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A hisT::Tn5 mutation affects production of microcins B17, C7, and H47 and colicin V
M C Rodríguez-Sáinz1, C Hernández-Chico, F Moreno
1Unidad de Genética Molecular, Hospital Ramón y Cajal, Madrid, Spain.
Abstract:
A Tn5 insertion decreasing the production of microcin B17 was mapped to 50.2 min on the Escherichia coli chromosome map. Sequence analysis showed that the insertion disrupted hisT, the gene encoding pseudouridine synthase I, a tRNA-modifying enzyme. hisT::Tn5 mutant cells were also shown to be defective for the production of other antibiotic peptides, such as microcin C7, microcin H47, and colicin V.
Insights
A mutation in the hisT gene, which modifies transfer RNA, reduces the production of microcin B17 and other peptide antibiotics in Escherichia coli. This finding links tRNA modification to antibiotic peptide biosynthesis.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Escherichia coli produces various peptide antibiotics, including microcins and colicins.
- The biosynthesis pathways for these antimicrobial peptides are complex and not fully understood.
- tRNA modification enzymes play crucial roles in cellular processes, but their involvement in antibiotic production is largely unexplored.
Purpose of the Study:
- To investigate the genetic basis for decreased microcin B17 production in a specific Escherichia coli mutant.
- To identify the gene disrupted by the Tn5 insertion and its role in antibiotic peptide biosynthesis.
- To determine if the identified gene affects the production of other related antimicrobial peptides.
Main Methods:
- Genetic mapping of a Tn5 insertion mutant.
- DNA sequencing to identify the disrupted gene.
- Phenotypic analysis of mutant strains for antibiotic peptide production.
- Comparative analysis of antibiotic production in wild-type and mutant E. coli.
Main Results:
- A Tn5 insertion was mapped to the hisT gene, encoding pseudouridine synthase I, a critical tRNA-modifying enzyme.
- The hisT::Tn5 mutant exhibited significantly reduced production of microcin B17.
- The mutant strain was also defective in the production of microcin C7, microcin H47, and colicin V.
Conclusions:
- The hisT gene, encoding a tRNA-modifying enzyme, is essential for the efficient production of multiple antibiotic peptides in Escherichia coli.
- Pseudouridine synthase I activity is implicated in the biosynthesis or regulation of microcins and colicins.
- This study reveals a novel link between tRNA modification and the production of antimicrobial peptide compounds.