Journal of General Virology

The influenza virus nucleoprotein: a multifunctional RNA-binding protein pivotal to virus replication

Agustín Portela¹ and Paul Digard²

¹ División de Productos Biológicos y Biotecnología, Agencia Española del Medicamento, Majadahonda 28220, Madrid, Spain
² Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK

All viruses with negative-sense RNA genomes encode a single-strand RNA-binding nucleoprotein (NP). The primary function of NP is to encapsidate the virus genome for the purposes of RNA transcription, replication and packaging. The purpose of this review is to illustrate using the influenza virus NP as a well-studied example that the molecule is much more than a structural RNA-binding protein, but also functions as a key adapter molecule between virus and host cell processes. It does so through the ability to interact with a wide variety of viral and cellular macromolecules, including RNA, itself, two subunits of the viral RNA-dependent RNA polymerase and the viral matrix protein. NP also interacts with cellular polypeptides, including actin, components of the nuclear import and export apparatus and a nuclear RNA helicase. The evidence for the existence of each of these activities and their possible roles in transcription, replication and intracellular trafficking of the virus genome is considered.

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© 2002 SGM

This article is now available in the April 2002 print issue of JGV (vol. 83, 723–734). The complete issue of the journal may be seen in electronic form on JGV Online.