查看文章

Disclosing the mechanisms that regulate reprogramming memory. We established computational procedure to find DNA methylation somatic memory sites (SMSs) at single CpGs and integrated them with genomics, epigenomics, transcriptomics and imprinting information. Reprogramming memory persists at late passages in low methylated regions. Contrarily to hypomethylated, hypermethylated SMSs occur at evolutionary conserved sites overlapping active transcription loci in dynamic chromatin regions. The epigenetic-memory molecular origin is the expression of source-cell transcription factors protecting hypomethylated SMSs in euchromatin from de novo methylation, keeping source-cell lineage-specific loci in induced pluripotent stem (iPS) cells incompletely silenced. Sites in lineage-specific genes of different-from-those-of-the-source-cell lineages remain …