Nucleosome Positioning

描述（由申请人提供）：细胞功能的底物包括转录、复制、重组和染色体分裂是染色质，而不是裸DNA。这些功能对所有生物体的发育和健康都是必不可少的。在染色体组织的初始阶段，DNA被压缩成一个重复的核小体阵列。核小体沿着DNA的详细定位对于负或正基因调控都是必不可少的。所有真核生物和所有含组蛋白的古生菌在其基因组的某些区域都含有核小体定位的强烈信号。据报道，核小体的独特局部排列在端粒和着丝粒，在已知的基因调控区域附近，以及在其他染色体位置；这些特殊的排列被认为是染色体功能所必需的。DNA序列本身强烈地偏向于包裹DNA的核小体的定位，并且已经阐明了涉及核小体定位的某些DNA序列规则或基序。这些发现表明，基因组DNA序列的进化是通过影响其染色质结构来促进其功能的。这项工作的长期目标是阐明染色体的分子结构与其功能之间的关系。本项目的目标是探索基因组DNA序列、核小体定位和染色体功能之间的关系。我们将从三个方面实现这些目标。在Aim 1中，我们描述了我们已经分离的酵母中最强核小体定位序列的作用。在目标2中，我们分析了核小体定位在特定酵母启动子上的作用。在目标3中，我们阐明了翻译核小体定位的信号。我们创建最强可能的核小体定位序列，表征其在体内的后果，并分析其在体外的机制。

DESCRIPTION (provided by applicant): The substrates for cellular functions including transcription, replication, recombination, and chromosome division are chromatin, not naked DNA. These functions are essential for the development and health of all organisms. In the initial level of chromosome organization, DNA is compacted into a repeating array of nucleosomes. The detailed positioning of nucleosomes along DNA can be essential for either negative or positive gene regulation. All eukaryotes and all histone-containing archaea contain strong signals for nucleosome positioning in certain regions of their genomes. Distinctive local arrangements of nucleosomes are reported at telomeres and centromeres, in the vicinity of known gene regulatory regions, and at other chromosomal locations; these particular arrangements are believed to be essential for chromosome function. The sequence of the DNA itself strongly biases the positioning of the nucleosomes into which the DNA is wrapped, and certain DNA sequence rules or motifs involved in nucleosome positioning have been elucidated. These findings imply that genomic DNA sequences are evolved to facilitate their function through effects on their chromatin structure. The long term aim of this work is to elucidate the relationship between the molecular architecture of chromosomes and their function. The goal of the present project is to explore the relationship between genomic DNA sequence, nucleosome positioning, and chromosome function. We will address these goals in three ways. In Aim 1 we characterize the role of the strongest nucleosome positioning sequences in yeast, which we have already isolated. In Aim 2 we analyze the role of nucleosome positioning at specific yeast promoters. In Aim 3 we elucidate the signals for translational nucleosome positioning. We create the strongest possible nucleosome positioning sequence, characterize its consequences in vivo, and analyze its mechanics in vitro.