Professor New Mexico State University Las Cruces, New Mexico
The amino acid transceptor protein Cationic Amino Acid Transporter 1 (CAT1) is part of the nutrient sensor in the fat body of mosquitoes. A member of the SLC7 family of cationic amino acid transporters it is paramount for the detection of elevated amino acid levels in the mosquito hemolymph after a blood meal and the subsequent changes in fat body gene expression. We performed re-annotation of Aedes aegypti CATs and selected the C-terminal tail of CAT1 to perform a yeast two-hybrid screen to identify putative interactors of this protein. One interesting interacting protein we identified was General Control Nonderepressible 1 (GCN1). We determined the expression pattern of GCN1 in several adult organs and structures using qRT-PCR and Western blots. Finally, we knocked down GCN1 using dsRNA and identified changes in downstream signaling intermediates and effects of knockdown on vitellogenesis and fecundity. In a screen for Ae. aegypti CAT1-interacting proteins we identified GCN1 as a putative interactor. GCN1 is highly expressed in ovaries and the mosquito fat body. We provide evidence that eIF2α phosphorylation changed during vitellogenesis and that RNAi knockdown of GCN1 in whole mosquitoes reduced egg clutch sizes of treated mosquitoes relative to controls. Our results demonstrate that Ae. aegypti CAT1 and GCN1 are likely interacting partners, and that GCN1 is necessary for proper egg development. Our data suggests that GCN1 is part of a nutrient sensor mechanism in various mosquito tissues involved in vitellogenesis.
