Transposition of a single copy of a sleeping beauty transposable element gene trap vector occurred between the 22nd and 23rd exons among 25 exons of this gene. This gene trap vector consists of the inverted repeat direct repeat sequence specific for sleeping beauty transposase flanking human BCL2 splice acceptor sequence, IRES, lacZ, poly A signal, a chimeric CAG promoter containing sequence from the chicken ACTB promoter, GFP, and splice donor sequence. This allele was generated from mice carrying TgTn(sb-lacZ,GFP)IR3Jtak and Tg(CAG-sb10)1Jtak. Western blotting with an N-terminal binging antibody revealed that there was no expression in the mouse, as was confirmed by immunohistochemistry of hippocampus, cerebral cortex, and caudate putamen.