能够在多种环境中生长， 能量产生模式包括有氧呼吸、厌氧发酵 和光合作用参与这些过程的基因的表达 已知受氧张力变化的影响， 光强度的变化。因此，这种有机体提供了自己作为一个 是研究氧和光对基因调控的重要模式系统 在许多生物系统中表达。

DESCRIPTION (provided by applicant): Alterations in oxygen tension are known to affect gene expression in all cell types. In bacterial systems, oxygen affects expression of a variety of genes involved in aerobic versus anaerobic energy generation such as nitrate reductase and cytochrome oxidase. The presence of oxygen reactive species, also affects expression of genes involved in defense against oxidative damage. A variety of additional metabolic processes such as carbon fixation, nitrogen fixation, and anoxygenic photosynthesis are also regulated in response to the presence or absence of oxygen. In yeast and algal cells, oxygen is known to affect transcription of oxidative defense genes as well as enzymes involved glycolysis. In mammalian cells, a growing number of genes are known to be oxygen regulated such as those coding for growth factors such as erythropoietin and vascular endothelithial growth factors that are key regulators for the synthesis of new capillary sprouts from preexisting vessels. Besides physiological roles, these growth factors are also involved in disease processes such as the stimulation of capillary formation during tumor growth. This proposal is centered on elucidating molecular details of how oxygen affects gene expression in bacteria. As a model system, we study oxygen regulated gene expression in Rhodobacter capsulatus which is closely related to the mitochondrial lineage. This species is capable of growth in a variety of energy generating modes including aerobic respiration, anaerobic fermentation and photosynthesis. The expression of genes involved in each of these processes is known to be affected by alterations in oxygen tension and well as by variations in light intensity. As such, this organism offers itself as an important model system to the study oxygen and light regulation of gene expression in a number of biological systems.