Chromatin Insulator Function and Nuclear Organization

染色质绝缘体功能和核组织

基本信息

批准号：
8148678
负责人：
Elissa Lei
金额：
$ 98.78万
依托单位：
NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/8148678
关键词：
Chromatin Nuclear

项目摘要

Drosophila harbors the largest known variety of chromatin insulator complexes including the functionally distinct gypsy and CTCF/CP190 classes, specified by the zinc-finger DNA binding proteins Su(Hw) and CTCF respectively. Our previous work showed that certain RNA silencing factors affect gypsy insulator activity. Because the gypsy and CTCF/CP190 classes of insulator complexes share the CP190 protein component and are proposed to utilize common mechanisms, we tested whether RNA silencing plays a general role in insulator activity by examining the effect of RNA silencing mutants on the CTCF/CP190 dependent Fab-8 insulator of the bithorax complex. Starting with a comprehensive genetic approach, we found that Argonaute2 (AGO2) but not other RNA silencing components are required for Fab-8 insulator activity. AGO2 and CP190 interact physically, and genome wide localization of AGO2 by chromatin immunoprecipitation followed by Illumina sequencing reveals extensive colocalization of AGO2 with CTCF/CP190 and other insulator proteins. However, AGO2 exhibits minimal overlap with regions of small interfering RNA (siRNA) production. Finally, depletion of either CTCF or CP190 results in loss of AGO2 association with insulators and other cis-regulatory regions. Our findings identify a novel nuclear role for AGO2 and suggest that Dicer and siRNA-independent recruitment of AGO2 to chromatin by insulator proteins promotes the definition of transcriptional domains throughout the genome.

果蝇拥有分别由锌指DNA结合蛋白SU（HW）和CTCF指定的最大的已知染色质绝缘子复合物，包括功能不同的吉普赛和CTCF/CP190类。我们以前的工作表明，某些RNA沉默因素会影响吉普赛绝缘体活性。 Because the gypsy and CTCF/CP190 classes of insulator complexes share the CP190 protein component and are proposed to utilize common mechanisms, we tested whether RNA silencing plays a general role in insulator activity by examining the effect of RNA silencing mutants on the CTCF/CP190 dependent Fab-8 insulator of the bithorax complex. 从一种全面的遗传方法开始，我们发现Argonaute2（AGO2），但不需要其他RNA沉默组件才是Fab-8绝缘子活性。 AGO2和CP190在物理上相互作用，并且通过染色质免疫沉淀对AGO2进行了广泛的定位，然后进行Illumina测序揭示了AGO2与CTCF/CP190和其他绝缘子蛋白的广泛共定位。但是，AGO2与小型干扰RNA（siRNA）产生区域的重叠最小。最后，CTCF或CP190的耗竭导致AGO2与绝缘体和其他顺式调节区域的关联。我们的发现确定了AGO2的新型核作用，并表明通过绝缘子蛋白对AGO2培养至染色质的DICER和siRNA无依赖性募集会促进整个基因组中转录结构域的定义。