A Drosophila PIAS homologue negatively regulates stat92E

Transcriptional activation by, and therefore the physiologic impact of, act ivated tyrosine-phosphorylated STATs (signal transducers and activators of transcription) may be negatively regulated by proteins termed PIAS (protein inhibitors of activated stats), as shown by previous experiments with mamm alian cells in culture. Here, by using the genetic modifications in Drosoph ila, we demonstrate the in vivo functional interaction of the Drosophila ho mologues stat92E and a Drosophila PIAS gene (dpias). To this end we use a L OF allele and conditionally overexpressed dpias in JAK-STAT pathway mutant backgrounds. We conclude that the correct dpias/stat92E ratio is crucial fo r blood cell and eye development.