CTCF_ER_ChIP. CTCF_ER_ChIP

CCCTC-binding factor (CTCF) is a conserved zinc finger transcription factor involved in chromatin looping. Recent evidence has shown a role for CTCF in ER biology. This experiment maps CTCF binding genome-wide in breast cancer cells and shows that CTCF binding does not change with estrogen or tamoxifen treatment. We find a small but reproducible proportion of CTCF binding events that overlap with both the nuclear receptor estrogen receptor and the forkhead protein FoxA1. These overlapping binding events are likely to be functional as they are biased towards estrogen-regulated genes. In addition, we identify cell-line specific CTCF binding events. These cell-line specific CTCF binding events are more likely to be associated with cell-line specific ER vinding events and are also more likely to be adjacent to genes that are expressed in that particular cell line. These data suggest a positive, pro-transcriptional role for CTCF in ER-mediated gene expression in breast cancer cells.