Interferon stimulated gene ISG20 induces an innate immune defense signature in primary human fibroblasts [SLAM-seq]

ISG20 is an interferon-regulated protein that exhibits Rnase activity thereby inhibiting the replication of a broad spectrum of RNA viruses. We identified ISG20 as a potential restriction factor against human cytomegalovirus (HCMV) that inhibits HCMV gene expression at the early stage of infection.In order to investigate whether ISG20 affects the half-life of cellular RNAs via its putative RNase activity, a SLAMseq experiment was performed. Interestingly, ISG20 expression resulted in an overall increased stablilty of cellular RNAs. Overall design: Lentiviral vectors were used to generate primary human fibroblasts (HFF) with doxycycline-inducible overexpression of ISG20 (HFF/ISG20) alongside control cells (HFF/CTRL). HFF/ISG20 and HFF/CTRL were treated for 24 h with doxycycline before total RNA was isolated and subjected to mRNA sequencing.To label newly synthesized RNA, HFFs were treated with 4-thiouridine (4sU) at a final concentration of 400 µM for 1 h prior to cell lysis. Cells without 4sU treatment were processed in parallel. Results are derived from two biological replicates (rep_1, rep_2).