In Vivo Regulation of the IκB Homologue cactus during the Immune Response of Drosophila

• Published in: The Journal of biological chemistry Vol. 273; no. 17; pp. 10463 - 10469
• Main Authors: Nicolas, Emmanuelle, Reichhart, Jean Marc, Hoffmann, Jules A., Lemaitre, Bruno
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 24.04.1998
• Subjects: BEAUVERIA BASSIANA; BINDING; BINDING PROTEINS; CACT GENE; CACTUS GENE; DEGRADATION; DIGESTIVE SYSTEM; DROSOPHILA MELANOGASTER; ESCHERICHIA COLI; EXPERIMENTAL INFECTION; FAT BODY; GENE EXPRESSION; GENES; GENETIC REGULATION; GENETICS; IMMUNE RESPONSE; IN VIVO EXPERIMENTATION; MESSENGER RNA; MICROCOCCUS; MICROCOCCUS LUTEUS; PROTEIN SYNTHESIS; PROTEINS; TRANSCRIPTION FACTORS
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.17.10463

The dorsoventral regulatory gene pathway (spätzle/Toll/cactus) controls the expression of several antimicrobial genes during the immune response of Drosophila. This regulatory cascade shows striking similarities with the cytokine-induced activation cascade of NF-κB during the inflammatory response in mammals. Here, we have studied the regulation of the IκB homologue Cactus in the fat body during the immune response. We observe that the cactusgene is up-regulated in response to immune challenge. Interestingly, the expression of the cactus gene is controlled by the spätzle/Toll/cactus gene pathway, indicating that the cactus gene is autoregulated. We also show that two Cactus isoforms are expressed in the cytoplasm of fat body cells and that they are rapidly degraded and resynthesized after immune challenge. This degradation is also dependent on the Toll signaling pathway. Altogether, our results underline the striking similarities between the regulation of IκB and cactusduring the immune response.