Flp-mediated excision of the parental Tpcn2tm1a(EUCOMM)Hmgu allele resulted in the removal of the promoter-driven neomycin selection cassette and the inserted lacZ reporter sequence, leaving behind exon 6 flanked by loxP sites. Further information on targeting strategies used for this and other IKMC alleles can be found at http://www.informatics.jax.org/mgihome/nomen/IKMC_schematics.shtml.