title: An insulin-like peptide regulates egg maturation and metabolism in the mosquito Aedes aegypti.
abstract: Ingestion of vertebrate blood is essential for egg maturation and transmission of disease-causing parasites by female mosquitoes. Prior studies with the yellow fever mosquito, Aedes aegypti, indicated blood feeding stimulates egg production by triggering the release of hormones from medial neurosecretory cells in the mosquito brain. The ability of bovine insulin to stimulate a similar response further suggested this trigger is an endogenous insulin-like peptide (ILP). A. aegypti encodes eight predicted ILPs. Here, we report that synthetic ILP3 dose-dependently stimulated yolk uptake by oocytes and ecdysteroid production by the ovaries at lower concentrations than bovine insulin. ILP3 also exhibited metabolic activity by elevating carbohydrate and lipid storage. Binding studies using ovary membranes indicated that ILP3 had an IC(50) value of 5.9 nM that was poorly competed by bovine insulin. Autoradiography and immunoblotting studies suggested that ILP3 binds the mosquito insulin receptor (MIR), whereas loss-of-function experiments showed that ILP3 activity requires MIR expression. Overall, our results identify ILP3 as a critical regulator of egg production by A. aegypti.
authors.affiliation: Departments of Entomology and Cellular Biology, University of Georgia, Athens, GA 30602, USA. mrbrown@uga.edu
authors.forename: Mark R
authors.initials: MR
authors.lastname: Brown
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Clark
authors.forename: Monika
authors.initials: M
authors.lastname: Gulia
authors.forename: Zhangwu
authors.initials: Z
authors.lastname: Zhao
authors.forename: Stephen F
authors.initials: SF
authors.lastname: Garczynski
authors.forename: Joe W
authors.initials: JW
authors.lastname: Crim
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Suderman
authors.forename: Michael R
authors.initials: MR
authors.lastname: Strand
mesh_terms: D000330:Aedes / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001769:Blood / Q000378:metabolism; D002417:Cattle; D005260:Female; D007301:Insect Hormones / Q000502:physiology*; D019476:Insect Proteins; D007328:Insulin; D008969:Molecular Sequence Data; D010063:Ovum / Q000378:metabolism / Q000502:physiology*; D036361:Peptide Hormones / Q000502:physiology*; D011972:Receptor, Insulin / Q000378:metabolism
chemical_list: D007301:Insect Hormones; D019476:Insect Proteins; D007328:Insulin; D036361:Peptide Hormones; D011972:Receptor, Insulin