Characterization of several putative genes potentially involved in diuresis in yellow fever mosquito, Aedes aegypti
Florence Schoderbek, David Price, Hannah Drumm, Lisa Drake, Stacy Rodriguez, Immo Hansen
Diuretic homeostasis is presented with several unusual challenges in Aedes aegypti, the primary vector for the dengue, chikungunya and yellow fever viruses. In addition to maintaining the ionic and fluid balance necessary for life, their diuretic system must adapt rapidly from maintaining this balance in an aquatic organism (the larvae) to a terrestrial organism (the adult). In addition, female Ae. aegypti take a blood meal, during which time they intake more than double their body mass. Following this they must remove excess salt and fluid quickly to regain mobility. The primary organ for urine production in Ae. aegypti are the Malpighian tubules (MTs). Within the MTs, there are transporters and other intra-and-extra-cellular mechanisms which are influenced by diuretic hormones responsible for the maintenance of osmotic balance. These mechanisms are involved in the transport of water and other solutes across or around cell membranes.
A model for the excretion of NaCl and KCl through transporters and paracellular pathways has been developed, and the function of many transporters involved in the model have been determined. However, several transporters that are part of the model have not been identified and represent black boxes. A Na+ transporter is hypothesized to be important but over 30 non-voltage gated transporters exist in Ae. aegypti's genome, and other genes important to proper diuretic function may exist. In order to study genes which may be important in diuresis we performed an RNA-seq analysis of the MTs of 4th instar larvae and adult females.
Using this approach we identified two genes of interest, pickpocket and calexcitin. We performed RNAi-mediated knockdown of these genes and performed a diuresis bioassay to observe the effect on mosquito diuresis. Understanding the role that these proteins play in mosquito diuresis and water homeostasis will provide novel approaches for insecticide development.
See more of: Student Poster Competition
