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
Google Scholar
Right arrow Articles by Demidenko, A. A.
Right arrow Articles by Nibert, M. L.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Demidenko, A. A.
Right arrow Articles by Nibert, M. L.

 Previous Article  |  Next Article 

Journal of Virology, June 2009, p. 5659-5670, Vol. 83, No. 11
0022-538X/09/$08.00+0     doi:10.1128/JVI.02192-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Probing the Transcription Mechanisms of Reovirus Cores with Molecules That Alter RNA Duplex Stability{triangledown}

Alexander A. Demidenko and Max L. Nibert*

Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115-5701

Received 16 October 2008/ Accepted 13 March 2009

The mammalian reovirus (MRV) genome comprises 10 double-stranded RNA (dsRNA) segments, packaged along with transcriptase complexes inside each core particle. Effects of four small molecules on transcription by MRV cores were studied for this report, chosen for their known capacities to alter RNA duplex stability. Spermidine and spermine, which enhance duplex stability, inhibited transcription, whereas dimethyl sulfoxide and trimethylglycine, which attenuate duplex stability, stimulated transcription. Different mechanisms were identified for inhibition or activation by these molecules. With spermidine, one round of transcription occurred normally, but subsequent rounds were inhibited. Thus, inhibition occurred at the transition between the end of elongation in one round and initiation in the next round of transcription. Dimethyl sulfoxide or trimethylglycine, on the other hand, had no effect on transcription by a constitutively active fraction of cores in each preparation but activated transcription in another fraction that was otherwise silent for the production of elongated transcripts. Activation of this other fraction occurred at the transition between transcript initiation and elongation, i.e., at promoter escape. These results suggest that the relative stability of RNA duplexes is most important for certain steps in the particle-associated transcription cycles of dsRNA viruses and that small molecules are useful tools for probing these and probably other steps.

* Corresponding author. Mailing address: Department of Microbiology and Molecular Genetics, Harvard Medical School, 200 Longwood Ave., Boston, MA 02115-5701. Phone: (617) 432-4838. Fax: (617) 738-7664. E-mail: mnibert{at}hms.harvard.edu

{triangledown} Published ahead of print on 18 March 2009.

Journal of Virology, June 2009, p. 5659-5670, Vol. 83, No. 11
0022-538X/09/$08.00+0     doi:10.1128/JVI.02192-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»