FIGURE 3.

Exogenous IFNβ can decrease the efficacy of LINE-1 retrotransposition in a MOV10-dependent manner. A, appearance of GFP-positive cells NIH3T3 cells that received indicated RNAi (control or against mouse IFNβ) or antibodies (control IgG or neutralizing antibody against mouse IFNβ, 10 μg/ml for 30 h) prior to being transfected with EN⁺ LINE-1 construct. Magnification bar: 10 μm. B, schematic layout of the experiment described in panel C. C, HeLa cells were transfected with LINE-1-GFP plasmid, incubated for four hours after transfection and then treated with PBS or IFNβ (500 IU/ml for 20 h). After that, cells were washed and incubated with fresh medium without IFN for 24 h and then subjected to 14 days of puromycin selection (3 μg/ml). Percentage of GFP-positive cells was then determined by FACS analysis. D, representative FACS plot diagram (forward scattering versus GFP) of HeLa cells that received indicated RNAi oligos (siCon, siMOV10, or siRNaseL) prior to transfection with LINE-1-GFP plasmid, IFNβ treatment (as indicated), puromycin selection, and FACS analysis. E, quantification of data from three independent experiments (described in panel D). F, relative mRNA levels of indicated genes in HeLa cells from experiments described in panels C–D were assessed by qPCR. Levels in siCON-transfected cells were taken as 1.0.