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 Mayuri Articles by Kuhn, R. J. Search for Related Content PubMed PubMed Citation Articles by Mayuri, Articles by Kuhn, R. J.

 Previous Article  |  Next Article 

Journal of Virology, August 2008, p. 7284-7297, Vol. 82, No. 15
0022-538X/08/$08.00+0     doi:10.1128/JVI.00224-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

Role for Conserved Residues of Sindbis Virus Nonstructural Protein 2 Methyltransferase-Like Domain in Regulation of Minus-Strand Synthesis and Development of Cytopathic Infection ^,

Mayuri,¹ Todd W. Geders,² Janet L. Smith,² and Richard J. Kuhn^1*

Markey Center for Structural Biology and Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907,¹ Life Sciences Institute and Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109²

Received 1 February 2008/ Accepted 7 May 2008

The plus-strand RNA genome of Sindbis virus (SINV) encodes four nonstructural proteins (nsP1 to nsP4) that are involved in the replication of the viral RNA. The 800-amino-acid nsP2 consists of an N-terminal domain with nucleoside triphosphatase and helicase activities and a C-terminal protease domain. Recently, the structure determined for Venezuelan equine encephalitis virus nsP2 indicated the presence of a previously unrecognized methyltransferase (MTase)-like domain within the C-terminal 200 residues and raised a question about its functional importance. To assess the role of this MTase-like region in viral replication, highly conserved arginine and lysine residues were mutated to alanine. The plaque phenotypes of these mutants ranged from large/wild-type to small plaques with selected mutations demonstrating temperature sensitive lethality. The proteolytic polyprotein processing activity of nsP2 was unaffected in most of the mutants. Some of the temperature-sensitive mutants showed reduction in the minus-strand RNA synthesis, a function that has not yet been ascribed to nsP2. Mutation of SINV residue R615 rendered the virus noncytopathic and incapable of inhibiting the host cell translation but with no effects on the transcriptional inhibition. This property differentiated the mutation at R615 from previously described noncytopathic mutations. These results implicate nsP2 in regulation of minus-strand synthesis and suggest that different regions of the nsP2 MTase-like domain differentially modulate host defense mechanisms, independent of its role as the viral protease.

---

* Corresponding author. Mailing address: Department of Biological Sciences, 915 W. State St., Lilly Hall of Life Sciences, Purdue University, West Lafayette, IN 47907-1393. Phone: (765) 494-1164. Fax: (765) 496-1189. E-mail: kuhnr{at}purdue.edu

Published ahead of print on 21 May 2008.

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

---

Journal of Virology, August 2008, p. 7284-7297, Vol. 82, No. 15
0022-538X/08/$08.00+0     doi:10.1128/JVI.00224-08
Copyright © 2008, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Frolov, I., Garmashova, N., Atasheva, S., Frolova, E. I. (2009). Random Insertion Mutagenesis of Sindbis Virus Nonstructural Protein 2 and Selection of Variants Incapable of Downregulating Cellular Transcription. J. Virol. 83: 9031-9044 [Abstract] [Full Text]