Silencing of Nicotiana benthamiana Xrn4p exoribonuclease promotes tombusvirus RNA accumulation and recombination

Hannah M. Jaag, Peter D. Nagy

Research output: Contribution to journalArticlepeer-review

60 Scopus citations

Abstract

The cytosolic 5′-to-3′ exoribonuclease Xrn1p plays a major role in recombination and degradation of Tomato bushy stunt tombusvirus (TBSV) replicon (rep)RNA in yeast, a model host (Serviene, E., Shapka, N., Cheng, C.P., Panavas, T., Phuangrat, B., Baker, J., and Nagy, P.D., 2005. Genome-wide screen identifies host genes affecting viral RNA recombination. Proc. Natl. Acad. Sci. U. S. A. 102(30), 10545-10550.). To test if the plant cytosolic 5′-to-3′ exoribonuclease Xrn4p, similar to the yeast Xrn1p, could also affect TBSV recombination, in this paper, we silenced XRN4 in Nicotiana benthamiana, an experimental host. The accumulation of tombusvirus genomic RNA and repRNA increased by 50% and 220%, respectively, in XRN4-silenced N. benthamiana. We also observed up to 125-fold increase in the emergence of new recombinants and partly degraded viral RNAs in the silenced plants. Using a cell-free assay based on a yeast extract, which supports authentic replication and recombination of TBSV, we demonstrate that the purified recombinant Xrn1p efficiently inhibited the accumulation of recombinants and partly degraded viral RNAs. Altogether, the data from a plant host and cell-free system confirm a central role for the plant cytosolic 5′-to-3′ exoribonuclease in TBSV replication, recombination and viral RNA degradation.

Original languageEnglish
Pages (from-to)344-352
Number of pages9
JournalVirology
Volume386
Issue number2
DOIs
StatePublished - Apr 10 2009

Bibliographical note

Funding Information:
The authors thank Judit Pogany and Daniel Barajas for valuable comments. The authors are grateful to Drs. Elena Serviene and A.W. Johnson for purified recombinant Xrn1p. This work was supported by the National Science Foundation (IOB-0517218).

Keywords

  • Exoribonuclease
  • Host factor
  • Nicotiana
  • RNA degradation
  • RNA recombination
  • Replication
  • Tomato bushy stunt virus
  • XRN1
  • XRN4
  • Yeast

ASJC Scopus subject areas

  • Virology

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