Methylation of the Corticotropin Releasing Hormone Gene Promoter in BeWo Cells: Relationship to Gene Activity

Figure 4

Methylation of individual CpG dinucleotides at 0 h and 72 h of culture (0 h and 72 h, resp.), after 72 h with 8-Br-cAMP (cAMP) and after 72 h with 5-AZA-dC (AZA), and the combination of the two (cAMP + AZA). Treatments are denoted on the horizontal axis and CpG numbers (shown in Figure 3) are indicated on the vertical axis. The heatmap shows % methylation according to the scale on the right. Three independent experiments with ten clones (randomly selected individual gene copies) sequenced at each time point were combined to calculate % methylation. The statistical significance of methylation frequency differences among the CpG sites at each treatment condition is shown on the top (Fisher’s exact test). The black crosses indicate significantly different methylation of CpGs 1, 2, 3, and 7 between 0 h and 72 h; crosses with white lining in the AZA fields denote significant CpG-site-specific differences compared to 72 h, and crosses with red lining in the cAMP + AZA fields denote significant differences of CpG site methylations as opposed to cAMP treatment alone (, Fisher’s exact test).