背景回顾：Organ initiation from the shoot apical meristem first gives rise to leaves during vegetative development and then flowers during reproductive development. LEAFY (LFY) is activated after floral induction and together with other factors promotes the floral program. LFY functions redundantly with APETALA1 (AP1) to activate the class B genes APETALA3 (AP3) and PISTILLATA (PI), the class C gene AGAMOUS (AG), and the class E gene SEPALLATA3, which leads to the specification of stamens and carpels, the reproductive organs of flowers. 

提出问题：Molecular and genetic networks that control the activation of AP3, PI, and AG in flowers have been well studied; however, much less is known about how these genes are repressed in leaves and how their repression is lifted in flowers. 

结果1-叶中ZP1/ZFP8抑制AP3/PI/AG：Here, we showed that two genes encoding Arabidopsis C2H2 ZINC FINGER PROTEIN (ZFP) transcription factors, ZP1 and ZFP8, act redundantly to directly repress AP3, PI, and AG in leaves. 

结果2-花中LFY/AP1抑制ZP1/ZFP8：After LFY and AP1 are activated in floral meristems, they down-regulate ZP1 and ZFP8 directly to lift the repression on AP3, PI, and AG. 

结论：Our results reveal a mechanism for how floral homeotic genes are repressed and derepressed before and after floral induction. 

茎尖分生组织起始的器官在营养发育阶段形成叶片，而在生殖发育阶段则会形成花。LEAFY基因在成花诱导后会被激活，与其他因子一起促进开花进程。LFY与AP1存在功能冗余，共同激活B类基因AP3和PI、C类基因AG以及E类基因SEP3，从而导致花器官雄蕊和心皮的特化。对于花中AP3、PI以及AG的分子和遗传网络调控机制已经研究得比较透彻了；但是，对于这些基因为何在叶片的表达会被抑制，而在花中这种抑制为何被移除，都不清楚。本文中，作者发现拟南芥中两个C2H2锌指蛋白ZP1和ZFP8存在功能冗余，在叶片中直接抑制AP3、PI以及AG的表达。当花分生组织中LFY和AP1被激活后，其能够直接下调ZP1和ZFP8的表达，从而移除后者对AP3、PI以及AG的抑制作用。本文的研究结果揭示了一个花同源异型基因如何在成花诱导前被抑制，而在成花诱导后被去抑制的分子机制。

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