Nucleozin targets influenza A nucleoprotein (NP), a multifunctional, RNA-binding protein necessary for virus replication.

Nucleozin blocked the cytoplasmic trafficking of ribonucleoproteins (RNPs) that had undergone nuclear export, promoting the formation of large perinuclear aggregates of RNPs along with cellular Rab11. This effect led to the production of much reduced amounts of often markedly smaller virus particles. The primary target of nucleozin is the viral RNP. IAV replication can be effectively inhibited by blocking cytoplasmic trafficking of the viral genome[1].

Nucleozin, that triggers the aggregation of NP and inhibits its nuclear accumulation. Nucleozin impeded influenza A virus replication in vitro with a nanomolar median effective concentration (EC(50)) and protected mice challenged with lethal doses of avian influenza A H5N1. Viral NP is a valid target for the development of small-molecule therapies[2].

For live imaging, cells were grown in chambered glass bottom dishes and maintained at 37°C in L-15 CO2-independent medium (Gibco) during analysis. Cells were transfected with GFP-NP and infected with PR8 12 h later. For nucleozin treatment, images were acquired for 5 min and then nucleozin was added to a final concentration of 2 μM before imaging for around 20 to 30 min . Images were acquired at 0.25 or 0.71 frame/s and processed with ImageJ[1].