Single-Molecule DNA Fiber Analyses to Characterize Replication Fork Dynamics in Living Cells

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• Understanding DNA replication in vivo is crucial for cell biology and requires advanced techniques.
• DNA fiber analysis has evolved from bacterial studies to single-molecule studies in human cells.

Purpose of the Study:

• To present a detailed protocol for the single-molecule DNA fiber assay.
• To investigate the role of RECQ1 helicase in regulating RPA and DNA synthesis.
• To explore the interaction between DDX11 helicase and Timeless during replication stress.

Main Methods:

• Single-molecule DNA fiber assay.
• Pulse-chase labeling experiments.
• Analysis of replication fork dynamics in human cells, including helicase-deficient cells.

Main Results:

• A model proposing RECQ1 helicase as a governor of RPA bioavailability for DNA synthesis.
• Characterization of the interactive role of DDX11 helicase and Timeless under replication stress.

Conclusions:

• The DNA fiber assay is a powerful tool for studying DNA replication dynamics at the single-molecule level.
• RECQ1 and DDX11 helicases play significant roles in maintaining genome stability during DNA replication and stress.