Perturbations in vertebrate iron homeostasis often have detrimental consequences. Although extensive knowledge of the translational regulation of vertebrate ferritin has been obtained, knowledge of the molecular mechanisms that regulate the transcription of the ferritin gene has been limited. The present work attempts to define the mechanism that activates the transcription of insect ferritin in the presence of excess iron.
We have found a set of cis-regulatory elements that are involved in the regulation of the mosquito HCH-ferritin gene using transient transfection and DNA-footprinting assays. In vertebrates, all response elements reported to date are located upstream of the transcriptional start-site, and only enhancers have been identified. Unlike its vertebrate homologues, the mosquito ferritin gene contains response elements throughout the gene. The insect regulatory elements identified include both enhancers and silencers. For the mosquito ferritin gene, our data suggest that cis-regulatory elements are located in the 5’-untranslated region, in introns, and in the open-reading frame. Finally, our preliminary data further suggest that the transcriptional control of the mosquito HCH-ferritin gene is deregulated in the presence of excess iron.
ACKNOWLEDGMENTS: This work was supported by the National Institutes of Health, National Institute of General Medicine grant GM55866 awarded to DQP.
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA