A Rapidly Inducible DNA Double-Strand Break to Monitor Telomere Formation, DNA Repair, and Checkpoint Activation

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• Studying genome integrity relies on precisely inducing DNA double-strand breaks (DSBs).
• Previous research in Schizosaccharomyces pombe was hindered by a lack of rapidly inducible systems for DSB generation.
• The development of inducible promoters around 2005 enabled new DSB systems.

Purpose of the Study:

• To describe a novel system for rapidly inducing a modified I-SceI endonuclease in Schizosaccharomyces pombe.
• To enable real-time monitoring of DNA metabolism and protein recruitment following a precisely induced DSB.
• To establish a simple assay for monitoring cell cycle checkpoint activation after a single DSB.

Main Methods:

• Utilizing a modified I-SceI endonuclease with no recognition sites in the S. pombe genome.
• Achieving rapid induction of the endonuclease, generating a DSB within 20 minutes.
• Employing a cell length measurement assay to monitor cell cycle checkpoint activation.

Main Results:

• The described system allows for the rapid and precise induction of a DSB.
• The system facilitates the introduction of complex substrates to study DSB effects in real time.
• A simple assay effectively monitors cell cycle checkpoint activation in response to a single DSB.

Conclusions:

• This system provides a powerful tool for investigating genome integrity and DNA repair mechanisms in S. pombe.
• The rapid induction and precise control of DSBs allow for detailed kinetic studies of DNA damage response.
• The methodology enables efficient monitoring of cell cycle checkpoint activation, crucial for understanding genome stability.