FIG. 10.

Nucleolar localization of RelA is required for UV-C-induced apoptosis. (A) Deleting aa 27 to 30 inhibits UV-C-induced nucleolar translocation of RelA. SW480 cells were transfected with 6 μg of GFP, GFP-RelA WT, or RelA Δ27-30 24 h prior to UV-C treatment (40 J/m²). The localization of GFP-tagged proteins was determined in live cells using an Axiovert 100 inverted fluorescent microscope (magnification, ×40) 8 h after treatment. (B) Expression of RelA Δ27-30 inhibits UV-C effects on cell viability. SW480 cells were transfected and UV-C treated as described above. Phase-contrast images (magnification, ×20) taken of randomly selected fields 24 h after treatment are shown. (C) Expression of RelA Δ27-30 inhibits UV-C effects on apoptosis. Annexin V apoptosis assays were performed on SW480 cells transfected with the specified GFP-tagged vectors 24 h after UV-C (40 J/m²) treatment. The percentages of cells expressing GFP-tagged protein undergoing apoptosis were determined by fluorescent microscopy in at least 250 transfected cells for each sample. The results are the means of at least three independent experiments ± standard errors.