Fig. 4: Pitx2 expression is deregulated in the DelB SAN and ventricles.

a Fold change expression levels of detectable TAD genes in P21 DelB (n = 9) vs. control littermates (dotted line) in the left and right atria and ventricles. Red and blue bars highlight upregulation (p = 0.0009) and downregulation (p = 0.0007) of Pitx2 respectively. Statistical significance was determined across four genotypes and within each tissue type using Kruskal–Wallis test followed by pairwise comparisons with Dunn’s multiple comparison tests in right and left atrial, and Welch’s ANOVA followed by Dunnett’s T3 multiple comparison tests in ventricles. Significant p values adjusted for multiple testing are shown in the graph. b Whole-tissue RNA sequencing was performed on micro-dissected SAN (in red) and RA regions (PCM pacemaker cardiomyocyte, LA left atrium, PV pulmonary vein, SVC superior caval vein, IVC inferior caval vein, RA right atrium, SAN sinoatrial node). Expression analysis of microdissected SANs of wild type and DelB mice show that Pitx2 and Larp7 are the only differentially expressed TAD genes between control (n = 8) and DelB (n = 7) adult SANs. Differential expression analysis was performed using the DESeq2 package. p values were corrected for multiple testing using a false discovery rate with 0.05. c Expression analysis of microdissected SANs of wild type and DelB mice show differential expression of genes between control and DelB adult mice. Blue dots highlight genes downregulated and red dots highlight genes upregulated in DelB mice. The differential expression analysis was performed using the DESeq2 package with a two-sided Wald test and multiple testing correction using a false discovery rate with 0.05. d Scatter plot showing the relative expression of genes enriched in the pacemaker cardiomyocyte cluster alongside the differential expression of genes between control (n = 8) and DelB (n = 7) SAN region. e Relative PITX2 expression in hiPSC-CM WT and hiPSC-CM-CTCF−/− ventricle like cardiomyocytes (hiPSC-VCM n = 8, n = 8) and pacemaker cell like cardiomyocytes (hiPSC-PCM n = 13, n = 19). Source data are provided as a Source Data file.