Cre-mediated excision of the parental 3110043O21Riktm1(KOMP)Mbp 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.