High Nucleotide Skew Palindromic DNA Sequences Function as Potential Replication Origins due to their Unzipping...

Area of Science:

• Molecular Biology
• Biophysics
• Genetics

Background:

• Replication origins in prokaryotes are known, but the sequence-specific DNA unzipping mechanism remains unclear.
• Understanding DNA sequence dependence is crucial for replication initiation.

Purpose of the Study:

• To model the sequence dependence of local double-stranded DNA melting.
• To identify DNA sequence features that facilitate replication initiation.

Main Methods:

• Developed a Markov chain model accounting for directional DNA unzipping and replication.
• Modeled the sequence dependence of local melting in double-stranded linear DNA segments.

Main Results:

• Generalized palindromic sequences with high nucleotide skews show a low kinetic barrier for local melting near melting temperatures.
• These sequences are identified as potential replication origins.
• Evidence found in replication origins of mitochondrial DNA, bacteria, archaea, and plasmids.

Conclusions:

• High-skew palindromic sequences are key determinants for replication origin function.
• The Markov chain model provides a mechanistic understanding of DNA sequence-dependent unzipping.