Related Experiment Videos
Thymidylate stress induces homologous recombination activity in mammalian cells
1Kihara Institute for Biological Research, Yokohama City University, Japan.
Abstract:
We studied whether homologous recombination activity in mammalian cells could be induced by thymidylate stress (thymidylate deprivation). In vitro recombination activity in cell extracts was measured with pSV2neo-derived plasmids. When prior to the preparation of extracts, mouse FM3A cells were grown in 5-fluorodeoxyuridine (FdUrd), an inducer of thymidylate stress, the homologous recombination activity was significantly induced, as judged from an increase in the number of neomycin-resistant bacterial colonies. Maximum induction was observed in cells treated with 1 microM FUdR for 16 h. However, 3-8 h of treatment of FM3A cells with the drug followed by an additional 8-16-h incubation in its absence was sufficient to induce the recombination activity while slightly reducing their growth rates. These results indicate that thymidylate stress induces homologous recombination activity in mammalian cells as observed in Escherichia coli and in yeast.
Insights
Thymidylate stress, or deprivation, significantly boosts homologous recombination activity in mammalian cells. This DNA repair mechanism can be induced by specific drug treatments, offering insights into cellular responses to DNA damage.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Homologous recombination is a crucial DNA repair pathway in eukaryotes.
- Previous studies suggested its induction in prokaryotes and yeast under stress conditions.
Purpose of the Study:
- To investigate if thymidylate stress induces homologous recombination activity in mammalian cells.
- To identify conditions for inducing this activity.
Main Methods:
- In vitro recombination assays using pSV2neo-derived plasmids in cell extracts.
- Treatment of mouse FM3A cells with 5-fluorodeoxyuridine (FdUrd) to induce thymidylate stress.
- Quantification of recombination by counting neomycin-resistant bacterial colonies.
Main Results:
- Thymidylate stress significantly induced homologous recombination activity in FM3A cells.
- Maximum induction was observed after 16 hours of treatment with 1 microM FdUrd.
- Partial induction occurred with shorter treatment durations followed by recovery periods.
Conclusions:
- Thymidylate stress is a potent inducer of homologous recombination in mammalian cells.
- This finding aligns with observations in bacteria and yeast, suggesting a conserved response.
- The study provides a method to modulate DNA repair pathways through controlled stress induction.