Figure 1.

Contraction kinetics of DNA methyltransferase(DNMT) 3A knockoutengineered heart tissue (EHT).

A, Normalized average contraction peaks of EHT from wild-type and knockout lines at a stimulation frequency of 1.5 Hz. Mean±SEM. B, Relaxation times from peak to 80% relaxation at 1.5 Hz. n=7-12 EHTs per group. C, Ratio of myosin heavy chain (MHC) isoforms in wild-type and DNMT3A^−/− EHTs. MYH7 and MYH6 abundance was measured by NanoString analysis, n=3. D, Ratio of atrial (MYL7, MLC2A) and ventricular myosin light chain (MYL2, MLC2V) isoforms, measured by RNA sequencing. n=3. E, Relative expression of atrial-specific marker genes. n=3, False discovery rate- (FDR-) adjusted P value. F, PITX2 promoter methylation, measured by reduced representation bisulfite sequencing. n=3–4. G, Pacing capture of wild-type and knockout EHT at frequencies from 0.7 Hz to 6 Hz, beating frequency of each EHT line plotted against the stimulation frequency. Each dot represents a single EHT measurement. ***P<0.001.