Generalized recombination: nucleotide sequence homology between Chi recombinational hotspots
Cell
|March 1, 1980
Summary
Chi sites enhance DNA recombination in E. coli by interacting with the RecA-RecBC system. A specific mutation in bacteriophage lambda
Area of Science:
- Molecular Biology
- Genetics
- Microbiology
Background:
- Chi sites are known to stimulate generalized recombination in E. coli.
- This stimulation is mediated by the RecA-RecBC-dependent system.
- Chi sites are found at four distinct loci in bacteriophage lambda.
Purpose of the Study:
- To determine the nucleotide sequence surrounding the chi B locus in bacteriophage lambda.
- To identify the specific DNA alterations that create a Chi recombinational hotspot.
- To investigate the potential recognition sequence for proteins involved in recombination.
Main Methods:
- DNA sequencing of the region surrounding the chi B locus.
- Site-directed mutagenesis to alter specific base pairs.
- Comparison of the chi + B sequence with the previously determined chi + C sequence.
Main Results:
- The nucleotide sequence surrounding the chi B locus was determined.
- Alteration of a single GC base pair (deletion or transversion to CG) created the chi + B hotspot.
- The chi + B sequence shares 23 out of 30 base pairs with the chi + C sequence.
Conclusions:
- A specific DNA sequence alteration is responsible for creating the Chi recombinational hotspot.
- A common sequence motif between chi + B and chi + C likely serves as a recognition site for a recombination-regulating protein.
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