The chicken cVg1 locus with computationally predicted conserved CTCF-binding sites in chick, human, and mouse is shown (genes represented in blue). This putative insulator region lies ∼200 kB upstream and ∼100 kB downstream of cVg1/GDF3 and harbours other genes such as CERS1/Lass1, COPE, DDX49 and HOMER3 upstream and UPF1 downstream of cVg1. Six putative enhancer regions (E1–E6), predicted using DREiVe, are displayed in pink. In chick, E1 (galGal4 genomic coordinates: chr28:3502783-3504834) and E2 (chr28:3504993-3508041) lie in the first intron of the bicistronic CERS1/Lass1 gene. E3 (chr28:3510154-3511032) and E4 (chr28:3,511,413-3,511,725) lie in intron 4 of CERS1/Lass1 and E5 (chr28:3471200-3471520) and E6 (chr28:3,471,946-3,472,230) respectively lie in introns 1 and 2 of HOMER3. E1 and E3 each contain conserved Pitx1 (black) and Pitx2 (green) binding sites. E2 and E4 do not contain any Pitx sites and E5 and E6 contain Pitx2-binding sites but no Pitx1-binding sites. The orthologous regions of human (chromosome 19) and mouse (chromosome 8) genomes are also shown. Note that the corresponding human region has been inverted, and that although all six elements are found within it, these appear in different order and are associated with different introns and intergenic regions than in chick and mouse.