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

• 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
• 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

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相互作用与基因表达，干细胞生物学和免疫功能的发育调控至关重要。免疫球蛋白（IG）基因最能示例长距离DNA相互作用的重要性，因为这些基因的体细胞重排需要将DNA序列的连接到大约3兆瓦。类似地，IG类开关重组（CSR）需要在开关区域DNA序列中形成构成和细胞因子诱导的环，以及增强子序列（E e e and和3'RR增强子）之间的相互作用，这些序列被200 kb分开。尽管在IG基因座上已经确定了许多长距离环，但控制其形成的分子机制仍不清楚。我们最近发表了新的观察结果，即转录因子YY1控制Ig域中的抗体库，并与冷凝蛋白，粘蛋白和Polycomb组（PCG）蛋白物理相互作用，所有这些蛋白都参与了长距离DNA环的形成。此外，YY1与Ig域内的这些蛋白质共定位表明，YY1控制了长距离DNA相互作用。为了进一步的支持，最近的证据表明，YY1在IGH，IG？和Th2细胞因子基因座的长距离DNA相互作用中起关键作用。值得注意的是，我们的初步数据表明，YY1有条件的敲除可以减少CSR，并大大消灭CSR所需的长距离DNA环。基于我们的组合数据，我们假设YY1可以通过本组分和细胞因子诱导的DNA结合来调节CSR，并随后募集蛋白质（冷凝蛋白，粘蛋白，PCG蛋白等），用于长期持续DNA环路形成。我们在最近开发的强大而创新的YY1有条件敲除/重建基本原发性Splenoctye系统中检验这一假设很有毒。由于YY1是一种普遍存在的蛋白质，因此其在DNA环形成中的作用必须特异性地和B细胞阶段特定于特定于细胞阶段，或者是通过翻译后修饰或通过开发调节的蛋白质 - 蛋白质相互作用来调节的。因此，除了确定YY1如何促进长距离DNA环的形成外，我们还将确定循环形成所需的YY1相互作用蛋白，并表征有关此过程的发育和诱导机制。定义YY1在CSR中的作用将提供对体液免疫组机制的基本见解，并可能导致长距离DNA相互作用的新范式，以及驱动淋巴细胞增多的翻译。我们拥有YY1功能的二十年经验，并开发了许多独特的分子克隆和一般修饰的小鼠线，以解决DNA环形成中的YY1功能。