B Lymphocyte Induced Maturation Protein

描述（由申请方提供）：B淋巴细胞诱导成熟蛋白-1（Blimp-1）是一种转录抑制因子，具有能够将B细胞驱动为分泌免疫球蛋白、非分裂、终末分化浆细胞表型的独特性质。在研究这种蛋白质的过程中，我们的长期目标是：1）了解Blimp-1在终末B细胞分化过程中的功能，2）使用Blimp-1作为切入点，以更好地了解负责决定生发后中心B细胞命运的调控机制，3）确定参与终末分化的通用机制。在当前的资助期内，我们在阐明Blimp-1的结构、调节和作用机制的基本方面以及在鉴定B细胞中由Blimp-1调节的基因表达程序方面取得了良好的进展。我们还创造了基因靶向小鼠，这些小鼠将产生在成熟B细胞中缺乏Blimp-1的动物。我们计划通过开展由4个具体目标组成的深入研究来利用这一进展。1)将使用在其B细胞中缺乏Blimp-1的小鼠来确定是否/何时需要Blimp-1来定型为浆细胞命运。将对B细胞发育和功能进行全面分析，并检测Blimp-1突变体或其他转录因子（如XBP-1）补充Blimp-1-/-表型的能力。衰老的小鼠将揭示Blimp-1是否在B细胞中具有肿瘤抑制活性。2)将使用其中生发中心B细胞发育成记忆细胞或浆细胞的短期培养系统来了解Blimp-1和其他转录调节因子何时/如何被诱导并在这些交替命运的定型期间起作用。我们将识别引导它们表达的信号。3)已建立的方法将用于确定来自IL-6、IL-10和TNF/TNFR的信号是否/如何激活Blimp-1转录。4)Blimp-1的基因抑制机制可能是不寻常的。我们将研究Blimp-1抑制的靶基因中的DNA和组蛋白是如何被修饰的，并确定当Blimp-1被撤回时，Blimp-1依赖的转录抑制是否可逆。我们将纯化含有Blimp-1的阻遏复合物并鉴定复合物的组分。

DESCRIPTION (provided by the applicant): B Lymphocyte Induced Maturation Protein-1 (Blimp-1) is a transcriptional repressor with the unique property of being able to drive B cells to an immunoglobulin secreting, non-dividing, terminally differentiated plasma cell phenotype. In studying this protein our long-term goals are to: 1) understand how Blimp-1 functions during terminal B cell differentiation, 2) use Blimp-1 as an entry point to gain a better understanding of the regulatory mechanisms responsible for determining post-germinal center B cell fates and 3) identify universal mechanisms involved in terminal differentiation. In the current grant period we have made good progress in elucidating basic aspects of Blimp-1 's structure, regulation and mechanism of action and in identifying gene expression programs regulated by Blimp-1 in B cells. We have also created gene-targeted mice that will give rise to animals lacking Blimp-1 in mature B cells. We plan to exploit this progress by carrying out in-depth studies consisting of 4 specific aims. 1) Mice lacking Blimp-1 in their B cells will be used to determine if/when Blimp-1 is required for commitment to plasma cell fate. A thorough analysis of B cell development and function will be performed and the ability of Blimp-1 mutants or other transcription factors like XBP-1 to complement the Blimp-1-/- phenotype will be tested. Aging the mice will reveal if Blimp-1 has tumor suppressor activity in B cells. 2) Short-term culture systems in which germinal center B cells develop into memory or plasma cells will be used to learn when/how Blimp-1 and other transcriptional regulators are induced and act during commitment to these alternate fates. We will identify signals that direct their expression. 3) Established approaches will be used to determine if/how signals from IL-6, IL-10 and TNF/TNFRs activate Blimp-1 transcription. 4) Blimp-1's mechanism of gene repression may be unusual. We will study how DNA and histones are modified in target genes repressed by Blimp-1 and determine if Blimp-1 -dependent transcriptional repression is reversible when Blimp-1 is withdrawn. We will purify Blimp-1-containing repression complexes and identify the components of the complexes.