We infected a transgenic Arabidopsis line (GxA), containing an amplicon-silenced 35S : : GFP transgene, with cauliflower mosaic virus (CaMV), a plant pararetrovirus with a DNA genome. Systemically infected leaves showed strong GFP fluorescence and amplicon transcripts were detectable in Northern blots, indicating that silencing of GFP had been suppressed during CaMV-infection. Transgenic Arabid...

The disruption of one of two dicer genes, dcl-2, of the chestnut blight fungus Cryphonectria parasitica was recently shown to increase susceptibility to mycovirus infection (G. C. Segers, X. Zhang, F. Deng, Q. Sun, and D. L. Nuss, Proc. Natl. Acad. Sci. USA 104:12902-12906, 2007). We now report the accumulation of virus-derived small RNAs (vsRNAs) in hypovirus CHV1-EP713-infected wild-type and ...

While tumor suppressor genes frequently undergo epigenetic silencing in cancer, how the instructions directing this transcriptional repression are transmitted in cancer cells remain largely unclear. Expression of cyclin-dependent kinase inhibitor 1C (CDKN1C), an imprinted gene on chromosomal band 11 p15.5, is reduced or lost in the majority of breast cancers. Here, we report that CDKN1C is supp...

Tospoviruses are plant-infecting viruses belonging to the family Bunyaviridae. We used a collection of wild-type, phylogenetically distinct tomato spotted wilt virus isolates and related silencing-suppressor defective mutants to study the effects on the small RNA (sRNA) accumulation during infection of Nicotiana benthamiana. Our data showed that absence of a functional silencing suppressor dete...

The quality control of mRNA maturation is a highly regulated process that surveys pre-mRNA integrity and eliminates improperly matured pre-mRNAs. In nature, certain viruses regulate the expression of their genes by hijacking the endogenous RNA quality control machinery. We demonstrate that the inclusion of 5' splice sites within the 3'-untranslated region of a reporter gene in plants alters the...

RNA viruses encode various RNA binding proteins that function in many steps of viral infection cycles. These proteins function as RNA helicases, methyltransferases, RNA-dependent RNA polymerases, RNA silencing suppressors, RNA chaperones, movement proteins, and so on. Although many of the proteins bind the viral RNA genome during different stages of infection, our knowledge about the coordinati...

UNLABELLED Most plant viruses counter the RNA silencing-based antiviral defense by expressing viral suppressors of RNA silencing (VSRs). In this sense, VSRs may be regarded as virulence effectors that can be recognized by the host as avirulence (avr) factors to induce R-mediated resistance. We made use of Agrobacterium-mediated transient coexpression of VSRs in combination with Potato virus X (...