Use of GAL4 factor-based yeast assay to quantify the effects of xenobiotics on RXR homodimer and RXR/PPAR heterodimer in scallop Chlamys farreri.

Retinoid X receptor (RXR) and peroxisome proliferators-activated receptors (PPAR) have been shown as important targets of endocrine disrupting effects caused by organotin compounds (OTCs). In vitro methods for non-model species are instrumental in revealing not only mechanism of toxicity but also basic biology. In the present study, we constructed the GAL4 factor-based recombinant yeast systems of RXRα/RXRα (RR), RXRα/PPARα (RPα) and RXRα/PPARγ (RPγ) of the scallop Chlamys farreri to investigate their transcriptional activity under the induction of OTCs (tributyltin chloride, triphenyltin chloride, tripropyltin chloride and bis(tributyltin)oxide), their spiked sediments and five other non‑tin compounds (Wy14643, rosiglitazone, benzyl butyl phthalate, dicyclohexyl phthalate and bis(2-ethylhexyl) phthalate). The results showed that the natural ligand of RXR, 9-cis-retinoic acid (9cRA), induces transcriptional activity in all three systems, while four OTCs induced the transcriptional activity of the RR and RPα systems. None of the five potential non‑tin endocrine disruptors induced effects on the RPα and RPγ systems. The spiked sediment experiment demonstrated the feasibility of the recombinant yeast systems constructed in this study for environmental sample detection. These results suggest that OTCs pose a threat to affect function of RXRα and PPARα of bivalve mollusks. The newly developed GAL4 factor-based yeast two-hybrid system can be used as a valuable tool for identification and quantification of compounds active in disturbing RXR and PPAR of bivalves.