Interaction of proteins involved in ecdysone and juvenile hormone signal transduction

Abstract

Ecdysteroids and juvenile hormones (JH) regulate a variety of developmental, physiological, behavioral, and metabolic processes. Ecdysteroids function through a heterodimeric complex of two nuclear receptors, ecdysone receptor (EcR) and ultraspiracle (USP). An 85 kDa protein identified in Drosophila melanogaster methoprene‐tolerant (Met) mutant binds to JH III with high affinity, and the mutant flies are resistant to juvenile hormone analog (JHA), methoprene. Reporter assays using the yeast two‐hybrid system were performed in order to study the molecular interactions between EcR, USP and Met. As expected, EcR fused to the B42 activation domain and USP fused to the LexA DNA binding domain interacted with each other and supported induction of the reporter gene in the presence of stable ecdysteroid analog, RG‐102240 or steroids, muristerone A and ponasterone A. The USP:USP homodimers supported expression of the reporter gene in the absence of ligand, and there was no significant increase in the reporter activity after addition of a JHA, methoprene. Similarly, Met:Met homodimers as well as Met:EcR and Met:USP heterodimers induced reporter activity in the absence of ligand and addition of ecdysteroid or JH analogs did not increase the reporter activity regulated by either homodimers or heterodimers of Met protein. Two‐hybrid assays in insect cells and in vitro pull‐down assays confirmed the interaction of Met with EcR and USP. These data suggest that the proteins that are involved in signal transduction of ecdysteroids (EcR and USP) and juvenile hormones (Met) interact to mediate cross‐talk between these two important hormones. Arch. Insect Biochem. Physiol. 2008. © 2008 Wiley‐Liss, Inc.

Methoprene-tolerant 1 regulates gene transcription to maintain insect larval status

“…However, the interaction between Met1 and USP1 may not rely on JH regulation because the overexpressed Met1 is co-immunoprecipitated with nonphosphorylated USP1 in DMSO-treated cells also. The 20E-or JH hormoneindependent interactions between Met and USP and between Met and EcRB1 has been reported in D. melanogaster (Bitra & Palli 2009) and B. mori (Guo et al 2012) respectively. Therefore, Met1 might repress 20E pathway gene transcription by repressing the formation of EcRB1/USP1 transcription complex and its binding to EcRE.…”

“…In Drosophila, the overexpression of Met in fat body results in precocious and enhanced programmed cell death and cell dissociation (Liu et al 2009). Met can also interact with EcR and USP in insect cells in an ecdysteroid or in a JH-regulation-independent manner, suggesting that the interaction among Met, EcR, and USP mediates the crosstalk between these two important hormones (Bitra & Palli 2009). Therefore, the basic function of Met in various insects is not really clear.…”

Heterodimer of two bHLH-PAS proteins mediates juvenile hormone-induced gene expression

“…To elucidate the molecular roles of Met in JH signaling, a number of proteins have been tested in vitro or in the cultured insect cells for their abilities to bind Met (9,28,32). The protein interactions with Met were largely independent of the presence of JH, or even repressed by JH.…”

Padrões Diferenciais de Expressão Gênica no Desenvolvimento das Castas de Apis mellifera, com Ênfase na Diferenciação das Operárias

“…Os miRNAs evoluíram como uma classe de moléculas reguladoras de inúmeros processos biológicos em eucariotos, como proliferação celular, diferenciação, apoptose, resposta a estresse, tumorigênese, entre outros (Banerjee & Slack, 2002;Banerjee et al, 2005;Bartel, 2004;2009). A busca por miRNAs, potenciais reguladores de jhe, resultou em 22 candidatos, dos quais apenas 9 com função já descrita na literatura.…”

“…usp is an ortholog of vertebrates retinoid-X receptor (RXR) (Yao et al, 1992(Yao et al, , 1993, considered at first as an orphan NR, but some studies have suggested it as a JH receptor, besides acting as part of ecdysteroid receptor (Xu et al, 2002;Barchuk et al, 2004), and indicating a cross-talk between ecdysteroid and JH action (Bitra and Palli, 2009). In Drosophila, EcR gives rise to three different isoforms, EcR-A, EcR-B1 e EcR-B2 (Yao et al, 1993;Talbot,1993), differentially expressed in a tissue-and stage-specific manner (Robinow et al, 1993;Truman et al, 1994).…”