Induction mechanism of imposex in marine gastropods by retinoids

自20世纪60年代以来，有机锡化合物被广泛用作船舶和渔网的防污剂，并因此释放到海洋环境中。水生无脊椎动物，特别是海洋腹足类动物，对三丁基锡（TBT）和三苯基锡（TPT）等有机锡化合物极为敏感。到目前为止，极低浓度的TBT或TPT已被证明会导致海洋腹足类动物的性侵（雄性生殖器重叠在雌性生殖器上）。虽然性致性的机制多年来一直存在争议，但我们已经报道了TBT和TPT是类视黄酮X受体（RXR）的有效激活剂，RXR的天然配体9-顺式视黄酸可诱导性致性。然而，在脊椎动物中，全反式维甲酸是众所周知的对早期发育的轴向模式和器官形成很重要的形态因子。在本研究中，我们从类维甲酸机制的进化史角度分析了全反式维甲酸的软体动物受体。

Organotin compounds have been widely used as antifouling pints for ships and fishing nets since the 1960s and have thus released into marine environments. Aquatic invertebrates, particularly marine gastropods, are extremely sensitive to organotin compounds such as tributyltin(TBT) and triphenyltin(TPT). So far, very low-concentartion of TBT or TPT have been shown to induce imposex(superimposition of male genitalia on female) in marine gastropods. Although the inposex induction mechanism has been controversial for many years, we have reported that TBT and TPT are potent and efficacious activators of retinoid X receptor(RXR), and the natural ligand of RXR, 9-cis retinoic acid, induces imposex. However, in vertebrates, all-trans retinoic acid is well-known morphogen important for axial patterning and organ formation in early development. In this study, we analyze the molluscan receptor for all-trans retinoic acid in the view of the evolutionary history of retinoid machinery.