Data from: Cambrian origin of the CYP27C1-mediated vitamin A1-to-A2 switch, a key mechanism of vertebrate sensory plasticity

The spectral composition of ambient light varies across both space and time. Many species of jawed vertebrates adapt to this variation by tuning the sensitivity of their photoreceptors via the expression of CYP27C1, an enzyme that converts vitamin A1 into vitamin A2, thereby shifting the ratio of vitamin A1-based rhodopsin to red-shifted vitamin A2-based porphyropsin in the eye. Here, we show that the sea lamprey (Petromyzon marinus), a jawless vertebrate that diverged from jawed vertebrates during the Cambrian period (approx. 500 Ma), dynamically shifts its photoreceptor spectral sensitivity via vitamin A1-to-A2 chromophore exchange as it transitions between photically divergent aquatic habitats. We further show that this shift correlates with high-level expression of the lamprey orthologue of CYP27C1, specifically in the retinal pigment epithelium as in jawed vertebrates. Our results suggest that the CYP27C1-mediated vitamin A1-to-A2 switch is an evolutionarily ancient mechanism of sensory plasticity that appeared not long after the origin of vertebrates.环境光的光谱组成会随空间与时间发生变化。诸多有颌脊椎动物可通过表达CYP27C1调节光感受器的敏感性以适应这种变化：CYP27C1是一种可将维生素A1转化为维生素A2的酶，能够调整眼部中以维生素A1为基础的视紫红质与红移型维生素A2为基础的视紫蓝质之间的比例。本研究表明，七鳃鳗（海七鳃鳗，Petromyzon marinus）是一种在寒武纪（约5亿年前）与有颌脊椎动物分化的无颌脊椎动物，它可在光环境差异显著的水生栖息地间迁移时，通过维生素A1到A2的生色团交换动态调节自身光感受器的光谱敏感性。本研究进一步发现，这种敏感性变化与七鳃鳗的CYP27C1直系同源基因的高表达存在关联，且该表达位点与有颌脊椎动物一致，均为视网膜色素上皮。本研究结果提示，由CYP27C1介导的维生素A1到A2转换是一种进化上古老的感官可塑性机制，其出现时间或与脊椎动物的起源相隔不远。