[Construction of partial denaturation charts for DNA with random base distribution]

Area of Science:

• Molecular Biology
• Virology
• Genetics

Background:

• Bacterial viruses (phages) like Tg9 and OB are crucial tools for studying host genetics.
• Understanding phage DNA structure is key to their replication and host interaction mechanisms.

Purpose of the Study:

• To investigate the base distribution and denaturation patterns of Tg9 and OB phage DNA.
• To map the locations of DNA melting regions and identify stable sequences.

Main Methods:

• DNA temperature transition profiles were analyzed to determine base distribution.
• Alkaline treatment with formaldehyde induced partial DNA denaturation.
• Electron microscopy was employed to visualize and map denatured regions along the DNA molecules.

Main Results:

• Both Tg9 and OB phage DNA demonstrated random base distribution.
• Distinct melting region maps were generated for Tg9 (4 peaks) and OB (7 peaks) DNA.
• Peak locations remained consistent despite varying denaturation levels and pH, indicating stable DNA regions.

Conclusions:

• The phage DNA sequences possess inherent stability, likely due to specific 'heat stolle' sequences.
• These stable regions influence the initial stages of DNA denaturation, providing insights into DNA structural properties.