A targeting vector containing a loxP flanked PGK-EM7-NeobpA cassette replaced Mirlet7c-2 and Mirlet7b which make up the Mirc31 cluster. Cre-mediated recombination removed the neo cassette. PCR sequencing confirmed the presence of the 801-bp genomic deletion of Mirlet7b and Mirlet7c-2. (J:236467)