Zfp57 mutant ES cell lines directly derived from blastocysts.

Zfp57 is a master regulator of genomic imprinting in mouse embryos. To further test its functions, we have derived multiple Zfp57 mutant ES clones directly from mouse blastocysts. Indeed, we found DNA methylation imprint was lost at most examined imprinting control regions in these Zfp57 mutant ES clones, similar to what was observed in Zfp57 mutant embryos in the previous studies. This result indicates that these blastocyst-derived Zfp57 mutant ES clones can be employed for functional analyses of Zfp57 in genomic imprinting.