Molecular characterization of Adh3 from the mollusc Nucella lapillus: tissue gene expression after tributyltin and retinol exposure

Interference of organotin with animal endocrine systems represents a notable case of physiological disruption. Caenogastropod molluscs are particularly sensitive to exposure to these compounds, developing a condition termed imposex, the superimposition of male sexual secondary features onto females. Recently, various studies have shown that the retinoic X receptor is a high-affinity ligand to tributyltin (TBT), while simultaneously hampering expression of the receptor gene. Curiously, in ascidians TBT has been shown to downregulate the expression of alcohol dehydrogenase class III (Adh3), an enzyme controversially linked with retinol oxidation. Here we isolate an Adh3 orthologue in Nucella lapillus, characterize its basal tissue expression profile and determine the gene expression dynamics in gonads and digestive gland upon TBT and retinol exposure. We find that TBT does not affect Adh3 expression in the tested tissues of N. lapillus. However, exposure to retinol, the precursor of retinoic acid in vertebrates, caused a significant downregulation of Adh3 levels in female gonads.