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Updated: May 9, 2026

Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
Published on: April 30, 2010
S-phase checkpoint proteins Tof1 and Mrc1 form a stable replication-pausing complex
Yuki Katou1, Yutaka Kanoh, Masashige Bando
1Genome Structure and Function Team, Human Genome Research Group, RIKEN Genomic Science Center, 1-7-22 Suehiro-cho, Japan.
Checkpoint proteins Tof1 and Mrc1 directly interact with DNA replication machinery. This interaction creates a stable complex that pauses replication and anchors DNA repair during cell cycle S phase.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Genome integrity is crucial, especially during S phase when DNA is vulnerable.
- Checkpoint pathways halt DNA replication upon damage, but the molecular link is unclear.
Purpose of the Study:
- To elucidate the molecular mechanism coupling checkpoint regulation and replication arrest.
- To identify proteins involved in stabilizing arrested replication forks.
Main Methods:
- Investigated protein interactions using Saccharomyces cerevisiae.
- Utilized hydroxyurea to induce replication stress and block chromosomal replication.
Main Results:
- Demonstrated direct interaction between checkpoint proteins Tof1, Mrc1, and the DNA replication machinery.
- Showed this assembly forms a stable pausing structure at arrested replication forks.
Conclusions:
- Checkpoint proteins Tof1 and Mrc1 are key components linking replication arrest and DNA repair.
- The stable complex formed is essential for anchoring DNA repair events at stalled forks.
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