MicroRNA 130 family regulates the hypoxia response signal through the P-body protein DDX6.

The transcription factor HIF-1α (hypoxia inducible factor 1α) has an essential role in the maintenance of oxygen homeostasis in metazoans. HIF-1α expression and activity in the hypoxic response is regulated at the translation and post-translational levels. However, the mechanism and modulator of HIF-1α translation during hypoxia is not fully understood. We found that HIF-1α expression during hypoxia was upregulated by the microRNA 130 (miR-130) family. Levels of the miR-130 family are elevated under hypoxia, and their target is DDX6 mRNA, which is a component of the P-bodies. Furthermore, we found that a decrease of DDX6 expression by the miR-130 family enhanced the translation of HIF-1α in an internal ribosome entry site element-dependent manner. These results reveal a new HIF-1α translational mechanism and a role for P-bodies in hypoxic stress.