Fig. 6.
Annotated percentage identity plot (Schwartz et al., 2000) of the Pax6 locus extending from 20 kb upstream of the P0 promoter to the downstream end contained within the YACs. The murine sequence, being more compact than the human locus, was used as baseline. Pairwise comparisons were made with the human and chicken PAX6/Pax6 loci. The length of the Pax6 transcription unit is depicted in yellow and the Elp4 transcription unit in orange. Exons are shown in pink. The interval in which the truncated downstream end of the individual YAC transgenes lies is marked above the plot. The positions of the two LoxP sites inserted into YAC Y374 are indicated by vertical lines, with red and blue arrowheads marking LoxP and FRT sites respectively. Conserved enhancer sequences of relevance to this study are highlighted with blue boxes. P/EE, pancreas/ectodermal enhancer (Williams et al., 1998; Kammandel et al., 1999), P, pancreas enhancer (Xu et al., 1999), α, intron 4 retinal enhancer (Plaza et al., 1995a; Kammandel et al., 1999), 7CE2, diencephalon enhancer (Kleinjan et al., 2004); E60+, ultraconserved enhancer (Kleinjan et al., in preparation); E100, C1170box123 enhancer (Griffin et al., 2002), EI/SIMO, lens, diencephalon, hindbrain enhancer (Kleinjan et al., 2001), HS2/3, retinal enhancer (Kleinjan et al., 2001). Inspection of the PIP plot for the region between the 3′ ends of Y001 and Y223/DTy54 revealed the presence of one highly conserved fragment, which we have termed RB. The enhancer regions analyzed in Figs. 7 and 8, RB and EI, are marked with red boxes.