Characterization of mRNA-protein complexes as modulators of cellular hypoxia response.

• Applicant: Dr. Isabel Naarmann-de Vries
• Subject Area: Cell Biology
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 280542466

Hypoxia is described as cellular lack of oxygen and strongly affects energy consuming processes as the activity of the Na-K-ATPase and mRNA translation. Thus, under hypoxic conditions global, 5´cap-dependent mRNA translation is inhibited. However, a subset of mRNAs escapes this inhibition by different mechanisms. Internal ribosome entry sites (IRESs) mediate the 5´cap-independent initiation of translation. Under hypoxia translation is favored at ER-bound ribosomes. Cis-elements in the untranslated regions (UTRs) of certain mRNAs and trans-acting proteins mediate their localization to the ER and thereby efficient translation under hypoxic conditions. Employing the MCF-7 cell system I will study the post-transcriptional control of gene expression during the hypoxic response utilizing protein occupancy profiling. RNA motifs differentially occupied with proteins will be identified by this method. Interacting RNA binding proteins (RBPs) will either be identified by RNA affinity chromatography in combination with mass spectrometry analysis or based on their known RNA binding motifs. The function of dynamic RNA-protein interactions in post-transcriptional control of gene expression during the hypoxic response will be analyzed in RNA interference, mRNA stability, ribosome profiling and in vitro translation experiments. These analyses will give insight into mechanisms, by which tumor cells escape hypoxic conditions limiting tumor growth.

• DFG Programme: Research Grants