Related Experiment Video
Updated: Jan 22, 2026

Potato Virus X-Based microRNA Silencing VbMS In Potato.
Published on: May 11, 2020
Efficient RNA silencing suppression activity of Potato Mop-Top Virus 8K protein is driven by variability and positive
Pruthvi B Kalyandurg1, Aminallah Tahmasebi2, Ramesh R Vetukuri3
1Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Linnean Center for Plant Biology, Uppsala, Sweden.
Abstract:
Previously, we investigated the evolution of Potato mop-top virus (PMTV) ORFs. Results indicate that positive selection acts exclusively on an ORF encoding the 8K protein, a weak viral suppressor of RNA silencing (VSR). However, how the extraordinary variability contributes to 8K-mediated RNA silencing suppression remains unknown. Here, we characterized the RNA silencing suppression activity of the 8K protein from seven diverse isolates. We show that 8K encoded by isolate P1 exhibits stronger RNA silencing suppression activity than the 8K protein from six other isolates. Mutational analyses revealed that Ser-50 is critical for these differences. By comparing small RNA profiles we found a lower abundance of siRNAs with U residue at the 5'-terminus after expression of the P1 8K compared to expression of 8K from isolate P125, an isolate with weak VSR activity. These results provide new clues as to the role of positive selection in shaping activities of VSRs.
Related Concept Videos
Position-effect Variegation
RNA Polymerase II Accessory Proteins
Viruses with RNA Genomes
RNA Interference
This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...
What are Viruses?
Alternative RNA Splicing
There are five types of alternative RNA splicing that vary in the ways the pre-mRNA segments are removed or retained in the mature mRNA. The first...

