Anti connexin 43 cx43

After differentiated for 15 days, the cells were fixed and incubated with primary antibodies (anti-MLC-2V, anti-α-actinin, anti-Ki67, anti-MHC, anti-connexin 43 (Cx43) and anti-cardiac troponin T (cTnT), 1:200, all from Abcam, Cambridge, MA, United States) for 60min at room temperature.

Cells were fixed in 4 % paraformaldehyde for 30 min, permeabilized for 15 min with 0.25 % Triton X-100, and blocked in 5 % BSA for 15 min. The cells were then incubated with the corresponding primary antibodies for 4 h at room temperature. Primary antibodies (1:200 dilutions) included anti-MLC-2 V, anti-α-actinin, anti-Ki67, anti-connexin 43 (Cx43) (rabbit polyclonal, Abcam) and mouse anti-cardiac troponin T (cTnT) (Abcam). After adequately washed with PBS, cells were incubated at room temperature for 1 h to corresponding FITC-conjugated anti-rabbit or Cy3-conjugated anti-mouse antibodies (Abcam, 1:200 dilution). DAPI (Invitrogen, 1:1,000 dilution) staining was used to identify nuclei. Analysis was performed using a confocal microscope (FV1000, Olympus).