– PK-1 (Ac10) is a baculovirus-encoded serine/threonine kinase,a pk-1 knockout AcMNPV failed to produce infectious progeny, while the pk-1 repair virus could rescue this defect.the kinase activity of PK-1 is essential in regulating viral propagation. Electron microscopy revealed that pk-1 deletion affected the formation of normal nucleocapsids.PK-1 appears to phosphorylate some viral or cellular proteins that are essential for DNA packaging to regulate nucleocapsid assembly.