DNA sequence recognition by a eukaryotic sequence-specific endonuclease, Endo.SceI, from Saccharomyces cerevisiae

Area of Science:

• Molecular Biology
• Enzymology
• Genetics

Background:

• Eukaryotic sequence-specific endonucleases play crucial roles in DNA manipulation.
• Endo.SceI is a unique endonuclease that cleaves double-stranded DNA.
• Understanding enzyme-DNA interactions is vital for molecular biology applications.

Purpose of the Study:

• To elucidate the DNA sequence requirements for Endo.SceI cleavage.
• To identify the specific DNA bases interacting with Endo.SceI during recognition.
• To define the minimal DNA region essential for Endo.SceI activity.

Main Methods:

• DNA synthesis to create specific substrates.
• Enzyme activity assays to determine cleavage efficiency.
• Methylation interference assays to map DNA-protein contacts.

Main Results:

• Endo.SceI generates cohesive ends with 4-base 3' overhangs.
• A 26-base pair asymmetric consensus sequence is recognized by Endo.SceI.
• A region from -10 to +16 base pairs is essential and sufficient for cleavage.
• Methylation interference identified a core recognition region (+7 to +14 bp).

Conclusions:

• The +7 to +14 base pair region is the primary determinant for Endo.SceI DNA binding and cleavage.
• This core region represents the critical interaction site for the endonuclease.
• The findings provide insights into sequence-specific DNA recognition mechanisms by endonucleases.