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Interaction between human MCM7 and Rad17 proteins is required for replication checkpoint signaling
Cheng-Chung Tsao1, Christoph Geisen, Robert T Abraham
1Program in Signal Transduction Research, Cancer Research Center, The Burnham Institute, La Jolla, CA 92037, USA.
The EMBO Journal
|November 13, 2004
Summary
Human MCM7 (hMCM7) interacts with Rad17 (hRad17) to activate cell-cycle checkpoints. This interaction is crucial for DNA damage signaling and S-phase checkpoint activation following UV exposure.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Human Rad17 (hRad17) is essential for activating cell-cycle checkpoints in response to DNA damage or replication stress.
- The DNA replication apparatus comprises core components that are critical for maintaining genomic stability.
Purpose of the Study:
- To identify novel interacting partners of hRad17 involved in DNA damage response.
- To elucidate the role of hMCM7 in the S-phase checkpoint activation pathway.
Main Methods:
- Small interfering RNA (siRNA) depletion of hRad17 and hMCM7 in HeLa cells.
- Analysis of hChk1 phosphorylation and S-phase checkpoint activation after UV irradiation or aphidicolin treatment.
- Assessment of ATR-containing nuclear foci formation in hMCM7-depleted cells.
Main Results:
- hMCM7 was identified as a novel binding protein of hRad17.
- Depletion of hRad17 or hMCM7 impaired UV- or aphidicolin-induced hChk1 phosphorylation and abolished UV-induced S-phase checkpoint activation.
- hMCM7 depletion resulted in defective formation of ATR foci after UV irradiation, indicating impaired ATR recruitment to damaged DNA.
Conclusions:
- hMCM7 plays a direct role in transmitting DNA damage signals from replication forks to the S-phase checkpoint machinery.
- hMCM7 is required for the stable recruitment of ATR to damaged DNA, facilitating checkpoint activation.
- The interaction between hRad17 and hMCM7 is critical for maintaining genomic integrity under genotoxic stress.