An 80kb BAC encoding the Spry2 locus was isolated from a CITB-CJ7 (129S1/Sv) BAC library. Southern blot analysis determined a copy number of 1-2 for line 2. RT-PCR analysis of E14.5 embryonic palate tissue showed that line 2 expressed the transgenic Spry2 at ~12.5% of wild-type levels.