G3BP1, G3BP2 and CAPRIN1 Are Required for Translation of Interferon Stimulated mRNAs and Are Targeted by a Dengue Virus Non-coding RNA
Figure 4
G3BP1, G3BP2 and CAPRIN1 depletion specifically inhibits translation of reporters under the control of ISG UTRs.
(A) Schematic representation of IFN-stimulated response element (ISRE)-driven firefly luciferase reporters under the control of ELF2, GAPDH, IFITM2 or PKR UTRs. (B to I) HuH-7 cells stably transfected with the above constructs were treated with control siGFP or siG12C#1 siRNAs, induced with 1000 UI/ml of IFN-β for 10 h and firefly luciferase mRNA determined by quantitative real-time RT-PCR and normalized to GAPDH mRNA levels (B–E). Firefly luciferase protein levels were determined by measuring luciferase activity and normalized to total protein concentration (F–I). Both mRNA and protein activity are expressed as fold induction from control, untreated cells (siGFP, IFN-). Fluc measurements for the GAPDH-Fluc, IFITM2-Fluc and PKR-Fluc constructs were derived from 5 independent experiments in triplicate (n = 15). Fluc measurements for the ELF2-Fluc were derived from 3 independent experiments in triplicate (n = 9). All Fluc mRNA levels were measured in two of these independent experiments (n = 6).