Induction mechanism of imposex in marine gastropods by retinoids

自20世纪60年代以来，有机锡化合物已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，对三丁基锡和三苯基锡等有机锡化合物极为敏感。迄今为止，极低浓度的三丁基锡化合物或三丁基锡化合物已被证明可诱导海洋腹足类动物性畸变（雄性生殖器与雌性生殖器重叠）。虽然多年来对性畸变的诱导机制一直存在争议，但我们已经报道TBT和TPT是有效的维甲酸X受体（RXR）激活剂，而RXR的天然配体9-顺式维甲酸（9-cis retinoic acid）诱导性畸变。然而，在脊椎动物中，全反式视黄酸是众所周知的形态发生剂，对早期发育中的轴向模式和器官形成很重要。在这项研究中，我们分析了软体动物受体全反式维甲酸的维甲酸的进化历史的观点。

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.