从文昌鱼化学防御系统分析、鉴定探索脊椎动物肝脏与化学防御系统起源

项目名称： 从文昌鱼化学防御系统分析、鉴定探索脊椎动物肝脏与化学防御系统起源

项目编号： No.31501856

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 动物学

项目作者： 张宇

作者单位： 中国海洋大学

项目金额： 19万元

中文摘要： 肝脏是脊椎动物特有器官，也是执行化学防御系统特别是生物转化和解毒作用的主要场所。关于脊椎动物肝脏和化学防御系统起源，迄今尚不十分清楚。文昌鱼肝盲囊被认为是脊椎动物肝脏同源器官，但对其化学防御系统迄今未见有研究报道。基于肝盲囊与肝脏同源性以及以前有关研究结果，我们提出“文昌鱼存在类似脊椎动物化学防御系统”这一假设。我们拟1）利用现有的文昌鱼基因组数据库、EST数据库以及cDNA数据库，全面系统预测文昌鱼的化学防御基因并进行进化分析；2）利用二代转录组测序技术，对化学物质处理后不同时间点的文昌鱼肝盲囊转录组进行测序，分析、建立文昌鱼肝盲囊中化学防御相关基因表达谱和信号通路；3）通过免疫共沉淀法和蔗糖梯度速度沉降法，研究文昌鱼AHR蛋白的化学防御功能。在此基础上揭示脊椎动物化学防御系统起源，并为肝脏起源于文昌鱼肝盲囊样组织提供更多支持或否定之证据，丰富和提升对脊椎动物化学防御系统和肝起源的认识。

中文关键词： 文昌鱼；化学防御系统；转录组测序；肝盲囊；细胞色素P450

英文摘要： Liver is an organ characteristic of vertebrates, which plays a critical role in chemical defense, especially detoxification. Despite an enormous progress on the chemical defense in vertebrates, the information remains rather limited regarding the origin of vertebrate liver and chemical defensome. Amphioxus, a basal chordate, has a hepatic caecum, which has long been considered as the homologous tissue to vertebrate liver, yet the study on the chemical defensome is still lacking in amphioxus to date. Based on the similarity of hepatic caecum to liver as well as the results of previous studies, we propose that amphioxus possesses a vertebrate-like chemical defensome. Our proposal is thus to prove this hypothesis. We will carry out the following researches: 1) Genome-wide survey and prediction of chemical defense genes from available amphioxus genome, ESTs, cDNAs; 2) RNA-seq analysis of chemical defense response in hepatic caecum after amphioxus exposed to xenobiotic PCB126; 3) Analysis of the chemical defense function of amphioxus AHR protein by assay of co-immunoprecipitation and velocity sedimentation on sucrose gradients. This will certainly allow us to illuminate the evolution of chemical defense gene network, and moreover, provide evidences to support or deny the notion that amphioxus hepatic caecum is the precursor of vertebrate liver.

英文关键词： Branchiostoma japonicum;Chemical defensome;RNA-seq;Hepatic caecum;CYP450