Biochemistry and Genetics of Chromatin Assembly Factors in Drosophila

描述（申请人提供）：生物体的遗传物质（DNA）储存在染色体中。了解正常发育和疾病中的细胞活动需要的不仅仅是DNA序列和基因组的个体特异性变异。关键的调控作用也发挥包装的基因组到一个保守的核蛋白复合物称为染色质。染色质的组装和维持是由两个家族的蛋白质，即组蛋白伴侣和ATP驱动的运动染色质重塑因子的协同作用。染色质的结构及其代谢的调节机制是独特重要的，因此在进化中高度保守。 我们工作的最终目标是了解染色质结构的建立与真核染色体功能调节之间的关系。我们将集中在一个系统的研究蛋白质，介导染色质组装。我们将分析基本的分子事件，并研究组蛋白伴侣和运动因子在体外（试管中）染色质组装过程中发生的界面相互作用。此外，我们将研究染色质组装因子在活体模式生物果蝇（果蝇）中的特定功能作用。我们将进行实验，以了解组装因子如何在体内改变染色质结构，并调节各种DNA指导的酶促过程，如转录，DNA复制和修复。 成熟精子的染色质在组成上与正常细胞染色质不同，特别是DNA高度浓缩。精子染色质是酶促静止的，由DNA与称为鱼精蛋白的富含半胱氨酸的小碱性蛋白质压缩形成。在受精时，卵子面临着将浓缩的精子染色质重塑成可接近的、有转录和复制能力的形式的挑战。我们最近发现细胞机制，介导精子染色质重塑在体外和体内。因此，我们也将研究介导精子染色质重塑的因素。 该项目的成功完成将导致介导各种形式的染色质组装的因子的全面的生物化学和生物学表征。在全球范围内，我们的工作将为染色体组装和维持在细胞功能调节中的作用提供见解，并将适用于理解，诊断和治疗涉及DNA代谢过程缺陷的人类疾病。

DESCRIPTION (provided by applicant): Genetic inheritance material of a living organism (DNA) is stored in chromosomes. Understanding of cellular activities in normal development and disease requires more than the DNA sequence and individual- specific variations of the genome. Critical regulatory roles are also played by packaging of the genome into a conserved nucleoprotein complex termed chromatin. Chromatin is assembled and maintained by a concerted action of two families of proteins, namely histone chaperones and ATP-driven motor chromatin remodeling factors. The structure of chromatin and the regulatory machinery of its metabolism are uniquely important and thus strongly conserved in evolution. The ultimate objective of our work is to understand the relationship between the establishment of chromatin structure and regulation of the function of eukaryotic chromosomes. We will focus on a systematic study of proteins that mediate chromatin assembly. We will analyze elementary molecular events and examine interactions at the interface of histone chaperones and motor factors that take place during chromatin assembly in vitro (in a test tube). In addition, we will investigate specific functional roles for chromatin assembly factors in a living model organism, fruit fly (Drosophila melanogaster). We will perform experiments to understand how the assembly factors alter chromatin structure in vivo and regulate various DNA-directed enzymatic processes, such as transcription, DNA replication and repair. The chromatin of mature sperm differs in composition from normal cell chromatin, in particular by an extraordinary high degree of DNA condensation. Sperm chromatin is enzymatically static and is formed by compaction of DNA with small basic, cysteine-rich proteins termed protamines. At fertilization, the egg faces the challenge of remodeling the condensed sperm chromatin into an accessible, transcription- and replication- competent form. We recently discovered cellular machinery that mediates sperm chromatin remodeling in vitro and in vivo. Thus, we will also study the factors that mediate sperm chromatin remodeling. The successful completion of this project will lead to a comprehensive biochemical and biological characterization of factors that mediate the assembly of various forms of chromatin. More globally, our work will provide insights into the role of chromosome assembly and maintenance in regulation of the cell function and will be applicable to understanding, diagnosis and treatment of human diseases that involve defects in processes of DNA metabolism.