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

RNAi、组蛋白修饰和 DDB1/CPSF 样复合物 Rik1

• 批准号: 7260675
• 负责人: ROBERT A MARTIENSSEN
• 金额: $ 42.85万
• 依托单位: COLD SPRING HARBOR LABORATORY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7260675
• 关键词: RNAi; Histone; Modification; DDB1; CPSF

DESCRIPTION (provided by applicant): The pericentromeric repeats of the fission yeast Schizosaccharomyces pombe are transcribed and subject to RNA interference (RNAi). This influences heterochromatic histone modification, which silences reporter genes and recruits proteins required for centromere function, including cohesin. This mechanism is conserved in mammals and plants, and has implications both for gene therapy as well as for the epigenetic basis for human disease. In fission yeast, the Rik1 complex is related to both cleavage and polyadenylation specificity factor (CPSF) and to DNA damage binding protein (DDB1) complexes and is required for RNAi and histone modification. It is recruited to heterochromatin by association with the highly conserved, transposase-related protein Cenp-B, in a process that also requires cleavage (slicing) of nascent heterochromatic transcripts by Argonaute. We will investigate how transcripts are initiated by Pol II and processed by RNAi and the exosome. We will determine how Rik1 is recruited by RNAi, how it influences histone methylation and demethylation, and how it interacts with the nuclear envelope. We will use state-of- the-art microarray profiling techniques, as well as ultra high resolution Structured Illumination microscopy. S. pombe is a particularly useful system to study RNAi mediated heterochromatin, because this seems to be the only function of RNAi in fission yeast (there are no known miRNA) and mutants are generally viable. It should be possible therefore to take one or more of these screens to saturation, providing a unique catalog of genes involved in the primitive function of RNAi. This "function appears to be conserved in archaebacteria, fission yeast, protozoans, plants and animals, and may provide insight into the evolution of the chromosome, and its relationship to repetitive or "junk" DNA. Transposable elements and other repeats are common to all of these genomes, and may hold the key to epigenetic mechanisms of gene regulation and chromosome function.

描述（由申请人提供）：转录裂殖酵母裂殖酵母的近着丝粒重复序列并进行RNA干扰（RNAi）。这会影响异染色质组蛋白的修饰，使报告基因沉默，并募集着丝粒功能所需的蛋白质，包括粘着蛋白。这种机制在哺乳动物和植物中是保守的，并且对基因治疗以及人类疾病的表观遗传基础都有意义。在裂殖酵母中，Rik 1复合物与切割和多聚腺苷酸化特异性因子（CPSF）以及DNA损伤结合蛋白（DDB 1）复合物相关，并且是RNAi和组蛋白修饰所需的。它通过与高度保守的转座酶相关蛋白Cenp-B结合而被招募到异染色质中，这一过程也需要Argonaute切割（切割）新生异染色质转录本。我们将研究转录本是如何由Pol II启动并由RNAi和外泌体加工的。我们将确定Rik 1如何被RNAi招募，它如何影响组蛋白甲基化和去甲基化，以及它如何与核膜相互作用。我们将使用最先进的微阵列分析技术，以及超高分辨率结构照明显微镜。S.粟酒裂殖酵母是研究RNAi介导的异染色质的特别有用的系统，因为这似乎是RNAi在裂殖酵母中的唯一功能（没有已知的miRNA），并且突变体通常是可行的。因此，应该有可能使这些筛选中的一个或多个达到饱和，从而提供参与RNAi原始功能的基因的独特目录。这种“功能”似乎在古细菌、裂变酵母、原生动物、植物和动物中是保守的，并可能提供对染色体进化及其与重复或“垃圾”DNA的关系的深入了解。转座因子和其他重复序列是所有这些基因组共有的，可能是基因调控和染色体功能的表观遗传机制的关键。