CTCF binding sites on <i>FMR1</i> locus.

<p>A schematic outline of CTCF binding sites spanning the <i>FMR1</i> locus (white dot = unmethylated CpG; black dot = methylated CpG). Triangles indicate CTCF binding sites. Promoter, exon 1, intron 2 and methylation boundary (indicated as MB) sites had been previously described <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003601#pgen.1003601-Ladd1" target="_blank">[33]</a>; the site present in the upstream methylated region (indicated as MR) was identified through the database available online <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003601#pgen.1003601-Bao1" target="_blank">[34]</a>. The transcription start site is reported as +1, as referred to Genbank L29074.