実験室内進化で迫る原始ウイルス形成過程

抄録

  Viruses, characterized by their nucleocapsid which encloses genetic material (either DNA or RNA), rely on host cells for replication. Their evolutionary origins remain one of the fundamental questions in biology, given the potential role they might have played in early life by facilitating genetic exchanges between cellular lineages.

  To get deep insight into the origins of viruses, we proceeded engineering and directed evolution of non-viral protein capsules that encapsulate mRNA to mimic evolutionary process of primitive viruses. We used lumazine synthase derived from the thermophilic bacteria, Aquifex aeolicus as a model nonviral protein capsid. After the several rounds of directed evolution, artificial nucleocapsid variants showing various architectures were obtained. Cryo-electron microscopy and X-ray footprinting analysis indicate a structural evolution in both protein and RNA to enhance encapsulation efficacy. These lab-engineered particles provide a novel platform to study the evolution of primordial viruses and virus alternative biotechnology.