Identification of steroid hormone signaling pathway in insect cell differentiation
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- Siaussat, D., Bozzolan, F., Porcheron, P. et al. Cell. Mol. Life Sci. (2007) 64: 365. doi:10.1007/s00018-007-6452-0
To dissect the steroid hormone signaling pathway involved in insect cell morphological differentiation, we extended the application of the doublestranded RNA-mediated interference (dsRNAi) method to the epidermal IAL-PID2 cell line from Plodia interpunctella Lepidoptera. We first demonstrated that dsRNA was capable of efficiently blocking the steroid hormone 20-hydroxyecdysone (20E) inducibility of proteins that belong to the nuclear receptor superfamily, including the ecdysone receptor (EcR), its partner Ultraspiracle (USP), the insect homolog of the vertebrate retinoid X receptor and the HR3 transcription factor. We then showed that inhibiting the 20E induction of EcR, USP or HR3 proteins prevented the increased synthesis of β tubulin and consequently the morphological transformation of cells. Thanks to this functional approach, we have shown, for the first time, the participation of EcR, USP and HR3 in a 20E signaling pathway that directs morphological differentiation in insect cells by regulating β tubulin expression.