Cre-mediated excision of the parental 1700012B09Riktm1(KOMP)Wtsi allele resulted in the removal of the neomycin selection cassette and critical exon(s) leaving behind the inserted lacZ reporter sequence. 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.