Targeted DNA methylation represses two enhancers of FLOWERING LOCUS T in Arabidopsis thaliana

First author: Johan Zicola; Affiliations: Max Planck Institute for Plant Breeding Research (马克斯普朗克植物育种研究所): Cologne, Germany

Corresponding author: Franziska Turck

FLOWERING LOCUS T (FT) plays a major role in regulating the floral transition in response to an inductive long day photoperiod in Arabidopsis thaliana. Expression of FT in leaves is dependent on the distal transcriptional enhancer Block C, located 5-kilobases (kb) upstream of the transcriptional start site (TSS). We expressed an inverted repeat of Block C to induce local DNA methylation and heterochromatin formation, which lead to FT downregulation in an inductive photoperiod. Using targeted DNA methylation as a tool to uncover further regulatory regions at the FT locus, we identified Block E, located 1 kb downstream of the gene, as a novel enhancer of FT. As Block C, Block E is conserved across Brassicaceae and located in accessible chromatin. Block C and E act as additive transcriptional enhancers that, in combination with the proximal FT promoter, control expression of FT in response to photoperiod in the leaf phloem.

拟南芥FT基因在长日照条件下调控植株成花转变过程中发挥重要的作用。FT基因在叶中的表达依赖于末端转录增强子Block C，位于转录起始位点上游5kb处。作者表达了一个Block C的反向重复序列来诱导区域化的DNA甲基化和异染色质的形成，进而导致FT在感应光周期时下调表达。利用靶向DNA甲基化技术来揭示FT位点上的调控区域，作者鉴定到了一个新的增强子Block E，其位于FT基因下游1kb处。Block C和Block E在十字花科不同物种之间十分保守，且位于常染色质区域。Block C和E作为附加的转录增强子，与FT基因的启动子区域一起控制叶韧皮部FT基因响应光周期时的表达。

通讯：Franziska Turck (https://www.mpipz.mpg.de/turck)

研究方向：拟南芥调控开花时间基因FT的转录调控网络。

doi: https://doi.org/10.1038/s41477-019-0375-2

Journal: Nature Plants

Published date: March 04, 2019