State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing 100871, People's Republic of China.
Sci Adv. 2022 Sep 9;8(36):eabn5057. doi: 10.1126/sciadv.abn5057.
Cytokinin plays critical roles in root development. Cytokinin signaling depends on activation of key transcription factors known as type B response regulators (ARRs). However, the mechanisms underlying the finely tuned regulation of type B ARR activity remain unclear. In this study, we demonstrate that the ERF-associated amphiphilic repression (EAR) motif-containing protein TCP interactor containing ear motif protein2 (TIE2) forms a negative feedback loop to finely tune the activity of type B ARRs during root development. Disruption of and its close homolog TIE1 causes severely shortened roots. TIE2 interacts with type B ARR1 and represses transcription of ARR1 targets. The cytokinin response is correspondingly enhanced in . We further show that ARR1 positively regulates and by directly binding to their promoters. Our findings demonstrate that TIEs play key roles in controlling plant development and reveal an important negative feedback regulation mechanism for cytokinin signaling.
细胞分裂素在根发育中发挥关键作用。细胞分裂素信号转导依赖于关键转录因子的激活，这些转录因子被称为 B 型应答调节因子（ARR）。然而，B 型 ARR 活性的精细调节机制尚不清楚。在这项研究中，我们证明了含有 EAR 基序的 ERF 相关的两亲性抑制（EAR）基序的蛋白 TCP 相互作用物含有 EAR 基序蛋白 2（TIE2）形成一个负反馈回路，以在根发育过程中精细调节 B 型 ARR 的活性。和其近源物 TIE1 的缺失会导致根严重缩短。TIE2 与 B 型 ARR1 相互作用，并抑制 ARR1 靶基因的转录。相应地，在 中细胞分裂素的反应增强。我们进一步表明，ARR1 通过直接结合其启动子正向调节 和 。我们的研究结果表明，TIEs 在控制植物发育中发挥关键作用，并揭示了细胞分裂素信号的一个重要负反馈调控机制。
