Detection of aberrant DNA methylation in undifferentiated and differentiated mouse ES cells compared to normal tissues

Embryonic stem cells can be differentiated in vitro to produce a variety of somatic cell types. We have employed the mDIP method combined with hybridization to a CpG islend microarray . We show that this differentiation is accompanied by an intrinsic process of extensive aberrant CpG island de novo methylation that includes developmental and cancer target genes. CpG-methylated genomic DNA was enriched using a methyl-DNA immunoprecipitation (mDIP) assay. DNA from the input and bound (enriched) DNA for each sample were labeled and hybridized on the array to define the methylation state of each region.