Cloning and Expression of Ecdysone Receptor and Retinoid X Receptor from Procambarus clarkii: Induction by Eyestalk Ablation.

Ecdysone receptor and retinoid X receptor are key regulators in molting. Here, full length ecdysone receptor () and retinoid X receptor () cDNAs from were cloned. Full length cDNA of has 2500 bp, encoding 576 amino acid proteins, and full length cDNA of has 2593 bp, in which a 15 bp and a 204 bp insert/deletion splice variant regions in DNA binding domain and hinge domain were identified. The two splice variant regions in result four isoforms: -4, encoding 525, 520, 457 and 452 amino acids respectively. was highly expressed in the hepatopancreas and eyestalk and was highly expressed in the eyestalk among eight examined tissues. Both and had induced expression after eyestalk ablation (ESA) in the three examined tissues. In muscle, and were upregulated after ESA, reached the highest level on day 3 after ESA and increased 33.5-fold relative to day 0, and reached highest the level on day 1 after ESA and increased 2.7-fold relative to day 0. In the hepatopancreas, and deased continuously after ESA, and the expression levels of and were only 0.7% and 1.7% on day 7 after ESA relative to day 0, respectively. In the ovaries, was upregulated after ESA, reached the highest level on day 3 after ESA, increased 3.0-fold relative to day 0, and the expression level of changed insignificantly after ESA ( > 0.05). The different responses of and after ESA indicates that different tissues play different roles (and coordinates their functions) in molting.