The ETS transcription factor ELF1 regulates a broadly antiviral program distinct from the type I interferon response
Fig 5
ELF1 downstream impact on interferon production and signaling.
a. Canonical interferon (IFN) signaling (solid arrows) and proposed second wave of ISG expression (dashed arrows). b. STAT1 protein expression in A549 STAT1–/–or control cells by Western blot. c. Mean ± SEM of % influenza A/WSN/1933 virus–infected (NP–positive) cells by high content microscopy in STAT1–/–A549 expressing ELF1, ISG and transcription factor IRF1 as positive control, or empty vector (n = 3). ANOVA with Dunnett's multiple comparison to empty. ****p<0.0001, ***p<0.001 *p<0.1. d. A549 transduced to express ELF1 wild type (wt), ELF1 loss–of function mutant R8A, IRF1 as positive control, or empty vector control. mRNA of type I and II interferons by RT–qPCR. Data is shown normalized to empty control, as mean ± SEM. ****p<0.0001, **p<0.01. e. Reporter assay for ISRE–driven transcription. 293T encoding firefly luciferase under the control of a promoter carrying the ISRE motif and stably expressing renilla luciferase as control was transfected to express GFP as negative control, MDA5 as positive control, or ELF1, ELF2, ELF3, ELF4 and ELF5, respectively. Data as mean ± SEM from n = 3 independent experiments. f. 293T luciferase reporter cells were treated as in (e), and subsequently stimulated by transfection of polyI:C. Data as mean ± SEM from n = 3 independent experiments.