The targeting construct is designed to insert a GFP reporter-GSGGS-OVA(229-359) fusion protein followed by an ACN cassette into exon 2 (the natural translation start site) of the gene. The ACN cassette includes a neomycin cassette, Cre recombinase and testes specific promoter (tACE) flanked by loxP sites. The tACE promoter allows expression of cre during spermatogenesis resulting in removal of the ACN cassette. (J:269925)