MafG controls the hypoxic response of cells by accumulating HIF-1α in the nuclei

We identified MafG as a protein that interacts with HIF-1 alpha, a key factor in hypoxic response, using the yeast two-hybrid system. Interaction between MafG and HIF-1 alpha was confirmed by surface plasmon resonance and by translocation to the nucleolus with the NoLS signal. A knockdown of MafG reduced erythropoietin (EPO) mRNA levels as well as luciferase reporter activity with the hypoxia response element. The knockdown of MafG did not change total HIF-1 alpha protein, but reduced the accumulation of HIF-1 alpha in the nuclei. These results suggest that MafG regulates the hypoxic response of cells by detaining HIF-1 alpha in the nuclei.