Viruses are ubiquitous pathogens of global impact. Prompted by the hypothesis that their earliest progenitors recruited host proteins for virion formation, we have used stringent laboratory evolution to convert a bacterial enzyme that lacks affinity for nucleic acids into an artificial nucleocapsid that efficiently packages and protects multiple copies of its own encoding messenger RNA. Revealing remarkable convergence on the molecular hallmarks of natural viruses, the accompanying changes reorganized the protein building blocks into an interlaced 240-subunit icosahedral capsid that is impermeable to nucleases, and emergence of a robust RNA stem-loop packaging cassette ensured high encapsidation yields and specificity. In addition to evincing a plausible evolutionary pathway for primordial viruses, these findings highlight practical strategies for developing nonviral carriers for diverse vaccine and delivery applications.

病毒是具有全球影响的普遍病原体。受其最早的祖细胞募集宿主蛋白以形成病毒粒子的假设的推动，我们使用严格的实验室进化将一种对核酸缺乏亲和力的细菌酶转化为一种人工核衣壳，该核衣壳有效地包装和保护其自身编码信使 RNA 的多个拷贝。揭示了天然病毒分子特征的显着趋同，伴随的变化将蛋白质构建块重组为一个交错的 240 个亚基的二十面体衣壳，核酸酶不能渗透，并且一个强大的 RNA 茎环包装盒的出现确保了高包裹产量和特异性. 除了证明原始病毒的合理进化途径之外，