Amylase cis-acting sequences mediate the alleviation of glucose repression by cAMP in Drosophila

alpha-Amylase gene expression is highly repressed by dietary glucose in Drosophila melanogaster. This glucose effect can be alleviated by exogenous adenosine 3':5'-cyclic monophosphate (cAMP). Here, we show that the relief of glucose repression by cAMP occurs at the level of amylase mRNA abundance. Furthermore, exogenous cAMP was shown to alleviate glucose repression of the transient expression of an amylase gene construct in transformed Amynull larvae. This construct contains only 109 base pairs of the promoter region; this is the minimal length of upstream sequence which is necessary for wild-type levels of amylase gene expression. These results indicate that cis-acting promoter elements located close to the transcriptional start site of the Drosophila amylase gene mediate both glucose repression and the cAMP-derepression effects.