Gene Expression Variability and Nuclear Territory Autonomy in Syncytia

合胞体的基因表达变异性和核域自主性

• 批准号: 10889832
• 负责人: Ameya Pranav Jalihal
• 金额: $ 2.9万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10889832
• 关键词: Gene; Expression; Variability; Nuclear; Territory

Title Gene expression variability and nuclear territory autonomy in syncytia Project Summary Syncytia are large, multinucleate cells that are found widely across biology. Algae, fungi, protists, and human tissues like muscle and placenta are all composed of syncytia. Such organization has even been proposed to be the ancestral eukaryotic state. Despite its prevalence across kingdoms of life, the organization and regulation of syncytial cells remain understudied. How do multiple nuclei shape the composition and function in syncytia? Syncytial algal and mammalian muscle cells show distinct gradients of local composition. Nuclei sharing the same cytoplasm in these cells show distinct transcriptional profiles. Work in the Gladfelter lab showed that in the syncytial fungus Ashbya gossypii, nuclei show asynchronous nuclear division, suggesting that cell-cycle signals are not shared in neighboring nuclei in these cells. Overall, these pieces of evidence suggest that the cytosolic composition in syncytial cells is highly heterogeneous despite lacking physical barriers to diffusion across the cell, and that syncytial nuclei can show autonomy in gene expression. It is unknown how the composition of nuclear-proximal cytosolic territories is regulated in syncytia, and how this impacts nuclear territory function. Extensive work in the Gladfelter lab has revealed that spatial clustering and non-random localization of transcripts underlies nuclear-autonomous division in Ashbya. Such non-random localization is mediated by the formation of RNA-protein condensates consisting of Whi3 protein. Whi3 condensates also modulate proper branching morphology in Ashbya by clustering transcripts involved in polar growth at hyphal tips. How Whi3 localization modulates translation from these transcripts in unknown. In general, it is unknown how nuclear territory composition and function are regulated by local variation in transcription and translation. In this proposal I will examine how local composition is influenced by spatial variability in transcription and translation in the genetically tractable model syncytial fungus Ashbya. In Aim 1 I will investigate sources of transcription variation between nuclei and the consequences of such variation on local territory function. By modulating transcription locally, I expect to establish the role of nuclear autonomous transcription in controlling variation in local biochemical function. In Aim 2 I will investigate the role of Whi3 condensation on spatial biases in translation. I will use manipulate Whi3 condensation locally to study the impact of condensates on local translation. In Aim 3 I will investigate which biochemical processes are globally coordinated versus those that are locally responsive across syncytial nuclei. This will reveal nuclear populations that show active or repressed transcription, and biochemical processes that are locally regulated. Upon the completion of this work, I expect to dissect the contribution of variation in transcription and regulated local translation in shaping the functionality of nucleus-associated cytosolic territories in Ashbya. The rationale for the proposed work is that it will provide insight into how local autonomy of nuclear territories can shape the biology of large multinucleate cells. Overall, this work will provide insights into organization and regulation of a widespread yet poorly understood cell-type.

合胞体中基因表达的变异性与核区域自主性 项目摘要 合胞体是广泛存在于生物学中的大型多核细胞。藻类、真菌、原生动物和人类 肌肉和胎盘等组织都是由合胞体组成的。这种组织甚至被提议用来 是祖传下来的真核国家。尽管它在生命王国中普遍存在，但它的组织和监管 对合体细胞的研究还不够深入。在合胞体中，多个核是如何决定其组成和功能的？ 合胞藻类和哺乳动物肌肉细胞显示出不同的局部成分梯度。共享的原子核 这些细胞中相同的细胞质表现出不同的转录特征。格拉菲特实验室的研究表明，在 合胞真菌Ashbya Cotsypii，细胞核显示出不同步的核分裂，表明细胞周期信号 并不存在于这些细胞的邻近细胞核中。总体而言，这些证据表明，细胞质 合体细胞中的成分是高度异质性的，尽管缺乏扩散的物理障碍 合体细胞核在基因表达上表现出自主性。尚不清楚它的组成是如何 合胞体中的核-近端胞质区域受到调控，以及这如何影响核区域的功能。 格拉菲特实验室的广泛研究表明，空间聚集和非随机局部化 文字记录是阿什比亚核自治部门的基础。这种非随机本地化是由 形成由Whi3蛋白组成的RNA-蛋白质凝聚体。Whi3凝析油也能适当地调节 通过在菌丝顶端聚集与极地生长有关的转录本，阿什比亚的分枝形态。How Whi3 本地化调整了这些未知转录本的翻译。总的来说，目前还不清楚核技术是如何 区域的组成和功能受转录和翻译的局部变异调节。 在这项建议中，我将研究局部成分如何受到转录和空间变异的影响 在遗传易驯化的合胞真菌模型Ashbya中的翻译。在目标1中，我将调查以下来源 细胞核之间的转录变异以及这种变异对局部功能的影响。通过 在局部调节转录，我希望确定核自主转录在控制中的作用 局部生化功能的变异。在目标2中，我将研究Whi3凝聚对空间偏向的作用 翻译过来。我将使用局部操纵Whi3凝结来研究凝析油对局部的影响 翻译。在目标3中，我将调查哪些生化过程是全球协调的，哪些是 是跨合体核团的局部反应。这将揭示显示活跃或受抑制的核群体 转录和生化过程是当地调节的。在这项工作完成后，我预计将 剖析转录和调节局部翻译中的变异在塑造细胞功能中的作用 阿什比亚的核相关胞质领土。拟议工作的理由是它将提供 洞察核领土的地方自治如何塑造大型多核细胞的生物学。总的来说， 这项工作将提供对一种广泛但知之甚少的细胞类型的组织和调控的见解。