Estrogen receptor action in three dimensions - looping the loop.

Due to advances in genomic technologies, our understanding of estrogen receptor (ER)-mediated transcription in breast cancer cells has evolved significantly in recent years. Genome-wide mapping experiments revealed thousands of ER-binding events, but linking them to the target genes has been an ongoing struggle. A recent paper describes a new technique, called ChIA-PET (chromatin interaction analysis using paired-end tag sequencing), that can directly address these questions. ChIA-PET is an unbiased approach for simultaneously identifying all genome-wide binding events of a transcription factor and those involved in long-range chromatin loops.