Expression of foreign proteins by antimicrobial peptide gene promoters in mosquitoes

Abstract

Background: The mosquito Aedes aegypti is a major vector for transmission of viruses causing dengue fever, yellow fever, Zika, and chikungunya infection. Functional analysis of mosquito genes and individual viral genes can be a powerful approach to study vector–virus interactions but is often hampered by a lack of suitable promoters to drive exogenous viral gene expression in mosquito cells in vitro and in vivo. Object: To search for potential promoter candidates that can be used to express foreign genes and particularly viral proteins in a mosquito model system. Materials and Methods: we characterized the ability of the promoters of three Ae. aegypti antimicrobial peptide (AMP) genes to drive the expression of marker proteins (luciferase, GFP, the NS3 protein of two flaviviruses, and rabies virus glycoprotein) in mosquito cells and adult female mosquitoes, and in other insect cells as well. Results: The promoters of the defensin A4 and cecropin B1 genes produced robust expression of luciferase and GFP in the Ae. aegypti cell line CCL125, Aedes albopictus cell line C6/36, Drosophila melanogaster cell line S2, and Spodoptera frugiperda cell line Sf21. These AMP gene promoters also had the ability to drive NS3 and GFP expression in adult tissues of Ae. aegypti, Ae. albopictus, and Culex tritaeniorhynchus in vivo, which may suggest evolutionary conservation of AMP gene promoter activity across mosquito lineages. Conclusions: These promoters could provide a valuable tool for ectopically expressing viral genes and studying their interactions with the mosquito vectors.

Keywords

• Expression promoter
• antimicrobial peptide gene
• mosquito