Rr27^tm2Tilg

Mutations were introduced at each of the 3 AB sites (AB-1, AB-2, and AB-3) located in the imprinting control region (ICR) upstream of the H19 transcription start site. Single loxP sites remained flanking the ICR after a floxed cassette containing a neomycin resistance gene and a cre recombinase gene was self-excised. The mutations were shown by EMSA to ablate binding activity. Imprint establishment and maintenance was unaffected in mutant mice. (J:86440)