UMR1332 BFP, INRA, Université de Bordeaux, 33882 Villenave d'Ornon Cedex, France.
Institut für Biochemie und Biologie, Universität Potsdam, 14476 Potsdam-Golm, Germany.
Plant Cell. 2018 Jan;30(1):83-100. doi: 10.1105/tpc.17.00653. Epub 2018 Jan 3.
In angiosperms, the gynoecium is the last structure to develop within the flower due to the determinate fate of floral meristem (FM) stem cells. The maintenance of stem cell activity before its arrest at the stage called FM termination affects the number of carpels that develop. The necessary inhibition at this stage of (), which is responsible for stem cell maintenance, involves a two-step mechanism. Direct repression mediated by the MADS domain transcription factor AGAMOUS (AG), followed by indirect repression requiring the C2H2 zinc-finger protein KNUCKLES (KNU), allow for the complete termination of floral stem cell activity. Here, we show that MINI ZINC FINGER2 (AtMIF2) and its homolog in tomato (), INHIBITOR OF MERISTEM ACTIVITY (SlIMA), participate in the FM termination process by functioning as adaptor proteins. AtMIF2 and SlIMA recruit AtKNU and SlKNU, respectively, to form a transcriptional repressor complex together with TOPLESS and HISTONE DEACETYLASE19. AtMIF2 and SlIMA bind to the and loci in the respective plants, leading to their repression. These results provide important insights into the molecular mechanisms governing (FM) termination and highlight the essential role of AtMIF2/SlIMA during this developmental step, which determines carpel number and therefore fruit size.
在被子植物中,由于花分生组织 (FM) 干细胞的决定命运,雌蕊是花中最后发育的结构。在称为 FM 终止的阶段之前,干细胞活性的维持会影响发育的心皮数量。在这个阶段,负责干细胞维持的 () 需要被抑制,这涉及一个两步机制。AGAMOUS (AG) 介导的 MADS 结构域转录因子的直接抑制,随后需要 C2H2 锌指蛋白 KNUCKLES (KNU) 的间接抑制,允许完全终止花分生组织细胞的活性。在这里,我们表明 MINI ZINC FINGER2 (AtMIF2) 和其在番茄中的同源物 (),MERISTEM ACTIVITY INHIBITOR (SlIMA),通过作为衔接蛋白参与 FM 终止过程。AtMIF2 和 SlIMA 分别募集 AtKNU 和 SlKNU,与 TOPLESS 和 HISTONE DEACETYLASE19 一起形成转录抑制复合物。AtMIF2 和 SlIMA 与相应植物中的 和 位点结合,导致它们被抑制。这些结果提供了对调控 (FM) 终止的分子机制的重要见解,并强调了 AtMIF2/SlIMA 在这个发育步骤中的重要作用,该步骤决定了心皮的数量,从而决定了果实的大小。