PROKARYOTIC GENE REGULATION BY LIGHT AND OXYGEN

描述：已知氧张力的改变会影响基因表达。 在所有细胞类型中表达。 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，以及 参与防御氧化损伤的基因。 各种附加 代谢过程，如CO2固定、固氮和缺氧 光合作用也受氧的转录调控。 在酵母和 在藻类细胞中，已知氧气会影响氧化防御的转录 基因以及参与糖酵解的酶。 在哺乳动物细胞中， 已知越来越多的基因是受氧调节的，例如 编码生长因子如促红细胞生成素和血管内皮细胞 生长因子是合成新毛细血管的关键调节因子， 从原有的血管中长出 除了生理作用，这些生长 因素也参与疾病过程，如刺激 肿瘤生长过程中的毛细血管形成。 该提案以 阐明了氧如何影响基因表达的分子细节， 细菌Rhodobacter capsulatus，它与 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、无氧 发酵和光合作用。 参与每一个基因的表达 已知这些过程中的一个受氧张力变化的影响 以及光强度的变化。 因此，这种生物提供了 作为研究光和氧的重要模型系统 基因表达的调控。

DESCRIPTION: 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, as well as genes involved in defense against oxidative damage. A variety of additional metabolic processes such as CO2 fixation, nitrogen fixation, and anoxygenic photosynthesis are also transcriptionally regulated by oxygen. In yeast and algal cells, oxygen is known to affect transcription of oxidative defense genes as well as enzymes involved in 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 the bacterium 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 as well as by variations in light intensity. As such, this organism offers itself as an important model system to the study of oxygen and light regulation of gene expression.