WC-1 and the Proximal GATA Sequence Mediate a Cis-/Trans-Acting Repressive Regulation of Light-Dependent Gene Transcription in the Dark
WC-1 and the Proximal GATA Sequence Mediate a Cis-/Trans-Acting Repressive Regulation of Light-Dependent Gene Transcription in the Dark
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DOI：
10.3390/ijms20122854
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发表时间：
2019-06-02
影响因子：
5.6
通讯作者：
Talora, Claudio
中科院分区：
文献类型：
--
作者：
Brenna, Andrea;Talora, Claudio
我们发现，白化病-3启动子的光响应元件（LREs）的近端GATA序列和WC-1的锌指结构域都参与了光调控基因的暗相关抑制控制机制。光影响从原核生物到哺乳动物的广泛生理过程。粗神经孢子虫是研究这一信号通路的重要模型系统。在分子水平上，由WC-1（蓝光光传感器）和WC-2（转录激活因子）形成的异源二聚体WHITE COLLAR Complex （WCC）是光依赖性基因表达的关键正调控因子。GATN （N表示任何其他核苷酸）重复序列是WCC识别的光依赖性基因启动子内的共识序列。远端GATN也被称为C-box，因为它与生物钟有关。然而，我们对近端GATN的作用知之甚少，并且在暗/光转换过程中控制光诱导基因转录的分子机制仍然不清楚。本研究首次发现，白化3基因靶启动子内近端GATA序列的突变或WC-1锌指结构域的缺失会导致光照依赖性基因在黑暗中的表达增加，从而有效地将光刺激和转录激活解耦。这是首次观察到顺式/反式抑制机制，这与迄今为止在真核世界中观察到的光依赖性调节机制不一致。
Simple Summary We observed that both the proximal GATA sequence in light-responsive elements (LREs) of the albino-3 promoter and the Zinc Finger Domain of WC-1 are involved in the dark-related repressive control mechanism of light-regulated genes.Abstract Light influences a wide range of physiological processes from prokaryotes to mammals. Neurospora crassa represents an important model system used for studying this signal pathway. At molecular levels, the WHITE COLLAR Complex (WCC), a heterodimer formed by WC-1 (the blue light photo-sensor) and WC-2 (the transcriptional activator), is the critical positive regulator of light-dependent gene expression. GATN (N indicates any other nucleotide) repeats are consensus sequences within the promoters of light-dependent genes recognized by the WCC. The distal GATN is also known as C-box since it is involved in the circadian clock. However, we know very little about the role of the proximal GATN, and the molecular mechanism that controls the transcription of light-induced genes during the dark/light transition it is still unclear. Here we showed a first indication that mutagenesis of the proximal GATA sequence within the target promoter of the albino-3 gene or deletion of the WC-1 zinc finger domain led to a rise in expression of light-dependent genes already in the dark, effectively decoupling light stimuli and transcriptional activation. This is the first observation of cis-/trans-acting repressive machinery, which is not consistent with the light-dependent regulatory mechanism observed in the eukaryotic world so far.