RNA degradation is key to control gene expression. The group of Dominique Gagliardi identified two new RNA degradation factors named RST1 and RIPR in the model plant Arabidopsis thaliana. RST1 and RIPR bind to the Ski complex and the RNA exosome, the main 3’-5’ exoribonuclease machinery in eukaryotes. Together, Ski, RST1, RIPR and the exosome ensure the efficient degradation of mRNAs. The efficient degradation of mRNAs is necessary to prevent their unwanted recognition by post transcriptional gene silencing (PTGS), which can be deleterious. For example, plants with mutated versions of RST1 or RIPR suffer from silencing of an mRNA encoding a wax biosynthesis factor and are therefore more vulnerable to water loss or pathogens.
While RIPR appears to be a plant-specific protein, proteins similar to RST1 are present in animals including humans. This work contributes to a better understanding of RNA degradation in eukaryotes and was published in the journal Nature Communications in August 2019.