The 5′CL-PCBP RNP complex, 3′ poly(A) tail and 2Apro are required for optimal translation of poliovirus RNA

In this study, we showed that the 5′CL-PCBP complex, 3′ poly(A) tail and viral protein 2Apro are all required for optimal translation of PV RNA. The 2Apro-mediated stimulation of translation was observed in the presence or absence of both the 5′CL and the 3′ poly(A) tail. Using protein–RNA tethering, we established that the 5′CL-PCBP complex is required for optimal viral RNA translation and identified the KH3 domain of PCBP2 as the functional region. We also showed that the 5′CL-PCBP complex and the 3′ poly(A) tail stimulate translation independent of each other. In addition to the independent function of each element, the 5′CL and the 3′ poly(A) tail function synergistically to stimulate and prolong translation. These results are consistent with a model in which the 5′CL-PCBP complex interacts with the 3′ poly(A)-PABP complex to form a 5′–3′ circular complex that facilitates ribosome reloading and stimulates PV RNA translation.