Epigenetic and Posttranslational Modifications in Light Signal Transduction and the Circadian Clock in Neurospora crassa.
Epigenetic and Posttranslational Modifications in Light Signal Transduction and the Circadian Clock in Neurospora crassa.
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DOI：
10.3390/ijms160715347
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发表时间：
2015-07-07
影响因子：
5.6
通讯作者：
Brenna A
中科院分区：
文献类型：
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作者：
Proietto M;Bianchi MM;Ballario P;Brenna A
蓝光是一种关键的非生物信号，在许多生物体中调节着各种各样的生理过程。其中一种现象是生物体内的昼夜节律，这种节律对蓝光的相位设置效应敏感，并受昼夜交替的光和暗的控制。生物钟由与细胞代谢和生化过程密切相关的自我调节的负反馈和正反馈循环组成。粗神经孢子虫为研究这些现象的分子机制提供了一个很好的模型。White Collar Complex （WCC）是一种蓝光受体和昼夜节律振荡器的转录因子，而Frequency （FRQ）是昼夜节律时钟起搏器，它们是神经孢子虫昼夜节律系统的核心。真核生物的生物钟依赖于转录/翻译反馈循环：一些蛋白质通过抑制其转录因子的活性来有节奏地抑制其自身的合成，在大约24小时的时间内产生自我持续的振荡。使自我持续振荡永久存在的基本机制之一是翻译后修饰（PTM）。缩写词PTM一般表示在各种类型的蛋白质上添加乙酰基、甲基、苏木基或磷酸基团。这种蛋白质可以是调节的或酶促的，也可以是染色质的组成部分。PTMs影响蛋白质稳定性、相互作用、定位、活性和染色质包装。染色质修饰和ptm与神经孢子虫生物钟功能的调节有关。对转录因子（如WCC）的表观遗传控制的研究为光依赖性基因转录的时间调节提供了新的见解。在这里，我们报道了表观遗传和蛋白PTMs在粗神经孢子虫生物钟调控中的作用。我们还提出了一个模型，说明了在蓝光控制生物钟的基础上的分子机制。
Blue light, a key abiotic signal, regulates a wide variety of physiological processes in many organisms. One of these phenomena is the circadian rhythm presents in organisms sensitive to the phase-setting effects of blue light and under control of the daily alternation of light and dark. Circadian clocks consist of autoregulatory alternating negative and positive feedback loops intimately connected with the cellular metabolism and biochemical processes. Neurospora crassa provides an excellent model for studying the molecular mechanisms involved in these phenomena. The White Collar Complex (WCC), a blue-light receptor and transcription factor of the circadian oscillator, and Frequency (FRQ), the circadian clock pacemaker, are at the core of the Neurospora circadian system. The eukaryotic circadian clock relies on transcriptional/translational feedback loops: some proteins rhythmically repress their own synthesis by inhibiting the activity of their transcriptional factors, generating self-sustained oscillations over a period of about 24 h. One of the basic mechanisms that perpetuate self-sustained oscillations is post translation modification (PTM). The acronym PTM generically indicates the addition of acetyl, methyl, sumoyl, or phosphoric groups to various types of proteins. The protein can be regulatory or enzymatic or a component of the chromatin. PTMs influence protein stability, interaction, localization, activity, and chromatin packaging. Chromatin modification and PTMs have been implicated in regulating circadian clock function in Neurospora. Research into the epigenetic control of transcription factors such as WCC has yielded new insights into the temporal modulation of light-dependent gene transcription. Here we report on epigenetic and protein PTMs in the regulation of the Neurospora crassa circadian clock. We also present a model that illustrates the molecular mechanisms at the basis of the blue light control of the circadian clock.