Mechanisms and function of alternative splicing in the plant circadian clock

植物生物钟中选择性剪接的机制和功能

• 批准号: BB/K006835/1
• 负责人: Hugh Nimmo
• 金额: $ 51.25万
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FK006835%2F1
• 关键词: Mechanisms; function; alternative; splicing; plant

Circadian rhythms are ubiquitous in nature: most organisms exhibit robust daily rhythms in biological processes, growth or behaviour. The most familiar rhythm to us is our sleep/wake cycle which is set to local time and gives rise to jet lag when time-zones are traversed. Rhythms are driven by 'circadian clocks' located in every living cell that continue to run even in the absence of external signals. These biological devices allow an organism to anticipate predictable environmental changes such as the regular day to night transitions and to adjust its behaviour accordingly. Circadian clocks comprise molecular circuits organised into feedback loops that generate the oscillatory behaviour of clock components. By linking to different molecular pathways through the cycle, the clock is able to regulate the timing of key pathways (e.g. metabolic, signalling, growth and development) through the day. Clockwork failure can have a large fitness costs to the organism; in humans it contributes to several disease states.Circadian clocks can operate over a temperature range. This is particularly important for plants that are exposed to the ever-changing environment. Chemical reaction rates are very sensitive to temperature change, yet the clock remains invariant in the face of daily temperature changes and a range of weather patterns through the seasons. Yet how this is achieved is not known. A key objective for this project is therefore to understand molecular processes that buffer the plant clock from temperature changes. This is important as maintaining clock function is essential for optimal photosynthesis, growth, and the timing of reproduction - factors that influence seed abundance (a yield output for crop plants). When genes are expressed the DNA sequence is first copied into RNA (transcription), the RNA is processed and then it directs synthesis of the corresponding protein (translation). In this project we focus on deciphering the role of post-transcriptional RNA processing (alternative splicing: AS) in temperature-dependent clock function in the model plant Arabidopsis. AS generates different transcripts from the same gene and thereby can modulate transcript and protein levels and functions. We have shown that AS is important in controlling clock gene expression. We will establish the extent of AS in clock input genes, how this is affected at low temperature and their influence expression/AS of clock genes. Plants experience continued and variable temperature changes throughout the day/night cycle - we will investigate the degree and timing of temperature change which is able to elicit a temperature-dependent AS response. Light also has a major influence on the clock and we will identify which AS events respond to light intensity changes and whether they are different from temperature-dependent events.A major question is how the different types of AS in different clock genes are regulated and how this mechanism contributes to temperature buffering of the circadian clockwork. We will use RNA sequencing to assess AS events during cooling. Co-expression and co-splicing network analysis will identify genes whose expression/splicing profiles correlate with those of the core clock and clock-associated genes to identify putative regulatory genes. We will also examine the natural genetic variation in this process and how this might aid our understanding. The role of AS in regulation of clock gene expression is highly relevant to crop plants and yield. To utilise the knowledge and approaches from our Arabidopsis research, we have started to examine AS control in potato and barley to begin the translation toward application. We anticipate that this work will provide new insights into what controls phenotypes such as earliness in barley and endodormancy in potato and ultimately lead to strategies for the generation of new genotypes that have increased robustness to temperature and other stresses that can affect plants.

昼夜节律在自然界中无处不在：大多数生物体在生物过程、生长或行为中表现出强大的每日节律。我们最熟悉的节奏是我们的睡眠/觉醒周期，它被设置为当地时间，当穿越时区时会引起时差。节奏是由位于每个活细胞中的“生物钟”驱动的，即使在没有外部信号的情况下，生物钟也会继续运行。这些生物装置使生物体能够预测可预测的环境变化，例如有规律的昼夜转换，并相应地调整其行为。生物钟包括组织成反馈回路的分子电路，该反馈回路产生时钟组件的振荡行为。通过与周期中不同的分子途径相联系，生物钟能够调节一天中关键途径（例如代谢，信号传导，生长和发育）的时间。生物钟的失灵会给生物体带来巨大的健康损失;在人类中，它会导致几种疾病状态。这对于暴露在不断变化的环境中的植物尤其重要。化学反应速率对温度变化非常敏感，但时钟在面对每日温度变化和一系列季节性天气模式时保持不变。然而，这是如何实现的尚不清楚。因此，该项目的一个关键目标是了解缓冲植物时钟免受温度变化影响的分子过程。这一点很重要，因为维持生物钟功能对于最佳光合作用、生长和繁殖时间至关重要--这些因素影响种子丰度（作物的产量）。当基因表达时，DNA序列首先被复制成RNA（转录），RNA被加工，然后它指导相应蛋白质的合成（翻译）。在这个项目中，我们专注于破译转录后RNA加工（选择性剪接：AS）在模式植物拟南芥中的温度依赖性时钟功能中的作用。AS从同一基因产生不同的转录本，从而可以调节转录本和蛋白质水平和功能。我们已经证明AS在控制时钟基因表达中是重要的。我们将建立时钟输入基因中AS的程度，这在低温下是如何受到影响的，以及它们对时钟基因表达/AS的影响。植物经历持续和可变的温度变化，在整个白天/黑夜周期-我们将调查的程度和时间的温度变化，这是能够引起温度依赖性AS响应。光对生物钟也有重要的影响，我们将确定哪些AS事件响应于光强度变化，以及它们是否与温度依赖性事件不同。一个主要的问题是不同生物钟基因中不同类型的AS是如何调节的，以及这种机制如何有助于生物钟的温度缓冲。我们将使用RNA测序来评估冷却期间的AS事件。共表达和共剪接网络分析将鉴定其表达/剪接谱与核心时钟和时钟相关基因的表达/剪接谱相关的基因，以鉴定推定的调控基因。我们还将研究这个过程中的自然遗传变异，以及这如何有助于我们的理解。AS在时钟基因表达调控中的作用与作物植株和产量高度相关。为了利用我们拟南芥研究的知识和方法，我们已经开始研究马铃薯和大麦中的AS控制，以开始向应用的转化。我们预计，这项工作将提供新的见解，什么控制表型，如大麦早熟和马铃薯内休眠，并最终导致战略的新基因型的产生，增加了对温度和其他压力，可以影响植物的鲁棒性。

项目成果

Global spatial analysis of Arabidopsis natural variants implicates 5'UTR splicing of LATE ELONGATED HYPOCOTYL in responses to temperature.

• DOI: 10.1111/pce.13188
• 发表时间: 2018-07
• 期刊: Plant, cell & environment
• 作者: James AB;Sullivan S;Nimmo HG
• 通讯作者: Nimmo HG

Arabidopsis thaliana PRR7 Provides Circadian Input to the CCA1 Promoter in Shoots but not Roots.

• DOI: 10.3389/fpls.2021.750367
• 发表时间: 2021
• 期刊: Frontiers in plant science
• 影响因子: 5.6
• 作者: Nimmo HG;Laird J
• 通讯作者: Laird J

Rapid and dynamic alternative splicing impacts the Arabidopsis cold response transcriptome

快速动态的选择性剪接影响拟南芥冷反应转录组

• DOI: 10.1101/251876
• 发表时间: 2018
• 作者: Calixto C

How does temperature affect splicing events? Isoform switching of splicing factors regulates splicing of LATE ELONGATED HYPOCOTYL (LHY).

• DOI: 10.1111/pce.13193
• 发表时间: 2018-07
• 期刊: Plant, cell & environment
• 作者: James AB;Calixto CPG;Tzioutziou NA;Guo W;Zhang R;Simpson CG;Jiang W;Nimmo GA;Brown JWS;Nimmo HG
• 通讯作者: Nimmo HG

AtRTD2: A Reference Transcript Dataset for accurate quantification of alternative splicing and expression changes in Arabidopsis thaliana RNA-seq data

• DOI: 10.1101/051938
• 发表时间: 2016-05
• 期刊: bioRxiv
• 作者: Runxuan Zhang;C. Calixto;Yamile Marquez;Peter Venhuizen;Nikoleta A Tzioutziou;Wenbin Guo;Mark A. Spensley;Nicolas Frei dit Frey;H. Hirt;A. James;H. G. Nimmo;A. Barta;M. Kalyna;John W. S. Brown