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Published on: September 1, 2018
Adaptive gene expression in Bacillus subtilis strains deleted for tetL
Yi Wei1, Gintaras Deikus, Benjamin Powers
1Department of Pharmacology and Biological Chemistry, Box 1603, Mount Sinai School of Medicine of New York University, New York, NY 10029, USA.
Journal of Bacteriology
|October 4, 2006
Summary
Deleting the tetL gene in Bacillus subtilis causes alkali and sodium sensitivity, unrelated to tetracycline resistance. Gene expression changes, including citM, appear adaptive to these new growth conditions.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- The tetL gene in Bacillus subtilis is associated with monovalent cation/proton activity.
- Deletion of tetL results in phenotypes beyond tetracycline resistance, including alkali and Na(+) sensitivity.
- These phenotypes are not fully reversed by restoring the tetL gene, suggesting secondary mutations.
Purpose of the Study:
- To investigate the phenotypes associated with tetL deletion in Bacillus subtilis.
- To understand the genetic basis of alkali and Na(+) sensitivity in tetL deletion strains.
- To identify gene expression changes resulting from tetL deletion and their adaptive significance.
Main Methods:
- Construction and analysis of Bacillus subtilis tetL deletion and tetL-restored strains.
- Phenotypic characterization focusing on growth properties, alkali sensitivity, and Na(+) sensitivity.
- Microarray analysis to compare transcriptomes of wild-type, tetL deletion, and tetL-restored strains.
Main Results:
- TetL deletion leads to phenotypes unrelated to tetracycline resistance, including alkali and Na(+) sensitivity.
- Restoration of tetL did not fully reverse these phenotypes, indicating secondary mutations.
- Microarray analysis revealed significant differential gene expression in the tetL deletion strain, with 37 genes up-regulated and 13 down-regulated.
- Up-regulation of the citM gene, encoding a citrate transporter, was identified as responsible for the Co(2+)-sensitive phenotype.
- Altered expression of ion-coupled solute transporters suggests an adaptive response to the loss of TetL functions.
Conclusions:
- Phenotypes resulting from tetL deletion in Bacillus subtilis are complex and involve secondary mutations.
- The citM gene's up-regulation contributes to specific sensitivities observed in tetL mutants.
- Changes in ion-coupled solute transporter expression represent an adaptive strategy for bacterial tolerance to alkali and Na(+) stress.
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