The Virion Host Shutoff Endonuclease (UL41) of Herpes Simplex Virus Interacts with the Cellular Cap-Binding Complex eIF4F

The herpes simplex virus Vhs endonuclease degrades host and viral mRNAs. Isolated Vhs cuts any RNA at many sites. Yet, within cells, it targets mRNAs and cuts at preferred sites, including regions of translation initiation. Previous studies have shown that Vhs binds the translation factors eIF4A and eIF4H. Here, we show that Vhs binds the cap-binding complex eIF4F. Association with eIF4F correlated with the ability of Vhs to bind eIF4A but not eIF4H. All Vhs proteins that degrade mRNAs associated with eIF4F. However, simply tethering an active endonuclease to eIF4F is not sufficient to degrade mRNAs. Binding to eIF4H may also be required.