STAT3 is a predicted regulator mediating the gene constrasts between MERS-CoV Eng 1 and MERS-CoV SA 1. Upstream Regulator Analysis in IPA was used to predict regulators and infer their activation state based on the literature and gene expression of target genes in the data set. STAT3 is the master regulator of a small causal network that postulates differential STAT3 activity in MERS-Co-V SA 1 and MERS-CoV Eng 1 infections. STAT3 activity affects a number of other regulators that explains the downstream gene expression changes in the data set. The color of the lines (edges) signifies the expected direction of effect between two nodes. Blue represents predicted inhibition and orange represents predicted activation. Yellow signifies inconsistency between the gene expression in the data set and the annotated relationship. The color of the node signifies the z-score calculated from the data set. Blue: z-score < -2 and orange: z-score > 2. The downstream genes show gene expression in infected cells relative to mock-infected cells. Green: down-regulated expression and red: upregulated expression).