Chromatin Structure and Dynamics

本项目的长期目标是了解细胞核中染色质的功能， 特别强调染色质结构和动力学的分子生物学。具体目标1 研究染色质组装，这是复制所需的基本生物学过程， 维持我们的染色体。介导染色质组装的两种关键酶是ACF和 CHD1马达蛋白。拟议的研究旨在直接检查 核小体由ACF和CHD1组装。特异性目标2检查人类HARP的功能， 与染色质装配和重塑因子的ATP酶亚基密切相关的蛋白质， 包括ACF和CHD1。HARP基因突变导致Schimke免疫性骨发育不良 （SIOD），通常导致儿童早期死亡。所提出的实验是一个系统的 HARP在体内和体外的功能分析，并将提供新的知识，应推进 SIOD的潜在治疗。具体目标3解决了四种人类HMGN蛋白的功能， 它们是丰富的非组蛋白染色体蛋白， 高亲和力结合位点。拟议的研究将确定和描述每种药物的相互作用， HMGN蛋白超过30 Mb的人类基因组，并研究该现象的分子基础 在体内观察。考虑到它们的丰度和核小体结合活性，HMGN蛋白可能 对染色质结构和活性有显著影响。 这些研究将使我们更好地理解染色质，并因此提供新的见解 人类疾病的分子基础和潜在治疗，如许多形式的癌症， 涉及染色质结构异常和染色质中DNA指导的过程。重要的是 HARP的分析应该揭示导致SIOD的分子事件的关键方面。

The long-term objective of this project is to understand the function of chromatin in the nucleus, with a particular emphasis on the molecular biology of chromatin structure and dynamics. Specific Aim 1 investigates chromatin assembly, a fundamental biological process that is required for the replication and maintenance of our chromosomes. Two key enzymes that .mediate chromatin assembly are the ACF and CHD1 motor proteins. The proposed studies are designed to examine directly the mechanisms by which nucleosomes are assembled by ACF and CHD1. Specific Aim 2 examines the function of human HARP, a protein that is closely related to the ATPase subunits of chromatin assembly and remodeling factors, which include ACF and CHD1. Mutations in HARP are responsible for Schimke immuno-osseous dysplasia (SIOD), which typically leads to death in early childhood. The proposed experiments are a systematic analysis of the function of HARP in vivo and in vitro, and will provide new knowledge that should advance the potential treatment of SIOD. Specific Aim 3 addresses the function of the four human HMGN proteins, which are abundant nonhistone chromosomal proteins that bind specifically to nucleosomes at two high-affinity binding sites. The proposed studies will identify and characterize the interactions of each of the HMGN proteins over 30 Mb of the human genome, and investigate the molecular basis for the phenomena observed in vivo. Given their abundance and nucleosome-binding activity, the HMGN proteins are likely to have a significant impact upon chromatin structure and activity. These studies should lead to a better understanding of chromatin, and should therefore provide new insights into the molecular basis and potential treatment of human diseases, such as many forms of cancer, that involve abnormalities in chromatin structure and DNA-directed processes in chromatin. Importantly, the analysis of HARP should reveal key aspects of the molecular events that lead to SIOD.