Structure and Function of Nucleosome Assembly Protein 1

描述（由申请人提供）：染色质起着两个重要的作用，但就其本质而言，它们是相互排斥的。一方面，染色质负责极端程度的DNA压缩，使真核基因组适合细胞核的范围。另一方面，它必须允许DNA的局部分解，才能让细胞机器进入基因组。介导各种水平的紧密染色质状态之间的相互转化的活性是需要接近基因组DNA的所有过程的关键调节剂。对这些生物学相关过程的机制和结构洞察是有限的。在这里，核小体组装蛋白1（NAP 1）家族的组蛋白伴侣在维持和调节染色质结构和流动性的作用将进行研究。目的1和2地址的伴侣与组蛋白相互作用的结构和分子基础，使用X-射线衍射以及生物化学和体内的方法。NAP 1介导的组蛋白去除和组蛋白交换的机制和生物学作用将通过严格的动力学分析结合染色质结构的体内检查来研究（目的3）。最后，翻译后修饰调节多细胞动物中NAP 1活性的新假设将在目标4中进行测试。这一建议的力量在于广泛的结构，生物物理，生物化学和遗传学方法的组合，以解决如何压缩DNA提供给细胞机器的高度重要的问题。 本课程将结合结构、生物物理和遗传学方法，研究组蛋白伴侣介导的染色质结构调节的分子机制和生物学相关性。

DESCRIPTION (provided by applicant): Chromatin plays two essential, yet by their very nature mutually exclusive roles. On one hand, chromatin is responsible for the extreme degree of DNA compaction that allows the eukaryotic genome to fit into the confines of the nucleus. On the other hand, it must permit the local unraveling of DNA to grant access of the cellular machinery to the genome. Activities that mediate the inter- conversion between various levels of compacted chromatin states are key regulators of all processes requiring access to genomic DNA. Mechanistic and structural insight into these biologically relevant processes is limited. Here, the role of the nucleosome assembly protein 1 (NAP1) family of histone chaperones in maintaining and modulating chromatin structure and fluidity will be investigated. Aims 1 and 2 address the structural and molecular basis for chaperone interaction with histones, using x-ray diffraction as well as biochemical and in vivo approaches. The mechanism and biological role of NAP1-mediated histone removal and histone exchange will be studied by rigorous kinetic analysis combined with in vivo examination of chromatin structure (aim 3). Finally, the novel hypothesis that a posttranslational modification regulates NAP1 activity in metazoans will be put to test in aim 4. The strength of this proposal lies in a combination of a broad spectrum of structural, biophysical, biochemical and genetic approaches to address the highly significant question of how compacted DNA is made available to the cellular machinery. The molecular mechanism and biological relevance of histone chaperone-mediated chromatin structure modulation will be investigated, using a combination of structural, biophysical, and genetic approaches.