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CST/Polα/primase-mediated fill-in synthesis at DSBs
Zachary Mirman1,2, Sarah Cai1,3, Titia de Lange1
1Laboratory for Cell Biology and Genetics, The Rockefeller University, New York, NY, USA.
Cell Cycle (Georgetown, Tex.)
|October 7, 2022
Summary
53BP1 protein controls DNA repair by influencing 3' overhang length through fill-in synthesis. This mechanism, involving CST/Polα/primase, is crucial in BRCA1-deficient cells and may be DNA sequence-dependent.
Area of Science:
- Molecular Biology
- Genetics
- Genomics
Background:
- DNA double-strand breaks (DSBs) are critical genomic threats requiring efficient repair.
- 53BP1 protein influences DSB repair pathway choice and fidelity.
- 53BP1, RIF1, and shieldin regulate 3' overhang length during DSB repair.
Purpose of the Study:
- To highlight recent evidence on 53BP1-mediated 3' overhang control via fill-in synthesis.
- To investigate the role of fill-in synthesis in BRCA1-deficient cells treated with PARPi.
- To explore the influence of DNA sequence at the break on repair pathway choice.
Main Methods:
- Review of recent evidence on 53BP1 function in DSB repair.
- Focus on CST/Polα/primase complex in fill-in synthesis.
- Analysis of BRCA1-deficient cells and PARPi treatment.
Main Results:
- 53BP1 controls 3' overhang length through fill-in synthesis by CST/Polα/primase.
- Fill-in synthesis plays a critical role in BRCA1-deficient cells treated with PARPi.
- DNA sequence at the DSB site may influence CST binding and subsequent fill-in synthesis.
Conclusions:
- Fill-in synthesis by CST/Polα/primase is a key mechanism for 3' overhang control by 53BP1.
- This mechanism is particularly important in BRCA1-deficient cells under PARPi treatment.
- DNA sequence context at DSBs can impact repair pathway choice by modulating CST/Polα/primase recruitment.
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