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Sld2 binds to origin single-stranded DNA and stimulates DNA annealing
Diane M Kanter1, Daniel L Kaplan
1Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.
Nucleic Acids Research
|November 27, 2010
Summary
Sld2 protein binds to single-stranded DNA at replication origins, a process enhanced by S-phase cyclin-dependent kinase (S-CDK) phosphorylation. This interaction facilitates DNA replication initiation and may maintain genome stability.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Sld2 is crucial for initiating DNA replication.
- The precise mechanism of Sld2's function in replication remains unclear.
- S-phase cyclin-dependent kinase (S-CDK) phosphorylation regulates Sld2's association with Dpb11.
Purpose of the Study:
- To investigate the mechanism of Sld2's role in DNA replication initiation.
- To determine how S-CDK phosphorylation affects Sld2's DNA binding and function.
- To explore Sld2's potential role in maintaining genome stability.
Main Methods:
- Utilized a phosphomimetic Sld2 mutant (Sld2T84D) to mimic S-CDK phosphorylation.
- Performed DNA binding assays using single-stranded (ss) DNA from replication origins.
- Assessed the effect of Sld2 and Dpb11 on ssDNA annealing.
Main Results:
- Sld2T84D directly binds to ssDNA at replication origins, with binding enhanced by S-CDK phosphorylation.
- Sld2T84D specifically binds to thymine-rich regions of origin DNA (ARS1).
- Sld2 and Dpb11 cooperate to enhance ssDNA annealing, suggesting a role in genome stability.
Conclusions:
- Sld2 binding to origin ssDNA, regulated by S-CDK phosphorylation, is critical for recruiting Dpb11 and initiating replication.
- Sld2-stimulated ssDNA annealing may be a key mechanism for ensuring genome stability during replication.
- This study elucidates a novel function of Sld2 in DNA replication initiation and genome maintenance.
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