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A new mutator strain of Bacillus subtilis
Molecular & General Genetics : MGG
|June 1, 1987
Summary
Bacillus subtilis strain SB1207 shows increased mutations at higher temperatures, likely due to DNA editing errors, not replication issues. This temperature-sensitive mutator affects both chromosomal and plasmid genes.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Bacillus subtilis is a common laboratory model organism.
- Temperature sensitivity can impact bacterial physiology and genetic stability.
- Mutator phenotypes can arise from various DNA repair or replication defects.
Purpose of the Study:
- To investigate the cause of a temperature-sensitive mutator phenotype in Bacillus subtilis strain SB1207.
- To determine if the mutator phenotype is SOS-independent.
- To elucidate the underlying molecular mechanism of increased mutation frequency.
Main Methods:
- Phenotypic characterization of Bacillus subtilis strain SB1207 at different temperatures.
- Analysis of mutation rates affecting both chromosomal and plasmid-borne genes.
- Exclusion of replication shut-off and thymine starvation as causes.
- Inference of the mutator mechanism based on base misincorporation frequency.
Main Results:
- Bacillus subtilis strain SB1207 exhibits a strong, SOS-independent mutator phenotype at elevated temperatures.
- This mutator phenotype affects both chromosomal and plasmid DNA.
- Lethality and the mutator effect are not caused by replication arrest or thymine deficiency.
- The high rate of base misincorporation suggests a defect in DNA editing rather than post-replication mismatch repair.
Conclusions:
- The temperature-sensitive mutator phenotype in Bacillus subtilis SB1207 is likely caused by a defect in DNA editing enzymes.
- This defect leads to increased base misincorporation and genetic instability at higher temperatures.
- Understanding this mechanism is crucial for studies using this strain under varying thermal conditions.