Mitochondrial hypoxic stress induces RNA editing by APOBEC3G in lymphocytes

Protein recoding by RNA editing is required for normal health and evolutionary adaptation. However, de novo induction of RNA editing in response to environmental factors is an uncommon phenomenon. While APOBEC3A edits many mRNAs in monocytes/macrophages in response to hypoxia and interferons, the physiological significance of such editing is unclear. Here we show that the related APOBEC3G cytidine deaminase induces site-specific C-to-U RNA editing in natural killer (NK), CD8+ T cells and lymphoma cell lines upon cellular crowding and hypoxia. RNA seq analysis of hypoxic NK cells reveals C-to-U recoding mRNA editing in dozens of genes including multiple translational and ribosomal genes. APOBEC3G promotes Warburg-like metabolic remodeling and reduces proliferation of HuT78 T cells under similar conditions. Hypoxia-induced RNA editing by APOBEC3G can be mimicked by the inhibition of mitochondrial respiration, and occurs independently of HIF-1α. Thus, APOBEC3G induces mRNA editing in lymphocytes to promote adaptation to mitochondrial hypoxic stress. 6 NK cells. 3 normoxia and 3 hypoxia treatment replicates.