A G-Box-Like Motif Is Necessary for Transcriptional Regulation by Circadian Pseudo-Response Regulators in Arabidopsis
A G-Box-Like Motif Is Necessary for Transcriptional Regulation by Circadian Pseudo-Response Regulators in Arabidopsis
复制标题
DOI：
10.1104/pp.15.01562
复制
发表时间：
2016-01-01
期刊：
影响因子：
7.4
通讯作者：
Farre, Eva M.
中科院分区：
文献类型：
--
作者：
Liu, Tiffany L.;Newton, Linsey;Farre, Eva M.
伪反应调节因子（PRRs）在维持昼夜节律和调节多种生物过程中发挥着重叠和独特的作用，包括开花，生长和非生物胁迫反应的光周期控制。PRR作为转录抑制因子，通过其保守的C-末端CCT（CONSTANS、CONSTANS样和CAB表达时间1 [TOC 1/PRR 1]）结构域，通过一种仍然知之甚少的机制与染色质结合。在这里，我们使用染色质免疫沉淀法和高通量测序（ChIP-seq）鉴定了PRR 9的全基因组靶标，并将其与PRR 7，PRR 5和TOC 1/PRR 1 ChIP-seq数据进行了比较。我们发现PRR结合位点位于低核小体占有率和高DNase I超敏性的基因组区域内。此外，拟南芥属物种之间的保守的非编码区丰富的PRR结合位点周围，表明PRR与功能相关的顺式调控区。PRRs共享大量的结合区域，我们的结果表明它们协调地将靶基因的表达限制在黎明前后。一个G盒样基序在PRR结合区过度表达，我们发现这个基序是PRR介导昼夜节律相关1和PRR 9转录调控所必需的。我们的研究结果进一步了解PRRs如何靶向特定的启动子，并为研究植物的昼夜节律调控网络提供了广泛的资源。
PSEUDO-RESPONSE REGULATORs (PRRs) play overlapping and distinct roles in maintaining circadian rhythms and regulating diverse biological processes, including the photoperiodic control of flowering, growth, and abiotic stress responses. PRRs act as transcriptional repressors and associate with chromatin via their conserved C-terminal CCT (CONSTANS, CONSTANS-like, and TIMING OF CAB EXPRESSION 1 [TOC1/PRR1]) domains by a still-poorly understood mechanism. Here, we identified genome-wide targets of PRR9 using chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) and compared them with PRR7, PRR5, and TOC1/PRR1 ChIP-seq data. We found that PRR binding sites are located within genomic regions of low nucleosome occupancy and high DNase I hypersensitivity. Moreover, conserved noncoding regions among Brassicaceae species are enriched around PRR binding sites, indicating that PRRs associate with functionally relevant cis-regulatory regions. The PRRs shared a significant number of binding regions, and our results indicate that they coordinately restrict the expression of target genes to around dawn. A G-box-like motif was overrepresented at PRR binding regions, and we showed that this motif is necessary for mediating transcriptional regulation of CIRCADIAN CLOCK ASSOCIATED 1 and PRR9 by the PRRs. Our results further our understanding of how PRRs target specific promoters and provide an extensive resource for studying circadian regulatory networks in plants.