Enhancer Of Polycomb Homolog 1 (EPC1)

The deduced 836-amino acid protein has a calculated molecular mass of 92 kD. It has EPcA, EPcB, and EPcC domains and a Qx region, all of which are highly conserved from yeast to humans. Endogenous EPC1 localized to nuclear domains and to the nuclear membrane in a human colorectal adenocarcinoma cell line. RFP interacted with EPC1 and that both proteins repressed gene transcription. Yeast 2-hybrid assays revealed that the coiled-coil domain of RFP associated with the EPcA domain and the C-terminal region of EPC. Both proteins coprecipitated from lysates of human cells and mostly colocalized in the nucleus. The coiled-coil domain of RFP and the C-terminal region of EPC1 repressed transcriptional activity in reporter gene assays, whereas the EPcA domain of EPC1 activated transcriptional activity.