Transcriptome Regulation by PARP13 in Basal and Antiviral States in Human Cells (RNA-Seq)

The RNA-binding protein PARP13 is a primary factor in the innate antiviral response. PARP13 can suppress translation and drive decay of bound viral and host RNA. PARP13 interacts with many proteins encoded by interferon-stimulated genes (ISG) to perform its antiviral activities, such as activation of the pathway mediated by post-translational addition ISG15 or ISGylation. The RNA-binding domains of both PARP13 and its primary cofactor, TRIM25, are required for antiviral activity. Here we perform enhanced crosslinking immunoprecipitation (eCLIP) and RNA-seq to investigate the role of PARP13 expression and RNA binding in transcriptome regulation within human cells. We find that PARP13 regulates the transcriptome in basal and antiviral states and that the antiviral response shifts PARP13 target localization, but not its binding preferences. We demonstrate that PARP13 expression supports the expression of ISGylation-related genes, including TRIM25. Using the common targets PARP13 and TRIM25 share, we assess their spatial relationship along transcripts and show that PARP13 and TRIM25 associate in part via RNA-protein interactions. Evidence from genomic data and molecular biology experiments provide insight into the geometry of PARP13's interface with its cofactor TRIM25 and implicates PARP13 in creating and maintaining a cellular environment poised for an antiviral response.