SRA

Kaposi's Sarcoma-associated herpesvirus (KSHV) transcripts are subject to degradation by at least two host-mediated nuclear RNA decay pathways, PABPN1 and PAPa/?-mediated RNA decay (PPD) and an ARS2-dependent decay pathway. KSHV expresses the multifunctional protein ORF57, which increases viral transcripts stability by protecting them preferentially from ARS2-dependent decay. However, a subset of viral transcripts succumb to PPD even in the presence of ORF57, but the role of PPD during KSHV infection is not completely understood. We inactivated both decay pathways using siRNA and monitored their contribution to viral gene expression in the presence of ORF57 by RNA-Seq at 24 hours post induction (hpi). Inactivation of PPD, but not ARS2-mediated decay, results in aberrant accumulation of late transcripts, which are typically expressed at 48 hpi. PPD exerts its functions post-transcriptionally as the upregulation of late genes is independent of viral transactivation factors needed for their expression. Remarkably, at their proper time of expression, PPD inactivation has no effect on late transcripts. We further show that PPD evasion by late transcripts requires the host factor NRDE2. In conclusion, our studies show that KSHV uses PPD to fine-tune the temporal expression of its genes by preventing their premature accumulation. Overall design: RNA-seq experiment to compare the contribution of the host-mediated RNA decay pathways, PABPN1 and PAPa/?-mediated RNA decay (PPD) and an ARS2-dependent decay pathway to KSHV gene expression. PPD and ARS2-dependent decay pathways were inactivated by depleting iSLK WT cells of PAPa/? or ARS2, respectively, using siRNAs.