TTG1 proteins regulate circadian activity as well as epidermal cell fate and pigmentation

First author: Chiara A. Airoldi; Affiliations: University of Cambridge (剑桥大学): Cambridge, UK

Corresponding author: Beverley J. Glover

The Arabidopsis genome contains three genes encoding proteins of the TRANSPARENT TESTA GLABRA 1 (TTG1) WD-repeat (WDR) subfamily. TTG1 is a known regulator of epidermal cell differentiation and pigment production, while LIGHT-REGULATED WD1 and LIGHT-REGULATED WD2 are known regulators of the circadian clock. Here, we discovered a new central role for TTG1 WDR proteins as regulators of the circadian system, as evidenced by the lack of detectable circadian rhythms in a triple lwd1 lwd2 ttg1 mutant. This shows that there has been subfunctionalization via protein changes within the angiosperms, with some TTG1 WDR proteins developing a stronger role in circadian clock regulation while losing the protein characteristics essential for pigment production and epidermal cell specification, and others weakening their ability to drive circadian clock regulation. Our work shows that even where proteins are very conserved, small changes can drive big functional differences.

拟南芥基因组包含三个编码TTG1 WD-repeat亚家族蛋白的基因。TTG1基因已知的功能是调控表皮细胞的分化和色素的产生，而LIGHT-REGULATED WD1/2两个基因则是生物钟的调控因子。本文中，作者发现lwd1 lwd2 ttg1三突变体中完全检测不到生物钟节律，说明TTG1 WDR蛋白在植物生物钟系统方面同样发挥着重要作用。本文的研究显示被子植物的TTG1 WDR蛋白由于蛋白序列的变化发生了亚功能化，有些TTG1 WDR蛋白演化出了很强的生物钟调控功能，但是也丢失了在色素生产和表皮细胞分化方面的功能；而与此同时，另外一些TTG1 WDR蛋白则在驱动生物钟调控方面的能力有所减弱。作者的研究表明，即使蛋白非常保守，一点小的变化也有可能驱动巨大的功能差异。

通讯：Beverley J. Glover (https://www.plantsci.cam.ac.uk/directory/glover-beverley)

个人简介：1996年，John Innes Centre，博士。

研究方向：植物吸引授粉者的性状发育和演化。

doi: https://doi.org/10.1038/s41477-019-0544-3

Journal: Nature Plants

Published date: November 11, 2019