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. © 2009 Elsevier Inc. All rights reserved.
Gupta, L., Molina-Cruz, A., Kumar, S., Rodrigues, J., Dixit, R., Zamora, R. E., & Barillas-Mury, C. (2009). The STAT Pathway Mediates Late-Phase Immunity against Plasmodium in the Mosquito Anopheles gambiae. Cell Host and Microbe, 5(5), 498–507. https://doi.org/10.1016/j.chom.2009.04.003