JVI Figure table search 04
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Barton, D. J.
Right arrow Articles by Flanegan, J. B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Barton, D. J.
Right arrow Articles by Flanegan, J. B.

 Previous Article  |  Next Article 

Journal of Virology, December 1999, p. 10104-10112, Vol. 73, No. 12
0022-538X/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.

Translating Ribosomes Inhibit Poliovirus Negative-Strand RNA Synthesis

David J. Barton,dagger B. Joan Morasco, and James B. Flanegan*

Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida 32610-0245

Received 1 June 1998/Accepted 25 August 1999

Poliovirus has a single-stranded RNA genome of positive polarity that serves two essential functions at the start of the viral replication cycle in infected cells. First, it is translated to synthesize viral proteins and, second, it is copied by the viral polymerase to synthesize negative-strand RNA. We investigated these two reactions by using HeLa S10 in vitro translation-RNA replication reactions. Preinitiation RNA replication complexes were isolated from these reactions and then used to measure the sequential synthesis of negative- and positive-strand RNAs in the presence of different protein synthesis inhibitors. Puromycin was found to stimulate RNA replication overall. In contrast, RNA replication was inhibited by diphtheria toxin, cycloheximide, anisomycin, and ricin A chain. Dose-response experiments showed that precisely the same concentration of a specific drug was required to inhibit protein synthesis and to either stimulate or inhibit RNA replication. This suggested that the ability of these drugs to affect RNA replication was linked to their ability to alter the normal clearance of translating ribosomes from the input viral RNA. Consistent with this idea was the finding that the protein synthesis inhibitors had no measurable effect on positive-strand synthesis in normal RNA replication complexes. In marked contrast, negative-strand synthesis was stimulated by puromycin and was inhibited by cycloheximide. Puromycin causes polypeptide chain termination and induces the dissociation of polyribosomes from mRNA. Cycloheximide and other inhibitors of polypeptide chain elongation "freeze" ribosomes on mRNA and prevent the normal clearance of ribosomes from viral RNA templates. Therefore, it appears that the poliovirus polymerase was not able to dislodge translating ribosomes from viral RNA templates and mediate the switch from translation to negative-strand synthesis. Instead, the initiation of negative-strand synthesis appears to be coordinately regulated with the natural clearance of translating ribosomes to avoid the dilemma of ribosome-polymerase collisions.


* Corresponding author. Mailing address: Department of Biochemistry and Molecular Biology, University of Florida, College of Medicine, P.O. Box 100245, Gainesville, FL 32610-0245. Phone: (352) 392-0688. Fax: (352) 392-2953. E-mail: Flanegan{at}ufl.edu.

dagger Present address: Department of Microbiology, University of Colorado Health Sciences Center, Denver, CO 80262.


Journal of Virology, December 1999, p. 10104-10112, Vol. 73, No. 12
0022-538X/99/$04.00+0
Copyright © 1999, American Society for Microbiology. All rights reserved.



This article has been cited by other articles:




Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. Mol. Cell. Biol. Microbiol. Mol. Biol. Rev.
Clin. Vaccine Immunol. ALL ASM JOURNALS

Copyright © 1999 by the American Society for Microbiology. All rights reserved.