The role and assembly mechanism of nucleoproteinin influenza A virus ribonucleoprotein complexes

摘要

The nucleoprotein of negative-strand RNA viruses forms a major component of theribonucleoprotein complex that is responsible for viral transcription and replication. However,the precise role of nucleoprotein in viral RNA transcription and replication is not clear. Herewe show that nucleoprotein of influenza A virus is entirely dispensable for replication andtranscription of short viral RNA-like templates in vivo, suggesting that nucleoprotein representsan elongation factor for the viral RNA polymerase. We also find that the recruitment ofnucleoprotein to nascent ribonucleoprotein complexes during replication of full-length viralgenes is mediated through nucleoprotein–nucleoprotein homo-oligomerization in a ‘tail loopfirst’orientation and is independent of RNA binding. This work demonstrates that nucleoproteindoes not regulate the initiation and termination of transcription and replication by theviral polymerase in vivo, and provides new mechanistic insights into the assembly andregulation of viral ribonucleoprotein complexes.