Functional analysis and regulation of nuclear import of dorsal during the immune response in Drosophila

EMBO J. 1995 Feb 1;14(3):536-45.

Abstract

In addition to its function in embryonic development, the NF-kappa B/rel-related gene dorsal (dl) of Drosophila is expressed in larval and adult fat body where its RNA expression is enhanced upon injury. Injury also leads to a rapid nuclear translocation of dl from the cytoplasm in fat body cells. Here we present data which strongly suggest that the nuclear localization of dl during the immune response is controlled by the Toll signaling pathway, comprising gene products that participate in the intracellular part of the embryonic dorsoventral pathway. We also report that in mutants such as Toll or cactus, which exhibit melanotic tumor phenotypes, dl is constitutively nuclear. Together, these results point to a potential link between the Toll signaling pathway and melanotic tumor induction. Although dl has been shown previously to bind to kappa B-related motifs within the promoter of the antibacterial peptide coding gene diptericin, we find that injury-induced expression of diptericin can occur in the absence of dl. Furthermore, the melanotic tumor phenotype of Toll and cactus is not dl dependent. These data underline the complexity of the Drosophila immune response. Finally, we observed that like other rel proteins, dl can control the level of its own transcription.

MeSH terms

  • Animals
  • Anti-Bacterial Agents / biosynthesis
  • Anti-Infective Agents / metabolism
  • Antimicrobial Cationic Peptides*
  • Biological Transport
  • Cell Nucleus / metabolism*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Drosophila / embryology
  • Drosophila / immunology*
  • Drosophila / metabolism*
  • Drosophila Proteins*
  • Fat Body / metabolism*
  • Gene Expression Regulation
  • Immunity / genetics
  • Immunohistochemistry
  • Insect Hormones / biosynthesis
  • Insect Hormones / genetics
  • Insect Hormones / metabolism
  • Insect Proteins*
  • Melanins / biosynthesis
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism
  • Mutation
  • Neoplasms / etiology
  • Neoplasms / genetics
  • Nuclear Proteins / isolation & purification
  • Nuclear Proteins / metabolism*
  • Phosphoproteins / genetics
  • Phosphoproteins / isolation & purification
  • Phosphoproteins / metabolism*
  • Receptors, Cell Surface*
  • Signal Transduction
  • Toll-Like Receptors
  • Transcription Factors*
  • Transcription, Genetic

Substances

  • Anti-Bacterial Agents
  • Anti-Infective Agents
  • Antimicrobial Cationic Peptides
  • DNA-Binding Proteins
  • DptA protein, Drosophila
  • Drosophila Proteins
  • Insect Hormones
  • Insect Proteins
  • Melanins
  • Membrane Glycoproteins
  • Nuclear Proteins
  • Phosphoproteins
  • Receptors, Cell Surface
  • Tl protein, Drosophila
  • Toll-Like Receptors
  • Transcription Factors
  • dl protein, Drosophila
  • cact protein, Drosophila
  • cecropin A