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The rec locus, a competence-induced operon in Streptococcus pneumoniae
B J Pearce1, A M Naughton, E A Campbell
1Laboratory of Molecular Infectious Diseases, Rockefeller University, New York, New York 10021.
Journal of Bacteriology
|January 1, 1995
Summary
Researchers identified a key genetic locus, rec, essential for bacterial transformation in pneumococci. This locus
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Bacterial transformation is a crucial process for genetic exchange.
- Competence, the ability to uptake external DNA, is a regulated state in bacteria.
- Understanding the genetic basis of transformation is vital for microbial genetics.
Purpose of the Study:
- To investigate the genetic factors governing competence and transformation (TFN) in pneumococci.
- To identify and characterize genes involved in the transformation process.
Main Methods:
- Developed a method using insertional inactivation and alkaline phosphatase (phoA) fusions to isolate TFN- mutants.
- Utilized DNA-RNA hybridization to analyze gene transcription.
- Employed Exp10-PhoA chimera as a reporter for gene expression analysis.
Main Results:
- Identified a 'rec' locus containing exp10 and recA genes, crucial for transformation.
- Exp10 is a likely membrane-associated protein.
- The 'rec' locus shows increased transcription during competence and is regulated by an competence-inducing activator.
- A TFN- mutant showed a 2-log unit decrease in transformation efficiency.
Conclusions:
- The 'rec' locus is directly required for genetic transformation in pneumococci.
- The expression of the 'rec' locus is regulated by the competence-inducing cell signaling pathway.
- This study elucidates a key genetic mechanism underlying bacterial transformation.