Flp-mediated excison of the parental Hiratm1a(EUCOMM)Wtsi allele resulted in the removal of the neomycin selection cassette and the inserted lacZ reporter sequence, leaving behind the loxP-flanked critical exon 4. 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. (J:173534, J:212533)