BRWD1 in adaptive humoral immunity

项目总结 最近，我们证明了谱系受限的Bromo和WD40结构域包含表观遗传学 阅读器BRWd1打开Igκ，使RAG蛋白能够在Jκ上组装。我们现在报告BRWD1有一个 在晚期B细胞发育中的作用要广泛得多。在距离结合部位最远5mb处，BRWd1 通过关闭B细胞发育早期表达的基因增强子和 打开那些在晚期表达的基因。在缺乏BRWD1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通常在早期发育阶段表达，但许多是 也是生发中心(GC)转录程序的一部分。BRWD1首先在小的Pre-B细胞中表达。 而Brwd1在幼稚滤泡(FO)中的表达较高，在第12天的GC B细胞中表达最高。在灯光下 区域(LZ)细胞，BRWD1在Myc-细胞中表达，它是一种受BRWD1抑制的转录因子。最后， GC暗区(DZ)和LZ中差异表达基因的分析 在小的Pre-B细胞中受BRWD1调控，预测BRWD1抑制DZ程序并诱导 LZ程序。这些数据表明，分离增殖和免疫球蛋白κ的遗传程序之间存在相似之处 发育中的重组和GC中将增殖与选择分开的重组。基于这些 根据研究结果，我们假设BRWD1是维持FO细胞特性所必需的。此外，我们假设 通过抑制DZ和诱导LZ遗传程序，BRWD1对GC依赖的体液起关键作用 豁免权。这些假设将在以下具体目标中得到检验： 目的1：获得Brwd1的条件等位基因。 目的2.确定BRWD1在维持滤泡B细胞特性中的作用。 目的3.确定BRWD1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.