Runx1^tm3.1Spe

A loxP site flanked targeting vector containing PGK-Neo selection cassette was utilized in the construction of this mutant. This selection cassette was inserted downstream of exon 4 of the targeted gene, and another loxP site was inserted upstream of exon 4. This construct was electroporated into 129S4/SvJae derived J1 embryonic stem (ES) cells. Chimeras were crossed to C57BL/6NTac mice for 3 generations then made homozygous. The mice were then crossed to (B6129S)F1/J with the resulting F2 intercrossed to generate homozygotes carrying the floxed allele. These mice were then crossed to transgenic mice expressing Cre recombinase (carrying the Tg(Cdh5-cre)1Spe, (VEC-cre) transgene on a mixed B6;129 background. (J:90431)