Fig. 5. Ate1 knockout results in defects in cardiac myocyte beating patterns. (A) Comparison of mean beats per minute (bpm), percentage of cells beating at high frequency, and percentage of cells with visible irregularities in the beating pattern between wild-type (WT) and knockout (KO) cultured myocytes derived from E12.5 embryonic mouse hearts. Calculations were made for 164 WT and 233 KO cells/islands for the left-most set of bars at low sampling rate (LS, two frames per second), 28 WT and 17 KO cells/islands for the next two sets of bars [calcium and phase, sampled at four frames per second for the same cell/islands in fluorescence (calcium) channel and phase-contrast], and 194 WT and 250 KO cells for the two right-hand sets of bars (irregular and high frequency). For images of individual beating curves, see Figs S4-6 in the supplementary material. (B) Examples of beating frequency curves, which were considered as regular, irregular or high frequency during manual calculation of the curves shown in Figs S4-S6 (see Figs S4-S6 in the supplementary material) to derive the percentages shown in A. (C) Illustration of how beat and calcium waves were measured from the total `gray level' in a region (square) of the beating cell that showed the most obvious changes (usually, the center). (D) Correlation plot between the physical beats observed in phase-contrast (x-axis) and calcium changes over time in the same cells (y-axis). For the most part, beats are correlated with calcium waves in both WT and KO cultures. For beating curves obtained by imaging of the same cells by phase-contrast and Fluo-4 calcium fluorescence, see Fig. S6 in the supplementary material.