Single-cell analysis of early antiviral gene expression reveals a determinant of stochasticIFNB1expression

RIG-I-like receptors (RLRs) are cytoplasmic sensors of viral RNA that trigger the signaling cascade that leads to type I interferon (IFN) production. Transcriptional induction of RLRs by IFN is believed to play the role of positive feedback to further amplify viral sensing. We found that RLRs and several other IFN-stimulated genes (ISGs) are induced early in viral infection independent of IFN. Expression of these early ISGs requires IRF3/IRF7 and is highly correlated amongst them. Simultaneous detection of mRNA ofIFNB1, viral replicase, and ISGs revealed distinct populations ofIFNB1expressing and non-expressing cells which are highly correlated with the levels of early ISGs but are uncorrelated with IFN-dependent ISGs and viral gene expression. Individual expression of RLRs madeIFNB1expression more robust and earlier, suggesting a causal relation between levels of RLR and induction of IFN.