Ighg1^{em1(cre/ERT2)Rsky}

Single guide RNAs and a targeting vector, designed to insert an internal ribosomal entry site (IRES) followed by a cre/ERT2 fusion gene into the 3' untranslated region of the immunoglobulin heavy constant gamma 1 (Ighg1) gene, and the Cas9 nuclease were introduced into the cytoplasm of C57BL/6NCrl fertilized eggs with well recognized pronuclei. (J:267281)