The coronavirus macrodomain is required to prevent PARP-mediated inhibition of virus replication and enhancement of IFN expression
(A) BMDMs were infected with WT or N1347A MHV and collected at 18 hpi. PARP expression was determined by RT-qPCR using primers listed in S3 Table and normalized to HPRT. PARP2 and PARP16 were undetectable and are not shown. (B) BMDMs isolated from WT, MAVS-/-, or IFNAR-/- mice were infected with WT or N1347A virus. Cells were collected at 18 hpi, and RNA levels of selected PARPs were determined by RT-qPCR and normalized to HPRT mRNA levels. (C) BMDMs from WT or IFNAR-/- mice were mock treated or treated with 1000 U IFNβ for 8 h, and RNA levels were determined by RT-qPCR and normalized to HPRT. PARPs 6 and 8 fell below the limit of detection and are not shown. The data in (A-C) show one experiment representative of two independent experiments; n = 3.