In vivo regulation of the IkappaB homologue cactus during the immune response of Drosophila.
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-kappaB during the inflammatory response in mammals. Here, we have studied the regulation of the IkappaB homologue Cactus in the fat body during the immune response. We observe that the cactus gene 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 IkappaB and cactus during the immune response.
Nicolas
E
E
Institut de Biologie Moléculaire et Cellulaire, UPR 9022 du CNRS, 15 rue René Descartes, 67084 Strasbourg Cedex, France.
Reichhart
J M
JM
Hoffmann
J A
JA
Lemaitre
B
B
D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004330:Drosophila / Q000196:embryology / Q000276:immunology*; D029721:Drosophila Proteins; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000378:metabolism; D007814:Larva / Q000276:immunology / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D015398:Signal Transduction; D051193:Toll-Like Receptors; D051841:Transcription Factor RelB; D014157:Transcription Factors
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D019476:Insect Proteins; D008562:Membrane Glycoproteins; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D011956:Receptors, Cell Surface; C068721:Tl protein, Drosophila; D051193:Toll-Like Receptors; D014157:Transcription Factors; D051841:Transcription Factor RelB; C077938:cact protein, Drosophila