The role of YY1 in constitutive and inducible DNA loop formation

YY1 在组成型和诱导型 DNA 环形成中的作用

基本信息

批准号：
8749047
负责人：
Michael Lee Atchison
金额：
$ 30.4万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-01 至 2018-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8749047
关键词：
Address Antibody Repertoire B-Lymphocytes Binding ChIP-seq Chromatin Loop Clustered Regularly Interspaced Short Palindromic Repeats Complex DNA DNA Binding DNA Sequence Data Defect Development Developmental Gene Expression Regulation Disease Enhancers Functional RNA Gene Rearrangement Genetic Transcription Genome Histones Immune Immunoglobulin Class Switching Immunoglobulin Genes Immunoglobulin Switch Recombination Immunoglobulins Knock-out Lamins Lead Lymphomagenesis Mediating Molecular Molecular Cloning Mus Phospho-Specific Antibodies Play Polycomb Post-Translational Protein Processing Process Proteins Publishing RNA Interference Role Site Splenocyte Staging System Testing Tissues Transcript Work YY1 Transcription Factor base cohesin condensin cytokine experience immune function innovation insight knock-down mutant novel protein protein interaction public health relevance reconstitution stem cell biology

项目摘要

DESCRIPTION: Long-distance DNA interactions are critically involved in developmental regulation of gene expression, stem cell biology, and immune functions. The immunoglobulin (Ig) genes best exemplify the importance of long- distance DNA interactions as somatic rearrangement of these genes requires linkage of DNA sequences separated by as much as 3 megabases. Similarly, Ig class switch recombination (CSR) requires formation of both constitutive and cytokine-inducible loops within switch region DNA sequences, and interactions between enhancer sequences (E¿ and 3'RR enhancers) that are separated by 200 kb. Although many long-distance loops have been identified at the Ig loci, the molecular mechanisms that control their formation remain unclear. We recently published the novel observation that the transcription factor YY1 controls antibody repertoires at the Ig¿ locus and physically interacts with condensin, cohesin, and Polycomb Group (PcG) proteins, all of which are involved in long-distance DNA loop formation. Moreover, co-localization of YY1 with these proteins within the Ig¿ locus suggests that YY1 controls long-distance DNA interactions. In further support, recent evidence shows that YY1 plays critical roles in long-distance DNA interactions at the IgH, Ig¿, and the Th2 cytokine loci. Notably, our preliminary data demonstrate that YY1 conditional knock-out reduces CSR and dramatically ablates long-distance DNA loops required for CSR. Based on our combined data, we hypothesize that YY1 developmentally regulates CSR by both constitutive and cytokine inducible binding to DNA, and subsequent recruitment of proteins (condensin, cohesin, PcG proteins, etc.) required for long-distance DNA loop formation. We are uniquely poised to test this hypothesis in our recently developed powerful and innovative YY1 conditional knockout/reconstitution primary ex vivo splenoctye system. As YY1 is a ubiquitous protein, its role in DNA loop formation must be regulated tissue-specifically and B cell stage-specifically by either post-translational modification, or by developmentally regulated protein-protein interactions. Therefore, in addition to determining how YY1 contributes to long-distance DNA loop formation, we will identify the YY1- interacting proteins required for loop formation, and characterize the developmental and inducible mechanisms governing this process. Defining the role of YY1 in CSR will provide foundational insights into humoral immune mechanisms, and may lead to new paradigms of long-distance DNA interactions, and the translocations that drive lymphomagenesis. We have over two decades experience with YY1 function and have developed numerous unique molecular clones and genetically modified mouse lines to address YY1 function in DNA loop formation.

描述：长距离 DNA 相互作用对于基因表达、干细胞生物学和免疫功能的发育调节至关重要。免疫球蛋白 (Ig) 基因最好地说明了长距离 DNA 相互作用的重要性，因为这些基因的体细胞重排需要连接。同样，Ig 类开关重组 (CSR) 需要在开关区域 DNA 序列内形成本构环和细胞因子诱导环，并相互作用。尽管在 Ig 位点上发现了许多长距离环，但控制其形成的分子机制仍不清楚。转录因子 YY1 控制 Ig¿ 处的抗体库YY1 与凝缩蛋白、粘连蛋白和多梳族 (PcG) 蛋白发生物理相互作用，所有这些蛋白都参与长距离 DNA 环的形成，而且 YY1 与这些蛋白在 Ig 内共定位。基因座表明 YY1 控制长距离 DNA 相互作用，最近的证据表明 YY1 在 IgH、Ig¿ 的长距离 DNA 相互作用中发挥关键作用。值得注意的是，我们的初步数据表明，YY1 条件性敲除会降低 CSR 并显着消除 CSR 所需的长距离 DNA 环。根据我们的综合数据，我们发现 YY1 通过组成型和细胞因子诱导与 DNA 结合，并随后募集长距离 DNA 环形成所需的蛋白质（凝缩蛋白、粘连蛋白、PcG 蛋白等）。由于 YY1 是一种普遍存在的蛋白质，它在 DNA 环形成中的作用必须通过组织特异性和 B 细胞阶段特异性来调节。因此，除了确定 YY1 如何促进长距离 DNA 环形成之外，我们还将确定 YY1 的作用。 YY1-环形成所需的相互作用蛋白，并表征控制该过程的发育和诱导机制，定义 YY1 在 CSR 中的作用将为体液免疫机制提供基础见解，并可能导致长距离 DNA 相互作用的新范例。我们在 YY1 功能方面拥有二十多年的经验，并开发了许多独特的分子克隆和转基因小鼠品系来解决 DNA 环形成中的 YY1 功能。