Function of Photobodies in Plant Light Signaling

摘要 细胞核是如何在功能上和动态地组织起来的，这是理解细胞核基本结构的一个核心问题。 包括基因组组织和转录调控的细胞过程。两种动物的间期 植物细胞核含有形态上不同的、非膜结合的亚核细胞器， 统称为核体。尽管越来越多的证据表明， 在基因调控和核体形态和组成变化中的作用， 与疾病相关的核体生物合成的精确功能和调节机制， 转录调控仍然知之甚少。一个主要的挑战是缺乏遗传模型 描述核小体在细胞信号传导的转录调控中的功能 途径。PI实验室的长期目标是利用光体--一种含有光感受器的， 光感受亚核结构域和光信号在拟南芥作为一个遗传模型，以阐明 核小体在细胞信号传导和转录调节中的功能。目前的数据支持中央 假设光体是基因调控中心，其中光响应基因的子集由 一种将基因激活与转录因子降解相结合的反式激活机制。这 这一假设是根据PI先前对两种新的光的分子遗传学研究制定的。 光体生物发生所需的信号组分，命名为HEMERA和爱马仕， 初步结果表明，一个子集的光响应基因的空间定位到光体。这里 PI计划通过以下具体目标来检验这一中心假设：（1）确定光体- 相关和HEMERA介导的转录激活机制;（2）确定爱马仕的作用 在光体的功能和生物起源;（3）确定基因组组织的机制， 光体这项研究是创新的，因为它利用了光体和感光体 信号作为遗传模型来研究神秘的核组织机制- 核小体在基因组组织和转录调控中的功能和生物起源。的 拟议的研究是重要的，因为它有望揭示新的机制，连接核体 生物起源和转录调控的特定机制。因为基因的基本机制 调节在植物，真菌和动物中是保守的，更好地了解光体在植物中的功能， 拟南芥将有助于理解基因组组织的进化保守原则 和转录调控，从而最终将加强我们对它们在转录过程中的误调节的理解。 人类疾病。

Abstract How the cell nucleus is functionally and dynamically organized is a central question to understanding basic cellular processes including genome organization and transcriptional regulation. The interphase of both animal and plant nuclei contain morphologically distinct, non-membrane-bounded subnuclear organelles that are collectively called nuclear bodies. Although accumulating evidence suggests that nuclear bodies play important roles in gene regulation and changes in the morphology and constitution of nuclear bodies have been associated with diseases, the precise function and regulatory mechanisms of nuclear body biogenesis in transcriptional regulation remain poorly understood. One major challenge has been the lack of genetic models to delineate the functions of nuclear bodies in the context of transcriptional regulation by cell signaling pathways. The long-term goal of the PI's laboratory is to utilize the photobody – a photoreceptor-containing, photosensory subnuclear domain – and light signaling in Arabidopsis as a genetic model to elucidate the function of nuclear bodies in cell signaling and transcriptional regulation. The current data support the central hypothesis that photobodies are gene regulatory hubs where a subset of light responsive genes is regulated by a transactivation mechanism that couples gene activation with the degradation of transcription factors. This hypothesis has been formulated on the basis of the PI's previous molecular genetic studies on two novel light signaling components required for photobody biogenesis, named HEMERA and HERMES, and on the preliminary result showing that a subset of light-responsive genes are spatially positioned to photobodies. Here the PI plans to test this central hypothesis by the following specific aims: (1) Determine the photobody- associated and HEMERA-mediated transcriptional activation mechanism; (2) Determine the role of HERMES in the function and biogenesis of photobodies; (3) Determine the mechanism of genome organization by photobodies. The proposed research is innovative, because it utilizes the photobody and photoreceptor signaling in Arabidopsis as a genetic model to investigate the enigmatic mechanisms of nuclear organization – the function and biogenesis of nuclear bodies in genome organization and transcriptional regulation. The proposed research is significant, because it is expected to uncover novel mechanisms linking nuclear body biogenesis and specific mechanisms of transcriptional regulation. Because basic mechanisms of gene regulation are conserved in plants, fungi, and animals, a better understanding of the function of photobodies in Arabidopsis will contribute to understanding of the evolutionarily conserved principles of genome organization and transcriptional regulation and thus will ultimately enhance our understanding of their misregulation in human diseases.