The S-Phase Arrest of Host Cells Caused by an Alpha-Herpesvirus Genome Replication Facilitates Viral Recruitment of RNA Polymerase II to Transcribe Viral Genes.

Herpesviruses rely on host RNA polymerae II (RNA Pol II) for their mRNA transcription, yet the mechanisms of which has been poorly defined, while certain herpesviruses can enhance viral gene transcription by altering the RNA Pol II location, modulating its phosphorylation, or directly interacting with RNA Pol II. However, the influence of herpesviruses on RNA Pol II transcription extends beyond these direct effects. Here, we present a novel mechanism by which the host cell cycle regulates viral gene transcription via RNA Pol II during infection by Anatid Herpesvirus 1 (AnHV-1), an avian alpha-herpesvirus. The results demonstrated that the formation of viral replication compartments (vRCs) and the subsequent recruitment of RNA pol II are positively correlated with AnHV-1 DNA synthesis. As viral DNA replication progresses, host cells are arrested in the S phase, which not only halts host gene transcription but also facilitates viral transcription. This cell cycle arrest in the S phase promotes viral DNA (vDNA) synthesis and vRC formation, which further enhances the preferential recruitment of RNA Pol II to viral promoters, enabling efficient viral gene transcription. We propose that this S phase arrest and the hijacking of RNA Pol II represent a novel mechanism by which AnHV-1 enhances viral transcription, offering a unique survival strategy compared to the known strategy in herpesviruses. These findings expand our understanding of herpesvirus-host interactions and highlight potential targets for antiviral strategies.