Genetic dissection of Sle2 contribution to SLE pathogenesis

本研究的目的是确定S/e2狼疮相关表型的致病基因。 NZM2410小鼠模型，以及这些基因在狼疮发病机制中的作用 发病机制。因此，S/e2，一个影响B细胞发育和功能的遗传位点，扮演着一个 在自身免疫发病机制中起主要作用。我们最近发现了三个独立的S/e2区，Sle2a， Sle2b和S/E2c影响B-1a细胞池的大小，但只有两个人，S/E2a和Sle2b贡献 与自身免疫发病机制有关。S/e2通过多种机制影响PERC B-1细胞数。 可能通过S/e2三个基因座中的每一个独立地介导。最后，我们长期以来 合作者钱德拉·莫汉博士(加州大学洛杉矶分校)已经证明，S/e2使用56R调解了耐受性的违反 抗DNA重链转基因模型。基于这些最新的结果和我们的战略 在对Sle1基因进行分析的基础上，我们提出了以下三个目标来鉴定S/e2基因： 1.构建S/E2A的高分辨率遗传图谱。Sle2b和S/E2C基因座。我们将生产B6.S/e2 同源重组亚株并筛选增加的perc B-1a细胞库。这一过程将是 迭代，直到每个轨迹都被映射到&lt；0.5厘米的临界间隔。此外，我们将监测联合- 用交互作图研究B-1a表型的分离及其对狼疮发病的作用 S/e2基因座与其他SLE易感基因座的相关性研究 2.研究3个S/e2基因座的表型特征。在遗传基因的同时 在作图工作中，我们将完善每个S/e2基因座的表型定义。这一目标具有双重目标： 阐明这些基因座在疾病机制中的作用机制，并促进 目标3的候选基因的选择。为了实现这一目标，我们将1)分配每一种机制 通过S/e2使B-1a细胞库增加到特定的S/e2基因座，2)比较 表达每个S/e2基因座的PERC B-1a细胞，以及3)确定三个S/e2基因座中的哪一个负责 使用56R模型研究对核抗原的耐受性丧失。 3.寻找与S/E2a相关的基因。Sle2b和S/E2c。目标1和目标2将提供一份清单 S/e2基因座的位置和功能候选基因。序列与表达 B6和B6.S/e2同源菌株之间的多态将被系统地表征 这些基因。然后将评估这些与B细胞功能相关的多态的功能 在同源菌株之间。功能多态的存在与位置之间的一致性 在临界区间内将提供强有力的证据表明该特定基因的NZM2410等位基因 负责相应的SLE易感表型。

The purpose of this proposal is to identify the genes responsible for the S/e2 lupus-associated phenotypes in the NZM2410 murine model, and to characterize the mechanisms by which these genes contribute to lupus pathogenesis. Consequently, S/e2, a genetic locus that affects B cell development and function, plays a major role in autoimmune pathogenesis. We have recently identify three independent S/e2 regions, Sle2a, Sle2b, and S/e2c, that affect the size of the B-1a cell pool, but only two of them, S/e2a and Sle2b contribute to autoimmune pathogenesis. S/e2 affects the number of perC B-1acells through multiple mechanisms, which could be mediated independently through each of the three S/e2 loci. Finally, our long-time collaborator Dr. Chandra Mohan (UTSW) has shown that S/e2 mediates a breach of tolerance using the 56R anti-DNA heavy chain transgenic model. Based on these recent results and on the strategy that we have been using to characterize the Sle1 genes, we propose the three following aims to identify the S/e2 genes: 1. To generate high resolution genetic maps of the S/e2a. Sle2b, and S/e2c loci. We will produce B6.S/e2 congenic recombinant sub-strains and screen them for increased perC B-1a cell pool. This process will be iterated until each locus has been mapped to a < 0.5 cM critical interval. In addition, we will monitor the co- segregation of the B-1a phenotype with the contribution to lupus pathogenesis using an interaction mapping approach between each of the S/e2 loci with other SLE susceptibility loci. 2. To characterize the phenotypes associated with each of the 3 S/e2 loci. Concurrent with the genetic mapping effort, we will refine the phenotypic definition of each S/e2 locus. This aim has the dual goal of elucidating the mechanisms by which these loci contribute to disease mechanisms, and facilitating the selection of candidate genes for Aim 3. To accomplish this goal, we will 1) assign each of the mechanisms by which S/e2 increases the B-1a cell pool to specific S/e2 loci, 2) compare the gene expression profile of perC B-1a cells expressing each S/e2 locus, and 3) determine which of the three S/e2 loci is responsible for the loss of tolerance to nuclear antigens using the 56R model. 3. To identify the genes corresponding to S/e2a. Sle2b, and S/e2c. Aims 1 and 2 will provide a list of positional and functional candidate genes for each of the S/e2 loci. Sequence and expression polymorphisms between the B6 and the B6.S/e2 congenic strains will be systematically characterized for these genes. The functionality of these polymorphisms relative to B cell functions will be then evaluated between the congenic strains. Congruity between the presence of a functional polymorphism and location within the critical interval will provide strong evidence that the NZM2410 allele of this specific gene is responsible for the corresponding SLE susceptibility phenotype.