凡纳滨对虾重组激活基因RAGs的结构与功能研究

脊椎动物重组激活基因RAGs介导的V(D)J基因重排为其适应性免疫系统对病原的特异性识别和免疫记忆提供了重要物质基础。RAGs的起源和进化一直是适应性免疫研究的热点。随着RAGs同源基因在进化地位更低等动物（头索动物和昆虫）中被发现，RAGs基因起源于转座子的假说得到更多证据的支持。然而，RAGs在无脊椎动物中的功能以及RAG2如何起源等关键问题仍不清楚。近期我们在对虾转录组中发现RAGs类似基因LvRAG1-like和LvRAG2-like，它们与头索动物文昌鱼的RAGs具有较高序列相似性且与脊椎动物RAGs具有类似的协同表达特征。本项目拟解析对虾RAG类似基因（LvRAGs-like）的结构特征及LvRAG1-like和LvRAG2-like蛋白的活性特点，探讨它们的生物学功能，以期为脊椎动物RAGs的起源与进化提供新的证据，同时也将丰富无脊椎动物免疫的基础理论。

Recombination-activating genes (RAGs) mediated V(D)J recombination provides an essential material foundation for the specific recognition to pathogens and immunological memory of their adaptive immune system in vertebrates. The origin and evolution of RAGs have been always a hot research topic for adaptive immunity. Along with the identification of RAGs homologues in animals at lower evolutionary position (such as cephalochordate and insects), more and more evidence support the hypothesis that RAGs originate from a transposable element. However, some key issues including the function of RAGs in invertebrate and the origin of RAG2 are still not clear. In our previous study, we identified the RAGs-like genes in the transcriptome of Litopenaeus vannamei (LvRAG1-like and LvRAG2-like). They shared high sequence similarity with RAGs homologues in lancelet and showed co-expression pattern which is similar to that of RAGs in vertebrates. The present study will reveal the gene structure of LvRAGs-like. The active characteristics of LvRAG1-like and LvRAG2-like protein will be clarified, and their biological functions in shrimp will be studied. The data will not only provide new evidence for the origin and evolution of RAGs, but also enrich our knowledge on the immune system in invertebrates.