Nuclear dynamics maintaining chromatin integrity during DNA replication

DNA 复制过程中核动力学维持染色质完整性

• 批准号: 10501685
• 负责人: Joshua Saldivar
• 金额: $ 38.21万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10501685
• 关键词: 3-Dimensional; ATR gene; Acute; Anabolism; Appearance; Cell division; Cells; Chromatin; Chromatin Structure; Conflict (Psychology); Coupling; DNA biosynthesis; DNA damage checkpoint; Enhancers; Ensure; Epigenetic Process; Equilibrium; Exhibits; Genes; Genetic; Genetic Enhancer Element; Genetic Transcription; Genome; Goals; Histones; Human Genome; Molecular Conformation; Nuclear; Pathway interactions; Phosphotransferases; Positioning Attribute; Process; Production; RNA Polymerase II; Research; S phase; Signal Transduction; Sum; Technology; biological adaptation to stress; mRNA Precursor; novel; prevent; programs; promoter; replication stress; transmission process

PROJECT SUMMARY The human genome is organized in 3-dimensional (3D) space, with spatially-distinct nuclear regions creating higher-level order that controls essential processes. For example, DNA replication occurs within nuclear foci that are spatially-separated from transcription condensates that contain active gene promoter and enhancer elements. Indeed, replication and transcription exhibit remarkable coordination ensuring genetic and epigenetic information are conserved upon cell division. Transcription condensates are temporally dynamic and undergo reorganization throughout S phase. How this level of control is achieved is poorly understood, and thus, it is unknown how replication and transcription remain spatially separated to prevent transcription-replication conflicts (TRCs) that destabilize the genome. We are uniquely positioned to answer this question given our recent progress uncovering ATR (ataxia-telangiectasia and rad3-related), a DNA damage checkpoint kinase, as a key regulator of transcription condensate function. ATR accumulates within condensates during S phase, signals a change in condensate composition, and alters the RNA polymerase II transcription cycle. Moreover, acute inhibition of ATR increases TRCs suggesting its function in transcription condensates is critical for coordinating replication and transcription. Interestingly, we have observed a subset of ATR-regulated condensates to co- localize with histone locus bodies, where the replication-dependent histones are transcribed and the resulting pre-mRNAs are processed coupling histone biosynthesis to S phase. Intriguingly, loss of ATR deregulates multiple steps of histone production and elevates histone levels correlating with a shutdown of replication and the appearance of markers of global replication catastrophe. This raises the question as to whether disruption of histone biosynthesis is a key driver of replication catastrophe upon loss of ATR signaling. We will answer this question and uncover the ATR-dependent mechanisms that couple histone biosynthesis within nuclear bodies to S phase. Our exciting progress stands in contrast to the classical view of ATR signaling as predominantly a driver of the replication stress response and implicates ATR as a key regulator of nuclear dynamics in 3D space during S phase. Finally, we will develop a novel 3D chromatin conformation technology to study how replication of transcriptionally-active regions impacts promoter-enhancer contacts. We will use the technology to elucidate the mechanisms that promote re-establishment of 3D interactions post-replication and ensure faithful transmission of 3D genome organization and the transcriptional identity of cells across S phase. In sum, my research program over the next five years will lead to important discoveries as to how cells maintain transcriptional states and genome organization during the highly dynamic period of S phase.

项目总结