F1 progeny mice carrying both the FLPo transgene and the Lox allele were backcrossed to wild-type mice to remove the FLPo transgene.
Mosaic, early embryonic, ubiquitous Cre mice (MeuCre40) [22] were crossed with Sp2wt/lzn mice to remove the LacZ-Neo selection cassette from the Sp2 tri-loxP-allele.
Mice that were shown to be heterozygous for the targeted allele were mated to Flip recombinase-expressing transgenic mice to remove the neo cassette.
These mice were then bred with Flpe mice to remove the Neo cassette.
These were crossed with Flp deleter mice to remove the neo cassette.
Heterozygote progeny were screened for germline transmission before crossing to Rosa26 Flp1 mice to remove the neo cassette.
Mice carrying the Cbfb f allele were subsequently generated by mating chimeric mice to germ-line FlpE mice to remove the Neo cassette (Rodriguez et al., 2000).
The resulting F1 heterozygous mice were bred with Zp3-Cre transgenic mice to remove the floxed neo in the female germline (see Materials and Methods).
Germline floxed mice (Tbx22 tm1(flox/exon0-2/NEO)Sta ) were bred to β-actin-Cre mice to remove the first three exons and create a Tbx22 deleted strain.
Following germline transmission of this Ablμ-loxP-Neo-loxP allele, female were bred with male protamine-Cre-transgenic mice to remove the Neo cassette.
To generate Optn ΔEx12/ΔEx12, the Optn D477N/D477N mice were first crossed to Flpe−/− mice to remove the Flpe transgene, and these mice were then crossed to Bal-1 Cre mice to delete exon 12.
