GENOMIC IMPRINTING OF MASH2, A MOUSE GENE REQUIRED FOR TROPHOBLAST DEVELOPMENT

The mouse gene Mash2 encodes a transcription factor required for devel opment of trophoblast progenitors. Mash2- homozygous mutant embryos di e at 10 days post-coitum from placental failure. Here we show that Mas h2 is genomically imprinted. First, Mash2+/- embryos inheriting a wild -type allele from their father die at the same stage as appears almost completely repressed by 8.5 days post-coitum. Finally, we have geneti cally and physically mapped Mash2 to the distal region of chromosome 7 , within a The mouse gene Mash2 encodes a transcription factor require d for development of cluster of imprinted genes, including insulin-2, insulin-like growth factor-2 and H19.