Max Planck Institute for Plant Breeding Research, Cologne, Germany.
College of Life Sciences, Capital Normal University, Beijing, China.
Nat Plants. 2019 Mar;5(3):300-307. doi: 10.1038/s41477-019-0375-2. Epub 2019 Mar 4.
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.
开花时间（FT）在调控拟南芥对诱导长日照光周期的花转变中起主要作用。FT 在叶片中的表达依赖于位于转录起始位点（TSS）上游 5 千碱基（kb）处的远端转录增强子块 C。我们表达了 Block C 的反向重复序列，以诱导局部 DNA 甲基化和异染色质形成，从而导致 FT 在诱导光周期中下调。我们使用靶向 DNA 甲基化作为揭示 FT 基因座上进一步调控区域的工具，鉴定出位于基因下游 1kb 处的 Block E 是 FT 的一个新的增强子。与 Block C 一样，Block E 在芸薹科植物中保守，并且位于可及染色质中。Block C 和 E 作为加性转录增强子，与近端 FT 启动子一起，控制叶片韧皮部中 FT 对光周期的表达。
