Figure 1

Temporal changes in RNA expression induced by ET-1 in cardiomyocytes. (a) The 1,494 probesets identified as significantly (FDR <0.05; 1.5-fold difference) up- or downregulated in response to ET-1 at 0.5, 1, 2 or 4 h were clustered using a Pearson complete correlation and are presented as a heatmap of the mean change at each time (Log₁₀ scale: cyan = zero, black = 1, red = 6). (b,c) K means clustering generated four groups (TC1-TC4) of downregulated transcripts (b), and seven groups (TC5-TC11) of upregulated transcripts (c). The numbers of different transcripts for each group are shown in parentheses. (d) Supervised clustering of TC11 identified three subclusters (TC11a, TC11b and TC11c; numbers of transcripts in each group in parentheses) demonstrating differential temporal and transient expression before 2 h. (Note that three genes exhibited apparent increases in excess of 20-fold (Egr4, 50-fold; c-Fos, 28-fold; FosB, 306-fold) and were excluded from this clustering because of the excessive bias introduced.) Statistical significance (repeated measures one-way ANOVA with Tukey post-test) p < 0.05 for all times versus all other times except for the following (not significantly different): TC2, 0.5 versus 1 h; TC3, 0 versus 4 h and 0.5 versus 2 h; TC4, 0.5 versus 4 h; TC5, 1 versus 2 or 4 h, 2 versus 4 h; TC6, 0 versus 0.5 or 1 h; TC7, 0 versus 0.5, 2 versus 4 h; TC8, 0 versus 0.5 or 1 h, 0.5 versus 1 h; TC9, 0 versus 0.5 or 4 h, 0.5 versus 4 h, 1 versus 2 h; TC10, 0 versus 0.5 h, 1 versus 4 h; TC11, 0 versus 2 or 4 h, 0.5 versus 1 h, 2 versus 4 h. (b-d) Results are means ± SEM for the numbers of transcripts given in parentheses. (e) Classification of genes regulated by ET-1 according to known or probable function (see Additional data file 1 for details).