The vaccinia virus I7L gene product is the core protein proteinase

Maturation of vaccinia virus (W) core proteins is required for the production of infectious virions. The W G1L and I7L gene products are the leading candidates for the viral core protein proteinase (vCPP). Using transient-expression assays, data were obtained to demonstrate that the I7L gene product and its encoded cysteine proteinase activity are responsible for vCPP activity.