Runx1^{tm1(cre/Esr1*)Ims}

A targeting vector was designed to insert a tamoxifen-inducible cre recombinase flanked by two mutated estrogen receptors and a floxed neo into the Runx1 gene downstream of the proximal (P2) promoter. The neo was subsequently removed via exogenous cre expression. A subsequent reference states that the allele was determined to be hypomorphic, with homozygotes developing to term but dying in the first postnatal day. (J:121435, J:182232)