Appropriate expression of imprinted genes on mouse chromosome 12 extends development of bi-maternal embryos to term

Recently, we reported that the restored regulation of imprinted gene expression from two regions – H19 differentially methylated region (H19-DMR) and intergenic germline-derived DMR (IG-DMR) – is sufficient for accomplishing full-term development in mice. In the present study, we determined the developmental ability of the bi-maternal embryos (BMEs) containing the non-growing oocyte genome with the IG-DMR deletion (ngΔch12) and fully-grown (fg) oocyte genome. Foetuses derived from ngΔch12/fg BMEs were alive at E19.5 but could not survive further. Comparison with BMEs derived from Igf2+/− ng/fg genomes suggests that bi-allelic H19 expression might be involved in foetal development.