Figure 1

Generation of YAC Y1123 and DTy54 transgenic mice. (A) Construct pDT-1 contained sequences expressing tau-GFP and conferring neomycin (neo) resistance, separated by an internal ribosomal entry site (IRES), terminated with polyadenylation and C2MAZ (pAC2m) sequences and flanked by 5' and 3' homology regions (5'HR and 3'HR). (B-C) Homologous recombination resulted in the introduction of this construct at the translation initiation site (ATG) in exon 4 of the human PAX6 locus, contained in YAC Y593 [17], to produce YAC Y1123. Successful integration of the modified PAX6 locus into the mouse genome was checked on Southern blots using cosmid FAT5 [17] as a probe and by PCR using primers indicated by filled circles in C (sequences in Methods). The modification was designed such that the tau-GFP and neomycin resistance cassettes would be controlled by the gene's regulatory elements and would prevent the production of PAX6 protein from the translational start site in exon 4. The position of the ELP4 gene is marked.