Host Shutoff in Influenza A Virus: Many Means to an End

• Main Authors: Rachel Emily Levene, Marta Maria Gaglia
• Format: Article
• Language: English
• Published: MDPI AG 2018-09-01
• Series: Viruses
• Subjects: host shutoff; PA-X; NS1; RNA-directed RNA polymerase; immune evasion; influenza
• Online Access: http://www.mdpi.com/1999-4915/10/9/475

Influenza A virus carries few of its own proteins, but uses them effectively to take control of the infected cells and avoid immune responses. Over the years, host shutoff, the widespread down-regulation of host gene expression, has emerged as a key process that contributes to cellular takeover in infected cells. Interestingly, multiple mechanisms of host shutoff have been described in influenza A virus, involving changes in translation, RNA synthesis and stability. Several viral proteins, notably the non-structural protein NS1, the RNA-dependent RNA polymerase and the endoribonuclease PA-X have been implicated in host shutoff. This multitude of host shutoff mechanisms indicates that host shutoff is an important component of the influenza A virus replication cycle. Here we review the various mechanisms of host shutoff in influenza A virus and the evidence that they contribute to immune evasion and/or viral replication. We also discuss what the purpose of having multiple mechanisms may be.