Characterization of the putative protein kinases specified by varicella-zoster virus genes 47 and 66

MRC Virology Unit, Institute of Virology, University of Glasgow, Church Street, Glasgow G11 5JR, U.K. The proteins predicted to be encoded by varicella-zoster virus (VZV) genes 47 and 66 display sequence similarity to the serine/threonine family of protein kinases. Homologues of gene 47 exist in -, - and -herpesviruses but homologues of gene 66 are specific to the -herpesviruses. Monospecific rabbit antisera were raised against two separate fusion proteins constructed from a portion of each protein fused to the carboxy terminus of -galactosidase. These antisera were used to characterize the 47 and 66 proteins in VZV-infected cells and in cells infected with vaccinia virus recombinants expressing each protein. The 47 protein is a 54K phosphoprotein which is distributed between the cytoplasmic and nuclear compartments of VZV-infected cells and is associated with the capsid/tegument fraction of purified VZV particles. Gene 66 encodes a 48K phosphoprotein when expressed by VZV or a vaccinia virus recombinant, and, in the latter case, the 66 protein was located exclusively in the cytoplasm. The 47 protein immuno-precipitated from VZV-infected cells could be phosphorylated in vitro , but the same protein produced by in vitro transcription and translation could not. This and other evidence indicates that additional proteins induced or encoded by VZV may be involved in the phosphorylation of the 47 protein. Received 10 May 1993; accepted 16 September 1993.