Investigating NP Interactions to Identify Novel Antiviral Targets in Influenza A Viruses

SMSU Event Center BC

Influenza A viruses can cause fatal respiratory infections. The viral ribonucleoprotein (vRNP) is responsible for influenza RNA synthesis and is comprised of many nucleoproteins (NP), the RNA genome segment, and the RNA dependent RNA polymerase (RdRP), a trimer of PA, PB1, and PB2. NP is a highly conserved structural component of the vRNP, but also interacts with both viral and host factors, making NP interactions of interest as possible targets for influenza inhibitors. In addition to direct protein interaction with subunits of the RdRP, NP also interacts with influenza NS1, a multifunctional viral protein, and host UAP56, a DEAD box RNA helicase. Our overall goal is to investigate NP interactions and identify novel antiviral targets. We examined NP interactions with PB2, NS1, and UAP56, each reported to influence vRNP activity. Along with wild type, two NP altered proteins were studied, NPbd3, speculated to disrupt interaction with PB2, and del20NP, reported to disrupt interaction with UAP56. Protein extracts were analyzed either for co-sedimentation of NP and interacting proteins in sucrose gradient ultracentrifugation fractions, or coimmunopurification of NP and interacting proteins. Our data reveal that while wild type NP co-sediments with PB2, as expected, NPbd3 does not, suggesting that NPbd3 is non- functional for vRNP activities because it does not interact with PB2. Co-immunopurification did confirm NP-NS1 interaction and will be used to examine interaction with NS1 mutants to comprehend the role NP-NS1 interaction may play in vRNP activity. Our data probe important NP interactions that may serve as 44 5th Annual Student Research Symposium viable antiviral targets.