Biochemistry and Genetics of Chromatin Assembly Factors in Drosophila

描述（由申请人提供）：生物体（DNA）的遗传物质储存在染色体中。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了基因组包装成一个保守的核蛋白复合体称为染色质。染色质的组装和维持是由两个蛋白家族的协同作用，即组蛋白伴侣和atp驱动的运动染色质重塑因子。染色质的结构及其代谢的调节机制具有独特的重要性，因此在进化中具有很强的保守性。我们工作的最终目的是了解染色质结构的建立与真核生物染色体功能调控之间的关系。我们将集中于对介导染色质组装的蛋白质的系统研究。我们将分析基本分子事件，并检查组蛋白伴侣和运动因子在体外染色质组装过程中发生的界面相互作用（在试管中）。此外，我们将研究染色质组装因子在活体模式生物果蝇（Drosophila melanogaster）中的特定功能作用。我们将进行实验来了解组装因子如何在体内改变染色质结构并调节各种DNA导向的酶促过程，如转录、DNA复制和修复。成熟精子的染色质在组成上不同于正常细胞的染色质，特别是DNA的高度凝结。精子染色质在酶作用上是静态的，是由DNA与小的碱性、富含半胱氨酸的蛋白质（称为精氨酸）压实而形成的。在受精过程中，卵子面临着将浓缩的精子染色质重塑为可接近的、转录和复制能力强的形式的挑战。我们最近在体外和体内发现了介导精子染色质重塑的细胞机制。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对介导各种形式染色质组装的因素进行全面的生化和生物学表征。在全球范围内，我们的工作将提供对染色体组装和维持在细胞功能调节中的作用的见解，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.