基因治疗是指借助于病毒载体或其它介质，将具有治疗作用的外源基因导入含缺陷基因的细胞内，替代、修复或干预缺陷基因，从源头根除致病诱因。然而病毒载体感染的非选择性及其免疫原性等不良反应阻碍了基因治疗的发展。本项目将基于前期建立的“基于基因密码扩展的在体蛋白质标记”新方法，探索在慢病毒和腺相关病毒膜蛋白的任意位点选择性引入化学功能团，建立温和、快速、高效、定量和特异引入靶头分子的方法，进而揭示重组病毒载体的结构与靶向性和免疫原性的关系，发现病毒载体膜蛋白的可修饰位点和不/低诱发免疫副反应的重组表位结构。更进一步，基于重组病毒载体的构效关系，设计和优化带靶头的新型病毒载体，提高其对特定细胞和组织的感染选择性，降低重组病毒载体免疫原性；同时构建含非天然氨基酸生物正交系统、并可高效包装自杀基因和shRNA沉默以及CRISPR修复系统的全新细胞株，为基因治疗用病毒载体的更新换代提供理论指导和实验依据。

With the aim to broaden the versatility of viral vector as a tool in gene therapy, we expand the genetic code in propagation of lentiviral vectors and adeno-associated vectors for site-specific incorporation of chemical moieties with unique properties. Through systematic exploration of the structure-function relationship of viral vectors by site-specific displaying azide- and other chemical moieties, the modifiable sites on vector surface are identified that neither affect the expression of envelope protein nor propagation or infectivity of progeny virus. Furthermore, via such incorporated chemical moieties a variety of probe, ligand and other functional molecules are conjugated, orthogonally and stoichiometrically, to viral vector to enhance their precise targeting as gene delivery vectors. Furthermore, via the introduction of the targeting entities at different sites, the structure of modified viral envelope and immunogenicity relationship are explored. By such a methodology a facile platform is established that will be demonstrated useful for tracking and targeting gene delivery of therapeutic genes such as TK suicide gene, shRNA-gene knockdown and CRISPR-mediated repairing systems. This study may provide a new direction for rational design of viral vector with significant impact on both basic research and therapeutic applications.