LEAFY is a pioneer transcription factor and licenses cell reprogramming to floral fate

第一作者：Run Jin

第一单位：宾夕法尼亚大学

通讯作者：Doris Wagner

 Abstract 

背景回顾：Master transcription factors reprogram cell fate in multicellular eukaryotes. Pioneer transcription factors have prominent roles in this process because of their ability to contact their cognate binding motifs in closed chromatin.

提出问题：Reprogramming is pervasive in plants, whose development is plastic and tuned by the environment, yet little is known about pioneer transcription factors in this kingdom.

主要发现：Here, we show that the master transcription factor LEAFY (LFY), which promotes floral fate through upregulation of the floral commitment factor APETALA1 (AP1), is a pioneer transcription factor.

结果1-体外试验：In vitro, LFY binds to the endogenous AP1 target locus DNA assembled into a nucleosome.

结果2-体内试验：In vivo, LFY associates with nucleosome occupied binding sites at the majority of its target loci, including AP1.

结果3-先锋TF作用机制：Upon binding, LFY ‘unlocks’ chromatin locally by displacing the H1 linker histone and by recruiting SWI/SNF chromatin remodelers, but broad changes in chromatin accessibility occur later.

结论：Our study provides a mechanistic framework for patterning of inflorescence architecture and uncovers striking similarities between LFY and animal pioneer transcription factor.

 摘 要 

在多细胞真核生物中，主效转录因子重编程细胞命运。先锋转录因子能够在闭合的染色质中接触到配对的结合基序，因而在该过程中具有十分突出的作用。重编程在植物中十分普遍，植物的发育具有高度可塑性，并且受到环境的精细调控，然而对于先锋转录因子在植物中的作用还了解不多。本文中，作者发现通过上调成花基因AP1的表达促进成花转变的主效转录因子LFY，是一个先锋转录因子。体外试验中，LFY能够结合到已经组装进核小体的内源AP1靶位点DNA上。体内试验中，LFY在大多数能够结合的靶位点上，均与核小体占据的结合位点相关联，其中就包括AP1。一旦结合上，LFY就会通过置换H1连接组蛋白和招募SWI/SNF染色质重塑因子，从而局部“解锁”染色质，但是染色质可及性更加广泛的变化要迟一点。本文的研究为花序结构的模式建成提供了一个机制框架，同时揭示了LFY和动物先锋转录因子之间的惊人相似之处。

doi: https://doi.org/10.1038/s41467-020-20883-w

Journal: Nature Communications

Published date: Jan 27, 2021