Ptprc^tm1(cre)Medv

The Cre recombinase encoding cDNA sequence, followed by the SV40 polyadenylation signal and a FRT-flanked puromycin resistance cassette, was inserted at the ATG translation initiation site in the second exon of the protein tyrosine phosphatase, receptor type, C (CD45) gene. The selection cassette was deleted by transient expression of FLPe in the correctly targeted ES cells. In mice bearing this allele and a GFP reporter transgene, fluorescence was observed only in CD45+ cells in the bone marrow, thymus, spleen and peripheral blood; the proportion of fluorescing cells of a given type appeared to correlate with the strength of CD45 expression. (J:152523)