Molecular Analyses of the individual function of the transcriptional Co-Activator BOB.1/OBF.1 in B versus T lymphocytes and its specific contribution to the Germinal Center Reaction

B 淋巴细胞与 T 淋巴细胞中转录共激活因子 BOB.1/OBF.1 个体功能的分子分析及其对生发中心反应的具体贡献

• 批准号: 397031396
• 负责人: Professorin Dr. Cornelia Brunner
• 金额: --
• 依托单位: Forschungsbereich Onkologie / Tumorimmunologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/397031396?language=en
• 关键词: Molecular; Analyses; individual; function; transcriptional

BOB.1/OBF.1 was originally described as a B cell specific transcriptional co-activator. BOB.1/OBF.1 itself has only very weak affinity to DNA but is recruited by the transcription factors Oct1 and Oct2 to the so called Octamer motif and thereby enhances Octamer-dependent transcription. BOB.1/OBF.1-deficient mice show severe defects at different stages of B cell development, but also in certain T cell populations, like TH1, TH2 or follicular T-helper cells (TFH). The main characteristic of BOB.1/OBF.1-deficient mice is the complete absence of germinal centers and consequently also of germinal center derived B cells, like plasma and memory B cells. However, the question is not fully understood, whether the lack of germinal centers is caused exclusively by the BOB.1/OBF.1 deficiency in B cells or if in addition an inefficient T cell help, provided particularly by TFH, also contributes to this severe phenotype. Because of the lack of appropriate tools to regulate BOB.1/OBF.1 expression in these terminal cell differentiation stages so far we were not able to define the exact impact of BOB.1/OBF.1 to the germinal center reaction by precise molecular analyses. Furthermore, there were only limited options to study BOB.1/OBF.1 deficiency in T cells in the presence of wildtype B cells and vice versa.We have now generated mice bearing floxed BOB.1/OBF.1 alleles. Such a mouse system allows the conditional deletion of BOB.1/OBF.1 expression and therefore the precise analyses of B- as well as T-cell differentiation and function in the absence of the transcriptional co-activator. Using our conditional system together with appropriate Cre expressing mouse lines we are now able to analyze the specific need of BOB.1/OBF.1 expression in early and also in late stages of B-cell development as well as the requirement of BOB.1/OBF.1 for the function of specific T cell subpopulations. A main focus of our project is the identification and further characterization of BOB.1/OBF.1 target genes in order to understand the influence of BOB.1/OBF.1 on B-cell development and function under physiological conditions. Moreover, these analyses allow us to understand how BOB.1/OBF.1 affects germinal center reaction if it is exclusively deleted in defined B and T cell subpopulations. Additionally, due to our newly generated system we are now able to characterize the individual relevance of BOB.1/OBF.1 under immune-pathological conditions and thus to further elucidate the role of BOB.1/OBF.1 in autoimmune processes. Therefore, the aim of the here proposed study is the identification of molecular mechanisms in which the transcriptional co-activator BOB.1/OBF.1 is involved during B and T cell development and differentiation as well as new functions of BOB.1/OBF.1 in those processes under physiological and also immune-pathological conditions.

BOB.1/OBF.1最初被描述为B细胞特异性转录共激活因子。BOB.1/OBF.1本身对DNA只有很弱的亲和力，但被转录因子Oct 1和Oct 2募集到所谓的八聚体基序，从而增强八聚体依赖性转录。BOB.1/OBF.1缺陷小鼠在B细胞发育的不同阶段显示出严重缺陷，但在某些T细胞群中也显示出严重缺陷，如TH 1、TH 2或滤泡T辅助细胞（TFH）。BOB.1/OBF.1缺陷型小鼠的主要特征是完全不存在生发中心，因此也完全不存在生发中心衍生的B细胞，如血浆和记忆B细胞。然而，这个问题还没有完全弄清楚，是否缺乏生发中心完全是由B细胞中的BOB.1/OBF. 1缺陷引起的，或者是否另外一个无效的T细胞帮助，特别是由TFH提供的，也有助于这种严重的表型。由于缺乏适当的工具来调节BOB.1/OBF. 1在这些终末细胞分化阶段的表达，到目前为止，我们无法通过精确的分子分析来确定BOB.1/OBF. 1对生发中心反应的确切影响。此外，在野生型B细胞存在的情况下研究T细胞中BOB.1/OBF. 1缺陷的选择有限，反之亦然。这样的小鼠系统允许BOB.1/OBF. 1表达的条件性缺失，并因此允许在不存在转录共激活因子的情况下精确分析B细胞以及T细胞的分化和功能。使用我们的条件系统与适当的Cre表达小鼠系，我们现在能够分析在B细胞发育的早期和晚期阶段中BOB.1/OBF.1表达的特定需求以及BOB.1/OBF.1对特定T细胞亚群功能的需求。我们项目的主要重点是鉴定和进一步表征BOB.1/OBF.1靶基因，以了解生理条件下BOB.1/OBF.1对B细胞发育和功能的影响。此外，这些分析使我们能够理解如果BOB.1/OBF. 1在限定的B和T细胞亚群中被专门删除，那么它如何影响生发中心反应。此外，由于我们新生成的系统，我们现在能够在免疫病理条件下表征BOB.1/OBF.1的个体相关性，从而进一步阐明BOB.1/OBF.1在自身免疫过程中的作用。因此，本文提出的研究的目的是鉴定在B和T细胞发育和分化过程中转录共激活因子BOB.1/OBF. 1参与的分子机制，以及BOB.1/OBF. 1在生理和免疫病理条件下在这些过程中的新功能。