Genetic Analysis of H19 and Igf2 Imprinting Regulation

H19 和 Igf2 印记调控的遗传分析

• 批准号: 6662470
• 负责人: NORA I ENGEL
• 金额: $ 5.01万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-10-01 至 2004-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6662470
• 关键词: DNA methylation; gene expression; gene targeting; genetic regulation; genomic imprinting; laboratory mouse; molecular genetics; nucleic acid sequence

Genomic imprinting is an epigenetic mechanism affecting a small group of genes in mammals and that results in monoallelic parental-specific expression. Many imprinted genes code for regulators of proliferation or differentiation, so alterations in their regulation can play a role in developmental abnormalities and cancer. Therefore, gaining a full comprehension of the mechanisms by which imprinting is regulated is crucial to understanding normal embryonic development and the pathogenesis of many human diseases. H19 and Igf2 are two linked genes with a similar temporal and tissue- specific pattern of expression and are imprinted. Hl9 is expressed from the maternal allele, whereas Igf2 is expressed paternally. The coordinate regulation of imprinting at these loci depends on a 2 kb differentially methylated domain (DMD) that lies upstream of the H19 gene. This DMD contains four GC-rich repeats that are highly conserved between the mouse, rat and human sequences, a fact that suggests that they are an important feature for the regulation of the domain. The four repeats exhibit methylation-dependent boundary activity in vitro. The first goal of these studies is to determine the requirement of the four CG-rich 21- by repeats within the DMD for the establishment of imprinting. The second aim is to determine whether methylation of specific CG dinucleotides within these repeats is a signal for the parental identity of the alleles. Both aims will be accomplished by gene targeting at the endogenous locus. These experiments will lead to enhanced understanding of the molecular mechanisms underlying imprinting.

基因组印记是一种影响哺乳动物中一小部分基因的表观遗传机制，导致单等位基因的亲本特异性表达。许多印记基因编码增殖或分化的调节因子，因此其调节的改变可以在发育异常和癌症中发挥作用。因此，获得一个完整的理解的机制，其中印记的调节是至关重要的，以了解正常的胚胎发育和许多人类疾病的发病机制。H19和Igf 2是两个相连的基因，具有相似的时间和组织特异性表达模式，并且是印记的。H19由母本等位基因表达，而Igf 2由父本表达。在这些位点的印记的协调调节依赖于一个2 kb的差异甲基化结构域（DMD），位于H19基因的上游。该DMD包含四个富含GC的重复序列，这些重复序列在小鼠、大鼠和人类序列之间高度保守，这一事实表明它们是该结构域调控的重要特征。这四个重复序列在体外表现出甲基化依赖的边界活性。这些研究的第一个目标是确定DMD内四个富含CG的21- by重复序列对于建立印迹的需求。第二个目的是确定这些重复序列中特定CG二核苷酸的甲基化是否是等位基因亲本身份的信号。这两个目标都将通过基因靶向内源基因座来实现。这些实验将导致加深理解的分子机制的印记。