ELF3朊病毒樣結構域是擬南芥的溫度傳感器
作者:
小柯機器人發布時間:2020/8/27 15:19:26
英國劍橋大學Philip A. Wigge小組近日取得一項新成果。他們的最新研究發現在擬南芥中EARLY FLOWERING 3 (ELF3)的朊病毒樣結構域可充當溫度傳感器。這一研究成果於2020年8月26日在線發表在《自然》上。
研究人員發現聚穀氨醯胺(polyQ)重複序列的長度與熱響應性相關。研究顯示,來自熱帶氣候植物中的ELF3蛋白並不能檢測到朊病毒結構域(PrD),其在高溫下具有活性並且缺乏熱響應性。 ELF3的溫度敏感性也受ELF4水平的調節,表明ELF4可以穩定ELF3的功能。在擬南芥和異源系統中,在較高溫度時,融合綠色螢光蛋白的ELF3以PrD依賴的方式在數分鐘內形成斑點。ELF3的 PrD純化片段響應體外溫度升高可逆地形成液滴,這些特性反映了由PrD直接賦予的生物物理響應。溫度誘導ELF3在活性和非活性狀態之間快速相轉換的能力代表了以前未知的熱敏機制 。
據了解,溫度控制著植物的生長和發育,而氣候變化已經改變了野生植物和農作物的物候。但是,植物感知溫度的機制尚不清楚。Evening複合物是植物節律的主要信號樞紐和核心組件。Evening複合體對溫度反應性轉錄起抑制作用,通過未知的機制為生長提供節律和溫度反應性。Evening複合體由ELF3、小α螺旋蛋白ELF4和LUX ARRYTHMO(LUX)組成,支架蛋白ELF3是溫度感受器的關鍵組成部分;LUX是將Evening複合體招募到轉錄靶點所需的DNA結合蛋白。ELF3包含一個polyQ重複序列,其嵌入預測的PrD中。
附:英文原文
Title: A prion-like domain in ELF3 functions as a thermosensor in Arabidopsis
Author: Jae-Hoon Jung, Antonio D. Barbosa, Stephanie Hutin, Janet R. Kumita, Mingjun Gao, Dorothee Derwort, Catarina S. Silva, Xuelei Lai, Elodie Pierre, Feng Geng, Sol-Bi Kim, Sujeong Baek, Chloe Zubieta, Katja E. Jaeger, Philip A. Wigge
Issue&Volume: 2020-08-26
Abstract: Temperature controls plant growth and development, and climate change has already altered the phenology of wild plants and crops1. However, the mechanisms by which plants sense temperature are not well understood. The evening complex is a major signalling hub and a core component of the plant circadian clock2,3. The evening complex acts as a temperature-responsive transcriptional repressor, providing rhythmicity and temperature responsiveness to growth through unknown mechanisms2,4,5,6. The evening complex consists of EARLY FLOWERING 3 (ELF3)4,7, a large scaffold protein and key component of temperature sensing; ELF4, a small α-helical protein; and LUX ARRYTHMO (LUX), a DNA-binding protein required to recruit the evening complex to transcriptional targets. ELF3 contains a polyglutamine (polyQ) repeat8,9,10, embedded within a predicted prion domain (PrD). Here we find that the length of the polyQ repeat correlates with thermal responsiveness. We show that ELF3 proteins in plants from hotter climates, with no detectable PrD, are active at high temperatures, and lack thermal responsiveness. The temperature sensitivity of ELF3 is also modulated by the levels of ELF4, indicating that ELF4 can stabilize the function of ELF3. In both Arabidopsis and a heterologous system, ELF3 fused with green fluorescent protein forms speckles within minutes in response to higher temperatures, in a PrD-dependent manner. A purified fragment encompassing the ELF3 PrD reversibly forms liquid droplets in response to increasing temperatures in vitro, indicating that these properties reflect a direct biophysical response conferred by the PrD. The ability of temperature to rapidly shift ELF3 between active and inactive states via phase transition represents a previously unknown thermosensory mechanism.
DOI: 10.1038/s41586-020-2644-7
Source: https://www.nature.com/articles/s41586-020-2644-7