Lemon K P, Grossman A D
Department of Biology, Building 68-530, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Science. 1998 Nov 20;282(5393):1516-9. doi: 10.1126/science.282.5393.1516.
Two general models have been proposed for DNA replication. In one model, DNA polymerase moves along the DNA (like a train on a track); in the other model, the polymerase is stationary (like a factory), and DNA is pulled through. To distinguish between these models, we visualized DNA polymerase of the bacterium Bacillus subtilis in living cells by the creation of a fusion protein containing the catalytic subunit (PolC) and green fluorescent protein (GFP). PolC-GFP was localized at discrete intracellular positions, predominantly at or near midcell, rather than being distributed randomly. These results suggest that the polymerase is anchored in place and thus support the model in which the DNA template moves through the polymerase.
针对DNA复制，人们提出了两种普遍模式。在一种模式中，DNA聚合酶沿着DNA移动（就像轨道上的火车）；在另一种模式中，聚合酶是固定不动的（就像一座工厂），DNA被拉着穿过。为了区分这两种模式，我们通过创建一种包含催化亚基（PolC）和绿色荧光蛋白（GFP）的融合蛋白，在活细胞中观察了枯草芽孢杆菌的DNA聚合酶。PolC-GFP定位于离散的细胞内位置，主要位于细胞中部或其附近，而非随机分布。这些结果表明聚合酶是固定在原位的，因此支持DNA模板穿过聚合酶的模式。
