Analysis of a bovine herpesvirus 1 recombinant virus that does not express the bICP0 protein.
Bovine herpesvirus 1 (BHV-1) infected-cell protein 0 (bICP0) stimulates productive infection by activating viral gene expression. In this study, an attempt was made to construct a recombinant virus with point mutations in the C(3)HC(4) zinc RING finger of bICP0, as this domain is necessary for activating viral transcription and productive infection. A virus was identified in bovine cells that induced small clusters of infected cells resembling a small plaque. Instead of the expected mutations within the zinc RING finger, this virus contained a point mutation within the initiating ATG of bICP0, a point mutation two bases downstream from the ATG mutation and deletion of flanking plasmid sequences used for homologous recombination. The bICP0 mutant was rescued with wild-type (wt) bICP0 sequences and the bICP0-rescued virus produced wt plaques. The bICP0-rescued virus and wt BHV-1, but not the mutant, expressed the bICP0 protein during productive infection of bovine cells, suggesting that the mutant virus was a null mutant. Consequently, the mutant was designated the bICP0 null mutant. Infection of bovine cells with the bICP0 null mutant resulted in at least 100-fold lower virus titres, indicating that bICP0 protein expression is important, but not required, for virus production. When bovine cells infected with the bICP0 null mutant virus were subcultured, the cells continued to divide, but viral DNA could be detected after more than 35 passages, suggesting that the bICP0 null mutant induced a persistent-like infection in bovine cells and that it may be useful for generating additional bICP0 mutants.
Geiser
V
V
Department of Veterinary and Biomedical Sciences, Nebraska Center for Virology and School of Biological Sciences, University of Nebraska, Lincoln, NE 68583, USA.
Zhang
Y
Y
Department of Veterinary and Biomedical Sciences, Nebraska Center for Virology and School of Biological Sciences, University of Nebraska, Lincoln, NE 68583, USA.
Jones
C
C
Department of Veterinary and Biomedical Sciences, Nebraska Center for Virology and School of Biological Sciences, University of Nebraska, Lincoln, NE 68583, USA.
D000818:Animals; D001483:Base Sequence; D002417:Cattle; D002460:Cell Line; D015967:Gene Expression Regulation, Viral; D007242:Herpesvirus 1, Bovine / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity*; D017874:Immediate-Early Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D017354:Point Mutation; D011995:Recombination, Genetic; D015534:Trans-Activators; D044767:Ubiquitin-Protein Ligases; D010948:Viral Plaque Assay; D014764:Viral Proteins; D014779:Virus Replication; D016335:Zinc Fingers
D017874:Immediate-Early Proteins; D015534:Trans-Activators; D014764:Viral Proteins; D044767:Ubiquitin-Protein Ligases; C051804:Vmw110 protein, Human herpesvirus 1; C086729:bICP0 protein, Bovine herpesvirus 1