DNA STRUCTURE AND ACCESSIBILITY IN CHROMATIN

染色质中的 DNA 结构和可及性

• 批准号: 2910172
• 负责人: Jeffrey J Hayes
• 金额: $ 18.41万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-05-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2910172
• 关键词: DNA; Xenopus; animal genetic material tag; chemical binding; chromatin; gene induction /repression; genetic promoter element; histones; molecular site; nucleic acid sequence; nucleic acid structure; nucleosomes; ribosomal DNA; transcription factor

DESCRIPTION (Adapted from Applicant's Abstract): Each eukaryotic cell must execute a complex program of specific gene expression. The resolution of many genetically-based diseases will depend upon the elucidation of all factors contributing to this program. Recent work has demonstrate that, in some instances, chromatin structure plays an important role in bringing about this pattern of specific expression and it is likely that the structural elements of chromatin have been integrated into many transcriptional control mechanisms. This role may be active, actually facilitating the activity of the transcriptional machinery, or it may be more passive, whereby the precise alignment of protein-DNA contacts in chromatin with critical cis-acting DNA elements within promoters is such that pathways to transcription are not hindered. Most DNA-binding transcription factors will not be able to access these critical elements unless they are situated in the accessible regions of chromatin between nucleosome core structures. Further, even elements in these accessible regions may be rendered inaccessible by the binding of linker histones and the formation of higher order structures of chromatin. The specific aim of this proposal is to develop a detailed structural understanding of how nucleosome cores and linker histones organize DNA and modulate the accessibility of trans-acting factors to DNA in chromatin. This will be accomplished by exploiting the ability of a DNA fragment containing a Xenopus 5S RNA gene to position nucleosomes. A set of homogeneous and well- defined model chromatin complexes will be constructed which will be amenable to comprehensive structural analyses by the use of high resolution chemical probes of DNA structure and functional analysis by assessment of the binding of various transcription factors. This approach circumvents the problem of heterogeneity usually associated with preparation of native chromatin complexes and problems with structural analysis of these large complexes by traditional methods such as X-ray crystallography. The functional and structural extent of influence of the nucleosome core into the accessible regions of chromatin will be precisely determined as well as assessment of effects due to linker histones and folding of these accessible regions. This investigation will be relevant to proposed models for the role of chromatin in 5S gene regulation and to general understanding of the complex role of chromatin structure in promoter architecture. The proposed work may also bear on long-standing issues concerning the conformation and configuration of linker DNA in higher- order chromatin structures.

描述（改编自申请人的摘要）：每个真核细胞 必须执行特定基因表达的复杂程序。 这 许多基于遗传疾病的解决将取决于 阐明所有有助于该计划的因素。 最近的工作 已经证明，在某些情况下，染色质结构扮演 在实现这种特定表达方式和 染色质的结构元素可能是 集成到许多转录控制机制中。 这个角色可能 保持活跃，实际上促进转录的活性 机械，或者可能更被动，从而确切的对齐方式 与关键顺式作用DNA元件的染色质中的蛋白-DNA接触 在促进者中，转录途径不是 阻碍。 大多数DNA结合转录因子将无法 访问这些关键要素，除非它们位于 核小体核心结构之间的染色质区域。 此外，即使是这些可访问区域中的元素也可以渲染 连接器组蛋白的结合和形成无法访问 染色质的高阶结构。 该提案的具体目的是开发详细的结构 了解核小体核心和接头组蛋白如何组织DNA 并调节反式作用因子对DNA的可访问性 染色质。 这将通过利用DNA的能力来实现 含有爪蟾5S RNA基因以定位核小体的片段。 一个 一组均匀且定义良好的模型染色质复合物将是 构建将适合全面的结构分析 通过使用高分辨率的DNA结构的化学探针和 通过评估各种结合的功能分析 转录因子。 这种方法绕过了 通常与天然染色质制备有关的异质性 这些大型复合物的结构分析的复合物和问题 通过传统方法，例如X射线晶体学。 功能 和核小体核心影响的结构范围 染色质的可访问区域将得到精确确定，并且 评估因接头组蛋白引起的影响和折叠 可访问区域。 这项调查将与提议有关 染色质在5s基因调节中的作用的模型和一般的模型 了解染色质结构在启动子中的复杂作用 建筑学。 拟议的工作也可能会在长期存在的问题上承担 关于较高的接头DNA的构象和构型 订购染色质结构。