This allele was generated by crossing mice bearing Sfpi1tm1Dgt with mice ubiquitously expressing FLP recombinase to produce progeny in which the FRT-flanked PGKneo cassette has been deleted. This leaves a single FRT site immediately upstream of the 5' member of a pair of loxP sites flanking the 3.4-kb upstream regulatory element (URE) that is located 14 kb upstream of the endogenous gene. Expression of the protein is unaffected by presence of the FRT or loxP sites. (J:90331, J:106788)