The exons 9 and 10, encoding the C-terminal portion of the DNA-binding domain and flanked by loxP sites, were removed after crossing with mice expressing cre in an epiblast-restricted manner allowing targeted recombination in all adult tissues. PCR showed that less than 10-15% of the functional Ets2tm3Rgo allele remained in adult tissues. Mammary tissue was nearly completely recombined. (J:102368)