Epx^{tm1.1(cre)Jlee}

A sequence encoding a mammalian codon-optimized cre recombinase was inserted at the start codon of the Epx locus by homologous recombination. An IRES was inserted before the coding exons of Epx, so that a dicstronic mRNA encoding cre and Epx would be generated. A neo selection cassette was included in the original construct, and was subsequently removed from the targeted allele by a backcross to a flp deleter mouse strain. It was determined that Epx expression was not rescued efficienty from the modified allele by the IRES. Flow cytometric GFP analyses of cell populations from offspring of eoCre mice and reporter animals demonstrated that cre expression is observed only in eosinophils. (J:198489)