Effect of ISG20 expression (wild-type or M1 mutant) on total RNA expression.

ISG20 is an interferon-induced 3'-to-5' RNA exonuclease that acts as a broad antiviral innate defense factor. At present, the features that expose RNA to the action of ISG20 remain unclear. However recent studies have pinpointed to RNA epitranscriptomic modifications as modulators that either expose or protect viral RNAs from ISG20, raising the question as to how cellular RNAs, on which these modifications are abundant, cope with ISG20. To obtain an unbiased perspective on this issue, we used RNAseq to pinpoint to the RNA elements that regulate the balance between susceptibility and resistance to ISG20. Cells (HEK293T) were co-transfected with a plasmid coding for GFP (serving as an ectopically expressed mRNA) and a plasmid coding for wild-type ISG-20 (ISG20_WT) or a mutant version (ISG20_M1) or a control plasmid (pcDNA3.1). We allowed cells to express these proteins for 24h before collecting total RNA and proceeding to high-throughput sequencing in order to asses the consequences of ISG20 expression on the cellular transcriptome.