The CaMV transactivator/viroplasmin interferes with RDR6-dependent trans-acting and secondary siRNA pathways in Arabidopsis

Shivaprasad, Padubidri V. and Rajeswaran, Rajendran and Blevins, Todd and Schoelz, James and Meins, Frederick and Hohn, Thomas and Pooggin, Mikhail M.. (2008) The CaMV transactivator/viroplasmin interferes with RDR6-dependent trans-acting and secondary siRNA pathways in Arabidopsis. Nucleic Acids Research, 36 (18). pp. 5896-5909.

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Official URL: http://edoc.unibas.ch/dok/A6205223

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Several RNA silencing pathways in plants restrict viral infections and are suppressed by distinct viral proteins. Here we show that the endogenous trans-acting (ta)siRNA pathway, which depends on Dicer-like (DCL) 4 and RNA-dependent RNA polymerase (RDR) 6, is suppressed by infection of Arabidopsis with Cauliflower mosaic virus (CaMV). This effect was associated with overaccumulation of unprocessed, RDR6-dependent precursors of tasiRNAs and is due solely to expression of the CaMV transactivator/viroplasmin (TAV) protein. TAV expression also impaired secondary, but not primary, siRNA production from a silenced transgene and increased accumulation of mRNAs normally silenced by the four known tasiRNA families and RDR6-dependent secondary siRNAs. Moreover, TAV expression upregulated DCL4, DRB4 and AGO7 that mediate tasiRNA biogenesis. Our findings suggest that TAV is a general inhibitor of silencing amplification that impairs DCL4-mediated processing of RDR6-dependent double-stranded RNA to siRNAs. The resulting deficiency in tasiRNAs and other RDR6-/DCL4-dependent siRNAs appears to trigger a feedback mechanism that compensates for the inhibitory effects.
Faculties and Departments:05 Faculty of Science > Departement Umweltwissenschaften > Ehemalige Einheiten Umweltwissenschaften > Molekulare Pflanzenvirologie (Hohn)
UniBasel Contributors:Pooggin, Mikhail
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:Oxford University Press
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:10 Oct 2017 09:09
Deposited On:31 Jan 2014 09:49

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