Cellular specificity of expression and regulation of Drosophila vitelline membrane protein 32E gene in the follicular epithelium: identification of cis-acting elements.

In this paper we analyze the expression in follicular cells and regulation of the vitelline membrane protein gene we identified in region 32E of the second chromosome of D. melanogaster (VMP32E). We report germ line transformation results obtained with different kinds of gene fusion leading to the identification of a follicular cell subpopulation involved in the expression of the VMP32E. We have characterized two 5' non-transcribed regions (-465/-249; -135/-39) where the cis-acting transcriptional regulatory sequences, directing tissue and temporal specificity, are contained. The region between -465 and -249, which appears to control transcriptional high efficiency, does not behave as an enhancer as it is incapable of conferring any expression to a reporter gene. The region between -135 and -39 can confer temporal specificity of expression of the VMP32E gene, albeit at a very low level. Most interestingly, sequence similarities to ecdysone response elements raise the possibility of hormonal control also for VMP gene expression.