A targeting vector was designed to insert an FRT flanked sequence containing the splice acceptor sequence from exon 2 of engrailed 2, EMCV IRES, a lacZ-neo cassette and SV40 polyA signal into intron 1. There was a loxP site on the 3' end and a second loxP site inserted into intron 2. RT-PCR confirmed that the cassette truncated the transcript before exon 2. A transcript encoding the first 121 amino acids of the locus fused to 40 frameshifted amino acids encoded by the second exon of engrailed 2 could be expressed. Transcript was not detected by RT-PCR of mutants. (J:107403)