A randomly integrated transgenic H19 imprinting control region acquires methylation imprinting independently of its establishment in germ cells

The imprinted expression of the mouse Igf2/H19 locus is governed by the differential methylation of the imprinting control region (ICR), which is established initially in germ cells and subsequently maintained in somatic cells, depending on its parental origin. By grafting a 2.9-kbp H19 ICR fragment into a human -globin yeast artificial chromosome in transgenic mice, we previously showed that the ICR could recapitulate im-printed methylation and expression at a heterologous locus, suggesting that the H19 ICR in the -globin locus contained sufficient information to maintain the methylation mark (K. Tanimoto, M. Shimotsuma, H. Mat