Fig. 5.

RNA- or iron-binding activity of PCBP1 are associated with different phenotypes in PCBP1-depleted cells. (A) Iron-binding activity of PCBP1 is required to suppress DNA damage in PCBP1-depleted cells. Tetracycline-inducible stable cell lines expressing PCBP1-Flag variants of WT, RNA-binding mutant (∆RNA), or iron-binding mutant (∆Fe) were transfected with NT or 3′UTR-PCBP1 siRNA and treated with (+P1^var) or without (−) doxycycline to induce PCBP1 variants (P1^var) for 48 h. Cells were fixed and stained with TUNEL/propidium iodide. The bar graph shows the percentage of TUNEL+ cells in each group. (B) RNA-binding activity of PCBP1 is required for cell viability in PCBP1-depleted cells. Tetracycline-inducible stable cell lines expressing EV or PCBP1-Flag variants (P1^var) of WT, RNA-binding mutant (∆RNA), or iron-binding mutant (∆Fe) were transfected with NT or 3′UTR-PCBP1 siRNA and treated with doxycycline (+P1^var) for 72 h, as indicated. Cell viability was assessed using cell counting kit eight assays in triplicates. All data are means ± SD of n = 3 independent experiments. Significant P values, as determined by two-way ANOVA and Dunnett’s multiple comparisons test, are shown. ns, not significant.