Figure 1.

Evolutionary conservation of the YY1 binding sites in the 1^st intron of YY1. The ECR (Evolutionary Conserved Region) browser shows that the 1^st exon and the beginning region of the 1^st intron of YY1 are well conserved among eight species: tetraodon, zebrafish, frog, opossum, cow, mouse, dog, and rhesus macaque. Human YY1 was used as a reference sequence for this alignment. The height of the graph peaks indicate the level of nucleotide identity, while blue and salmon colors indicate exon and intron regions, respectively (A). The genomic sequences of the 1^st intron of YY1 from 11 different species were also manually aligned: one each from purple sea urchin, sea squirt and amphioxus, two from each of two fish, one from frog, and five from mammals. The YY1 binding sequences marked in blue and green indicate the perfectly and imperfectly-matched YY1 binding sequences, respectively. The arrows on the right side of the sequences or under the YY1 binding sequences indicate the orientation of individual YY1 binding sites (B). The genomic region surrounding the five YY1 binding sites located within the 1^st intron of mouse YY1. The YY1 binding sites are indicated by thick arrows with orientations, while the 1^st exon by a closed rectangle. The thin arrows underneath the genomic layout indicate the position and direction of primer sets used for the PCR amplification of ChIP DNAs. The amplified PCR products of each region are shown as the following order: Input (lane 1), the ChIP DNA with rabbit normal serum (lane 2), and the ChIP DNA with YY1 antibody (lane 3) (C).