Influenza A virus RNA-dependent RNA polymerase complex (IAV RdRp)

The Influenza A virus RNA-dependent RNA polymerase (RdRp) complex is a heterotrimeric assembly consisting of the PA, PB1, and PB2 subunits, which are essential for the transcription and replication of the viral genome within the host cell nucleus (Te Velthuis & Fodor, 2016, Nature Reviews Microbiology). This complex, often associated with the viral nucleoprotein (NP) to form the ribonucleoprotein (vRNP) complex, utilizes a unique 'cap-snatching' mechanism where it cleaves the 5' caps from host pre-mRNAs to prime viral mRNA synthesis (Pflug et al., 2014, Nature). Because the RdRp is highly conserved across different influenza strains and lacks a direct human homolog, it serves as a critical target for antiviral therapy (Hayden & Shindo, 2019, The Lancet Infectious Diseases). Drugs like Baloxavir marboxil specifically inhibit the PA endonuclease activity, while others like Favipiravir act as nucleoside analogs to disrupt the PB1 catalytic core (Noshi et al., 2018, Scientific Reports). Targeting this machinery is vital for treating severe infections and managing pandemic threats, although the high mutation rate of the virus frequently leads to the development of drug-resistant variants, such as the I38T mutation in the PA subunit (Omoto et al., 2018, Scientific Reports).

Other names

Influenza A virus polymerase complexvRNP complexViral ribonucleoprotein complexIAV replication machineryRNA-directed RNA polymerase complex

Inhibition of the PA subunit endonuclease activity to prevent 'cap-snatching' (e.g., Baloxavir marboxil), inhibition of the PB1 subunit catalytic activity via chain termination or lethal mutagenesis (e.g., Favipiravir), or inhibition of the PB2 subunit cap-binding site (e.g., Pimodivir) (Reis & McCauley, 2019, BioEssays).