Visualization and interpretation of eukaryotic DNA replication intermediates in vivo by electron microscopy

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• Detailed understanding of DNA replication is crucial for molecular biology.
• Structural insights into DNA replication intermediates are essential.
• Existing methods provide limited structural information on in vivo replication.

Purpose of the Study:

• To outline procedures for visualizing and interpreting in vivo DNA replication intermediates.
• To demonstrate the utility of psoralen cross-linking and electron microscopy for studying DNA replication.
• To provide a method applicable to various biological systems.

Main Methods:

• In vivo stabilization of replication structures using psoralen cross-linking.
• Extraction and enrichment of cross-linked DNA replication intermediates.
• Visualization of intermediates using transmission electron microscopy.
• Application to budding yeast, Xenopus egg extracts, and cultured mammalian cells.

Main Results:

• Successfully visualized fine architecture of in vivo DNA replication intermediates.
• Revealed basic mechanisms of DNA duplication.
• Demonstrated the perturbation of DNA replication by various forms of replication stress.
• Established a robust protocol for structural analysis of replication.

Conclusions:

• Psoralen cross-linking combined with electron microscopy is a powerful approach for structural analysis of in vivo DNA replication.
• This method provides critical insights into DNA duplication mechanisms and replication stress responses.
• The outlined procedures are valuable for researchers studying DNA replication across different model systems.