The Drosophila jing gene is a downstream target  in the Trachealess/Tango tracheal pathway.
Primary branching in the Drosophila trachea is regulated by the Trachealess (Trh) and Tango (Tgo) basic helix-loop-helix-PAS (bHLH-PAS) heterodimers, the POU protein Drifter (Dfr)/Ventral Veinless (Vvl), and the Pointed (Pnt) ETS transcription factor. The jing gene encodes a zinc finger protein also required for tracheal development. Three Trh/Tgo DNA-binding sites, known as CNS midline elements, in 1.5 kb of jing 5′ cis-regulatory sequence (jing1.5) previously suggested a downstream role for jing in the pathway. Here, we show that jing is a direct downstream target of Trh/Tgo and that Vvl and Pnt are also involved in jing tracheal activation. In vivo lacZ enhancer detection assays were used to identify cis-regulatory elements mediating embryonic expression patterns of jing. A 2.8-kb jing enhancer (jing2.8) drove lacZ expression in all tracheal cell lineages, the CNS midline and Engrailed-positive segmental stripes, mimicking endogenous jing expression. A 1.3-kb element within jing2.8 drove expression that was restricted to Engrailed-positive CNS midline cells and segmental ectodermal stripes. Surprisingly, jing1.5-lacZ expression was restricted to tracheal fusion cells despite the presence of consensus DNA-binding sites for bHLH-PAS, ETS, and POU domain transcription factors. Given the absence of Trh/Tgo DNA-binding sites in the jing1.3 enhancer, these results are consistent with previous observations suggesting a combinatorial basis to Trh-/Tgo-mediated transcriptional regulation in the trachea.
Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada.
Tatiana
T
Morozova
Joanne
J
Hackett
Yalda
Y
Sedaghat
Margaret
M
Sonnenfeld
D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator / Q000378:metabolism; D001483:Base Sequence; D002490:Central Nervous System / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics* / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D017930:Genes, Reporter; D018398:Homeodomain Proteins / Q000378:metabolism; D007763:Lac Operon; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D015398:Signal Transduction; D014132:Trachea / Q000196:embryology; D014157:Transcription Factors / Q000378:metabolism*
D029721:Drosophila Proteins; C063459:En protein, Drosophila; D018398:Homeodomain Proteins; C421383:JING protein, Drosophila; D009687:Nuclear Proteins; D014157:Transcription Factors; C109766:tgo protein, Drosophila; C099995:trh protein, Drosophila; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator