Influenza virus polymerase confers independence of the cellular cap-binding factor eIF4E for viral mRNA translation

The influenza virus mRNAs are structurally similar to cellular mRNAs nevertheless; the virus promotes selective translation of viral mRNAs despite the inhibition of host cell protein synthesis. The infection proceeds normally upon functional impairment of elF4E cap-binding protein, but requires functional elF4A helicase and elF4G factor. Here, we have studied whether the presence of cis elements in viral mRNAs or the action of viral proteins is responsible for this elF4E-independence. The elF4E protein is required for viral mRNA translation in vitro, indicating that cis-acting RNA sequences are not involved in this process. We also show that PB2 viral polymerase subunit interacts with the elF4G protein. In addition, a chimeric mRNA containing viral UTR sequences transcribed by the viral polymerase out of the infection is successfully translated independently of an impaired elF4E factor. These data support that the viral polymerase is responsible for the elF4E independence of influenza virus mRNA translation. (C) 2011 Elsevier Inc. All rights reserved.