A loxP site was inserted upstream of exon 3. An FRT-flanked neomycin resistance cassette with a 3' loxP site was inserted in exon 3 downstream of the site for induction of Mir 7 degradation. Flp-mediated recombination removed the selection cassette and left the coding sequence of exon 3 through the Mir 7 site floxed. (J:265657)