CHROMATIN DOMAIN STRUCTURE/FUNCTION

目前的基因调控模型表明，间期染色体 被分成大的、功能不同的染色质结构域， 促进单个基因座的独立调节。 通常 这些结构域的大小为几十到几百kbp。 实际 建立的结构和分子机制 然而，对这些领域仍然知之甚少。 迄今只有 间接的结构分析已经可以用来分析染色质 这些领域的结构。 一个关键的限制是技术上的 与直接可视化大规模 围绕特定基因的染色质折叠。 我们的长期目标 是为了剖析特定基因位点的大规模染色质折叠， 分析这些折叠基序的顺式和反式决定簇， 为了确定这一水平染色质的功能意义， 组织在转录调控方面。 我们在本项目期间的具体目标是解决 以下问题：1.大规模染色质的变化 组织伴随转录激活？2.做SAR/MAR 序列在组织染色质中有直接的结构作用 域名？3.域边界元素之间的关系是什么， 通过分子测定和与细胞学相关的序列来定义， 定义域边界？4. LCR序列是否改变了大规模的 染色质组织？ 使用新的可视化方法，在体内动态的特定基因 将直接观察位点，光学和电子显微镜将 应用于可视化大规模染色质组织， 这些染色体区域的核定位。 这些可视化 能力将允许直接测试几个基于结构的 染色质结构域组织和基因调控的模型。 此外，委员会认为， 这些研究很可能为未来的机制奠定基础。 研究旨在剖析顺式和反式决定因素的作用， 染色质结构域的结构和功能。 从这些研究中获得的见解应有助于指导 设计未来的基因构建体和人工染色体 疗法

Current models of gene regulation suggest that interphase chromosomes are divided into large, functionally distinct, chromatin domains, facilitating independent regulation of individual gene loci. Typically these domains are tens to hundreds of kbp in size. The actual structural and molecular mechanisms underlying the establishment of these domains, however, have remained poorly understood. To date, only indirect structural assays have been available to analyze the chromatin structure of these domains. A key limitation has been the technical difficulty associated with directly visualizing the large-scale chromatin folding surrounding specific genes. Our long term objectives are to dissect the large-scale chromatin folding of specific gene loci, to analyze the cis and trans determinants of these folding motifs, and to determine the functional significance of this level of chromatin organization with regard to transcriptional regulation. Our specific aims for this project period will be to address the following questions: 1. What changes in large-scale chromatin organization accompany transcriptional activation? 2. Do SAR/MAR sequences have a direct, structural role in organizing chromatin domains? 3. What is the relationship between domain boundary elements, defined by molecular assays, and sequences associated with cytologically defined domain boundaries? 4. Do LCR sequences alter large-scale chromatin organization? Using novel visualization methods, in vivo dynamics of specific gene loci will be observed directly and light and electron microscopy will be applied to visualize the large-scale chromatin organization and nuclear positioning of these chromosomal regions. These visualization capabilities will allow direct testing of several structural based models of chromatin domain organization and gene regulation. Moreover, these studies are likely to lay the foundation for future mechanistic studies aimed at dissecting the role of cis and trans determinants of chromatin domain structure and function. Insight acquired from these studies should be of help in guiding the design of future constructs and artificial chromosomes used in gene therapy.