Hyeogsun Kwon
Major Professor: Dr. Patricia Pietrantonio
Ph.D. Candidate
"Characterization of a calcitonin receptor-like receptor (AaegGPRCAL 1) and its in vivo functional analysis from Aedes aegypti."
The production of primary urine (diuresis) is regulated by the action of multiple hormones, including corticotropin-releasing factor (CRF)-like diuretic hormone 44 (DH44), calcitonin-like diuretic hormone 31 (DH31 ) and Aedes kin ins. The Drosophila calcitonin gene-related peptide (DH31 ) increases cyclic AMP levels in mammalian cells expressing the cognate receptor and regulates cation (K+/Na+) excretion from the Malpighian tubules of Anopheles gambiae and A. aegypti. The contribution of the calcitonin receptor-like receptor 1 (GPRCAL 1) to water excretion has not been yet elucidated in any insect, therefore, we investigated this role of GPRCAL 1 in the female of A. aegypti. We cloned the AaegGPRcal1 cDNA from female Malpighian tubules and performed receptor RNAi by delivering dsRNA through intrathoracic injection. We investigated the RNAi effect by continuously measuring female water loss in a precision humidity chamber for 1 h after blood feeding, and by relative quantification of Malphighian tubule receptor mRNA by quantitative PCR (qPCR). The mosquitoes that underwent knock-down of the AaegGPRcal1 transcript exhibited 17-30% reduction in water excretion compared to the negative controls (injected with EGFP dsRNA or RNAi buffer). Consistent with these "findings, analysis of three independent replications by qPCR revealed a 22-33% reduction in AaegGPRcal1 transcript expression in receptor dsRNA-injected females than in controls. To our knowledge this is the first RNAi-induced phenotype allowing the quantification of the contribution of a single GPCR from Family B to water loss in any invertebrate. Therefore, the GPRCAL 1 may represent a target for the development of a novel pesticide.