CTCF and infection: Finally, a significant increase in the level of H3K27Me3 was detected in nearly the entire proviral genome 5’ to the CTCF site in PBMCs infected with HTLV-1ΔCTCF compared to HTLV-1p12Stop or WT HTLV-1, with levels 1-10 times fold higher over input values compared to the control infections.