An FRT site was inserted into intron 1 and an FRT flanked hyg cassette site was inserted after the last exon via homologous recombination. This allele was originally created in tandem with Dppa4tm1Yam. These alleles are in cis to each other. Flp mediated recombination removed the hyg cassette. Elevated transcript expression, but not protein expression, was detected in the testes of mice heterozygous for this allele and Dppa4tm1.1Yam.