The genomic RNA components of three nepoviruses, arabis mosaic (ArMV), cherry leaf roll (CLRV), and strawberry latent ringspot (SLRV), were translated in rabbit reticulocyte lysate. Each component (except the RNA-2 of CLRV) directed the synthesis of proteins that corresponded in size to their theoretical coding capacity. The RNA-1 components of all three viruses were translated to yield polyproteins of Mr 250k, which were autocatalytically processed to yield up to five cleavage products. The primary products of translation of the RNA-2 components of ArMV (Mr 115k and 105k), CLRV (Mr 165k) and SLRV (Mr 99k and 96k) were polyproteins that were stable on incubation, but which underwent proteolytic processing in the presence of the corresponding RNA-1 and its translation products. These polyproteins were immunoprecipitated using antisera to appropriate virions indicating that the RNA-2 sequences encode the coat protein cistrons.