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Different action of MMS and EMS in UV-sensitive strains of Aspergillus nidulans
1Department of Plant Biology, La Sapienza University, Rome, Italy.
Abstract:
The repair of methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) damages has been investigated in the fungus Aspergillus nidulans. 4 UV-sensitive mutants, namely uvsB, uvsD, uvsF and uvsH have been tested for their sensitivity and mutability to the above-mentioned agents. The results obtained show that: (1) uvsB and uvsD mutants are no more sensitive than the wild-type strain to the lethal action of EMS. In contrast, they are more sensitive to MMS; (2) uvsF and uvsH mutants are more sensitive than the wild type to EMS at 37 degrees C but not at 20 degrees C. However, they are more sensitive than the wild type to MMS at 37 degrees C as well as at 20 degrees C; (3) the mutation frequencies after treatment with either MMS or EMS plotted against survival are not altered in the UV-sensitive strains compared to the wild-type strain. From these data it may be concluded that the repair of lethal lesions induced by ethylating and methylating agents is under the control of different pathways. Furthermore the mutants tested are not involved in the mutagenic process.
Insights
Different pathways repair methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) DNA damage in Aspergillus nidulans. UV-sensitive mutants show varied sensitivities, indicating distinct repair mechanisms for these genotoxic agents.
Area of Science:
- Molecular Biology
- Genetics
- Mycology
Background:
- DNA damage from methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) requires specific repair mechanisms.
- Understanding these pathways is crucial for comprehending genome stability and mutagenesis.
Purpose of the Study:
- To investigate the DNA repair pathways for MMS and EMS in the fungus Aspergillus nidulans.
- To determine the involvement of specific UV-sensitive mutants (uvsB, uvsD, uvsF, uvsH) in the repair of MMS and EMS-induced DNA damage.
Main Methods:
- Assessing the sensitivity of wild-type and UV-sensitive mutant strains of Aspergillus nidulans to MMS and EMS.
- Evaluating the mutation frequencies in these strains following exposure to MMS and EMS.
Main Results:
- Mutants uvsB and uvsD exhibited increased sensitivity to MMS but not EMS compared to the wild-type.
- Mutants uvsF and uvsH showed enhanced sensitivity to both MMS and EMS, with temperature-dependent sensitivity to EMS.
- Mutation frequencies were not significantly altered in the tested UV-sensitive mutants compared to the wild-type.
Conclusions:
- The repair of lethal DNA lesions induced by MMS and EMS involves distinct genetic pathways in Aspergillus nidulans.
- The investigated UV-sensitive mutants are not directly involved in the mutagenic response to MMS and EMS.
