GFP Reporters Detect the Activation of the Drosophila JAK/STAT Pathway in Vivo

Gene Expr Patterns. 2007 Jan;7(3):323-31. doi: 10.1016/j.modgep.2006.08.003. Epub 2006 Aug 22.

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster / embryology
  • Drosophila melanogaster / metabolism*
  • Embryo, Nonmammalian / metabolism*
  • Gene Expression Regulation, Developmental
  • Genes, Reporter
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism*
  • Janus Kinases / metabolism*
  • STAT Transcription Factors / metabolism*
  • Signal Transduction*
  • Suppressor of Cytokine Signaling Proteins / genetics
  • Transcription Factors / metabolism*

Substances

  • Drosophila Proteins
  • STAT Transcription Factors
  • Socs36E protein, Drosophila
  • Stat92E protein, Drosophila
  • Suppressor of Cytokine Signaling Proteins
  • Transcription Factors
  • Green Fluorescent Proteins
  • Janus Kinases
  • hop protein, Drosophila