Analysis of molecular evolution of sex steroid hormone receptors

雌激素是包括人类在内的大多数脊椎动物卵巢分化所必需的。雌激素的作用主要是通过雌激素受体（ER）介导的，ER是激素激活的转录因子。为了了解ER的分子进化，我们试图从文昌鱼、古鱼类和其他物种中分离编码ER的cDNA。我们发现作为无脊椎动物的文昌鱼已经具有ER基因。我们的功能分析表明，ER作为一个依赖于转录因子的功能可能是通过进化过程中获得的。

Estrogens are necessary for ovarian differentiation in most vertebrates including human. Estrogen actions are largely mediated through the estrogen receptors (ERs), which are hormone activated transcription factors. To understand the molecular evolution of ER, we tried to isolate cDNAs encoding ERs from amphioxus, ancient fishes, and other species. We found that amphioxus that is an invertebrate has already possessed the ER gene. Our functional analyses suggest that the function of ER as a hormone-dependent transcription factor might be gained through the evolutionary process.