First Flp- and then Cre-mediated excision of the parental Stat1tm1a(EUCOMM)Wtsi allele resulted in the removal of the promoter-driven neomycin selection cassette, the IRES-BetaGal reporter expression cassette and critical exon(s). 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:267220)