Avoiding replication trainwrecks - are accessory replicative helicases needed to underpin replication of protein-bound DNA?

避免复制失败——是否需要辅助复制解旋酶来支持蛋白质结合 DNA 的复制？

• 批准号: BB/G005915/1
• 负责人: Peter McGlynn
• 金额: $ 38.52万
• 依托单位: University of Aberdeen
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2009
• 资助国家: 英国
• 起止时间: 2009 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FG005915%2F1
• 关键词: Avoiding; replication; trainwrecks; accessory; replicative

For an organism to grow it is necessary that the cells of that organism divide and multiply. But for a cell to divide into two requires that the genetic material within that cell is copied. This allows both daughter cells to inherit a complete copy of the genetic blueprint. Without this blueprint a cell cannot function correctly and will die ultimately. Unfortunately, copying the genetic material of a cell is a very complex process, in part because there is a huge amount of DNA needed to carry the genetic code of even a simple organism such as a bacterium. The complexity of this process, and its critical importance, has led to the evolution of very complex cellular machines that can duplicate the large amounts of DNA found in cells. These cellular machines can copy the DNA very rapidly and very accurately. However, we now know that these machines are not perfect and often break down whilst trying to copy the genetic code. Why do they break down? One major problem is damage to the DNA caused by certain chemicals in the environment and also by radiation such as ultraviolet light from the sun. But another problem might be caused by the cell itself. The DNA carrying the genetic code does not actually exist in isolation within the cell but is completely coated in molecules called proteins. These proteins are essential for nearly every process within the cell and so a conflict exists between the necessity for these proteins and the need to copy the DNA. Our own, and others', work has demonstrated that these proteins can stop the DNA from being copied. We have recently discovered that certain enzymes within a cell (called DNA helicases) might help during duplication of DNA by facilitating the movement of DNA copying machines through protein-DNA complexes. This study aims to establish whether these enzymes do promote copying of DNA and what features of these enzymes are needed for such a function. This will be achieved by studying these enzymes in isolation and also within the context of the cell. These studies may help us to understand how cells duplicate their genetic material in the face of many potential blocks. Blockage of DNA copying is potentially catastrophic for a cell. Failure to copy the DNA prevents a cell from dividing to give two viable daughter cells. But blockage can also lead to errors during this DNA copying process. These errors can cause mutations and consequent malfunctions in daughter cells. In complex organisms, including humans, these malfunctions can take the form of genetic diseases and the onset of cancer. Our work will help understand how these risks might be minimised.

对于有机体的生长，该有机体的细胞必须分裂和繁殖。但细胞要分裂成两个，就需要复制该细胞内的遗传物质。这使得两个子细胞都能继承遗传蓝图的完整副本。如果没有这个蓝图，细胞就无法正常运作并最终死亡。不幸的是，复制细胞的遗传物质是一个非常复杂的过程，部分原因是即使是细菌等简单生物体的遗传密码也需要大量的DNA来携带。这一过程的复杂性及其至关重要性导致了非常复杂的细胞机器的进化，这些机器可以复制细胞中发现的大量 DNA。这些细胞机器可以非常快速且非常准确地复制 DNA。然而，我们现在知道这些机器并不完美，并且在尝试复制遗传密码时经常发生故障。他们为什么会崩溃？其中一个主要问题是环境中的某些化学物质以及太阳紫外线等辐射对 DNA 造成的损害。但另一个问题可能是由细胞本身引起的。携带遗传密码的DNA实际上并不是孤立地存在于细胞内，而是完全被称为蛋白质的分子包裹着。这些蛋白质对于细胞内几乎每个过程都是必需的，因此这些蛋白质的必要性和复制 DNA 的需要之间存在冲突。我们自己和其他人的工作已经证明这些蛋白质可以阻止 DNA 被复制。我们最近发现细胞内的某些酶（称为 DNA 解旋酶）可能有助于 DNA 复制，促进 DNA 复制机器通过蛋白质-DNA 复合物的运动。本研究旨在确定这些酶是否确实促进 DNA 复制以及此类功能需要这些酶的哪些特征。这将通过单独研究这些酶以及在细胞内研究这些酶来实现。这些研究可能有助于我们了解细胞在面对许多潜在的障碍时如何复制其遗传物质。 DNA 复制的阻断对细胞来说可能是灾难性的。 DNA 复制失败会阻止细胞分裂产生两个可存活的子细胞。但在 DNA 复制过程中，阻塞也会导致错误。这些错误可能会导致子细胞突变并随后出现故障。在包括人类在内的复杂生物体中，这些功能障碍可能表现为遗传性疾病和癌症。我们的工作将有助于了解如何最大限度地减少这些风险。

项目成果

Localization of an accessory helicase at the replisome is critical in sustaining efficient genome duplication.

• DOI: 10.1093/nar/gkq889
• 发表时间: 2011-02
• 期刊: Nucleic acids research
• 影响因子: 14.9
• 作者: Atkinson J;Gupta MK;Rudolph CJ;Bell H;Lloyd RG;McGlynn P
• 通讯作者: McGlynn P

Interaction of Rep and DnaB on DNA.

• DOI: 10.1093/nar/gkq975
• 发表时间: 2011-03
• 期刊: Nucleic acids research
• 影响因子: 14.9
• 作者: Atkinson J;Gupta MK;McGlynn P
• 通讯作者: McGlynn P

Helicases that underpin replication of protein-bound DNA in Escherichia coli.

支持大肠杆菌中蛋白质结合 DNA 复制的解旋酶。

• DOI: 10.1042/bst0390606
• 发表时间: 2011
• 期刊: Biochemical Society transactions
• 影响因子: 3.9
• 作者: McGlynn P