RNA Packaging of Virus-Like Particles

While VLPs are not able to replicate as the native viruses, they incorporate cellular RNAs. The level of each RNA species incorporated dependents on the amount of RNA available as free in the cellular  pool. The ability to incorporate different RNA or non viral molecules open a wide range of the possible applications of these VLPs, as protein cage increasing  flexibility in designing tailored nanoparticles which carry new material, both on the externally surface of the VLPs and internally.

We investigated the ability of plant-produced MRFV-VLPs to encapsidate host cellular RNAs as well as a foreign reporter genes. High levels of MRFV-VLPs was obtained by transient expression in N. benthamiana using a pGD-based vector (agroinfiltration) and a Potato virus X (PVX)-based vector. PCR tests on purified VLPs showed that VLPs produced by agroinfiltration resulted in amplified products corresponding to the MRFV CP gene, whereas VLPs produced using the PVX-based vector resulted in products corresponding to the PVX genome. Experiments to determine if reporter gene RNAs were encapsidated into MRFV-VLPs resulted in amplified products corresponding to the sequence of the foreign RNA. Our results suggest that highly represented foreign RNAs may drive MRFV-VLP assembly toward a programmed packaging.