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.

标题 合胞体中的基因表达变异性和核区域自主性 项目概要 合胞体是在生物学中广泛存在的大型多核细胞。藻类、真菌、原生生物和人类 肌肉和胎盘等组织都是由合胞体组成的。甚至有人提议建立这样的组织 是真核生物的祖先状态。尽管它在生命王国中普遍存在，但组织和监管 合体细胞的作用仍有待研究。多核如何塑造合胞体的组成和功能？ 合胞藻和哺乳动物肌肉细胞显示出不同的局部组成梯度。核共享 这些细胞中相同的细胞质显示出不同的转录谱。 Gladfelter 实验室的工作表明，在 合胞真菌 Ashbya gossypii，细胞核显示异步核分裂，表明细胞周期信号 这些细胞中的相邻细胞核不共享。总的来说，这些证据表明细胞质 尽管缺乏跨细胞扩散的物理障碍，但合胞体细胞的组成具有高度异质性 细胞，并且合胞核可以显示基因表达的自主性。其组成如何尚不清楚 近核胞质区域在合胞体中受到调节，以及这如何影响核区域功能。 Gladfelter 实验室的大量工作表明，空间聚类和非随机定位 转录本是阿什比亚核自治分裂的基础。这种非随机定位是由 形成由 Whi3 蛋白组成的 RNA 蛋白缩合物。 Whi3 缩合物也能适当调节 通过在菌丝尖端聚集参与极性生长的转录本来研究阿什比亚中的分支形态。怎么样Wh3 本地化调节这些未知转录本的翻译。一般来说，尚不清楚核能如何 区域的组成和功能受到转录和翻译的局部变异的调节。 在这个提案中，我将研究转录和空间变异如何影响局部组成。 在遗传易处理模型合胞真菌 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区域功能的影响。经过 局部调节转录，我希望建立核自主转录在控制中的作用 局部生化功能的变化。在目标 2 中，我将研究 Whi3 凝聚对空间偏差的作用 在翻译中。我将在局部使用操纵Whi3凝结来研究凝结对局部的影响 翻译。在目标 3 中，我将研究哪些生化过程是全局协调的，哪些是全局协调的 跨合胞核有局部反应。这将揭示表现出活跃或抑制的核群体 转录和局部调节的生化过程。完成这项工作后，我期望 剖析转录变异和调节局部翻译在塑造转录功能中的贡献 阿什比亚（Ashbya）中与细胞核相关的胞质区域。拟议工作的理由是它将提供 深入了解核区域的局部自主性如何塑造大型多核细胞的生物学。全面的， 这项工作将为了解广泛但知之甚少的细胞类型的组织和调节提供见解。