DXZ4 chromatin adopts an opposing conformation to that of the surrounding chromosome and acquires a novel inactive X-specific role involving CTCF and antisense transcripts

CTCF binds to a single region of DXZ4 on the Xi only. (A) ChIP with CTCF co-immunoprecipitates DXZ4 DNA in females only. The samples shown are one example of four independent male and female cell line ChIP experiments that showed the same result. (B) Close-up of ChIP-chip data for a single 3-kb DXZ4 monomer (0–3000 bp) with CTCF in a male and female sample. The coordinates at the top of the image represent nucleotides 114,785,064–114,788,023 of Human Genome Build HG17. Immediately below the line is the NimbleGen Signal Map 1.8 output for the CTCF ChIP-chip. The width of the signal indicates the extent of the hybridization.