The True Story and Advantages of RNA Phage Capsids as Nanotools

RNA phages are often used as prototypes for modern recombinant virus-like particle (VLP) technologies. Icosahedral RNA phage VLPs can be formed from coat proteins (CPs) and are efficiently produced in bacteria and yeast. Both genetic fusion and chemical coupling have been successfully used for the production of numerous chimeras based on RNA phage VLPs. In this review, we describe advances in RNA phage VLP technology along with the history of the Leviviridae family, including its taxonomical organization, genomic structure, and important role in the development of molecular biology. Comparative 3D structures of different RNA phage VLPs are used to explain the level of VLP tolerance to foreign elements displayed on VLP surfaces. We also summarize data that demonstrate the ability of CPs to tolerate different organic (peptides, oligonucleotides, and carbohydrates) and inorganic (metal ions) compounds either chemically coupled or noncovalently added to the outer and/or inner surfaces of VLPs. Finally, we present lists of nanotechnological RNA phage VLP applications, such as experimental vaccines constructed by genetic fusion and chemical coupling methodologies, nanocontainers for targeted drug delivery, and bioimaging tools.