Research article

Manipulating insulin signaling to enhance mosquito reproduction

Anam J Arik¹ , Jason L Rasgon^2,3 , Kendra M Quicke¹ and Michael A Riehle¹

¹Department of Entomology – University of Arizona, Tucson, AZ, USA

²The W. Harry Feinstone Department of Molecular Microbiology and Immunology – Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA

³The Johns Hopkins Malaria Research Institute – Johns Hopkins University, Baltimore, MD, USA

author email corresponding author email

BMC Physiology 2009, 9:15doi:10.1186/1472-6793-9-15

Published:	20 August 2009

Abstract

Backgrond

In the mosquito Aedes aegypti the insulin/insulin growth factor I signaling (IIS) cascade is a key regulator of many physiological processes, including reproduction. Two important reproductive events, steroidogenesis in the ovary and yolk synthesis in the fat body, are regulated by the IIS cascade in mosquitoes. The signaling molecule phosphatase and tensin homolog (PTEN) is a key inhibitor of the IIS cascade that helps modulate the activity of the IIS cascade. In Ae. aegypti, six unique splice variants of AaegPTEN were previously identified, but the role of these splice variants, particularly AaegPTEN3 and 6, were unknown.

Results

Knockdown of AaegPTEN or its specific splice variant AaegPTEN6 (the splice variant thought to regulate reproduction in the ovary and fat body) using RNAi led to a 15–63% increase in egg production with no adverse effects on egg viability during the first reproductive cycle. Knockdown of AaegPTEN3, expressed predominantly in the head, had no effect on reproduction. We also characterized the protein expression patterns of these two splice variants during development and in various tissues during a reproductive cycle.

Conclusion

Previous studies in a range of organisms, including Drosophila melanogaster and Caenorhabditis elegans, have demonstrated that disruption of the IIS cascade leads to decreased reproduction or sterility. In this study we demonstrate that knockdown of the IIS inhibitor PTEN can actually increase reproduction in the mosquito, at least during the first reproductive cycle.