Is DNA methylation correlated with nucleosome occupancy?
DNA methylation can determine nucleosome positioning. Using a novel bioinformatics pipeline, we show a striking anti-correlation between nucleosome occupancy and DNA methylation at CTCF regions that is not present at promoters. DNA methylation determines nucleosome occupancy in the 5'-CpG islands of tumor suppressor genes. In contrast, exons demonstrate a high degree of methylation and nucleosome occupancy. Although global DNA demethylation has been observed after treatment, it is unclear to what extent demethylation induces changes in nucleosome occupancy, a key determinant of gene expression. In order to systematically evaluate potential diversities among CGIs and ultimately to illuminate the link between diversity of CGIs and their epigenetic variation, we analyzed the nucleotide-resolution DNA methylation maps  of multiple cellular origins. Using this global approach, we observe the dependency of nucleosome occupancy upon the DNA methylation status. Exonic DNA methylation seems to function together with exonic nucleosomes and H3K36me3 for the proper splicing of transcripts with different expression levels. Transcription, histone modifications, and DNA methylation alter this "ground state" by having distinct effects on both nucleosome positioning and occupancy. 