轉錄因子COL12是COP1/SPA E3連接酶的底物，參與開花時間和植物結構的調節

02-02

本論文於2017年11月29日在線發表於Plant Physiology，原文題目如下：

The transcription factor COL12 is a substrate of the COP1/SPA E3 ligase and regulates flowering time and plant architecture

摘要：

在整個植物生命周期中，環境光線環境控制植物發育的許多方面。擬南芥中，光信號的關鍵抑制子是COP1/SPA E3泛素連接酶，它引起內源發育相關途徑的許多調節子的降解，從而實現這種複雜的控制。這包括負責開花時間的光周期控制的CONSTANS（CO）轉錄因子。有16個類CONSTANS蛋白質，而它們的功能只是部分被研究。這裡，我們發現14個COL蛋白在體外結合COP1和SPA1。我們隨後關注COL12並顯示COL12在體內結合COP1和SPA蛋白。 COL12蛋白在COP1依賴性的黑暗中降解，表明COL12是COP1/SPA泛素連接酶的底物。COL12的過表達通過降低FT的表達，特別在長日照條件下引起晚開花。這種表型在遺傳上依賴於CO。與這一發現一致，COL12在體內與CO物理上相互作用，表明COL12通過抑制CO蛋白功能來抑制開花。COL12過表達並沒有改變CO蛋白的穩定性。因此COL12可能抑制CO的活性，而不是CO的水平。 COL12的過表達也通過增加蓮座葉分枝的數量和降低花序高度來影響植物結構。這些表型是不依賴CO的。因此，我們推測COL12通過依賴CO和不依賴CO的機制來影響植物發育。

Abstract：

The ambient light environment controls many aspects of plant development throughout a plants life cycle. Such complex control is achieved because a key repressor of light signaling, the Arabidopsis COP1/SPA E3 ubiquitin ligase, causes the degradation of multiple regulators of endogenous developmental pathways. This includes the CONSTANS (CO) transcription factor which is responsible for photoperiodic control of flowering time. There are 16 CONSTANS-like proteins whose functions are only partly understood. Here, we show that 14 COL proteins bind COP1 and SPA1 in vitro. We subsequently focused on COL12 and show that COL12 binds COP1 and SPA proteins in vivo. The COL12 protein is degraded in darkness in a COP1-dependent fashion, indicating that COL12 is a substrate of the COP1/SPA ubiquitin ligase. Overexpression of COL12 causes late flowering specifically in long day conditions by decreasing the expression of FT. This phenotype is genetically dependent on CO. Consistent with this finding, COL12 physically interacts with CO in vivo, suggesting that COL12 represses flowering by inhibiting CO protein function. We show that COL12 overexpression did not alter CO protein stability. It is therefore likely that COL12 represses the activity of CO rather than CO levels. Overexpression of COL12 also affects plant architecture by increasing the number of rosette branches and reducing inflorescence height. These phenotypes are CO-independent. Hence, we suggest that COL12 affects plant development through CO-dependent and CO-independent mechanisms.

每日一詞
ambient
英[??mbi?nt]
美[??mbi?nt]
adj. 環境; 周圍的，包圍著的; 產生輕鬆氛圍的;

[例句]Another ambient temperature sensor is the vapor-filled bellows.

另一種空氣溫度感測器是充氣波紋管。