Functional analysis of regulatory elements controlling the expression of the ecdysone-regulated Drosophila ng-1 gene

The steroid hormone ecdysone controls multiple aspects of insect developmen t, including larval moults and metamorphosis, and can induce specific genet ic responses in different tissues. The definition of the molecular mechanis ms able to mediate this tissue-specific responsiveness may greatly contribu te to understanding how such an accurate genetic response is achieved. In t his work we have identified, by transgenic analysis, the regulatory element s directing the expression of ng-l, an ecdysone-regulated Drosophila gene s howing a highly specific developmental expression profile. Our results show that an ecdysone-responsive element located within the ng-l coding region is necessary for high-level gene expression, whereas the gene's spatial and temporal expression profile is fully controlled by a distinct upstream reg ulatory region. This region binds a set of transcriptional factors, includi ng the FKH regulatory protein, which can potentially modulate the ecdysone genetic regulated response. (C) 2001 Elsevier Science Ireland Ltd. All righ ts reserved.