Both strands of DNA are replicated simultaneously, but they have opposite polarities. A trombone model has been proposed to explain how replication machinery that moves in one direction can accomplish this feat. In this model, the lagging strand forms a loop that allows it to enter the replication machinery in the same direction as the leading strand. This study uses single molecule techniques to examine this process in real time, and it finds that this loop is reinitiated with the priming of every Okazaki fragment, and released when the previous fragment is encountered by the replisome.
- Samir M. Hamdan
- Joseph J. Loparo
- Antoine M. van Oijen