Restriction maps of the targeting constructs, targeted alleles, Southern blot probes, and PCR primers for IRES-CreER knock-in alleles at the ChAT, NFL, TH, and VAMP2 loci.

For each knock-in allele, a cassette consisting of an IRES-CreER, the pBR322 Tetracycline resistance gene (TetR), and an Frt-flanked phosphoglycerate kinase promotor neomycin resistance gene (FNF) was inserted into the 3′ untranslated region of the target gene as indicated. The PGK-neo casette was subsequently removed in vivo by Flp recombinase. The sizes of the homology regions used for the targeting constructs were: ChAT, 9.5 kb; NFL, 7.0 kb; TH, 9.2 kb; and VAMP2, 9.1 kb. For Southern blot hybridization, the probes indicated beneath the maps of the targeted loci were used, and genomic DNAs from the four groups of targeted ES cells and germ-line transmitted mice were cleaved with the following restriction enzymes: ChAT, Stu I and BamH I; NFL, EcoR V; TH, BamH I; and VAMP2, Nco I.