Quantitative Chromatin Protein Dynamics During Replication Origin Firing in Human Cells

Area of Science:

• Cell Biology
• Molecular Biology
• Genetics

Background:

• Accurate genome duplication relies on regulated DNA replication origin firing.
• The molecular mechanisms of origin firing in human cells are not fully understood.
• Budding yeast studies have provided foundational knowledge, but human complexity remains to be elucidated.

Purpose of the Study:

• To systematically analyze protein recruitment to chromatin during induced origin firing in human cells.
• To provide time-resolved dynamics of the S phase chromatin proteome.
• To identify novel factors involved in human DNA replication origin firing.

Main Methods:

• Developed a proteomics approach to analyze protein recruitment during induced origin firing.
• Used a CHK1 kinase inhibitor to synchronize dormant origin firing (DOF).
• Assessed the S phase chromatin proteome at various time points.

Main Results:

• Characterized time-resolved loading dynamics of 3269 proteins, including replication machinery and origin firing factors.
• Validated known temporal dynamics of proteins during replication fork activation and DNA damage.
• Identified the condensin II subunit NCAPH2 as a novel factor crucial for origin firing and replication.

Conclusions:

• The study provides a comprehensive resource for investigating protein recruitment dynamics in human replication origin firing.
• The identified temporal proteome data offers insights into replication fork dynamics and associated DNA damage.
• NCAPH2 is a newly discovered factor essential for efficient DNA replication in human cells.