DNA methylation and histone modifications are two major epigenetic marks in mammalian cells. Previous studies have revealed that these two mechanisms interact although a quantitative model of these is still lacking in mammalian cells. Here we sought to develop such a model by systematically evaluating the quantitative relationship between DNA methylation and the core histone modification marks in human epigenomes. This model reflects the interactions of ADD and PWWP domains of DNA methyltransferase (DNMTs) with histone 3 lysine tails. Our analysis integrated 35 whole genome bisulphite sequencing data sets (about 800 million CpG sites), 35 chromatin states and 175 ChIP-Seq histone modification profiles across 35 human cell types. The logistic regression model we built shows that more than half of the variance across DNA methylomes can be explained by the five-core histone modification across varied types of human cell and tissue samples. Importantly, we find that H3K4me3 has a dramatic effect in DNA methylation patterning, highlighting the essential interaction between ADD domain of DNMTs and histone 3 lysine 4 in human. Moreover, our model suggests DNA methylation is generally inhibited by the presence of H3K4me3, H3K4me1 and H3K27me3, while increased levels are found in regions that are marked by H3K9me3 and H3K36me3. In summary, our results provide a comprehensive evaluation of the crosstalk between DNA methylation and histone modification in a variety of human cell types, and shows that DNA methylation patterns can be largely explained by interactions between histone 3 lysine tails and specific domains of DNA methyltransferases.
Keywords: DNA methylation imputation; Epigenetic interaction; epigenetic modelling.