Chromatin Structure and Dynamics

描述（由申请人提供）：该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。特异性目标1研究染色质组装，这是染色体复制和维持所需的基本生物学过程。两个关键的酶。介导染色质组装的是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组装的机制。特异性目的2研究了人类HARP的功能，该蛋白与染色质组装和重塑因子（包括ACF和CHD1）的atp酶亚基密切相关。HARP的突变是导致Schimke免疫-骨发育不良（SIOD）的原因，SIOD通常导致儿童早期死亡。本实验是对HARP在体内和体外功能的系统分析，并将为推进SIOD的潜在治疗提供新的知识。特异性Aim 3研究了四种人类HMGN蛋白的功能，这些蛋白是丰富的非组蛋白染色体蛋白，在两个高亲和力结合位点特异性结合核小体。拟议的研究将确定和表征每个HMGN蛋白在人类基因组30 Mb上的相互作用，并研究在体内观察到的现象的分子基础。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重大影响。这些研究应该导致对染色质的更好理解，因此应该为涉及染色质结构异常和染色质dna导向过程的许多形式的癌症等人类疾病的分子基础和潜在治疗提供新的见解。重要的是，对HARP的分析应该揭示导致SIOD的分子事件的关键方面。

DESCRIPTION (provided by applicant): 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.