3-5-1- RIG-I like receptor signaling
The RIG-I like receptors are cytoplasmic sensors that detect viral RNA PAMPs in a wide range of cell types. The RLRs RIG-I and melanoma differentiation-associated gene 5 (MDA5) are ISGs that are transcribed during SARS-CoV infection in vitro and SARS-CoV could probably be detected by the same sensors. RLR signaling leads to the activation of several transcription factors, such as interferon regulatory factor 3 (IRF3), IRF7, and nuclear factor-kB (NF-kB). IRF3 and IRF7 initiate transcription of IFNs type I (IFN-α and IFN-β), which are important for antiviral responses. NF-kB mediated transcription of proinflammatory cytokines has been linked to the pathogenesis of ARDS (Galani et al., 2010). While the correlation of severe SARS-CoV disease with different transcriptional regimes is promising, the key to finding determinants of increased SARS-CoV pathogenesis maybe understanding the way innate immune sensing mechanisms initiate transcription at critical junctures during infection and the types of innate immune sensing that are protective (Totura & Baric, 2012).