Nuclear localization of influenza B polymerase proteins and their binary complexes

Qiji Deng, Dan Wang, Xiaoxiao Xiang, Xiaofei Gao, Philip R. Hardwidge, Radhey Kaushik, Thorsten Wolff, Suvobrata Chakravarty, Feng Li

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


The viral RNA-dependent RNA polymerases of influenza A and B are trimeric complexes of PA, PB1, and PB2 subunits that are crucial for both transcription and replication of the viral genome. Unlike the significant progress made recently in understanding nuclear transport and molecular assembly of influenza A polymerase, little is known about the influenza B polymerase, although influenza B viruses cause severe upper respiratory disease in humans. The aim of this study was to characterize nuclear localization of the influenza B RNA polymerase proteins and binary complexes. We demonstrated that each polymerase protein has a nuclear localization function, and among them, the PB2 protein exclusively locates to the nucleus while PA and PB1 proteins are associated with the cytoplasm and the nucleus. Furthermore, we show that pairwise binary complexes are formed among the influenza B subunits (PA-PB1, PA-PB2, and PB1-PB2) and both PB1-PB2 and PA-PB2 complexes are predominantly associated with the nucleus while the PA-PB1 complex exhibits both nuclear and cytoplasmic fluorescence signals. Results of our studies represent the first step toward the understanding of nuclear transport and molecular assembly within the influenza B polymerase complex.

Original languageEnglish
Pages (from-to)49-53
Number of pages5
JournalVirus Research
Issue number1-2
StatePublished - Mar 2011

Bibliographical note

Funding Information:
We thank Elizabeth Kolb for editing the manuscript and thank members of the Li lab for helpful discussions and critical reviews of the manuscript. We thank Ruben Donis at the CDC for providing Flu B reagents. We acknowledge the use of the SDSU-Functional Genomics Core Facility supported in part by NSF/EPSCoR Grant No. 0091948, the Center of Excellence in Drought Tolerance through the South Dakota 2010 Initiative and the South Dakota Agri. Exp. Station. Research in the S.C. laboratory is supported by the South Dakota Agri. Exp. Station and the South Dakota 2010 Research Center, BCAAP (Biological Control and Analysis of Applied Photonics). This work was supported by the South Dakota Agricultural Experiment Station (3AH203 to F.L.) and Public Health Service grants (AI0781775 and K02AI076125-02) from NIAID to F.L.


  • Influenza B virus
  • Nuclear localization
  • Polymerase

ASJC Scopus subject areas

  • Cancer Research
  • Virology
  • Infectious Diseases


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