Cloning and comparative analysis of the retinoid X receptor in two marine gastropods with varying sensitivity to imposex under tributyltin contamination

Abstract

The Retinoid X Receptor (RXR) has been identified as a primary target in diverse endocrine disruption processes resulting from exposure to tributyltin (TBT), particularly concerning imposex development in gastropods. Two partial open reading frames encoding RXR were successfully isolated from the marine gastropods Buccinastrum deforme (BgRXR) and Trophon geversianus (TgRXR). These edible species, residing in the same area and exposed to similar environmental pollution conditions in Patagonia, Argentina, display different levels of imposex development. Here, we present a thorough functional characterization of both RXRs, examining their responsiveness and modulation by 9-cis-retinoic acid (9-cis-RA) and TBT. BgRXR and TgRXR exhibited dose-dependent activation by both 9-cis-RA and TBT, in luciferase reporter assays. TgRXR displayed higher transcriptional activation than BgRXR triggered by both tested ligands, whereas only BgRXR was activated by low TBT concentrations. Our findings highlight RXR’s role in imposex development, emphasizing the importance of species-specific factors in response to environmental contaminants.