Quail P H
Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
Semin Cell Dev Biol. 2000 Dec;11(6):457-66. doi: 10.1006/scdb.2000.0199.
The phytochrome family of sensory photoreceptors transduces environmental light signals to responsive nuclear genes by poorly defined pathways. The recent application of yeast two-hybrid library screens to the identification of components that physically interact with members of the phytochrome family has dramatically altered previous views of the likely intracellular signaling pathways. The evidence indicates that one pathway involves light-triggered translocation of the photoreceptor molecule from cytoplasm to nucleus where it binds specifically in its biologically active form to a promoter-bound basic helix-loop-helix protein. The phytochrome molecules are proposed to function as integral, light-switchable components of transcriptional regulator complexes targeting environmental light signals directly and instantly to specific gene promoters.
光敏色素家族的感光光受体通过定义不清的途径将环境光信号转导至响应性核基因。最近，酵母双杂交文库筛选技术被用于鉴定与光敏色素家族成员发生物理相互作用的组分，这极大地改变了以往对可能的细胞内信号传导途径的看法。有证据表明，一条途径涉及光触发光受体分子从细胞质向细胞核的转运，在细胞核中，光受体分子以其生物活性形式特异性结合到与启动子结合的碱性螺旋-环-螺旋蛋白上。有人提出，光敏色素分子作为转录调节复合物的组成部分，可直接且即时地将环境光信号靶向特定基因启动子，其功能受光开关调控。
