SAF-A promotes origin licensing and replication fork progression to ensure robust DNA replication

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Chromatin organization is vital for biological processes like DNA replication.
• Scaffold-attachment factor A (SAF-A), also known as HNRNPU, influences chromatin structure.

Purpose of the Study:

• To investigate the role of SAF-A in DNA replication progression and resumption.
• To analyze the impact of SAF-A depletion on replication origins, fork dynamics, and timing.

Main Methods:

• SAF-A depletion using cellular assays.
• Analysis of origin licensing and activation.
• Replication fork progression and DNA synthesis rate measurements.
• Single-cell replication timing analysis.
• Assessment of DNA damage markers (γ-H2AX) and cell quiescence.

Main Results:

• SAF-A depletion reduces origin licensing in G1 and activation in S phase.
• Replication fork progression is less consistent, decreasing DNA synthesis rate.
• SAF-A depletion blurs early/late replication domain boundaries and reconciles discordant replication timing and compartmentalization.
• SAF-A-depleted cells exhibit increased γ-H2AX and a tendency towards quiescence.

Conclusions:

• SAF-A is essential for normal DNA replication progression and resumption.
• SAF-A ensures robust DNA replication, supporting continuous cell proliferation.
• SAF-A plays a significant role in regulating replication timing and maintaining genome stability.