NF-κB has emerged as a central component of the cellular signaling machinery that serves as an important regulatory role in inflammation, immunity, and oncogenesis. During UV exposure, a positive correlation between NF-κB/Rel activation and its translocation to the nucleus, and phosphorylation and degradation of I-κB protein have been known in mammal. While the mechanisms involved in NF-κB activation upon inflammatory response are well documented both in flies and mammals, little is known that Drosophila NF-κB plays any functional roles in UV irradiation. In this study, using a null mutant of Relish, Drosophila NF-κB, we investigated a role of Drosophila NF-κB in response to UV irradiation. We found UV-induced NF-κB activation through gel mobility shift assay with the κB binding sequences of defensin promoter region. Relish null mutant larvae were more sensitive to UV-induced pigmentation, immunosuppression and apoptosis of hemocytes than wild-type. These results suggest that Drosophila NF-κB protein is involved in immune response and serves as an anti-apoptosis factor against UV irradiation.

Keywords: NF-κB, Relish, UV, Drosophila