Influenzavirusisaseriouspublichealththreatcausingsignificantmorbidityandmortality.Seasonalinfections are punctuated by pandemic outbreaks with the potential for widespread infection and disease. This is exemplifiedbytheemergenceofthe2009H1N1pandemicvirusthatrapidlybecamethedominantcirculating strain.Inspiteofthisrisk,thereareonlytwomainclassesofapprovedantivirals,andonlytheneuraminidase inhibitors are efficacious against currently circulating strains. There is a clear need for the discovery of new antiviral therapies and the identification of novel antiviral targets. The influenza virus polymerase is an attractive target for antiviral development. The polymerase assembles with genomic RNA and the viral nucleoprotein(NP)toformlargeribonucleoprotein(RNP)complexes.TheRNPsmediatebothtranscriptionof viralmRNAandreplicationoftheviralgenome.RNPassemblyandpolymeraseactivityareessentialforviral replication, yet how these events are regulated has long remained unclear. We have generated data suggesting that post-translational modifications of NP and the viral polymerase dynamically regulate the formationofRNPs,andtheresultantsynthesisofviralRNAs.Theoverallgoalofthisproposalistounderstand howpost-translationalmodificationsregulateinfluenzavirusRNPassemblyandpolymeraseactivity.Ourfirst objective (Aim 1) is to establish the mechanisms by which phosphorylation regulates NP oligomerization. TheseexperimentsidentifyhostkinasesandphosphatasesthatregulateNPphosphorylationanddemonstrate howthiscontrolsthetransitionofNPfromamonomertothehigher-orderoligomerpresentintheRNP.Wewill alsodefinethetemporalpatternsofNPphosphorylationandhowtheseimpactthetransitionfromtranscription ofviralmRNAstoreplicationoftheviralgenome.Oursecondobjective(Aim2)istodeterminethefunctional consequencesofnovelpost-translationalmodificationswerecentlyidentifiedontheviralpolymeraseandNP. Experiments will determine the host factors mediating this modification and the biological impact during infections.CompletionofthisaimwilldefineacompletelynewregulatorymechanismcontrollingRNPactivity. Theresultsfromthisproposalwillestablishamechanisticunderstandingoftheviralandhostfactorsregulating assembly and function of the RNP and identify exciting new targets that can be exploited for the rational developmentofanti-influenzavirustherapies.
The influenza virus replication machinery is a key player in establishing infection and determining its pathogenicity. These studies will provide insight into the viral and host factors that regulate the influenza replication machinery, how it controls viral replication, and may ultimately identify new targets for therapeutic intervention.
| Baker, Steven F; Ledwith, Mitchell P; Mehle, Andrew (2018) Differential Splicing of ANP32A in Birds Alters Its Ability to Stimulate RNA Synthesis by Restricted Influenza Polymerase. Cell Rep 24:2581-2588.e4 |
| Dawson, Anthony R; Mehle, Andrew (2018) Flu's cues: Exploiting host post-translational modifications to direct the influenza virus replication cycle. PLoS Pathog 14:e1007205 |
| Czakó, Rita; Vogel, Leatrice; Lamirande, Elaine W et al. (2017) In Vivo Imaging of Influenza Virus Infection in Immunized Mice. MBio 8: |
| Mondal, Arindam; Dawson, Anthony R; Potts, Gregory K et al. (2017) Influenza virus recruits host protein kinase C to control assembly and activity of its replication machinery. Elife 6: |
| Kirui, James; Mondal, Arindam; Mehle, Andrew (2016) Ubiquitination up-regulates influenza virus polymerase function. J Virol : |
