The STAT pathway mediates late-phase immunity against Plasmodium in the mosquito Anopheles gambiae

Cell Host Microbe. 2009 May 8;5(5):498-507. doi: 10.1016/j.chom.2009.04.003.


The STAT family of transcription factors activates expression of immune system genes in vertebrates. The ancestral STAT gene (AgSTAT-A) appears to have duplicated in the mosquito Anopheles gambiae, giving rise to a second intronless STAT gene (AgSTAT-B), which we show regulates AgSTAT-A expression in adult females. AgSTAT-A participates in the transcriptional activation of nitric oxide synthase (NOS) in response to bacterial and plasmodial infection. Activation of this pathway, however, is not essential for mosquitoes to survive a bacterial challenge. AgSTAT-A silencing reduces the number of early Plasmodium oocysts in the midgut, but nevertheless enhances the overall infection by increasing oocyst survival. Silencing of SOCS, a STAT suppressor, has the opposite effect, reducing Plasmodium infection by increasing NOS expression. Chemical inhibition of mosquito NOS activity after oocyte formation increases oocyte survival. Thus, the AgSTAT-A pathway mediates a late-phase antiplasmodial response that reduces oocyst survival in A. gambiae.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Anopheles / classification
  • Anopheles / genetics
  • Anopheles / immunology*
  • Anopheles / parasitology*
  • Base Sequence
  • Cell Line
  • Female
  • Host-Parasite Interactions
  • Insect Proteins / chemistry
  • Insect Proteins / genetics
  • Insect Proteins / immunology*
  • Malaria / immunology
  • Malaria / parasitology
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Molecular Sequence Data
  • Nitric Oxide Synthase / genetics
  • Nitric Oxide Synthase / metabolism
  • Oocysts / growth & development
  • Oocysts / physiology
  • Phylogeny
  • Plasmodium / growth & development*
  • Plasmodium / physiology
  • STAT Transcription Factors / chemistry
  • STAT Transcription Factors / genetics
  • STAT Transcription Factors / immunology*
  • Sequence Alignment
  • Signal Transduction*


  • Insect Proteins
  • STAT Transcription Factors
  • Nitric Oxide Synthase