Fig 2: Blocking TAK1 phosphorylation increases expression of SAN transcription factors in cardiomyocytes. (A) Beat rate data day 21 cardiomyocytes from R1, TAK1 constitutive, TAK1-inducible with DOX, and R1 with OXO. Statistical significance was determined by ANOVA. (B) Live cell imaging of day 21 cardiomyocytes from R1 and (C) R1 with OXO treatment, imaging fluorescence from the aMHC:GFP cardiac promoter reporter. (D) Quantification of Shox2 (control N=110, OXO N=80), Islet1 (control N=48, OXO N=44), and HCN4 (control N=118, OXO N=123) expression in cardiac cells as assessed by ICC, with and without OXO treatment. Data represents means±s.e. of at least three independent experiments. Statistical significance was determined by an unpaired two-tailed t-test. **P<0.01, ***P<0.001, ****P<0.0001.

Fig 3: Relative protein expressions of R1, B1, B1 DOX-treated EBs at day 21. Tbx5, MAP3k7/TAK1, HCN4 and Cx43 proteins were assessed by western blot. Data represent means±s.e. of three independent experiments, normalized to GAPDH. Statistical significance was determined by unpaired two-tailed t-test. *P<0.05, **P<0.01.