The small GTPase Rheb is a key component linking amino acid signaling and TOR in the nutritional pathway that controls mosquito egg development
Autor(es): Roy Saurabh G,Raikhel Alexander S
Resumo: Mosquitoes transmit numerous devastating human diseases because they require blood feeding for egg development. Previously, we have shown that the nutritional Target-of-Rapamycin (TOR) pathway mediates blood-meal activation of mosquito reproductive cycles. Blood-derived amino acid (AA) signaling through the nutrient-sensitive TOR kinase is critical for the transcriptional activation of the major yolk protein precursor (YPP) gene, vitellogenin (Vg), initiation of vitellogenesis and egg development. In this study, we provide in vitro and in vivo evidence that the Rheb GTPase (Ras Homologue Enriched in Brain), which is an upstream activator of TOR, is required for AA-mediated activation of the TOR pathway in the fat body of the mosquito Aedes aegypti. Using RNA interference (RNAi) methods, we showed that Rheb was indispensable in AA-induced phosphorylation of S6 kinase, a key downstream substrate of TOR activation. Rheb RNAi depletion resulted in significant downregulation of Vg transcription and translation in the mosquito fat body, which was monitored in vivo after blood meal or in vitro organ culture after AA stimulation. Egg development was severely hindered in mosquitoes with a Rheb RNAi depletion background. This study represents a notable step in deciphering molecular pathways controlling reproduction of this important vector of human diseases.
Palavras-Chave: RNA interference; S6 kinase; Vitellogenin; Egg development; Fat body; Nutrition
Imprenta: Insect Biochemistry and Molecular Biology, v. 41, n. 1, p. 62-69, 2011
Identificador do objeto digital: 10.1016/j.ibmb.2010.10.001
Descritores: Aedes aegypti - Cell ; Aedes aegypti - Genome ; Aedes aegypti - Pathogenesis ; Aedes aegypti - Proteins ; Aedes aegypti - RNA ; Aedes aegypti - Molecular methods
Data de publicação: 2011
