The Drosophila melanogaster ortholog of human NFAT transcription factors has a conserved role in immunity -

Abstract

The five vertebrate NFAT transcription factors (NFAT1-5) are required for heart development and for the innate and adaptive immune systems. The Rel-homology domain (RHD) of the single Drosophila Nfat homolog has 56percent sequence identity with that of NFAT5, the primordial member of vertebrate NFATs. It also shares a role with NFAT5 in regulating the osmotic stress response. Based on this conservation and on the similarities of Drosophila and vertebrate heart development and innate immunity, this study investigates whether Drosophila Nfat also has roles in cardiogenesis and immunity. Results show that although no role for Drosophila Nfat in dorsal vessel development can be concluded from our observations, it does possess a function in the systemic immune response of this organism. Flies which are mutant for this gene are shown to be highly susceptible to gram-positive bacteria and fungi, which can be explained by the observed impaired induction of the Drosomycin antimicrobial peptide (AMP) in response to challenge with such microorganisms. Our results suggest that the Nfat transcription factor in Drosophila is a component of the Toll signaling pathway.