Serpent regulates Drosophila immunity genes in the larval fat body through an essential GATA motif.
Insects possess a powerful immune system, which in response to infection leads to a vast production of different antimicrobial peptides. The regulatory regions of many immunity genes contain a GATA motif in proximity to a kappaB motif. Upon infection, Rel proteins enter the nucleus and activate transcription of the immunity genes. High levels of Rel protein-mediated Cecropin A1 expression previously have been shown to require the GATA site along with the kappaB site. We provide evidence demonstrating that the GATA motif is needed for expression of the Cecropin A1 gene in larval fat body, but is dispensable in adult fat body. A nuclear DNA-binding activity interacts with the Cecropin A1 GATA motif with the same properties as the Drosophila GATA factor Serpent. The GATA-binding activity is recognized by Serpent-specific antibodies, demonstrating their identity. We show that Serpent is nuclear in larval fat body cells and haemocytes both before and after infection. After overexpression, Serpent increases Cecropin A1 transcription in a GATA-dependent manner. We propose that Serpent plays a key role in tissue-specific expression of immunity genes, by priming them for inducible activation by Rel proteins in response to infection.
Department of Molecular Biology, Arrhenius Laboratories for Natural Sciences, Stockholm University, S-106 91 Stockholm, Sweden.
U M
UM
Petersen
L
L
Kadalayil
K P
KP
Rehorn
D K
DK
Hoshizaki
R
R
Reuter
Y
Y
Engström
D000818:Animals; D023181:Antimicrobial Cationic Peptides; D002467:Cell Nucleus / Q000378:metabolism; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000196:embryology / Q000235:genetics* / Q000276:immunology; D005216:Fat Body / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D050980:GATA Transcription Factors; D005786:Gene Expression Regulation; D017344:Genes, Insect / Q000235:genetics*; D017930:Genes, Reporter; D006434:Hemocytes / Q000276:immunology / Q000378:metabolism; D007301:Insect Hormones / Q000235:genetics; D007814:Larva / Q000166:cytology / Q000235:genetics* / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology; D009687:Nuclear Proteins / Q000378:metabolism; D009928:Organ Specificity; D010455:Peptides / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D020218:Response Elements / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
D023181:Antimicrobial Cationic Peptides; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D050980:GATA Transcription Factors; D007301:Insect Hormones; D008070:Lipopolysaccharides; D009687:Nuclear Proteins; D010455:Peptides; D014157:Transcription Factors; C103965:srp protein, Drosophila; C031161:cecropin A; D004247:DNA