FIG 8.

Model for regulation of FMDV replication by polyprotein processing. The 3B₃^T>K substitution drives rapid processing preferentially down one pathway, as demonstrated by the reduced levels of of 2C and 3D^pol with increased formation of 3AB_1,2,3 and 3CD. To support replication of the 3B₃^T>K replicon in trans, the entire non structural polyprotein is required to deliver a complex of functional components including 2C and 3D^pol, as demonstrated by the wild-type processing schematic. This likely provides products from alternative cleavage pathways such as 3B_1,2,3 and 3CD.