The transcription factor FLC confers a flowering response to vernalization by repressing meristem competence and systemic signaling in Arabidopsis
The transcription factor FLC confers a flowering response to vernalization by repressing meristem competence and systemic signaling in Arabidopsis
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DOI：
10.1101/gad.373506
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发表时间：
2006-04-01
影响因子：
10.5
通讯作者：
Coupland, G
中科院分区：
文献类型：
--
作者：
Searle, I;He, YH;Coupland, G
拟南芥茎尖分生组织的花发育是响应不同组织中感知的环境信号而发生的。在叶子的维管组织（韧皮部）中检测到光周期，并促进产生诱导分生组织开花的系统信号。春化作用是对冬季温度的反应，克服了光周期花诱导的障碍。在拟南芥中，这种阻断是由开花抑制剂引起的，这些抑制剂包含几种相关的 MADS-box 转录因子，其中最重要的是 FLC。我们发现，FLC 通过抑制叶片中至少两种系统信号的产生来延迟开花，其中一种信号由 RAF 激酶抑制剂样蛋白 FT 控制。减少这些信号的表达会间接抑制分生组织花诱导相关基因的表达。此外，分生组织中的FLC表达通过直接抑制SOC1 MADS-box转录因子的表达并阻止bZIP转录因子FD的上调来损害对FT信号的响应。 FLC 导致开花极度延迟，需要抑制该层次结构中多个水平的基因。 FLC:HA 融合蛋白在体内直接结合 FD 和 SOC1 的启动子区域以及 FT 的第一个内含子。因此，春化作用减轻了叶子和分生组织中关键调控基因的转录抑制，从而允许叶子中产生系统信号并赋予分生组织响应这些信号的能力。
Floral development at the Arabidopsis shoot apical meristem occurs in response to environmental cues that are perceived in different tissues. Photoperiod is detected in the vascular tissue of the leaf (phloem) and promotes production of a systemic signal that induces flowering at the meristem. Vernalization, the response to winter temperatures, overcomes a block on photoperiodic floral induction. in Arabidopsis, this block is caused by inhibitors of flowering that comprise several related MADS-box transcription factors, the most prominent of which is FLC. We show that FLC delays flowering by repressing production in the leaf of at least two systemic signals, one of which is controlled by the RAF kinase inhibitor-like protein FT. Reducing expression of these signals indirectly represses expression of genes involved in floral induction at the meristem. In addition, FLC expression in the meristem impairs response to the FT signal by directly repressing expression of the SOC1 MADS-box transcription factor and preventing up-regulation of the bZIP transcription factor FD. Repression of genes acting at multiple levels in this hierarchy is required for the extreme delay in flowering caused by FLC. An FLC:HA fusion protein binds directly in vivo to the promoter regions of FD and SOC1 and to the first intron of FT. Thus vernalization relieves transcriptional repression of key regulatory genes in both the leaf and meristem, allowing production of systemic signals in the leaves and conferring competence on the meristem to respond to these signals.