Disruption of the varicella-zoster virus dUTPase and the adjacent ORF9A gene results in impaired growth and reduced syncytia formation in vitro.
Varicella-zoster virus (VZV) open reading frame 8 (ORF8) is predicted to encode the viral dUTPase and the adjacent gene, ORF9A, is thought to encode a membrane protein homologous to HSV-1 UL49.5. A fusion protein, in which the amino portion of glutathione-S-transferase was fused to amino acids 5 to 396 of VZV ORF8 protein, had dUTPase activity in vitro. Construction of a mutant VZV with stop codons or a deletion in the ORF8 gene resulted in loss of viral dUTPase activity. Antibody to VZV ORF9A protein demonstrated a 7-kDa protein located in the membranes of virus-infected cells. Insertion of stop codons into VZV ORF9A resulted in VZV that produced smaller plaques than parental virus. Inactivation of both VZV ORF8 and ORF9A resulted in a virus that grew to lower titers and was impaired for syncytia formation when compared to parental virus. In contrast, a similar mutation in HSV-1 has no effect on growth of the virus in vitro. These results identify loci in the VZV genome that are required for a syncytial phenotype in vitro.
Ross
J
J
Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland 20892, USA.
Williams
M
M
Cohen
J I
JI
D017353:Gene Deletion; D015967:Gene Expression Regulation, Viral; D005814:Genes, Viral; D016679:Genome, Viral; D014645:Herpesvirus 3, Human / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D011755:Pyrophosphatases / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics
D011993:Recombinant Fusion Proteins; D011755:Pyrophosphatases; C020020:dUTP pyrophosphatase