Mechanisms restraining the accumulation of antibody secreting cells

B淋巴细胞是唯一一种能够发育成抗体分泌细胞（ASC）的免疫细胞类型，这种细胞类型通常被称为浆细胞。定义调节ASC发育、寿命和调节ASC分泌抗体数量的基因和细胞过程是基本问题，其答案可能与体内许多其他动态细胞系统相关。这些知识的实际应用与疫苗的开发、自身免疫/过敏疾病的干预、ASC数量异常增加对健康衰老的影响以及哺乳动物细胞合成生物疗法的生产直接相关。B淋巴细胞的激活和ASC的发展途径是由基因转录的动态变化以及mRNA定位、翻译和稳定性的转录后调控所支撑的。这些因素共同决定了蛋白质的产生地点、时间和数量。ASC功能和存活的翻译控制机制是一个成熟的领域，需要在新兴和重要的前沿生物科学领域进一步发现：这些包括将应激反应与细胞分化的分子生物学联系起来；避免蛋白质毒性；以及细胞寿命的决定因素。这些知识可能与几乎所有的生物系统和在生物技术或医学环境中的实际应用有关。该项目建立在一个新的基因筛选RNA结合蛋白（RBP），调节ASC的发展和生存。筛选发现了ASC积累所需的基因，以及删除后导致ASC形成和存活增加的基因。该筛选结果已发表在预印本服务器上，该资助提案旨在了解两种多蛋白复合物[CCR4NOT和EIF3]中模块的体内免疫学、细胞生物学和分子机制，这两种复合物已知是转录、RNA衰变和翻译的基础。这些模块是否限制ASC的发展或存活，或者它们是否在体内同时影响两者？在ASC中，CCR4NOT和EIF3模块是否在物理和功能上相互耦合以形成连接转录mRNA稳定性和翻译的连续体？它们是否调节稳态应激反应，如内质网和氧化应激，这是ASC分泌输出的基础？它们是否介导了一种将蛋白质停滞与营养感知和氧化感知途径联系起来的机制？这些模块成分是由只在高等真核生物中发现的基因编码的，因此可能对多细胞生物的独特生物学很重要。我们建议使用定量评估ASC形成和体内功能的方法来研究这些基因，因为这是一种强大的生理选择系统。我们建议将其与细胞生物学的体外研究结合起来，通过综合数据驱动的转录组学方法，考虑到mRNA的丰度和周转及其翻译效率。此外，我们将确定由限制ASC功能的基因编码的蛋白质所在的多蛋白复合物的组成和位置。这种方法的结合可以为控制基因表达的不同过程如何耦合以调节细胞功能和稳态提供机制见解。

The B lymphocyte is the only immune cell type capable of development into the antibody secreting cell (ASC) a cell type commonly referred to as the plasma cell. Defining the genes and cellular processes that regulate ASC development, lifespan and what regulates the amount of antibody secreted by an ASC are fundamental questions -with answers that are likely to be relevant to many other dynamic cell systems in the body. The practical application of this knowledge is of direct relevance to the development of vaccines, interventions for autoimmune/allergic conditions, the impact on healthy ageing of abnormally increased numbers of ASC and the production of synthetic biological therapeutics by mammalian cells. B lymphocyte activation and the pathway of ASC development is underpinned by dynamic changes in gene transcription coupled to post-transcriptional regulation of mRNA localisation, translation and stability. These act together to determine, where, when and in what amounts proteins are produced. The mechanisms of translational control of ASC function and survival is an area ripe for further discoveries in the emerging and important areas of frontier bioscience: these include linking the molecular biology of stress responses to cell differentiation; the avoidance of proteotoxicity; and the determinants of cellular longevity. Knowledge of these may have relevance to almost all biological systems and practical application in biotechnology or medical contexts.This project builds on a new genetic screen for RNA binding proteins (RBP) that regulate the development and survival of ASC. The screen identified genes that were required for the accumulation of ASC and also genes which, when deleted, led to increased ASC formation and survival. The findings of this screen have been published on a preprint server, and this grant proposal is seeking to understand the in vivo immunology, the cell biology and molecular mechanism of modules within two multiprotein complexes [CCR4NOT and EIF3] known to be fundamental for transcription, RNA decay and translation.Do these modules limit ASC development or survival, or do they affect both in vivo? Are the CCR4NOT and EIF3 modules coupled physically and functionally to each other in ASC to form a continuum that connects transcription mRNA stability and translation? Are they regulating homeostatic stress responses such as ER and oxidative stress that is fundamental for the secretory output of ASC? Do they mediate a mechanism to interlink proteostasis with nutrient sensing and oxidative sensing pathways? The module components are encoded by genes only found in higher eukaryotes and thus likely to be important for the unique biology of multicellularity.We propose to study these genes using methods that evaluate quantitatively ASC formation and function in vivo as this is the powerful physiological system of choice. We propose to combine this with in vitro studies of cell biology informed by integrative data-driven transcriptomics methods that take into account the abundance and turnover of mRNA and its translation efficiency. Furthermore, we will determine the composition and location of the multiprotein complexes in which the protein encoded by the genes that limit ASC function reside. This combination of approaches can provide mechanistic insight into how the different processes which control gene expression are coupled to regulate cell function and homeostasis.