Brassinosteroid-induced gene repression requires specific and tight promoter binding of BIL1/BZR1 via DNA shape readout
Brassinosteroid-induced gene repression requires specific and tight promoter binding of BIL1/BZR1 via DNA shape readout
复制标题
DOI：
10.1038/s41477-022-01289-6
复制
发表时间：
2022-12-15
期刊：
影响因子：
18
通讯作者：
Miyakawa, Takuya
中科院分区：
文献类型：
--
作者：
Nosaki, Shohei;Mitsuda, Nobutaka;Miyakawa, Takuya
brz - insensitivity - long 1 (BIL1)/ brassinazol - resistant 1 （BZR1）及其同源物是植物特异性转录因子，可将植物激素brassinosteroids （BRs）的信号转导为转录应答，从而控制植物的各种生理过程。尽管BIL1/BZR1上调了一些BR-responsive genes，下调了其他基因，但BIL1/BZR1双重作用的分子机制尚不清楚。本研究表明，BIL1/BZR1对br响应性转录抑制需要BIL1/BZR1单独与含有已知6bp核心结合基序的DNA片段的10bp元件紧密结合。此外，生化和结构证据表明，对核心基序两侧的两个核碱基的选择性是通过BIL1/BZR1的DNA形状读出来实现的，而不是直接识别核碱基。这些结果阐明了BIL1/BZR1转录抑制的分子和结构基础，有助于进一步了解BIL1/BZR1在br应答基因调控中的双重作用。
BRZ-INSENSITIVE-LONG 1 (BIL1)/BRASSINAZOLE-RESISTANT 1 (BZR1) and its homologues are plant-specific transcription factors that convert the signalling of the phytohormones brassinosteroids (BRs) to transcriptional responses, thus controlling various physiological processes in plants. Although BIL1/BZR1 upregulates some BR-responsive genes and downregulates others, the molecular mechanism underlying the dual roles of BIL1/BZR1 is still poorly understood. Here we show that BR-responsive transcriptional repression by BIL1/BZR1 requires the tight binding of BIL1/BZR1 alone to the 10 bp elements of DNA fragments containing the known 6 bp core-binding motifs at the centre. Furthermore, biochemical and structural evidence demonstrates that the selectivity for two nucleobases flanking the core motifs is realized by the DNA shape readout of BIL1/BZR1 without direct recognition of the nucleobases. These results elucidate the molecular and structural basis of transcriptional repression by BIL1/BZR1 and contribute to further understanding of the dual roles of BIL1/BZR1 in BR-responsive gene regulation.