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A Co-Opted DEAD-Box RNA helicase enhances tombusvirus plus-strand synthesis.

Authors :
Nikolay Kovalev
Judit Pogany
Peter D Nagy
Source :
PLoS Pathogens, Vol 8, Iss 2, p e1002537 (2012)
Publication Year :
2012
Publisher :
Public Library of Science (PLoS), 2012.

Abstract

Replication of plus-strand RNA viruses depends on recruited host factors that aid several critical steps during replication. In this paper, we show that an essential translation factor, Ded1p DEAD-box RNA helicase of yeast, directly affects replication of Tomato bushy stunt virus (TBSV). To separate the role of Ded1p in viral protein translation from its putative replication function, we utilized a cell-free TBSV replication assay and recombinant Ded1p. The in vitro data show that Ded1p plays a role in enhancing plus-strand synthesis by the viral replicase. We also find that Ded1p is a component of the tombusvirus replicase complex and Ded1p binds to the 3'-end of the viral minus-stranded RNA. The data obtained with wt and ATPase deficient Ded1p mutants support the model that Ded1p unwinds local structures at the 3'-end of the TBSV (-)RNA, rendering the RNA compatible for initiation of (+)-strand synthesis. Interestingly, we find that Ded1p and glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which is another host factor for TBSV, play non-overlapping functions to enhance (+)-strand synthesis. Altogether, the two host factors enhance TBSV replication synergistically by interacting with the viral (-)RNA and the replication proteins. In addition, we have developed an in vitro assay for Flock house virus (FHV), a small RNA virus of insects, that also demonstrated positive effect on FHV replicase activity by the added Ded1p helicase. Thus, two small RNA viruses, which do not code for their own helicases, seems to recruit a host RNA helicase to aid their replication in infected cells.

Details

Language :
English
ISSN :
15537366 and 15537374
Volume :
8
Issue :
2
Database :
Directory of Open Access Journals
Journal :
PLoS Pathogens
Publication Type :
Academic Journal
Accession number :
edsdoj.1af53dee1b69415bb421f4704dc652a9
Document Type :
article
Full Text :
https://doi.org/10.1371/journal.ppat.1002537