Fig. 3. Molecular characterization of defects in NICD1-activated hearts. The differences between the right and left ventricles were examined by whole mount (A,B,E,F) or section (C,D,G,H) in situ hybridization using probes Cited1 (A-D) or Hand1 (E-H). To demarcate the boundaries between both the atrial and ventricular chambers and the AV canal, chamber markers Anf (I,J), Smpx (K,L) and AV canal markers Bmp2 (M,N) and Tbx2 (O,P) were used as probes. Boundaries between the chambers and AV canal became less evident in the NICD1-activated heart (indicated by arrows in J and L). AV canal marker expression is also downregulated in the NICD1-activated hearts (indicated by brackets in M-P). Abbreviations: LA, left atrium; RA, right atrium; LV, left ventricle; RA, right ventricle. Scale bars: 200 µm in C,G.