Several viruses have been proven to inhibit the formation of RNA processing bodies (P-bodies); however, knowledge regarding whether enterovirus blocks P-body formation remains unclear, and the detailed molecular mechanisms and functions of picornavirus regulation of P-bodies are limited. Here, we show the crucial role of 2A protease in inhibiting P-bodies to promote viral replication during enterovirus 71 infection. Moreover, we found that the activity of 2A protease is essential to inhibit P-body formation, which was proven by the result that infection with EV71-2AC110S, a 2A protease activity-inactivated recombinant virus, failed to block the formation of P-bodies. Furthermore, we show that DDX6, a scaffolding protein of P-bodies, interacted with viral RNA to facilitate viral replication rather than viral translation, by using a Renilla luciferase mRNA reporter system and nascent RNA capture assay. Altogether, our data first demonstrate that the 2A protease of enterovirus inhibits P-body formation to facilitate viral RNA synthesis by recruiting the P-body components to viral RNA. IMPORTANCE Processing bodies (P-bodies) are constitutively present in eukaryotic cells and play an important role in the mRNA cycle, including regulation of gene expression and mRNA degradation. The P-body is the structure that viruses manipulate to facilitate their survival. Here, we show that the 2A protease alone was efficient to block P-body formation during enterovirus 71 infection, and its activity is essential. When the assembly of P-bodies was blocked by 2A protease, DDX6 and 4E-T, which were required for P-body formation, bound to viral RNA to facilitate viral RNA synthesis. We propose a model revealing that EV71 manipulates P-body formation to generate an environment that is conducive to viral replication by facilitating viral RNA synthesis: 2A protease blocked P-body assembly to make it possible for virus to take advantage of P-body components.
Keywords: 2A protease; DDX6/4E-T complex; enterovirus; processing body.