Developmental Gene Expression of Inward-Rectifying Potassium Channels in the Yellow Fever Mosquito

Undergraduate #96
Discipline: Biological Sciences
Subcategory: Genetics

Elizabeth-Michelle Statler - Ohio State University
Co-Author(s): Travis Calkins and Edna Alfaro Inocente, The Ohio Agricultural Research and Development Center, Wooster, OH

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Mosquitoes are vectors for numerous pathogens that are detrimental to human and animal health. Currently, the efficacy of insecticides used to control mosquito vectors is eroding due to the emergence of resistance. Thus, it is crucial to develop new insecticides. Research on mosquito gene expression may facilitate the development of new insecticides by revealing novel genes to target. Here we quantify the developmental expression of genes encoding inward- rectifying potassium (Kir) channels in the mosquito Aedes aegypti to identify which Kir genes may play key roles in the mosquito life cycle. We focus on Kir channels, because they play fundamental roles in neuromuscular, epithelial, and endocrine function in other animals. Thus, they are potentially valuable genes to target with new insecticides. Previous studies have determined that A. aegypti possesses five genes encoding Kir channel subunits (Kir1, Kir2A, Kir2B, Kir2B’, and Kir3), but no previous study has quantified the expression of the Kir genes during development and after a blood meal. We predict changes in Kir gene expression during development and after blood-feeding due to the contrasting physiological stresses during each life stage and post-blood meal. Using quantitative real-time RT-PCR (qPCR) in larval, pupal, adult male, and non-bloodfed and bloodfed adult female mosquitoes, we show that the expression of the Kir2A is significantly higher in larvae and adult females compared to pupae, whereas Kir2B is significantly higher in adult females compared to both pupae and larvae. On the other hand, Kir3 is significantly lower in adult females compared to all other life stages. At 24 h after a blood meal, the expression of Kir1, Kir2B, and Kir2B’ significantly increases in the Malpighian tubules, whereas that of Kir3 is lower. In the ovaries and midgut, respectively, Kir2A and Kir3 are significantly higher after a blood meal. Our study provides evidence for dynamic quantitative changes in Kir gene expression during mosquito development and after the ingestion of a blood meal, which is consistent with the notion that Kir channels play key physiological roles in mosquitoes and may be promising molecular targets for the development of new insecticides.

Funder Acknowledgement(s): Summer Research Opportunities Program

Faculty Advisor: Peter Piermarini,