Characterization of the proteinase specified by varicella-zoster virus gene 33.

Varicella-zoster virus (VZV) genes 33 and 33.5 are predicted to encode the VZV proteinase and its substrate (the assembly protein) respectively. These genes were expressed in insect cells using recombinant baculovirus and it was confirmed that gene 33 encodes a proteinase capable of autoproteolytic processing at two positions. When VZV gene 33.5 was co-expressed with the VZV proteinase, processing of the VZV33.5 gene product was observed. A polyclonal antiserum to the VZV assembly protein domain highlighted a set of proteins in VZV infected HEL cells identical to those identified in insect cells expressing VZV genes 33 and 33.5. To facilitate further characterization of the VZV proteinase the enzyme was purified by affinity chromatography from an E. coli expression system and in vitro activity was observed.