(A) Western blot analysis to show increased and decreased diphospho-ERK1/2 levels in avian heart valve precursor cells infected for 48 hours with AdV-caMEK1 and AdV-dnMEK1 respectively, compared to AdV-GFP controls. (B) qPCR to show fold changes in Scx expression in avian valve precursor cells following AdV-caMEK1 and AdV-dnMEK1 infection for 4, 16 and 48 hours, compared to AdV-GFP controls (n=4), *=p<0.05. (C) Representative Western Blot to indicate CSPG expression in avian valve precursor cells following AdV-GFP, AdV-caMEK1 and AdV-dnMEK1 treatments for 48 hours. (D) Densitometry quantitation of Western blot analysis in (C), *=p<0.05 using one-way ANOVA plus a post-hoc test. (E–G) Immunohistochemistry to detect CSPG expression in avian VP cell cultures infected with AdV-GFP (E), AdV-caMEK1 (F) or AdV-dnMEK1 (G).