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

<p>For each knock-in allele, a cassette consisting of an <i>IRES-CreER</i>, the pBR322 Tetracycline resistance gene (<i>TetR</i>), and an Frt-flanked phosphoglycerate kinase promotor neomycin resistance gene (<i>FNF</i>) was inserted into the 3′ untranslated region of the target gene as indicated. The <i>PGK</i>-<i>neo</i> casette was subsequently removed in vivo by Flp recombinase. The sizes of the homology regions used for the targeting constructs were: <i>ChAT</i>, 9.5 kb; <i>NFL</i>, 7.0 kb; <i>TH</i>, 9.2 kb; and <i>VAMP2</i>, 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: <i>ChAT</i>, <i>Stu</i> I and <i>Bam</i>H I; <i>NFL</i>, <i>Eco</i>R V; <i>TH</i>, <i>Bam</i>H I; and <i>VAMP2</i>, <i>Nco</i> I.