Fig. 6.

Cartoon illustrating the differences between (A–C) a monopartite virus (MS2) and (D–F) multipartite virus (BMV). (A) The monopartite genome of MS2 with its sequence-specific packaging signals. (B) The monopartite MS2 particle with its RNA strongly interacting with particular sites of the MS2 CP. (C) The viral lifecycle of a monopartite virus occurs in the cytosol, and the virus relies on sequence-specific interactions to preferentially package its own RNA. (D) The multipartite BMV genome has four RNAs of varying length and sequence. (E) The multipartite BMV is composed of a mixture of three different particles, one containing RNA1, another containing RNA2, and a third containing both RNAs 3 and 4. Additionally, the RNA interacts nonspecifically with the CP. (F) The multipartite BMV replicates and assembles in replication factories—separate lipid vesicles (gray regions) created by the viral infection, allowing it to preferentially package its own genome.