美国哈佛医学院George M. Church、Eric D. Kelsic等研究人员合作通过全面解析腺相关病毒（AAV）的衣壳适应性图谱，发现一个关键基因并能够实现机器指导的设计。相关论文于2019年11月29日发表在《科学》杂志上。

研究人员生成了完整的一阶AAV2衣壳适应性图谱，描述了跨多个与体内递送相关的功能的所有单密码子取代、插入和缺失。研究人员在VP1区域发现了一个移码基因，该基因表达与膜相关的辅助蛋白，其通过竞争性排斥作用限制了AAV的产生。突变分布揭示了表面暴露和掩埋残基的重要性，并且一些表型图谱定义了大多数变异。

最后，研究人员通过算法设计和实验验证了多种体内靶向衣壳库，其可行性远超过随机诱变方法。这些结果证明了系统诱变解密复杂基因组的能力以及经验性机器指导蛋白质工程的潜力。

据了解，AAV衣壳可以提供转化性基因治疗，但我们对AAV生物学的了解仍然不完整。

附：英文原文

Title: Comprehensive AAV capsid fitness landscape reveals a viral gene and enables machine-guided design

Author: Pierce J. Ogden, Eric D. Kelsic, Sam Sinai, George M. Church

Issue&Volume: 2019/11/29

Abstract: Adeno-associated virus (AAV) capsids can deliver transformative gene therapies, but our understanding of AAV biology remains incomplete. We generated the complete first-order AAV2 capsid fitness landscape, characterizing all single-codon substitutions, insertions, and deletions across multiple functions relevant for in vivo delivery. We discovered a frameshifted gene in the VP1 region that expresses a membrane-associated accessory protein that limits AAV production through competitive exclusion. Mutant biodistribution revealed the importance of both surface-exposed and buried residues, with a few phenotypic profiles characterizing most variants. Finally, we algorithmically designed and experimentally verified a diverse in vivo targeted capsid library with viability far exceeding random mutagenesis approaches. These results demonstrate the power of systematic mutagenesis for deciphering complex genomes and the potential of empirical machine-guided protein engineering.

DOI: 10.1126/science.aaw2900

Source: https://science.sciencemag.org/content/366/6469/1139