Functions, mechanisms, and therapeutic potential of chromatin looping

染色质环化的功能、机制和治疗潜力

基本信息

批准号：
8559656
负责人：
Gerd A Blobel
金额：
$ 51.77万
依托单位：
CHILDREN'S HOSP OF PHILADELPHIA
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-08-05 至 2018-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8559656
关键词：
Accounting Address Adult Area Basic Science Biological Models Biology Cell Nucleus Cells Chromatin Chromatin Fiber Chromatin Loop Clinical Complex DNA Binding DNA-Directed RNA Polymerase Development Developmental Gene Dimerization Disease model Elements Embryo Engraftment Enhancers Erythroid Cells Fetal Hemoglobin GATA1 gene Gene Activation Gene Expression Gene Expression Profile Gene Expression Regulation Genes Genetic Transcription Genome Genomics Globin Growth Hemoglobinopathies Higher Order Chromatin Structure Human Interphase Left Locus Control Region Mediating Mus Nature Nuclear Play Positron-Emission Tomography Proteins Regulatory Element Research Research Design Role Sickle Cell Anemia Specificity Staging Stem cells Structure System Technology Testing Therapeutic Time Transcriptional Regulation Transplantation Work Zinc Fingers cell type design erythroid Kruppel-like factor fetal globin genome-wide improved in vivo mammalian genome mouse model novel novel strategies promoter public health relevance research study stem three dimensional structure

项目摘要

DESCRIPTION (provided by applicant): The eukaryotic genome is non-randomly organized in the interphase nucleus. Critical control elements can physically contact each other to form chromatin loops. Looped configurations of the chromatin fiber have been described at numerous gene loci, however, the mechanism by which these structures are established and their functional relationship with gene expression have remained unclear. The transcription co-factor Ldb1 is critical for establishing looped chromatin interactions at the murine ¿-globin locus. Specifically, we showed that tethering Ldb1 to the locus via artificial zinc finger proteins in immature erythroid cells is sufficient to promote a looped interaction between the ¿-globin enhancer and promoter and potently activate transcription. This suggested for the first time that chromatin looping causally underlies gene expression and raised the possibility that forced chromatin looping might be employed to effectively manipulate gene expression. This proposal builds on these findings by investigating in Specific Aim 1 the mechanisms of Ldb1 function and its broad role in genome organization. In Specific Aim 2 we will further develop the approach of forced chromatin looping to enhance and broaden its usefulness. In Specific Aim 3 we will examine forced chromatin looping as an approach to developmentally reprogram the murine and human ¿-globin locus. In Specific Aim 4 proof-of-concept studies will examine whether reactivation of fetal hemoglobin via chromatin looping can ameliorate sickle cell anemia in a humanized mouse model. To our knowledge, the manipulation of higher order chromatin structure for the purpose of regulating gene expression is unique and novel in its design. The juxtaposition of complex regulatory elements promises more dramatic changes in gene activation when compared to conventional approaches, and might also be exploited to repress gene transcription for exploratory or therapeutic purposes.

描述（由申请人提供）：真核基因组在间期核中是非随机组织的，关键控制元件可以彼此物理接触以形成染色质纤维的环状结构，然而，在许多基因位点上都已描述过。这些结构的建立机制及其与基因表达的功能关系仍不清楚。转录辅助因子 Ldb1 对于在小鼠中建立环状染色质相互作用至关重要。具体来说，我们表明，通过未成熟红系细胞中的人工锌指蛋白将 Ldb1 束缚到该基因座足以促进 ¿珠蛋白增强子和启动子，并有效激活转录，这首次表明染色质成环是基因表达的因果关系，并提出了可能采用强制染色质成环来有效操纵基因表达的可能性。目标 1 Ldb1 功能机制及其在基因组组织中的广泛作用在具体目标 2 中，我们将进一步开发强制染色质环化方法，以增强和扩大其用途。 3 我们将研究强制染色质循环作为小鼠和人类发育性重编程的方法 ¿具体目标 4 概念验证研究将检查通过染色质环重新激活胎儿血红蛋白是否可以改善人源化小鼠模型中的镰状细胞性贫血。调节基因表达的设计独特且新颖，与传统方法相比，复杂调节元件的并置有望使基因激活发生更显着的变化，并且还可以用于抑制基因转录。用于探索或治疗目的。