RNAi, Histone Modification and the DDB1/CPSF-like Complex Rik1

RNAi、组蛋白修饰和 DDB1/CPSF 样复合物 Rik1

基本信息

批准号：
9177193
负责人：
ROBERT A MARTIENSSEN
金额：
$ 42.24万
依托单位：
COLD SPRING HARBOR LABORATORY
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-08-01 至 2021-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9177193
关键词：
Aging Binding Proteins Biochemical Biological Models Biological Process CRISPR/Cas technology Cancer Immunology Science Cell Cycle Cell division Cells Centromere Childhood Chromatin Chromosome Structures Chromosomes Cleavage And Polyadenylation Specificity Factor Complex Cullin Proteins DNA DNA Damage DNA Polymerase II DNA Repair DNA Sequence DNA biosynthesis DNA replication fork DNA-Directed DNA Polymerase DNA-Directed RNA Polymerase Development Disease Ensure Epigenetic Process Failure Fission Yeast Funding Gene Expression Gene Silencing Genes Genetic Genetic Recombination Genetic Screening Genetic Transcription Genomic Instability Health Heterochromatin Histones Human Human body Hypoxia Inherited Insecta Ligase Maintenance Malignant Neoplasms Mediating Mental Retardation Mitosis Modeling Modification Molds Mutation Neoplasm Metastasis Neuronal Differentiation Neurons Phase Plants Play Proteins RAD52 gene RNA Interference Recombinant DNA Recruitment Activity Repetitive Sequence Replication Origin Reporting Research Role S Phase Saccharomycetales Site Small RNA Specificity Stem cells Stress System Time Transcript Ubiquitination Untranslated RNA X Inactivation Yeasts cancer stem cell cancer therapy chromosome replication cullin 4A driving force embryonic stem cell gene function genome integrity genome-wide histone methyltransferase histone modification homologous recombination imprint innovation mutant nervous system disorder novel paralogous gene recombinational repair repaired targeted treatment transcription factor S-II tumor tumorigenesis ubiquitin ligase ubiquitin-protein ligase

项目摘要

Project Summary Heterochromatin comprises tightly compacted repetitive regions of eukaryotic chromosomes. It is inherited through mitosis and has roles in transcriptional silencing, centromere specification and genome integrity, which profoundly impact epigenetic mechanisms in health and disease. We have found that the epigenetic inheritance of heterochromatin in the fission yeast S.pombe requires RNA interference (RNAi) to guide histone modification, which occurs during the DNA replication phase of the cell cycle. S.pombe centromeric repeats have an alternating arrangement of small RNA clusters and origins of replication that makes collision of the transcription and replication machineries all but inevitable. We found that RNAi promotes release of RNA polymerase (Pol II) during S phase, allowing completion of DNA replication by the leading strand DNA polymerase, which recruits the histone-modifying Rik1 complex to spread heterochromatin along with DNA replication. In the absence of RNAi, stalled forks are repaired by homologous recombination (HR) without histone modification, so that HR is essential in the absence of RNAi, and reduces the copy number of rDNA repeats. This model may explain the participation of non-coding RNA and DNA repair in many examples of epigenetic silencing, such as imprinting and X-inactivation. Recently, we have found that RNAi is essential for viability in quiescent cells (G0), which are predominant in yeast and play critical roles in cancer, stem cells and neuronal disease. Genetic screens have revealed that the Rik1 complex and Pol II are both involved in this novel function for RNAi, implicating both heterochromatic silencing and DNA repair. S.pombe is an outstanding model system for cell cycle research, heterochromatic silencing, and RNAi. We will examine the roles of DNA replication, RNA Polymerase release, DNA recombination and repair in heterochromatic histone modification mediated by the Rik1 complex and RNAi.

项目概要异染色质包含真核生物紧密压缩的重复区域染色体。它通过有丝分裂遗传，并在转录沉默中发挥作用，着丝粒规范和基因组完整性，深刻影响表观遗传健康和疾病的机制。我们发现表观遗传裂殖酵母中的异染色质需要 RNA 干扰 (RNAi) 来引导组蛋白修饰，发生在细胞周期的 DNA 复制阶段。粟酒裂殖酵母着丝粒重复序列具有小 RNA 簇的交替排列以及导致转录和复制碰撞的复制起点机械几乎是不可避免的。我们发现RNAi促进RNA聚合酶的释放 (Pol II) 在 S 期，允许前导链完成 DNA 复制 DNA 聚合酶，招募组蛋白修饰 Rik1 复合物进行扩散异染色质与 DNA 复制一起。在没有 RNAi 的情况下，停滞的分叉是通过同源重组 (HR) 修复，无需组蛋白修饰，因此 HR 在没有 RNAi 的情况下是必需的，并减少 rDNA 重复的拷贝数。这模型可以解释非编码RNA和DNA修复在许多疾病中的参与表观遗传沉默的例子，例如印记和 X 失活。最近，我们发现RNAi对于静止细胞（G0）的活力至关重要，这在酵母中占主导地位，在癌症、干细胞和神经元中发挥关键作用疾病。遗传筛选显示 Rik1 复合体和 Pol II 都是参与了 RNAi 的这一新功能，涉及异染色质沉默和 DNA修复。 S.pombe 是细胞周期研究的杰出模型系统，异染色质沉默和RNAi。我们将研究 DNA 复制的作用，异染色质组蛋白中 RNA 聚合酶的释放、DNA 重组和修复由 Rik1 复合物和 RNAi 介导的修饰。