Objective: To investigate the effect of the well-defined RNA elements (VR, RCS2, CS2, CS1 and SL) within the 3'untranslated region (UTR) on dengue virus (DEN) translation.
Methods: We constructed a virus induced reporter gene (VIRG) by inserting the firefly luciferase (LUC) gene between 5'- and 3'-UTRs of DEN2-43 genome. Subsequently, a series of modified VIRGs consisting of different RNA elements in the 3'UTR were constructed. A 3'UTR-deficient VIRG was also constructed. The translational efficiency of all VIRGs was then analyzed by LUC detection, real time RT-PCR and Western blot assays.
Results: The translation of 3'UTR-deficient VIRG was abolished. The translational efficiency of VIRG with RNA element VR was comparable with that of VIRG with unmodified 3'UTR. The translational efficiency of VIRG with RNA elements RCS2 or CS2 was significantly higher while the translational efficiency of VIRG with RNA elements CS1 or SL was substantially lower than that of VIRG with RNA element VR.
Conclusion: These results suggested that 3'UTR was indispensable for DEN translation, and some RNA elements within 3'UTR might either up-regulate or down- regulate translation.