This Article Full Text Full Text (PDF) Supplemental material Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Li, Z. Articles by Kawaoka, Y. Search for Related Content PubMed PubMed Citation Articles by Li, Z. Articles by Kawaoka, Y.

 Previous Article  |  Next Article 

Journal of Virology, May 2009, p. 4153-4162, Vol. 83, No. 9
0022-538X/09/$08.00+0     doi:10.1128/JVI.02642-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Mutational Analysis of Conserved Amino Acids in the Influenza A Virus Nucleoprotein ^,

Zejun Li,¹ Tokiko Watanabe,¹ Masato Hatta,¹ Shinji Watanabe,¹ Asuka Nanbo,¹ Makoto Ozawa,² Satoshi Kakugawa,² Masayuki Shimojima,² Shinya Yamada,² Gabriele Neumann,¹ and Yoshihiro Kawaoka^1,2,3,4*

Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin—Madison, 2015 Linden Drive, Madison, Wisconsin 53706,¹ Division of Virology, Department of Microbiology and Immunology,² International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan,³ ERATO Infection-Induced Host Responses Project, Japan Science and Technology Agency, Saitama 332-0012, Japan⁴

Received 22 December 2008/ Accepted 10 February 2009

The nucleoprotein (NP), which has multiple functions during the virus life cycle, possesses regions that are highly conserved among influenza A, B, and C viruses. To better understand the roles of highly conserved NP amino acids in viral replication, we conducted a comprehensive mutational analysis. Using reverse genetics, we attempted to generate 74 viruses possessing mutations at conserved amino acids of NP. Of these, 48 mutant viruses were successfully rescued; 26 mutants were not viable, suggesting a critical role of the respective NP amino acids in viral replication. To identify the step(s) in the viral life cycle that is impaired by these NP mutations, we examined viral-genome replication/transcription, NP localization, and incorporation of viral-RNA segments into progeny virions. We identified 15 amino acid substitutions in NP that inhibited viral-genome replication and/or transcription, resulting in significant growth defects of viruses possessing these substitutions. We also found several NP mutations that affected the efficient incorporation of multiple viral-RNA (vRNA) segments into progeny virions even though a single vRNA segment was incorporated efficiently. The respective conserved amino acids in NP may thus be critical for the assembly and/or incorporation of sets of eight vRNA segments.

---

* Corresponding author. Mailing address: Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin—Madison, 2015 Linden Drive, Madison, WI 53706. Phone: (608) 265-4925. Fax: (608) 265-5622. E-mail: kawaokay{at}svm.vetmed.wisc.edu

Published ahead of print on 18 February 2009.

Supplemental material for this article may be found at http://jvi.asm.org/.

---

Journal of Virology, May 2009, p. 4153-4162, Vol. 83, No. 9
0022-538X/09/$08.00+0     doi:10.1128/JVI.02642-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Eifan, S. A., Elliott, R. M. (2009). Mutational Analysis of the Bunyamwera Orthobunyavirus Nucleocapsid Protein Gene. J. Virol. 83: 11307-11317 [Abstract] [Full Text]