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Gene regulation from the inactive X in activated B cells

激活 B 细胞中非活性 X 的基因调控

基本信息

批准号：
10397666
负责人：
Montserrat C Anguera
金额：
$ 50.57万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-06-01 至 2024-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10397666
关键词：
Alleles Amino Acids Antibodies Autoimmune Autoimmune Diseases Autoimmunity B-Cell Activation B-Lymphocytes Binding CXCR3 gene ChIP-seq Chromatin Chromosomes Cre lox recombination system DNA Data Disease Exhibits Failure Female Foundations Gene Dosage Gene Duplication Gene Expression Gene Expression Regulation Gene Silencing Genes Genetic Genetic Transcription Heterochromatin Human Hybrids Immune Immunity Impairment Knowledge Lamin Type B Lead Link Location Lupus Lymphocyte Mature B-Lymphocyte Mediating Modeling Modification Molecular Mus Nuclear Patients Pattern Play Predisposition Process Proteins Publishing RNA Research Proposals Rest Role Sex Chromatin Somatic Cell Structural Protein Suggestion Testing Transcript Untranslated RNA Up-Regulation Work X Chromosome X Inactivation YY1 Transcription Factor Zinc Fingers base capture hybridization analysis of RNA targets cohesin cohesion condensin conditional knockout density dosage ds-DNA experimental study gene repression innovation insight male mouse model novel overexpression prevent transcriptome sequencing

项目摘要

Project Summary The X-chromosome is enriched with immunity-related genes, therefore X-linked genes need to be regulated to prevent abnormal expression. Females use X-chromosome Inactivation (XCI) to equalize X-linked gene expression, where one X maintained transcriptionally silent by continuous expression of the long noncoding RNA Xist and enrichment of heterochromatin modifications. We have recently discovered that female lymphocytes have a unique and dynamic mechanism to maintain XCI, unlike other somatic cells. Resting mature B cells lack Xist RNA and heterochromatin marks on the Xi, and these modifications return to the Xi through a YY1-mediated mechanism upon stimulation. Our in-press work indicates that preventing Xist RNA localization to the Xi by conditional knock-out of YY1 impairs heterochromatin enrichment on the Xi, and increases X-linked expression. In preliminary work, we found that B-cell specific deletion of one Xist allele (mb1CRE XistCKO/+) dramatically reduced Xist localization patterns over the Xi, reduced heterochromatin enrichment, and increased expression of specific X-linked genes. Moreover, this increase in X-linked gene expression was accompanied by increased antibodies to double-stranded DNA, a hallmark of autoimmunity. We hypothesize that Xist RNA localization to Xi is required to keep Xi at the nuclear periphery to maintain transcriptional repression in activated B cells, and that failure to localize Xist RNA disrupts Xi nuclear organization and perturbs X-linked gene expression, with consequent predisposition to autoimmunity. We will test our hypothesis with the following aims: (1) Do temporal and sequence-specific occupancy of YY1, Xist RNA, and heterochromatin marks on the Xi maintain transcriptional repression in activated splenic B cells? (2) Do chromosome structural proteins cooperate with YY1 to localize Xist RNA within Xi territory at the nuclear periphery for transcriptional repression in activated splenic B cells? (3) Are Cxcr3, Itm2a, Syn1 and Cfp overexpressed in lupus mouse models and does increased dosage predispose to autoimmunity? IMPACT: The results from these experiments will yield fundamental insight about the lymphocyte-specific mechanisms that regulate expression from the Xi, and will advance our understanding of the female-bias underlying B cell mediated autoimmune disorders.

项目概要 X染色体富含免疫相关基因，因此需要调节X连锁基因防止表达异常。女性使用 X 染色体失活 (XCI) 来平衡 X 连锁基因表达，其中一个 X 通过长非编码的连续表达而保持转录沉默 RNA Xist 和异染色质修饰的富集。我们最近发现，女性与其他体细胞不同，淋巴细胞具有独特且动态的机制来维持 XCI。休息成熟 B 细胞缺乏 Xist RNA 和 Xi 上的异染色质标记，这些修饰又返回到 Xi 通过刺激后 YY1 介导的机制。我们正在出版的工作表明，预防 Xist RNA 通过条件性敲除 YY1 定位到 Xi 会损害 Xi 上的异染色质富集，并且增加 X 连锁表达。在前期工作中，我们发现 B 细胞特异性删除一个 Xist 等位基因 (mb1CRE XistCKO/+) 显着减少了 Xi 上的 Xist 定位模式，减少了异染色质特定 X 连锁基因的富集和表达增加。此外，X连锁基因的增加表达伴随着双链 DNA 抗体的增加，这是自身免疫的标志。我们假设 Xist RNA 定位于 Xi 是使 Xi 保持在核外围以维持激活 B 细胞中的转录抑制，并且 Xist RNA 定位失败会破坏 Xi 核组织并扰乱 X 连锁基因表达，从而导致自身免疫的倾向。我们将测试我们的假设，目标如下：(1) YY1、Xist 的时间和序列特定占用情况 Xi 上的 RNA 和异染色质标记维持激活的脾 B 细胞中的转录抑制？ (2) 染色体结构蛋白是否与 YY1 合作将 Xist RNA 定位在核的 Xi 区域内激活的脾 B 细胞中转录抑制的外周？ (3) 是Cxcr3、Itm2a、Syn1和Cfp 在狼疮小鼠模型中过度表达，增加剂量是否会导致自身免疫？影响：这些实验的结果将产生关于淋巴细胞特异性机制的基本见解调节 Xi 的表达，并将促进我们对 B 细胞潜在的女性偏见的理解介导的自身免疫性疾病。