Identification of hexamerin core promoter elements necessary for specific transcriptional synergism between juvenile hormone and 20-OH ecdysone

Molecular mechanisms by which genes are activated by hormone/nuclear receptor complexes has been an active field of study. In insect systems, the most well understood mechanisms are those involving the steroid hormone 20-OH ecdysone. Also examined, but still less well understood, are those mechanisms involving juvenile hormone. Most efforts to understand either system have focused on the role of ‘upstream’ or ‘downstream’ enhancers to which the particular liganded receptor binds. It does not appear that the enhancer-bound, liganded receptors directly contact the basal transcription apparatus at the “core promoter” (the region between and containing the TATA box and initatior). However, the core promoter sequences of 20-OH ecdysone-sensitive, or JH-sensitive, genes that are necessary for the enhancer-bound, liganded receptors to affect transcription are essentially unknown. We report here the results of current studies that have identified a core promoter motif, of a “hexamerin” gene, that is necessary for synergistic interaction between 20-OH ecdysone and juvenile hormone. Supported in part by NIH.