Deletion of the us7 and us8 genes of pseudorabies virus exerts a differential effect on the expression of early and late viral genes
The pseudorabies virus (PRV; also known as Suid herpesvirus-1) is a neurotropic herpesvirus of swine. The us7 and us8 genes of this virus encode the glycoprotein I and E membrane proteins that form a heterodimer that is known to control cell-to-cell spread in tissue culture and in animals. In this study, we investigated the effect of the deletion of the PRV us7 and us8 genes on the genome-wide transcription and DNA replication using a multi-time-point quantitative reverse transcriptase-based real-time PCR technique. Abrogation of the us7/8 gene function was found to exert a drastic but differential effect on the expression of PRV genes during lytic infection. In the mutant virus, all kinetic classes of viral genes were significantly down-regulated at the first 6 h of infection, while having been upregulated later. The level of upregulation was the highest in the immediate-early (IE) and the early (E) genes; lower in the early-late (E/L) genes; and the lowest in the late (L) genes. The relative contribution of the L transcripts to the global transcriptome became lower, while the rest of the transcripts were expressed at a higher level in the mutant than in the wild-type virus.
KeywordsPseudorabies virus Herpesvirus Glycoprotein RT-PCR Transcriptome
This research was supported by the Swiss-Hungarian Cooperation Programme, Grant No.: SH/7/2/8 to ZB and by the Bolyai János Scholarship of the Hungarian Academy of Sciences: 2015-18 to DT.
NP took part in PK-cell propagation, reverse transcription, and quantitative real-time PCR reactions, as well as data analysis. ZC performed reverse transcription and quantitative real-time PCR reactions. EP prepared the targeting plasmid. DT performed data analysis, drafted the manuscript, performed reverse transcription reactions and qPCR experiments. ZB coordinated the study, propagated viruses, generated the recombinant PRV, drafted and corrected the manuscript. All authors have read and approved the final manuscript.
Compliance with ethical standards
Conflicts of interest
The author declares no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
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