Host Determinants of Influenza RNA Synthesis.

Influenza viruses are a leading cause of seasonal and pandemic respiratory illness. Influenza is a negative-sense single-stranded RNA virus that encodes its own RNA-dependent RNA polymerase (RdRp) for nucleic acid synthesis. The RdRp catalyzes mRNA synthesis, as well as replication of the virus genome (viral RNA) through a complementary RNA intermediate. Virus propagation requires the generation of these RNA species in a controlled manner while competing heavily with the host cell for resources. Influenza virus appropriates host factors to enhance and regulate RdRp activity at every step of RNA synthesis. This review describes such host factors and summarizes our current understanding of the roles they play in viral synthesis of RNA.