AHR38, a homolog of NGFI-B, inhibits formation of the functional ecdysteroid receptor in the mosquito Aedes aegypti
Autor(es): Zhu, JS; Miura, K; Chen, L; Raikhel, AS
Resumo: In anautogenous mosquitoes, vitellogenesis, the key event in egg maturation, requires a blood meal. Consequently, mosquitoes are vectors of numerous devastating human diseases. After ingestion of blood, 20-hydroxyecdysone activates yolk protein precursor (YPP) genes in the metabolic tissue, the fat body. An important adaptation for anautogenicity is the previtellogenic developmental arrest (the state-of-arrest) preventing the activation of YPP genes in previtellogenic females prior to blood feeding. Here, we show that a retinoid X receptor homolog, Ultraspiracle (AaUSP), which is an obligatory partner in the functional ecdysteroid receptor, exists at the state-of-arrest as a heterodimer with the orphan nuclear receptor AHR38, a homolog of Drosophila DHR38 and nerve growth factor-induced protein B, Yeast two-hybrid and glutathione S-transferase pull-down assays demonstrate that AHR38 can interact strongly with AaUSP, AHR38 also disrupts binding of ecdysteroid receptor to ecdysone response elements. Cell co-transfection of AHR38 with AaEcR and AaUSP inhibits ecdysone-dependent activation of a reporter gene by the ecdysteroid receptor. Co-immunoprecipitation experiments indicate that AaUSP protein associates with AHR38 instead of AaEcR in fat body nuclei at the state-of-arrest.
Palavras-Chave: AHR38; 20-hydroxyecdysone; Mosquito vitellogenesis; Nuclear receptor; Protein interaction
Imprenta: EMBO Journal, v. 19, n. 2, p. 253-262, 2000
Identificador do objeto digital: 10.1093/emboj/19.2.253
Descritores: Aedes aegypti - Cell ; Aedes aegypti - DNA ; Aedes aegypti - Proteins
Data de publicação: 2000
