The allele was generated by targeted replacement of the terminal exon 14 of the Mki67 locus with a modified exon 14 sequences with upstream FRT flanked neomycin cassette, and downstream mCherry fusion construct, IRES sequence, and CreERT2 cDNA. Mice were crossed with actin-FLPe mice to excise the neomycin selection cassette. (J:301684)