Replisome Proximal Protein Associations and Dynamic Proteomic Changes at Stalled Replication Forks

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• DNA replication is crucial for cell division, ensuring genetic information transfer.
• Replication forks require coordinated protein assembly and are vulnerable to genotoxic stressors.
• Understanding protein interactions is key to deciphering DNA replication and repair mechanisms.

Purpose of the Study:

• To identify protein associations within core replication machinery.
• To investigate how genotoxic stress impacts these interactions.
• To uncover novel proteins involved in DNA replication stress response.

Main Methods:

• Proximity-dependent biotin identification was employed to map protein associations.
• The study focused on four core replication components: helicase, DNA polymerases, replication protein A, and histone chaperones.
• The impact of hydroxyurea, a genotoxic stressor, on protein interactions was analyzed.

Main Results:

• A network of 108 nuclear proteins associated with core replication components was identified.
• Hydroxyurea treatment modulated these interactions, with 45 proteins enriched and 63 depleted.
• Hydroxyurea also caused redistribution of 11 interactors, indicating replisome reorganization under stress.
• Several poorly characterized proteins were identified as potential new players in DNA replication stress response.

Conclusions:

• The study provides a comprehensive proteomic framework for understanding cellular responses to DNA replication obstacles.
• It reveals the dynamic nature of the replisome under genotoxic stress.
• New putative proteins involved in DNA replication arrest have been uncovered.