Figure 1.

Genome-wide expression profiling of epigenetic enzyme genes reveals a potential role for disruptor of telomeric silencing 1-like (DOT1L) in cardiomyocyte (CM) differentiation and maturation. (a) Custom qRT-PCR array card assessing the relative expression of 85 epigenetic enzyme genes at different stages of cardiac differentiation of mouse embryonic stem cells (mES; days 1, 2, 5, and 9). Data are presented as –ΔΔCt relative to expression at day 0. On the left, heatmap of differential expression levels; on the right, graphs highlighting five groups of differentially expressed genes. (b) On the left, relative qRT-PCR of Dot1L mRNA expression at day 0, 1, 2, 5, and 9 of mES differentiation; mRNA levels are normalized to 18 s and expressed as mean±S.D. On the right, representative Western blot of mES cells at 0, 1, 2, 5, and 9 days of differentiation. The expression levels for POU5F1, α/βMYH, and DOT1L are normalized to that of lamin B (LAM b), whereas the expression of H3K79me2 is normalized to that of unmodified H3. (c) Custom qRT-PCR array card assessing the relative expression of 85 epigenetic enzyme genes in mouse cardiac cells at different stages of development (embryos at E8.5, E10.5, E12.5, E14.5; P1 pups, and adult). Data are presented as –ΔΔCt relative to E8.5 expression. The mean of three biological replicates is shown. On the left, heatmap of differential expression levels; on the right, graphs highlighting five groups of differentially expressed genes. (d) On the left, qRT-PCR of relative mRNA expression of Dot1L in mES, cardiomyocytes from embryonic day E14.5 (Cme_14.5), and cardiomyocytes from post-natal day 1 (CM_P1) and 2-month-old adult (CM_A) mice. Graphs of mean±S.D. of three biological replicates. *P<0.05 versus mES; **P<0.01 versus mES; ^##P<0.01 versus CMe; ^§§P<0.01 versus CMp. On the right, Western blot analysis for the expression of DOT1L (normalized to LAM b) and H3K79me2 (normalized to unmodified H3)