Model of H19-mediated regulation of Igf2, Slc38a4, and Peg1 genes. In WT cells, the H19 lncRNA interacts with the MBD1 protein and recruits it to the Igf2 DMR1, both on the maternal and paternal allele (Upper Left). This recruitment induces H3K9me3 on both alleles, probably via interaction with an H3K9 KMT. In H19−/+ cells, MBD1 cannot be recruited to the Igf2 DMR1, leading to a loss of H3K9me3 (Upper Right). This results in an increase of Igf2 transcription, concomitant with a loss of Igf2 imprinting. On the Slc38a4 and Peg1 paternal DMRs, the H19 lncRNA recruits MBD1 and induces H3K9me3 (Lower Left). In absence of H19, the lack of binding of MBD1 results in a loss of H3K9me3 and in overexpression of the paternal allele (Lower Right). Therefore, H19 exerts a fine-tuned regulation of these genes, by modulating the presence of the repressive H3K9me3 histone mark on the active alleles.