文昌鱼抗金葡菌感染差减文库的构建及免疫相关基因分析

Construction of Subtractive Library Against Staphylococcus aureus and Analysis of Immune-related Genes in Amphioxus

适应性免疫的起源一直是免疫学研究的关键问题.文昌鱼被认为是最接近于脊椎动物的祖先,自从被发现以来一直是研究脊椎动物起源与进化机制的经典模式动物.为了在文昌鱼中寻找适应性免疫系统的分子证据,采用金黄色葡萄球菌感染文昌鱼以调查免疫的起源.应用抑制性差减杂交(SSH)技术,通过对差减文库克隆序列的测定,共获得588个表达序列标签(EST).对这些EST进行生物信息学分析和进一步功能分类,发现了一些免疫上调基因,如免疫调控基因、凋亡相关基因、细胞黏附相关基因、转录相关基因、信号传导相关基因等,以及一些非免疫相关基因;这些基因在文昌鱼中绝大多数为首次报道.金黄色葡萄球菌差减文库的成功构建,为调查文昌鱼抗细菌感染的分子事件提供了重要线索,对于这些新发现基因的进一步研究将有助于深入了解免疫系统起源与进化的机制.

The evolution of the adaptive immune system is one of the fundamental questions in immunology. Amphioxus, the closest living invertebrate relative to the vertebrates, has been widely regarded as one of the most important species for the investigation of the origin and evolution of the vertebrates. In order to search the molecular evidences which are involved in the adaptive immune system evolution, amphioxus was infected by Staphylococcus aureus and the subtractive library was constructed. In the library, 588 novel expressed sequence tags （ESTs） were obtained through suppression subtractive hybridization （SSH）, and most of the identified ESTs were reported for the first time in amphioxus. Bioinformatics analysis showed that the genes encoded by these novel ESTs were involved in various functions such as immune response, apoptosis, cell adhesion, transcriptional regulation, signal transduction and so on. It is the first time to report the construction of the suppression subtractive hybridization library from Staphylococcus aureus challenged amphioxus. The library provides the important clues for further investigations of the molecular events that occurred during the development of adaptive immune system, and further functional studies of these newly identified genes will be helpful for the understanding of the origin and phylogeny of the vertebrate immune system.