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Constitutive expression of a complement-like protein in toll and JAK gain-of-function mutants of Drosophila

M Lagueux1, E Perrodou, E A Levashina

  • 1Institut de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique, Unité Propre de Recherche, Strasbourg, France. M.Lagueux@ibmc.u-strasbg.fr

Proceedings of the National Academy of Sciences of the United States of America
|October 12, 2000
PubMed

Insights

Drosophila possesses four novel complement-like genes. Their expression increases after immune challenge, suggesting a role in host defense, particularly involving the JAK-STAT and Toll pathways.

Area of Science:

  • Immunology
  • Genetics
  • Molecular Biology

Background:

  • The complement system and alpha(2)-macroglobulin superfamily are crucial in host defense and proteinase regulation.
  • Understanding innate immunity in model organisms like Drosophila provides insights into conserved biological mechanisms.

Purpose of the Study:

  • To identify and characterize novel genes in Drosophila with similarities to complement C3/alpha(2)-macroglobulin superfamily proteins.
  • To investigate the expression patterns and regulation of these genes, particularly in response to immune challenges.
  • To explore the involvement of the Janus kinase (JAK) and Toll pathways in the regulation of these complement-like genes.

Main Methods:

  • Gene expression analysis in Drosophila during development and after immune challenge.
  • Identification of genes encoding proteins homologous to the thiolester-containing protein superfamily.
  • Analysis of gene expression in Drosophila mutants for Janus kinase (JAK) hop and Toll pathways.

Main Results:

  • Four Drosophila genes encoding proteins similar to complement C3/alpha(2)-macroglobulin superfamily proteins were identified.
  • These genes show low-level transcription throughout development, with significant upregulation following immune challenge.
  • Constitutive expression of one gene was observed in gain-of-function mutants of JAK hop and Toll, with reduced inducibility in loss-of-function hop mutants.

Conclusions:

  • Drosophila expresses novel complement-like proteins potentially involved in host defense.
  • The expression of these genes is regulated by immune challenges and influenced by the JAK-STAT and Toll signaling pathways.
  • These findings contribute to understanding the innate immune system in Drosophila and the evolution of complement-like proteins.

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