Interplay between RNA Pol II transcription and DNA replication

RNA Pol II转录是在我们的基因组中产生基因拷贝的过程，这些基因主要用作细胞中蛋白质生产的模板，使它们能够表达表征其细胞身份的因素；DNA复制是一个细胞复制其基因组的过程，产生两个相同的副本传递给子细胞。因此，从定义上讲，它们都是任何活细胞在其生命的某个时刻都会发现一起进行的基本过程。然而，我们知道转录和复制可以相互干扰，影响它们的功能，并最终导致DNA损伤和基因组不稳定。这是细胞生物学中的一个基本生物学问题，对此我们还没有明确的认识，这对细胞生长和人类健康都有直接的影响。然而，RNA Pol II转录和DNA复制之间的完整相互作用实际上迄今为止尚不清楚。因此，为了确定转录和复制是如何在基因组中组织的，以避免对基因组稳定性产生负面影响，我们在细胞周期进程中同时分析了这两个过程。我们已经揭示了转录和复制是如何以及在哪里相互影响的。我们发现，当复制通过一个转录基因时，它会降低暂时的转录活性；转录反过来影响基因的复制进程；我们还发现，与周围区域相比，转录基因中难以复制的区域的复制延迟，推迟到细胞周期进程的后期。到目前为止，我们已经发现了这两个过程是如何协调的，以及它们是如何相互影响的，在基因组水平上的第一个描述，确定了对这种关系至关重要的关键分子过程。在我们的提案中，我们现在将更详细地描述调节转录和复制之间相互作用的分子机制。我们将确定转录如何调节基因内的DNA复制进程，以及它如何影响DNA复制开始位置的选择，即DNA复制起点。我们将确定维持转录起始位点周围的RNA Pol II对于保持这些位点在基因组中位置的标志可能很重要，尽管这意味着将DNA合成延迟到细胞周期的稍后时刻；我们还将确定哪些途径调节这种DNA合成。此外，我们将分析这种相互作用的代价对基因组稳定性的影响。总之，我们打算剖析RNA Pol II转录和DNA复制之间的相互作用，达到迄今为止从未达到的水平。

RNA Pol II transcription is the process that generates copies of the genes in our genome, that are mainly used as a template for the production of proteins in cells, allowing them to express the factors that characterise their cellular identity; DNA replication is the process through which a cell duplicates its genome, generating two identical copies to pass on to daughter cells. They are therefore by definition both essential processes that any living cell at some point in their life will find doing together. However, we know that transcription and replication can interfere with each other affecting their functions, and ultimately inducing DNA damage and genome instability. This is a fundamental biological question in cell biology, for which we have no clear understanding, and that has direct consequences for cell growth as well as human health. Nevertheless, the complete interplay between RNA Pol II transcription and DNA replication is actually so far unknown. In order therefore to determine how transcription and replication are organised in the genome to avoid negative consequences for genome stability, we have analysed both processes at the same time during cell cycle progression. We have so uncovered how and where transcription and replication affect each other. We found that when replication passes through a transcribed gene it reduces temporally transcription activity; transcription vice versa affects replication progression through genes; we also found that difficult to replicate regions in transcribed genes have their replication delayed compared to the surrounding area, postponed to later stages in cell cycle progression. All together we have uncovered so far, the first description on how these two processes are coordinated and how exactly they affect each other, at the genome wide level, identifying key molecular processes that are crucial for this relationship. In our proposal we are now going to characterise in greater detail the molecular mechanisms regulating the interplay between transcription and replication. We will determine how transcription regulates DNA replication progression inside genes but also how it affects the choice of where DNA replication starts, called DNA replication origins. We will determine how maintaining the RNA Pol II around transcription start sites might be important to keep a signpost of where these sites are in the vastity of the genome, although this means delaying DNA synthesis across them to a later moment in the cell cycle; we will also determine which pathways regulate this DNA synthesis. Moreover, we will analyse the impact on genome stability that comes as cost of this interplay. Altogether, we intend dissecting the interplay between RNA Pol II transcription and DNA replication to a level so far never achieved.