The Role of Transcription in Replication Blockage at Common Fragile Sites

转录在常见脆弱位点复制阻断中的作用

• 批准号: 33299041
• 负责人: Dr. Anne Helmrich
• 金额: --
• 依托单位: Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC)
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2006
• 资助国家: 德国
• 起止时间: 2005-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/33299041?language=en
• 关键词: Role; Transcription; Replication; Blockage; Common

My previous studies suggested a relation between genomic regions containing very large transcriptionally active genes and preferred sites of disturbed replication, seen in metaphase chromosomes as uncondensed chromatin at common fragile sites (CFSs). CFSs are predetermined chromosomal breakage regions and have been implicated to have a causative role in cancer. The present proposal is aimed to study the interdependence of transcription, replication and chromosome condensation at CFSs. Some first results that I obtained by comparing different cell types in which three long genes are expressed or not, show indeed the involvement of transcription of these genes in CFS formation. I will now investigate if the colocalization of RNA Pol II with DNA polymerase is favoured at CFSs. In parallel, results of replication timing analysis across large CFS genes will be compared to active/inactive transcription and to CFS formation. By overexpressing positive transcription elongation factors I will investigate whether an abnormally slow transcription of these large genes could be a potential cause of the observed delayed replication at CFSs. To test for an involvement of perturbed coupling of transcription and replication in chromatin remodeling, I also plan to analyze histone modifications within CFSs. The combined results of this project are expected to (i) give new insights into the intertwining of distinct processes, such as Pol II transcription elongation, replication and chromosome condensation, in living cells and (ii) to better understand CFS formation.

我以前的研究表明，包含非常大的转录活性基因的基因组区域和干扰复制的首选位点之间的关系，在中期染色体中，常见的脆性位点（CFS）的未凝聚的染色质。CFS是预先确定的染色体断裂区域，并且已经暗示在癌症中具有致病作用。本研究的目的是研究CFSs中转录、复制和染色体凝聚的相互依赖性。我通过比较三个长基因表达或不表达的不同细胞类型获得的一些初步结果表明，这些基因的转录确实参与了CFS的形成。我现在将研究RNA Pol II与DNA聚合酶的共定位是否有利于CFS。同时，将跨大CFS基因的复制定时分析的结果与活性/非活性转录和CFS形成进行比较。通过过度表达阳性转录延伸因子，我将研究这些大基因的异常缓慢转录是否可能是所观察到的延迟复制的潜在原因。为了检测染色质重塑中转录和复制的干扰偶联的参与，我还计划分析CFS中的组蛋白修饰。该项目的综合结果预计将（i）为活细胞中不同过程的交织提供新的见解，如Pol II转录延伸，复制和染色体浓缩，以及（ii）更好地了解CFS的形成。