LoxP sequences flanking the first through fourth coding exons and loxP sequences flanking the Neo expression cassette were targeted to the Caspase 6 gene. In-vitro mediated cre-deleted resulted in removal of neo cassette leaving two lox P sites flanking coding exons 1 to 4 (or exons 2 to 5 if the first non-coding exon is included). (J:147112)