| 作者： | Suhua Feng, Cristina Martinez, Giuliana Gusmaroli, Yu Wang, Junli Zhou, Feng Wang, Liying Chen, Lu Yu, Juan M. Iglesias-Pedraz, Stefan Kircher, Eberhard Sch？fer, Xiangdong Fu, Liu-Min Fan & Xing Wang Deng |
|---|---|
| 刊物名称： | Nature |
| DOI： | |
| 联系作者： | |
| 英文联系作者： | |
| 卷： | |
| 摘要： | Light and gibberellins (GAs) mediate many essential and partially overlapping plant developmental processes. DELLA proteins are GA-signalling repressors that block GA-induced development1. GA induces degradation of DELLA proteins via the ubiquitin/proteasome pathway2, but light promotes accumulation of DELLA proteins by reducing GA levels3. It was proposed that DELLA proteins restrain plant growth largely through their effect on gene expression4, 5. However, the precise mechanism of their function in coordinating GA signalling and gene expression remains unknown. Here we characterize a nuclear protein interaction cascade mediating transduction of GA signals to the activity regulation of a light-responsive transcription factor. In the absence of GA, nuclear-localized DELLA proteins accumulate to higher levels, interact with phytochrome-interacting factor 3 (PIF3, a bHLH-type transcription factor) and prevent PIF3 from binding to its target gene promoters and regulating gene expression, and therefore abrogate PIF3-mediated light control of hypocotyl elongation. In the presence of GA, GID1 proteins (GA receptors) elevate their direct interaction with DELLA proteins in the nucleus, trigger DELLA protein's ubiquitination and proteasome-mediated degradation, and thus release PIF3 from the negative effect of DELLA proteins. |
