Gangappa Sreeramaiah N, Kumar S Vinod
Cell and Developmental Biology Department, John Innes Centre, Norwich NR4 7UH, UK.
Cell and Developmental Biology Department, John Innes Centre, Norwich NR4 7UH, UK.
Cell Rep. 2017 Jan 10;18(2):344-351. doi: 10.1016/j.celrep.2016.12.046.
Plant growth and development are defined by environmental cues. The transcription factor PHYTOCHROME INTERACTING FACTOR 4 (PIF4) is the central signaling hub that integrates environmental cues, including light and temperature, to regulate growth and development. The thermosensory mechanisms controlling the PIF4-mediated temperature response, and its integration with other environmental responses, remain poorly understood. DE-ETIOLATED 1 (DET1) and CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1), key regulators of light signaling, have been proposed to control thermosensory growth by transcriptional regulation of PIF4, through ELONGATED HYPOCOTYL 5 (HY5). Here, we show that DET1/COP1 and HY5 regulate thermosensory elongation through distinct mechanisms. DET1 and COP1 are essential for promoting PIF4 expression and stabilizing PIF4 protein. Furthermore, HY5 inhibits elongation growth through competitive chromatin binding to PIF4 targets, not through transcriptional regulation of PIF4. Our findings reveal a mechanistic framework in which DET1/COP1 and HY5 regulatory modules act independently to regulate growth through the environmental signal integrator PIF4.
植物的生长和发育由环境信号决定。转录因子光敏色素相互作用因子4（PIF4）是整合包括光和温度在内的环境信号以调控生长和发育的核心信号枢纽。控制PIF4介导的温度响应的热感测机制，以及它与其他环境响应的整合，仍知之甚少。去黄化1（DET1）和组成型光形态建成1（COP1）是光信号的关键调节因子，有人提出它们通过ELONGATED HYPOCOTYL 5（HY5）对PIF4进行转录调控来控制热感测生长。在这里，我们表明DET1/COP1和HY5通过不同机制调节热感测伸长。DET1和COP1对于促进PIF4表达和稳定PIF4蛋白至关重要。此外，HY5通过与PIF4靶标竞争性结合染色质来抑制伸长生长，而不是通过对PIF4的转录调控。我们的研究结果揭示了一个机制框架，其中DET1/COP1和HY5调节模块通过环境信号整合器PIF4独立发挥作用来调控生长。
