A targeting vector was designed to insert a FRT site followed by an splice acceptor (SA) fused to the internal ribosomal entry site (IRES) and a lacZ gene, a loxP site, a neomycin resistance gene cassette, a second FRT site and a second loxP site (FRT-lacZ-loxP-Neo-FRT-loxP) intron 1 and a third loxP site immediately downstream of the exon2. This was intended to create a knockout-first conditional-ready reporter knockout allele. (J:238868)