Identification and mapping of the promoter for the gene encoding the ferritin heavy-chain homologue of the yellow fever mosquito Aedes aegypti

Abstract

Mosquitoes are responsible for the transmission of numerous human diseases. The recent development of transgenic mosquitoes provides a new tool to examine molecular interactions between insect vectors and the pathogens they transmit. One focus in generating transgenic mosquito lies on expressing anti-pathogenic proteins at primary sites of pathogenic invasions, specifically the mosquito gut. Promoters that direct the expression of anti-pathogenic proteins in the mosquito gut are thus sought after because they may provide ways to hinder pathogenic development in the mosquito. Here, we report the identification and mapping of a strong promoter from the Aedes aegypti ferritin heavy-chain homologue (HCH) gene. All known insect ferritin HCH genes are expressed in the gut and inducible by an iron overload. Our transfection assays and DNase I footprinting analyses show that the mosquito ferritin HCH-gene contains regulatory elements both upstream and downstream of the transcriptional start site. The promoter of this gene contains a CF2 site, two GATA-binding sites, an E2F site, a TATA-box, an AP-1 site and a C/EBP binding site.