THE PK-1 GENE OF AUTOGRAPHA-CALIFORNICA MULTINUCLEOCAPSID NUCLEAR POLYHEDROSIS-VIRUS ENCODES A PROTEIN-KINASE

Open reading frame (ORF) 9 of the EcoRI I fragment of the baculovirus Autographa californica multinucleocapsid nuclear polyhedrosis virus (A cMNPV) genome encodes a protein, PK-1, which has strong similarity to serine-threonine protein kinases. The published sequence of the pk-1 g ene contains an error that, when corrected, extends the ORF by 228 nuc leotides. Transcription of pk-1 was first detectable by primer extensi on at 12 h post-infection, accumulating to high levels during the very late phase of infection. PK-1 produced in rabbit reticulocyte lysates was able to phosphorylate histone H1. Together, our results suggest t hat ORF 9 encodes a protein kinase that is expressed during the beginn ing of the late and throughout the very late phases of AcMNPV infectio n.