DNA-binding profiling of human hormone nuclear receptors via fluorescence correlation spectroscopy in a cell-free system.

The nuclear hormone receptors (NHRs), a family of transcription factors, bind directly to the hormone response elements (HREs) to regulate gene expression. In this study, we describe a comprehensive NHR-HRE profiling analysis with a new high-throughput DNA binding assay system utilizing wheat germ cell-free protein production and fluorescence correlation spectroscopy (FCS). This approach revealed NHR binding to natural response elements and new heterodimeric NHR-HRE bindings. We analyzed 408 possible binding combinations between 34 human NHRs and 12 different HREs, and identified 205 NHR-HRE binding combinations, 124 of which have not been previously reported. Thus, this study provides a novel biochemical classification of the human NHRs, as well as describing a novel approach to the large-scale analysis of DNA-protein interactions.