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Updated: Jan 31, 2026
Analysis of DNA Double-strand Break DSB Repair in Mammalian Cells
Published on: September 8, 2010
Promotion of homology-directed DNA repair by polyamines
Chih-Ying Lee1, Guan-Chin Su1, Wen-Yen Huang2
1Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617, Taiwan.
Abstract:
Polyamines, often elevated in cancer cells, have been shown to promote cell growth and proliferation. Whether polyamines regulate other cell functions remains unclear. Here, we explore whether and how polyamines affect genome integrity. When DNA double-strand break (DSB) is induced in hair follicles by ionizing radiation, reduction of cellular polyamines augments dystrophic changes with delayed regeneration. Mechanistically, polyamines facilitate homologous recombination-mediated DSB repair without affecting repair via non-homologous DNA end-joining and single-strand DNA annealing. Biochemical reconstitution and functional analyses demonstrate that polyamines enhance the DNA strand exchange activity of RAD51 recombinase. The effect of polyamines on RAD51 stems from their ability to enhance the capture of homologous duplex DNA and synaptic complex formation by the RAD51-ssDNA nucleoprotein filament. Our work demonstrates a novel function of polyamines in the maintenance of genome integrity via homology-directed DNA repair.
Insights
Polyamines, crucial for cell growth, are now found to maintain genome integrity. They enhance DNA repair through homologous recombination, supporting cell regeneration after DNA damage.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Polyamines are known to promote cancer cell growth and proliferation.
- The role of polyamines in other cellular functions, particularly genome integrity, is not well understood.
Purpose of the Study:
- To investigate the role of polyamines in maintaining genome integrity.
- To elucidate the mechanism by which polyamines affect DNA double-strand break (DSB) repair.
Main Methods:
- Induction of DNA double-strand breaks (DSBs) in hair follicles using ionizing radiation.
- Assessment of polyamine levels and their impact on DSB repair pathways.
- Biochemical reconstitution and functional analyses of RAD51 recombinase activity.
Main Results:
- Reduced cellular polyamines exacerbated DNA damage and delayed regeneration in hair follicles.
- Polyamines specifically facilitate homologous recombination-mediated DSB repair.
- Polyamines enhance RAD51 recombinase activity by promoting homologous duplex DNA capture and synaptic complex formation.
Conclusions:
- Polyamines play a novel and critical role in maintaining genome integrity.
- This function is primarily mediated through the enhancement of homology-directed DNA repair pathways, particularly involving RAD51.
- Understanding polyamine-mediated DNA repair offers new insights into cellular responses to DNA damage.
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