Sendai Virus Infection Induces Expression of Novel RNAs in Human Cells

Innate antiviral immune responses are driven by virus-induced changes in host gene expression. While much research on antiviral effectors has focused on virus-inducible mRNAs, recent genome-wide analyses have identified hundreds of novel target sites for virus-inducible transcription factors and RNA polymerase. These sites are beyond the known antiviral gene repertoire and their contribution to innate immune responses is largely unknown. In this study, RNA-sequencing of mock-infected and Sendai virus-infected cells was performed to characterize the virus-inducible transcriptome and identify novel virus-inducible RNAs (nviRNAs). Virus-inducible transcription was observed throughout the genome resulting in expression of 1755 previously RefSeq-annotated RNAs and 1545 nviRNAs. The previously-annotated RNAs primarily consist of protein-coding mRNAs, including several well-known antiviral mRNAs that had low sequence conservation but were highly virus-inducible. The previously-unannotated nviRNAs were mostly noncoding RNAs with poor sequence conservation. Independent analyses of nviRNAs based on infection with Sendai virus, influenza virus, and herpes simplex virus 1, or direct stimulation with IFNα revealed a range of expression patterns in various human cell lines. These phylogenetic and expression analyses suggest that many of the nviRNAs share the high inducibility and low sequence conservation characteristic of well-known primary antiviral effectors and may represent dynamically evolving antiviral factors.