Dissection of the archaeal DNA replication fork in vivo and in vitro

DNA是生物体的蓝图。任何物种要繁殖，无论是单细胞微生物还是人类，都必须能够复制自己的DNA；从而确保它将遗传指令传递给后代。在细胞中，DNA形成双螺旋结构。为了使分子复制，双螺旋被解开，两条链都被复制以产生两个子分子。DNA解压缩和复制时形成的结构被称为复制叉。本研究计划描述了一系列旨在研究DNA在复制叉中解压缩和复制的机制的实验。我们建议在一类微生物中研究复制终止的分子基础，称为古细菌。我们研究的古细菌生长在温泉环境中，比如在黄石国家公园发现的。因为这些生物生长在80摄氏度的环境中，它们的细胞机制异常强健，这种稳定性极大地帮助了我们对生物化学的分析。此外，在过去的几年里，越来越明显的是，古细菌用来复制DNA的机制是我们自己细胞使用的机制的简化版本。因此，我们的研究不仅揭示了古细菌的复制终止过程，也可能为人类细胞DNA复制叉的进化和机制提供宝贵的见解。

DNA is the blueprint for living organisms. For any species to propagate, be it a single celled microbe or a human being, it must be able to duplicate its DNA; thereby ensuring that it passes its genetic instructions onto its progeny. In cells, DNA forms a double helix. For the molecule to replicate, the double helix unzips and both strands are copied to generate two daughter molecules. The structure formed as DNA unzips and is copied is termed the replication fork. This research proposal describes a series of experiments designed to investigate the mechanims by which DNA is unzipped and copied in the replication fork. We propose to study the molecular basis of replication termination in a class of microbe, termed the Archaea. The Archaea we work on grow in hot spring environments, such as found in Yellowstone National Park. Because the organisms grow at 80 degrees centigrade, their cellular machinery is unusually robust and this stability greatly aids our analyses of the organism's biochemistry. Furthermore, over the last few years it has become increasingly apparent that the machinery that Archaea use to duplicate their DNA is a simplified version of the machinery that our own cells use. Therefore, as well as shedding light on the process of replication termination in the archaea, our studies may also yield invaluable insights into the evolution and mechanism of DNA replication fork action in human cells too.