During replication, topological stress builds ahead of the polymerase. Current models propose that linear eukaryotic chromosomes are divided into topological domains, and that stress is relieved by the activity of a topoisomerase. Here, it is found that replication stress seems to be present throughout the chromosome, rather than in domains, and that the relief of stress in longer chromosomes is facilitated by the activity of the cohesin/condensin-like Smc5/6 complex as well as by topoisomerase. They propose that the Smc5/6 complex prevent formation of topological tension ahead of the replication fork by promoting fork rotation, leading to the formation of sister chromatin intertwinings behind.
- Andreas Kegel
- Hanna Betts-Lindroos
- Camilla Sjögren
