细胞器代谢网络在内共生过程中的结构变化及适应性研究

项目名称： 细胞器代谢网络在内共生过程中的结构变化及适应性研究

项目编号： No.30800199

项目类型： 青年科学基金项目

立项/批准年度： 2009

项目学科： 生物科学

项目作者： 王卓

作者单位： 上海交通大学

项目金额： 20万元

中文摘要： "内共生学说"认为叶绿体起源于蓝藻，线粒体起源于αrotobacteria，内共生过程中细胞器丢失了不必需的基因，并且相当量的基因转移到核基因组中。丢失或向核内转移大量基因以及核编码蛋白重新搬运回内共生细胞器后，叶绿体和线粒体的代谢网络结构与其祖先细胞相比发生了怎样的变化？这种变化对细胞器的功能特化、系统的稳健性及适应性有哪些影响？以往的研究大多通过基因组或蛋白质组的信息分析内共生过程中基因的丢失、转移和改变，还未见从代谢网络的系统观点揭示内共生过程中进化机制及适应性的研究。本项目利用现有数据库和文献信息重构叶绿体与蓝藻、线粒体与αrotobacteria的代谢网络，比较拓扑结构的相同和不同，发现水平基因转移模式，阐明网络进化机制，揭示代谢网络结构的变化对系统稳健性和适应性的影响，对于更深入理解内共生过程中的进化机制具有重要价值，对于从系统生物学水平研究物种进化具有重要的理论意义。

中文关键词： 叶绿体；线粒体；代谢网络；水平基因转移；系统稳健性

英文摘要： According to endosymbiosis, chloroplast descended from cyanobacteria and mitochondria descended from αrotobacteria. During endosymbiosis, the original organelle lost unnecessary genes, and many genes were transferred to the nuclear genome. As a result, the majority of the enzymes in organelle metabolic networks are nucleus-encoded, translated in cytosol, and then imported into organelle. After this complex processes, do the metabolic networks of chloroplast and mitochondria change compared with their ancestors? What is the effect of such changes on specialization, robustness and adaption of organelle？Most of previous studies analyzed gene loss, transfer and diversification during endosymbiosis based on genomics or proteomics. Nobody explored the evolutionary mechanism and adaption during endosymbiosis from system viewpoint of metabolic network. For this project, we will reconstruct the metabolic networks of chloroplast, cyanobacteria, mitochondria and αrotobacteria by collecting information from databases and literatures; compare the sameness and difference of topological structure; found the pattern of horizontal gene transfer; clarify the evolutionary mechanism of metabolic network; elucidate the influence of network structure changes on system robustness and adaption. It is quite important for deeply uncover the evolutionary mechanism during endosymbiosis, and theoretically significant for research on species evolution at the systems biology level.

英文关键词： chloroplast; mitochondria; metabolic network; Horizontal Gene Transfer; system robustness.