Regulation of B Cell Development and Function by Zfp521

Zfp521 对 B 细胞发育和功能的调节

• 批准号: 8401781
• 负责人: James R. Hagman
• 金额: $ 40.73万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-03 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8401781
• 关键词: Antibodies; Antibody Formation; B-Cell Development; B-Lymphocytes; Binding; Binding Sites; Biochemical; Biochemistry; Bioinformatics; Bone Marrow; Calorimetry; Cell Lineage; Cellular biology; ChIP-seq; Chromatin; Chronic Lymphocytic Leukemia; Commit; Complex; Consensus; Crystallography; DNA; DNA Binding; Development; Epigenetic Process; Flow Cytometry; Gene Expression Profiling; Gene Rearrangement; Gene Targeting; Generations; Genes; Genetic Transcription; Genome; Glean; Hematopoietic stem cells; Immature B-Lymphocyte; Immune response; Immunoglobulin Genes; In Vitro; Knockout Mice; Laboratories; Location; Lymphopoiesis; Mature B-Lymphocyte; Measures; Modeling; Molecular; Mus; Nuclear Protein; Process; Proteins; Proto-Oncogenes; RNA analysis; Reagent; Regulation; Regulator Genes; Relative (related person); Research; Site; Structural Models; Structure; Surface Plasmon Resonance; System; Testing; Time; Titrations; Transcriptional Regulation; base; chromatin modification; design; experience; in vitro activity; in vivo; leukemia/lymphoma; mutant; novel; progenitor; programs; promoter; protein protein interaction; protein structure; transcription factor

DESCRIPTION (provided by applicant): Summary B cell development in the bone marrow proceeds in a stepwise process from multipotent hematopoietic stem cells (HSCs) to committed immature B lymphocytes. Research has elucidated a B cell-specific regulatory network of transcription factors necessary for the development of early B cells. These proteins include Early B cell Factor 1 (EBF1), which drives B lineage specification and commitment. Although much is known about EBF1, there are many unanswered questions concerning its regulation in B cells and its potential for protein- protein interactions. Several lines of evidence point to Zfp521 (Evi3/ZNF521/EHZF) as a co-regulator of gene transcription with EBF1. Zfp521 interacts physically with EBF1 and can repress its activity in vitro. Zfp521 is co- expressed with EBF1 in developing B cells. However, little is known concerning functions of Zfp521 in B cell development. Specifically, the mechanisms by which Zfp521 modulates activities of EBF1 and the basis and consequences of physical interactions between Zfp521 and EBF1 are unknown. We have demonstrated that early B cell development is perturbed greatly in the absence of Zfp521. This is evidenced by a lack of expression of markers of late pro-B cells and pre-B cells and decreased immature B cells in bone marrow of Zfp521-deficient mice. As a mechanism that integrates the activities of both Zfp521 and EBF1, recent studies in our laboratory using newly developed antibody reagents detected Zfp521 binding to promoters that also bind EBF1. Co-occupancy of Zfp521 and EBF1 on these genes suggests a new model for co-regulation of B lymphopoiesis. In this manner, EBF1, the B lineage determination factor, is regulated by Zfp521 in developing B cells. Hypotheses: Zfp521 is critically important for B cell lymphopoiesis and function. We propose that it regulates the B cell program via EBF1-dependent and -independent mechanisms. Zfp521 interacts with EBF1 to limit its DNA binding, but Zfp521 also assembles complexes with EBF1 on target gene DNA. Determining the basis of interactions between EBF1 and Zfp521 at the molecular level is critical for understanding how the B cell regulatory network generates mature B cells capable of secreting antibodies in humoral immune responses. Therefore, we will: Determine how Zfp521 regulates gene transcription in developing B cells. Determine how Zfp521 functions in the B cell regulatory network by identifying its binding sites in pro- B cells. Define structural requirements and functional consequences of Zfp521 interactions with EBF1. PUBLIC HEALTH RELEVANCE: This project focuses on the functions of a novel nuclear protein, Zfp521, in B cell development and function. ZFp521 is required for the efficient production of antibody-producing B cells. Mice lacking Zfp521 have fewer B cells relative to normal mice. In part, Zfp521 functions by regulating EBF1, the B cell lineage determination/commitment factor. Zfp521 inhibits DNA binding by EBF1, but also binds DNA together with EBF1 in the context of chromatin in B cells. Zfp521 is a proto-oncogene that, when over-expressed, generates B cell leukemias and lymphomas, but little is known concerning these mechanisms.

描述（由申请人提供）：骨髓中的摘要B细胞发育在从多能造血干细胞（HSC）到承诺的未成熟B淋巴细胞的逐步过程中进行。研究阐明了B细胞特异性的转录因子的调节网络，这是早期B细胞开发所必需的。这些蛋白质包括早期的B细胞因子1（EBF1），该因子驱动B谱系规范和承诺。尽管对EBF1知之甚少，但关于其在B细胞中调节及其蛋白质相互作用的潜力的未解决问题。几条证据指向ZFP521（EVI3/ZNF521/EHZF）作为基因转录与EBF1的共同调节剂。 ZFP521与EBF1的物理相互作用，可以在体外抑制其活性。 ZFP521与EBF1在发育中的B细胞中共同表达。但是，关于ZFP521在B细胞发育中的功能知之甚少。具体而言，ZFP521调节EBF1活动的机制以及ZFP521和EBF1之间物理相互作用的基础和后果是未知的。 我们已经证明，在没有ZFP521的情况下，早期B细胞发育受到极大的干扰。在ZFP521缺陷小鼠的骨髓中缺乏标志物的表达，降低了未成熟的B细胞，这证明了这一点。作为整合ZFP521和EBF1活性的机制，我们在实验室中使用了新开发的抗体试剂在实验室进行的研究，检测到ZFP521与启动子结合也结合EBF1的ZFP521。这些基因上ZFP521和EBF1的同时占领表明了B淋巴细胞的共同调节的新模型。以这种方式，在发育中的B细胞中，ZFP521调节了B谱系测定因子EBF1。假设：ZFP521对于B细胞淋巴管和功能至关重要。我们建议它通过EBF1依赖性和非依赖性机制来调节B细胞程序。 ZFP521与EBF1相互作用以限制其DNA结合，但是ZFP521还与靶基因DNA上的EBF1组装了复合物。在分子水平上确定EBF1和ZFP521之间的相互作用的基础对于了解B细胞调节网络如何产生能够在体液免疫反应中分泌抗体的成熟B细胞。因此，我们将：确定ZFP521如何调节发育中的B细胞中的基因转录。通过确定ZFP521在B细胞调节网络中的功能，通过识别其在ProB细胞中的结合位点的功能。定义ZFP521与EBF1相互作用的结构要求和功能后果。 公共卫生相关性：该项目着重于新型核蛋白ZFP521在B细胞发育和功能中的功能。 ZFP521是有效产生抗体产生B细胞所必需的。相对于正常小鼠，缺乏ZFP521的小鼠的B细胞较少。在某种程度上，ZFP521通过调节EBF1（B细胞谱系的确定/承诺因子）发挥作用。 ZFP521抑制EBF1的DNA结合，但在B细胞中染色质的背景下，DNA与EBF1结合。 ZFP521是一种原始癌基因，当过表达时会产生B细胞白血病和淋巴瘤，但关于这些机制知之甚少。