Late stages of the influenza A virus replication cycle — a tight interplay between virus and host

Abstract

Influenza A virus (IAV) is the causative agent of a febrile illness in humans, commonly referred to as‘the flu’. IAV causes seasonal epidemics and sporadic pandemics, imposing a huge burden on human health and economy. IAV are enveloped viruses belonging to the family of Orthomyxoviridae, whose members are characterized by a single-stranded segmented RNA genome of negative polarity (Palese & Shaw, 2007). Unlike most other RNA viruses, orthomyxoviruses replicate in the nucleus of the infected cell (Cros & Palese, 2003). While nuclear replication confers several advantages, such as access to the cellular splicing machinery, the virus faces the challenge of overcoming the nuclear envelope. Due to its small genome size of 13.5 kb, IAV relies heavily on cellular factors to complete its life cycle. In this review we focus on late stages of infection and describe the interplay between the virus and its host in the process of vRNP nuclear export, transport of viral proteins to the assembly site, genome packaging, as well as budding and release of virions.