Fig. 7. Summary of the main features of the Mnt mutation. (A) The situation in wild type with the endoderm enhancers (E), the mesoderm enhancers for tongue and skeletal muscle (M1), and the mesodermal enhancers for heart, lung and kidney (M2) activating paternal Igf2 and maternal H19. (B) The Mnt situation with disruption of the M1 enhancers, isolation of the M2 enhancers, maternal methylation at the H19 DMR (hence the absence of a functional boundary on the maternal allele), absence of H19 expression, and subsequent biallelic activation of Igf2 from the remaining active enhancers (E).
