For efficient Influenza virus (IAV) replication, several cellular barriers and host factors must be overtaken by the virus to complete its life cycle.
The host factor PARP1 has been demonstrated to participate in cellular events responding to DNA damage or cellular stress.
PARP1 is an interacting partner of IAV polymerases required for efficient IAV replication and necessary for synthesis of the viral nucleoprotein (NP).
Initiation of synthesis of the viral genomic RNA (vRNA) is thought to require hairpin (or panhandle/corkscrew) RNA loop structures formed by both the 5' and 3' ends of the cRNA (Pritlove, 1995; Crow, 2004; Park, 2003; Deng, 2006). The cRNA promoter has a similar structure to the vRNA promoter, but slight sequence differences are believed to result in a stronger cRNA promoter. As with the vRNA promoter, the polymerase is thought to first bind to the 5' end of the cRNA, then to the 3' end, and subsequently initiate RNA synthesis.