Detection of UV-induced activation of NF-kappaB in a recombinant human cell line by means of Enhanced Green Fluorescent Protein (EGFP).

The cellular protection reaction known as ultraviolet (UV) response leads to increased transcription of several genes. Parts of this transcriptional response are transmitted via activation of the Nuclear factor kappaB (NF-kappaB). The contribution of different UV radiation qualities to this process is not yet known. In a previous work, a stably transfected human cell line was developed which indicates activation of the NF-kappaB pathway by fluorescence of the reporters Enhanced Green Fluorescent Protein (EGFP) and its destabilized variant (d2EGFP) thereby allowing a fast and reliable monitoring of UV effects on the NF-kappaB pathway. Cells were exposed to a mercury low-pressure lamp or to simulated sunlight of different wavelength ranges and subjected to flow cytometric analysis after different post-irradiation periods. Growth capacity of cells after UV irradiation was quantified using a luminance measurement of crystal violet stained cell layers. In contrast to UVC and UVB, UVA radiation induced d2EGFP expression and NF-kappaB activation in a non-cytotoxic dose range. These results show that NF-kappaB plays a role in the UVA-induced gene activation in a non-cytotoxic dose range in a human epithelial cell line.