VARICELLA-ZOSTER VIRUS ASSEMBLY PROTEIN P32 P36 IS PRESENT IN DNA-CONTAINING AS WELL AS IMMATURE CAPSIDS/

Varicella-zoster virus (VZV) produces a group of nucleocapsid proteins (the p32/p36 nucleoprotein complex) which are the VZV analogues of th e herpes simplex virus type 1 (HSV-1) and cytomegalovirus (CMV) assemb ly proteins. There are multiple components in the VZV p32/p36 complex, with major proteins of 32 and 36 kDa and minor proteins of 34 and 38 kDa. In HSV-1 the assembly proteins have been shown to be present in i mmature (B) capsids, but are removed prior to the formation of mature (C) capsids containing the viral DNA genome. Our work has shown that V ZV produces capsids corresponding to the B and C forms. However, in co ntrast to HSV-1, VZV also produces ''B/C'' capsids that appear to cont ain both the assembly proteins and the viral DNA genome. Possible mech anisms for this are discussed. In addition, it was shown that VZV caps ids appear to lack the 36 and 38 kDa proteins, and based on this obser vation we suggest that these may represent unprocessed forms of the as sembly protein. In both HSV and CMV, a much larger, crossreactive prot ein has been identified as the full-length product of the gene coding for the assembly protein. The homologous VZV gene (ORF 33) theoretical ly has the capacity to produce a 66 kDa protein. However, no such prot ein is readily apparent in VZV-infected cells. The presence of an immu noreactive 64 kDa protein was demonstrated in purified VZV capsids whi ch may represent the full-length ORF 33 protein. (C) 1995 Wiley-Liss, Inc.