BRWD1 in adaptive humoral immunity

项目摘要 最近，我们证明了谱系限制的BROMO和WD 40结构域包含表观遗传 阅读器BRWD 1打开IGκ并使RAG蛋白能够在Jκ处组装。我们现在报告BRWD 1有一个 在晚期B细胞发育中发挥更广泛的作用。在距离结合位点最多5 mb处，BRWD 1 通过关闭在B细胞发育早期表达的基因的增强子来重塑染色质景观， 打开那些在晚期表达的基因。在BRWD 1缺失的情况下，超过7000个基因发生了异常。 表达。虽然这些基因中的许多在早期发育阶段正常表达，但许多在早期发育阶段表达。 也是Germinal Center（GC）转录程序的一部分。BRWD 1首先在小的前B细胞中表达。 然而，Brwd 1表达在幼稚卵泡（FO）中高得多，在第12天的GC B细胞中最高。鉴于 区（LZ）细胞中，BRWD 1在Myc-细胞中表达，这是一种被BRWD 1抑制的转录因子。最后， 分析GC暗区（DZ）和LZ中差异表达的基因，与那些差异表达的基因相比， 在小的前B细胞中由BRWD 1调节，预测BRWD 1抑制DZ程序并诱导细胞凋亡。 LZ程序。这些数据表明，分离增殖和IGκ的遗传程序之间存在相似性。 发育中的重组和GC中将增殖与选择分离的那些。基于这些 研究结果，我们假设BRWD 1是维持FO细胞身份所必需的。此外，我们假设 通过抑制DZ和诱导LZ遗传程序，BRWD 1对GC依赖性体液免疫至关重要。 免疫力这些假设将在以下具体目标中进行检验： 目的1：获得Brwd 1的条件等位基因。 目标二。确定BRWD 1在维持滤泡B细胞特性中的作用。 目标3。确定BRWD 1在获得性免疫中的作用。

PROJECT SUMMARY Recently, we demonstrated that the lineage-restricted BROMO and WD40 domain containing epigenetic reader BRWD1 opens Igκ and enables assembly of RAG proteins at Jκ. We now report that BRWD1 has a much broader role in late B cell development. At distances of up to 5 mb from sites of binding, BRWD1 reshaped chromatin landscape by closing enhancers of genes expressed early in B cell development and opening those of genes expressed in late stages. In the absence of BRWD1, over 7000 genes were aberrantly expressed. While many of these genes were normally expressed in earlier developmental stages, many were also part of the germinal center (GC) transcription program. BRWD1 is first expressed in small pre-B cells. However, Brwd1 expression was much higher in naïve follicular (FO) and highest in day 12 GC B cells. In light zone (LZ) cells, BRWD1 is expressed in Myc- cells, a transcription factor repressed by BRWD1. Finally, analysis of genes differentially expressed in GC dark zone (DZ) and LZ, compared to those differentially regulated by BRWD1 in small pre-B cells, predicted that BRWD1 represses the DZ program and induces the LZ program. These data suggest similarities between genetic programs that separate proliferation and Igκ recombination in development and those that segregate proliferation from selection in GCs. Based on these findings, we hypothesize that BRWD1 is required for maintaining FO cell identity. Furthermore, we hypothesize that, by repressing DZ and inducing LZ genetic programs, BRWD1 is critical for GC-dependent humoral immunity. These hypotheses will be tested in the following Specific Aims: Aim 1: Derive a conditional allele of Brwd1. Aim 2. Determine role of BRWD1 in maintaining follicular B cell identity. Aim 3. Determine the role of BRWD1 in adaptive immunity.