According to the allele molecular image presented by the International Knockout Mouse Consortium, this allele has one FRT site, an engrailed 2 splice acceptor sequence, an EGFP and cre/ERT2 expression cassette, a single Rox site remaining after a flanked puromycin resistance cassette removal, and a single loxP site replaced genomic region containing exons 2 through part of exon 6.