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Uncovering the biomolecular function of the R-octasome--a nucleosome-like particle with only H3 and H4 histones

揭示 R-octasome 的生物分子功能——一种仅含有 H3 和 H4 组蛋白的核小体样颗粒

基本信息

批准号：
10657120
负责人：
Edward E Luk
金额：
$ 31.63万
依托单位：
STATE UNIVERSITY NEW YORK STONY BROOK
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-04-01 至 2027-01-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10657120
关键词：
Affect Affinity Antibodies Arginine Binding Biochemical Biological Biological Process Biology Biophysics Cancer Biology Cell Nucleus Cell Proliferation Cell physiology Cells Chemicals Chromatin Chromatin Fiber Chromatin Modeling Chromatin Structure Collaborations Cryoelectron Microscopy Cysteine DNA Data Data Set Dimerization Electron Microscopy Eukaryota Eukaryotic Cell Gene Expression Gene Silencing Genes Genetic Genetic Transcription Genome Genomics Grant Heterochromatin Histone H2A Histone H3 Histone H4 Histones Human In Vitro Left Length Link Maintenance Malignant Neoplasms Maps Methodology Minor Modification Molecular Molecular Conformation Mutagenesis Mutation N-terminal Nature Negative Staining Normal Cell Nuclear Nuclease Protection Assays Nucleoproteins Nucleosomes Outcomes Research Paper Positioning Attribute Productivity Property Publishing Recombinants Resolution Role Saccharomyces cerevisiae Sedimentation process Shapes Site Structure Testing Therapeutic Intervention Variant Yeasts adduct chromatin remodeling crosslink dimer gene function in vivo insight mutant new therapeutic target novel particle reconstitution stoichiometry telomere tumor tumor progression

项目摘要

7. PROJECT SUMMARY/ABSTRACT The chromatin landscape of eukaryotic cells is decorated with landmarks characterized by covalent modifications and variant nucleoprotein structures. Some of these chromatin marks contribute to productive transcription, while others are involved in the establishment and maintenance of silenced chromatin regions. The fact that more than half of human cancers have mutations in genes encoding histones and chromatin regulators underscores the importance of understanding the fundamental mechanism of chromatin remodeling in cells. The canonical nucleosome, which has an inner core consisted of two copies each of histone H2A, H2B, H3, and H4 and an outer DNA coil of 147 bp in length, represents the predominant packaging unit of cellular chromatin. But emerging evidence suggests that nucleoproteins with alternative histone stoichiometries and DNA wrapping configurations are present. These variant packaging units can significantly alter the biophysical and biochemical properties of chromatin, potentially affecting a wide spectrum of nuclear functions. In the proposed studies, we focus on a nucleosome-like particle, called the R-octasome, in which its core is made up of eight subunits of the arginine-rich histone H3 and H4 (without H2A and H2B). Although it has been known for >40 years that R-octasomes can be assembled in vitro, the biological relevance is unknown. Using new structural data of the R-octasome, we strategically placed cysteine probes in yeast H3 and showed by site-directed crosslinking that structures specific to R-octasomes are present in yeast cells, providing the first evidence that R-octasomes exist in vivo. To further study the nature of R-octasomes, in Aim 1, we propose to develop a methodology to purify native R-octasomes from yeast that can be used for biochemical, genomic, and structural studies. To study the biological roles of R-octasomes, in Aim 2, we will interrogate the role of R- octasomes in telomeric gene silencing, as analysis of site-specific chemical mapping data suggest that R- octasomes are linked to telomeres. In parallel, we will investigate how R-octasomes function as substrates of ATP-dependent chromatin remodelers. Finally, in Aim 3, we will explore the role of R-octasomes in higher- order chromatin organization, as our structural data suggest that R-octasomes can nucleate the concatenation of additional H3 and H4 histones. Overall, the outcome of this research will give new insights into how eukaryotes use the highly conserved H3 and H4 as multi-functional substrates to modulate genomic functions.

7. 项目总结/文摘