生物谷報(bào)道：植物中很多至關(guān)重要的發(fā)育過程由光和赤霉素共同調(diào)控，然而我們對(duì)二者之間對(duì)話的分子基礎(chǔ)還沒有充分了解?，F(xiàn)在，兩個(gè)小組在本期《自然》上報(bào)告的結(jié)果顯示了一個(gè)信號(hào)級(jí)聯(lián),，它有助于光和赤霉素對(duì)植物生長進(jìn)行協(xié)調(diào)的控制,。在沒有赤霉素時(shí)，DELLA蛋白抑制轉(zhuǎn)錄因子PIF3（一種光敏素相互作用蛋白）與基因啟動(dòng)子結(jié)合,。赤霉素誘導(dǎo)DELLA蛋白的降解,，從而允許PIFs與它們的目標(biāo)啟動(dòng)子結(jié)合，并調(diào)控基因表達(dá),。光通過一個(gè)光反應(yīng)器發(fā)揮作用,，來使PIF4失去穩(wěn)定性,。所以,，DELLA蛋白及PIF家族成員之間的競(jìng)爭(zhēng)性相互作用，似乎是將光與赤霉素聯(lián)系在一起的關(guān)鍵因素,。（科學(xué)時(shí)報(bào)）
生物谷推薦英文原文：
Nature 451, 475-479 (24 January 2008) | doi:10.1038/nature06448; Received 28 September 2007; Accepted 1 November 2007
Coordinated regulation of Arabidopsisthaliana development by light and gibberellins
Suhua Feng1,2,7, Cristina Martinez1,8, Giuliana Gusmaroli1,8, Yu Wang3,8, Junli Zhou2,8, Feng Wang2, Liying Chen2, Lu Yu2, Juan M. Iglesias-Pedraz4, Stefan Kircher5, Eberhard Schäfer5, Xiangdong Fu6, Liu-Min Fan3 & Xing Wang Deng1,2,3
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8104, USA
National Institute of Biological Sciences, Zhongguancun Life Science Park, Beijing 102206, China
Peking–Yale Joint Center for Plant Molecular Genetics and Agrobiotechnology, and National Laboratory for Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China
Departamento Genética Molecular de Plantas, Centro Nacional de Biotecnología-CSIC, Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain
Institut für Biologie II/Botanik, Albert Ludwigs Universität, Freiburg D-79104, Germany
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100080, China
Present address: Howard Hughes Medical Institute, University of California at Los Angeles, Los Angeles, California 90095-1606, USA.
These authors contributed equally to this work.
Correspondence to: Xing Wang Deng1,2,3 Correspondence and requests for materials should be addressed to X.W.D. (Email: [email protected]).
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.
