Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8602 Japan.
Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa, Nagoya, 464-8602 Japan.
Plant Cell Physiol. 2023 Dec 6;64(11):1397-1406. doi: 10.1093/pcp/pcad107.
Circadian clocks are biological timekeeping systems that coordinate genetic, metabolic and physiological behaviors with the external day-night cycle. The clock in plants relies on the transcriptional-translational feedback loops transcription-translation feedback loop (TTFL), consisting of transcription factors including PSUEDO-RESPONSE REGULATOR (PRR) proteins, plant lineage-specific transcriptional repressors. Here, we report that a novel synthetic small-molecule modulator, 5-(3,4-dichlorophenyl)-1-phenyl-1,7-dihydro-4H-pyrazolo[3,4-d] pyrimidine-4,6(5H)-dione (TU-892), affects the PRR7 protein amount. A clock reporter line of Arabidopsis was screened against the 10,000 small molecules in the Maybridge Hitfinder 10K chemical library. This screening identified TU-892 as a period-lengthening molecule. Gene expression analyses showed that TU-892 treatment upregulates CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1) mRNA expression. TU-892 treatment reduced the amount of PRR7 protein, a transcriptional repressor of CCA1. Other PRR proteins including TIMING OF CAB EXPRESSION 1 were altered less by TU-892 treatment. TU-892-dependent CCA1 upregulation was attenuated in mutants impaired in PRR7. Collectively, TU-892 is a novel type of clock modulator that reduces the levels of PRR7 protein.
生物钟是一种生物计时系统，它使基因、代谢和生理行为与外部的昼夜周期协调一致。植物中的时钟依赖于转录-翻译反馈环（TTFL），包括转录因子，如 PSUEDO-RESPONSE REGULATOR（PRR）蛋白，植物谱系特异性转录抑制剂。在这里，我们报告了一种新型的合成小分子调节剂，5-(3,4-二氯苯基)-1-苯基-1,7-二氢-4H-吡唑并[3,4-d]嘧啶-4,6(5H)-二酮（TU-892），影响 PRR7 蛋白的含量。我们对拟南芥的时钟报告系进行了筛选，以对抗 Maybridge Hitfinder 10K 化学文库中的 10000 种小分子。该筛选确定 TU-892 是一种延长周期的分子。基因表达分析表明，TU-892 处理上调 CIRCADIAN CLOCK-ASSOCIATED 1（CCA1）mRNA 的表达。TU-892 处理降低了 CCA1 的转录抑制剂 PRR7 蛋白的含量。其他 PRR 蛋白，如 TIMING OF CAB EXPRESSION 1，受 TU-892 处理的影响较小。PRR7 受损突变体中，TU-892 依赖的 CCA1 上调被减弱。总的来说，TU-892 是一种新型的时钟调节剂，可降低 PRR7 蛋白的水平。
