Patent ID: 8354389

Claim:
A targeting construct, comprising from 5′ to 3′: a. a mouse targeting arm; b. a first recombinase recognition site; c. a nucleic acid sequence encoding a selectable marker operably linked to a first promoter; d. a second promoter operably linked to a recombinase gene, wherein the recombinase gene encodes a recombinase that recognizes the first and a second recombinase recognition site; e. a 3′-UTR comprising an miRNA recognition site, wherein the miRNA recognition site recognizes an mmu-miRNA that is active in mouse ES cells but not in differentiated cells that is selected from an miR 292-3p and an miR 294; f. the second recombinase recognition site, wherein the first recombinase recognition site and the second recombinase recognition site are oriented to direct an excision; and, g. a mouse targeting arm.