Figure 4

DNA methylation of the CpG island containing XIST P2. Schematic of the 5′ end of XIST showing P1 and P2 with the intervening 5′ A repeats. Methylation levels shown for each site are the average of two male cell lines, three female cell lines, two Xa and four Xi-containing hybrids, and the HT1080 with XIST transgenic line. Shown below is the location of the pyrosequencing assays (A to D) designed to assess methylation at 18 of the 23 CpG sites in the intermediate density CpG island. Also shown are the YY1 sites (based on consensus sequence 5′-CCGCCATNTT-3′ from http://www.uniprot.org/uniprot/P25490) as well as the CpGs analysed by Illumina 450 K Bead Chip.