title: GFP reporters detect the activation of the Drosophila JAK/STAT pathway in vivo.
abstract: JAK/STAT signaling is essential for a wide range of developmental processes in Drosophila melanogaster. The mechanism by which the JAK/STAT pathway contributes to these processes has been the subject of recent investigation. However, a reporter that reflects activity of the JAK/STAT pathway in all Drosophila tissues has not yet been developed. By placing a fragment of the Stat92E target gene Socs36E, which contains at least two putative Stat92E binding sites, upstream of GFP, we generated three constructs that can be used to monitor JAK/STAT pathway activity in vivo. These constructs differ by the number of Stat92E binding sites and the stability of GFP. The 2XSTAT92E-GFP and 10XSTAT92E-GFP constructs contain 2 and 10 Stat92E binding sites, respectively, driving expression of enhanced GFP, while 10XSTAT92E-DGFP drives expression of destabilized GFP. We show that these reporters are expressed in the embryo in an overlapping pattern with Stat92E protein and in tissues where JAK/STAT signaling is required. In addition, these reporters accurately reflect JAK/STAT pathway activity at larval stages, as their expression pattern overlaps that of the activating ligand unpaired in imaginal discs. Moreover, the STAT92E-GFP reporters are activated by ectopic JAK/STAT signaling. STAT92E-GFP fluorescence is increased in response to ectopic upd in the larval eye disc and mis-expression of the JAK kinase hopscotch in the adult fat body. Lastly, these reporters are specifically activated by Stat92E, as STAT92E-GFP reporter expression is lost cell-autonomously in stat92E homozygous mutant tissue. In sum, we have generated in vivo GFP reporters that accurately reflect JAK/STAT pathway activation in a variety of tissues. These reporters are valuable tools to further investigate and understand the role of JAK/STAT signaling in Drosophila.
authors.affiliation: Pharmacology Department, New York University School of Medicine, New York, NY 10016-6402, USA.
authors.forename: Erika A
authors.initials: EA
authors.lastname: Bach
authors.forename: Laura A
authors.initials: LA
authors.lastname: Ekas
authors.forename: Aidee
authors.initials: A
authors.lastname: Ayala-Camargo
authors.forename: Maria Sol
authors.initials: MS
authors.lastname: Flaherty
authors.forename: Haeryun
authors.initials: H
authors.lastname: Lee
authors.forename: Norbert
authors.initials: N
authors.lastname: Perrimon
authors.forename: Gyeong-Hun
authors.initials: GH
authors.lastname: Baeg
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism*; D053612:Janus Kinases / Q000378:metabolism*; D050791:STAT Transcription Factors / Q000378:metabolism*; D015398:Signal Transduction; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D050791:STAT Transcription Factors; C460659:Socs36E protein, Drosophila; C105675:Stat92E protein, Drosophila; D050826:Suppressor of Cytokine Signaling Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D053612:Janus Kinases; C085845:hop protein, Drosophila