Structure of the unique tetrameric STENOFOLIA homeodomain bound with target promoter DNA.
Structure of the unique tetrameric STENOFOLIA homeodomain bound with target promoter DNA.
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DOI：
10.1107/s205979832100632x
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发表时间：
2021-08-01
期刊：
影响因子：
--
通讯作者：
Deng J
中科院分区：
文献类型：
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作者：
Pathak PK;Zhang F;Peng S;Niu L;Chaturvedi J;Elliott J;Xiang Y;Tadege M;Deng J
STENOFOLIA同源结构域以四聚体形式结合启动子DNA， α3螺旋在主凹槽和小凹槽中结合DNA。同源盒转录因子是动物和植物形态发生和发育的关键调控因子。在植物中，wuschel相关同源盒（WOX）家族转录因子作为几个发育程序的中心组织者，从胚胎模式到分生干细胞的维持，通过转录激活和抑制机制。Medicago truncatula STENOFOLIA （STF）基因是叶片横向发育的主要调控因子。本文以2.1 Å分辨率报道了STF （STF-HD）配合物及其启动子DNA的同域（HD）晶体结构。STF-HD以四聚体的形式结合DNA，包住几乎整个结合的DNA表面。STF-HD四聚体通过将一个原聚体的c端尾部以首尾相连的方式对接到另一个原聚体头部的保守疏水表面上，从而实现了部分稳定。STF-HD特异性结合TGA基序，尽管启动子序列也包含TAAT基序。螺旋α3不仅在主槽中作为碱基读取器，而且通过位于其c端的基本残基在次要槽中提供DNA结合。本文报道的植物结构和功能数据为WOX家族转录因子中植物特异性hd的dna结合机制提供了新的见解。
The STENOFOLIA homeodomain binds promoter DNA as a tetramer and the α3 helix binds DNA in both the major and minor grooves. Homeobox transcription factors are key regulators of morphogenesis and development in both animals and plants. In plants, the WUSCHEL-related homeobox (WOX) family of transcription factors function as central organizers of several developmental programs ranging from embryo patterning to meristematic stem-cell maintenance through transcriptional activation and repression mechanisms. The Medicago truncatula STENOFOLIA (STF) gene is a master regulator of leaf-blade lateral development. Here, the crystal structure of the homeodomain (HD) of STF (STF-HD) in complex with its promoter DNA is reported at 2.1 Å resolution. STF-HD binds DNA as a tetramer, enclosing nearly the entire bound DNA surface. The STF-HD tetramer is partially stabilized by docking of the C-terminal tail of one protomer onto a conserved hydrophobic surface on the head of another protomer in a head-to-tail manner. STF-HD specifically binds TGA motifs, although the promoter sequence also contains TAAT motifs. Helix α3 not only serves a canonical role as a base reader in the major groove, but also provides DNA binding in the minor groove through basic residues located at its C-terminus. The structural and functional data in planta reported here provide new insights into the DNA-binding mechanisms of plant-specific HDs from the WOX family of transcription factors.