Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany.
Institute of Biochemistry, University of Cologne, Cologne, Germany.
Nat Plants. 2022 Sep;8(9):1082-1093. doi: 10.1038/s41477-022-01213-y. Epub 2022 Aug 15.
How specificity is conferred within gene regulatory networks is an important problem in biology. The basic helix-loop-helix PHYTOCHROME-INTERACTING FACTORs (PIFs) and single zinc-finger CYCLING DOF FACTORs (CDFs) mediate growth responses of Arabidopsis to light and temperature. We show that these two classes of transcription factor (TF) act cooperatively. CDF2 and PIF4 are temporally and spatially co-expressed, they interact to form a protein complex and act in the same genetic pathway to promote hypocotyl cell elongation. Furthermore, PIF4 substantially strengthens genome-wide occupancy of CDF2 at a subset of its target genes. One of these, YUCCA8, encodes an auxin biosynthesis enzyme whose transcription is increased by PIF4 and CDF2 to contribute to hypocotyl elongation. The binding sites of PIF4 and CDF2 in YUCCA8 are closely spaced, and in vitro PIF4 enhances binding of CDF2. We propose that this occurs by direct protein interaction and because PIF4 binding alters DNA conformation. Thus, we define mechanisms by which PIF and CDF TFs cooperate to achieve regulatory specificity and promote cell elongation in response to light.
基因调控网络中特异性是如何赋予的，是生物学中的一个重要问题。基本螺旋-环-螺旋 PHYTOCHROME-INTERACTING FACTORS（PIFs）和单锌指 CYCLING DOF FACTORS（CDFs）介导拟南芥对光和温度的生长反应。我们表明，这两类转录因子（TF）协同作用。CDF2 和 PIF4 在时间和空间上共表达，它们相互作用形成蛋白质复合物，并在相同的遗传途径中发挥作用，促进下胚轴细胞伸长。此外，PIF4 大大增强了 CDF2 在其部分靶基因上的全基因组占据。其中一个是编码生长素生物合成酶的 YUCCA8，其转录被 PIF4 和 CDF2 增加，有助于下胚轴伸长。PIF4 和 CDF2 在 YUCCA8 中的结合位点紧密间隔，体外 PIF4 增强了 CDF2 的结合。我们提出，这是通过直接的蛋白质相互作用发生的，因为 PIF4 结合改变了 DNA 构象。因此，我们定义了 PIF 和 CDF TF 协同作用以实现调节特异性并响应光促进细胞伸长的机制。
